Jeremy A. Alland, MD

Finger injuries are often seen in the primary care physician’s office. The evidence—and our experience in sports medicine—indicates that many of these injuries can be managed conservatively with bracing or injection; a subset, however, requires surgical referral. In this article, we provide a refresher on finger anatomy (see “A guide to the anatomic structures of the digits of the hand”^1,2) and review the diagnosis and management of 4 common soft-tissue finger and thumb injuries in adults: trigger finger, jersey finger, mallet finger, and skier’s thumb (TABLE^2-18).

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JFP07106206_t1.JPG

Trigger finger

Also called stenosing flexor tenosynovitis, trigger finger is caused by abnormal flexor tendon movement that results from impingement at the level of the A1 pulley.

Causes and incidence. Impingement usually occurs because of thickening of the A1 pulley but can also be caused by inflammation or a nodule on the flexor tendon.^3,4 The A1 pulley at the metacarpal head is the most proximal part of the retinacular sheath and therefore experiences the greatest force upon finger flexion, making it the most common site of inflammation and constriction.⁴

JFP07106206_f.JPG

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.⁵ The condition typically affects the long and ring fingers of the dominant hand; most cases occur in women in the sixth and seventh decades.^3-5

Multiple systemic conditions predispose to trigger finger, including endocrine disorders (eg, diabetes, hypothyroidism), inflammatory arthropathies (gout, ­pseudogout), and autoimmune disorders (rheumatoid arthritis, sarcoidosis).^3,5 Diabetes commonly causes bilateral hand and multiple digit involvement, as well as more severe disease.^3,5 Occupation is also a risk factor for trigger finger because repetitive movements and manual work can exacerbate triggering.⁴

Presentation and exam. Patients report pain at the metacarpal head or metacarpophalangeal (MCP) joint, difficulty grasping objects, and, possibly, clicking and catching of the digit and locking of the digit in flexion.^3,5

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.

On exam, there might be tenderness at the level of the A1 pulley over the volar MCP joint or a palpable nodule. In severe cases, the proximal interphalangeal (PIP) joint or entire finger can be fixed in flexion.⁵ Repeated compound finger flexion (eg, closing and opening a fist) or holding a fist for as long as 1 minute and then slowly opening it might provoke triggering.

More than 60% of patients with trigger finger also have carpal tunnel syndrome.⁵ This makes it important to assess for (1) sensory changes in the distribution of the median nerve and (2) nerve compression, by eliciting Phalen and Tinel signs.^4,5

Continue to: Imaging

Imaging. Trigger finger is a clinical diagnosis. Imaging is therefore unnecessary for diagnosis or treatment.⁵

Treatment. Trigger finger resolves spontaneously in 52% of cases.³ Most patients experience relief in 8 to 12 months.³

First-line treatment is injection of a corticosteroid into the flexor tendon sheath, which often alleviates symptoms.^4,5 Injection is performed at the level of the A1 pulley on the palmar surface, just proximal to the MCP joint at the level of the distal palmar crease⁶ (FIGURE 1). The needle is inserted at an oblique angle until there is an increase in resistance. The needle is then slightly withdrawn to reposition it in the tendon sheath; 0.5 to 1 mL of 50% corticosteroid and 50% local anesthetic without epinephrine is then injected.⁶

JFP07106206_f1.JPG

The cure rate of trigger finger is 57% to 70% with 1 injection and 82% to 86% after 2 injections.^3,4,19

Many patients experience symptom relief in 1 to 4 weeks after a corticosteroid injection; however, as many as 56% experience repeat triggering within 6 months—often making multiple injections (maximum, 3 per digit) necessary.^19,20 Patients who have a longer duration of symptoms, more severe symptoms, and multiple trigger fingers are less likely to experience relief with injections.^3,5

Continue to: Splinting is an effective treatment...

Splinting is an effective treatment for patients who cannot undergo corticosteroid injection or surgery. The MCP or PIP joint is immobilized in extension while movement of the distal interphalangeal (DIP) joint is maintained. Instruct the patient that the splint must be worn day and night; splinting is continued for ≥ 6 weeks.²¹ Splinting relieves symptoms in 47% to 70% of cases and is most effective in patients whose symptoms have been present for < 6 months.^3,7

Patients whose trigger finger is locked in flexion and those who have not experienced improvement after 2 or 3 corticosteroid injections should be referred for surgery.⁴ The surgical cure rate is nearly 100%; only 6% of patients experience repeat triggering 6 to 12 months postoperatively.^4,7,22

Jersey finger

Causes and incidence. Jersey finger is caused by avulsion injury to the flexor digitorum profundus (FDP) tendon at its insertion on the distal phalanx.^8,9 It occurs when a flexed finger is forced into extension, such as when a football or rugby player grabs another player’s jersey during a tackle.^9,10 This action causes the FDP tendon to detach from the distal phalanx, sometimes with a bony fragment.^9,11 Once detached, the tendon might retract proximally within the finger or to the palm, with consequent loss of its blood supply.⁹

Although jersey finger is not as common as the other conditions discussed in this article,⁹ it is important not to miss this diagnosis because of the risk of chronic disability when it is not treated promptly. Seventy-five percent of cases occur in the ring finger, which is more susceptible to injury because it extends past the other digits in a power grip.^8,9

Presentation and exam. On exam, the affected finger lies in slight extension compared to the other digits; the patient is unable to actively flex the DIP joint.^8,9 There may be tenderness to palpation over the volar distal phalanx. The retracted FDP tendon might be palpable more proximally in the digit.

Continue to: Imaging

Imaging. Anteroposterior (AP), oblique, and lateral radiographs, although unnecessary for diagnosis, are recommended to assess for an avulsion fragment, associated fracture, or dislocation.^9,11 Ultrasonography or magnetic resonance imaging is useful in chronic cases to quantify the degree of tendon retraction.⁹

Treatment. Refer acute cases of jersey finger for surgical management urgently because most cases require flexor tendon repair within 1 or 2 weeks for a successful outcome.⁹ Chronic jersey finger, in which injury occurred > 6 weeks before presentation, also requires surgical repair, although not as urgently.⁹

Complications of jersey finger include flexion contracture at the DIP joint and the so-called quadriga effect, in which the patient is unable to fully flex the fingers adjacent to the injured digit.⁸ These complications can cause chronic disability in the affected hand, making early diagnosis and referral key to successful treatment.⁹

Mallet finger

Also called drop finger, mallet finger is a result of loss of active extension at the DIP joint.^12,13

Causes and incidence. Mallet finger is a relatively common injury that typically affects the long, ring, or small finger of the dominant hand in young to middle-aged men and older women.^12,14,23 The condition is the result of forced flexion or hyperextension injury, which disrupts the extensor tendon.^6,14

Continue to: Sudden forced flexion...

Sudden forced flexion of an extended DIP joint during work or sports (eg, catching a ball) is the most common mechanism of injury.^12,15 This action causes stretching or tearing of the extensor tendon as well as a possible avulsion fracture of the distal phalanx.¹³ Mallet finger can also result from a laceration or crush injury of the extensor tendon (open mallet finger) or hyperextension of the DIP joint, causing a fracture at the dorsal base of the distal phalanx.¹²

Presentation. Through any of the aforementioned mechanisms, the delicate balance between the flexor and extensor tendons is disrupted, causing the patient to present with a flexed DIP joint that can be passively, but not actively, extended.^6,12 The DIP joint might also be painful and swollen. Patients whose injury occurred > 4 weeks prior to presentation (chronic mallet finger) might also have a so-called swan-neck deformity, with hyperextension of the PIP joint in the affected finger.¹²

Imaging. AP, oblique, and lateral radiographs are recommended to assess for bony injury.

Treatment. Splinting is the first-line treatment for almost all mallet finger injuries that are not the result of a laceration or crush injury. Immobilize the DIP joint in extension for 6 to 8 weeks, with an additional 2 to 4 weeks of splinting at night.^6,12 The splint must be worn continuously in the initial 6 to 8 weeks, and the DIP joint should remain in extension—even when the patient is performing daily hygiene.¹² It is imperative that patients comply with that period of continuous immobilization; if the DIP joint is allowed to flex, the course of treatment must be restarted.¹³

Many different types of splints exist; functional outcomes are equivalent across all of them.^24,25 In our practice, we manage mallet finger with a volar-based splint (FIGURE 2), which is associated with fewer dermatologic complications and has provided the most success for our patients.²³

JFP07106206_f2.JPG

Continue to: Surgical repair of mallet finger injury...

Surgical repair of mallet finger injury is indicated in any of these situations^12,14:

• injury is caused by laceration
• there is volar subluxation of the DIP joint
• more than one-third of the articular surface is involved in an avulsion fracture.

Patients who cannot comply with wearing a splint 24 hours per day or whose occupation precludes wearing a splint at all (eg, surgeons, dentists, musicians) are also surgical candidates.¹²

Surgical and conservative treatments have similar clinical and functional outcomes, including loss of approximately 5° to 7° of active extension and an increased risk of DIP joint osteoarthritis.^12,14,24 Patients with chronic mallet finger can be managed with 6 weeks of splinting initially but will likely require surgery.^6,12,13

Skier’s thumb

This relatively common injury is a tear of the ulnar collateral ligament (UCL) at the MCP joint of the thumb.¹⁶

Causes and incidence. Skier’s thumb occurs when a valgus force hyperabducts the thumb,¹⁶ and is so named because the injury is often seen in recreational skiers who fall while holding a ski pole.^15-17 It can also occur in racquet sports when a ball or racquet strikes the ulnar side of thumb.¹⁶

Continue to: In chronic cases...

In chronic cases, the UCL can be injured by occupational demands and is termed gamekeeper’s thumb because it was first described in this population, who killed game by breaking the animal's neck between the thumb and index finger against the ground.^16,18 A UCL tear causes instability at the thumb MCP joint, which affects a person’s ability to grip and pinch.^2,16,18

Presentation. On exam, the affected thumb is swollen and, possibly, bruised. There might be radial deviation and volar subluxation of the proximal phalanx. The ulnar side of the MCP joint is tender to palpation.¹⁶ If the distal UCL is torn completely, it can displace proximally and present as a palpable mass over the ulnar side of the MCP joint, known as a Stener lesion.¹⁶

Symptoms of trigger finger are pain at the metacarpal head or in the MCP joint, difficulty grasping objects, clicking and catching of the digit, and locking of the digit in flexion.

Stress testing of the MCP joint is the most important part of the physical exam for skier’s thumb. Stabilize the metacarpal neck and apply a valgus stress on the proximal phalanx at both 0° and 30° of MCP flexion (FIGURE 3), which allows for assessment of both the proper and accessory bands of the UCL.^2,16 (A common pitfall during stress testing is to allow the MCP joint to rotate, which can mimic instability.²) Intra-articular local anesthesia might be necessary for this exam because it can be painful.^16,18,26 A stress exam should assess for laxity and a soft or firm endpoint; the result should be compared to that of a stress exam on the contralateral side.^16,17

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Imaging. AP, oblique, and lateral radiographs of the thumb should be obtained to assess for instability, avulsion injury, and associated fracture. Subluxation (volar or radial) or supination of the proximal phalanx relative to the metacarpal on imaging suggests MCP instability of the MCP joint.^16,17

If the stress exam is equivocal, magnetic resonance imaging is recommended for further assessment.^2,18

Continue to: Stress radiographs...

Stress radiographs (ie, radiographs of the thumb with valgus stress applied at the MCP joint) can aid in diagnosis but are controversial. Some experts think that these stress views can further damage the UCL; others recommend against them because they carry a false-negative rate ≥ 25%.^15,16 If you choose to perform stress views, order standard radiographs beforehand to rule out bony injury.¹⁷

Treatment. UCL tears are classified as 3 tiers to guide treatment.

• Grade 1 injury (a partial tear) is characterized by pain upon palpation but no instability on the stress exam.
• Grade 2 injury (also a partial tear) is marked by laxity on the stress exam with a firm endpoint.
• Grade 3 injury (complete tear) shows laxity and a soft endpoint on a stress exam^16,17; Stener lesions are seen only in grade 3 tears.^16,17

Grades 1 and 2 UCL tears without fracture or with a nondisplaced avulsion fracture can be managed nonoperatively by immobilizing the thumb in a spica splint or cast for 4 to 6 weeks.^16,18 The MCP joint is immobilized and the interphalangeal joint is allowed to move freely.^2,16,17

Grade 3 injuries should be referred to a hand specialist for surgical repair.¹⁶ Patients presenting > 12 weeks after acute injury or with a chronic UCL tear should also be referred for surgical repair.¹⁶

CORRESPONDENCE
Caitlin A. Nicholson, MD, 1611 West Harrison Street, Suite 300, Chicago, IL 60612; Caitlin.nicholson@gmail.com

Finger injuries are often seen in the primary care physician’s office. The evidence—and our experience in sports medicine—indicates that many of these injuries can be managed conservatively with bracing or injection; a subset, however, requires surgical referral. In this article, we provide a refresher on finger anatomy (see “A guide to the anatomic structures of the digits of the hand”^1,2) and review the diagnosis and management of 4 common soft-tissue finger and thumb injuries in adults: trigger finger, jersey finger, mallet finger, and skier’s thumb (TABLE^2-18).

JFP07106206_B1.JPG

JFP07106206_t1.JPG

Trigger finger

Also called stenosing flexor tenosynovitis, trigger finger is caused by abnormal flexor tendon movement that results from impingement at the level of the A1 pulley.

Causes and incidence. Impingement usually occurs because of thickening of the A1 pulley but can also be caused by inflammation or a nodule on the flexor tendon.^3,4 The A1 pulley at the metacarpal head is the most proximal part of the retinacular sheath and therefore experiences the greatest force upon finger flexion, making it the most common site of inflammation and constriction.⁴

JFP07106206_f.JPG

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.⁵ The condition typically affects the long and ring fingers of the dominant hand; most cases occur in women in the sixth and seventh decades.^3-5

Multiple systemic conditions predispose to trigger finger, including endocrine disorders (eg, diabetes, hypothyroidism), inflammatory arthropathies (gout, ­pseudogout), and autoimmune disorders (rheumatoid arthritis, sarcoidosis).^3,5 Diabetes commonly causes bilateral hand and multiple digit involvement, as well as more severe disease.^3,5 Occupation is also a risk factor for trigger finger because repetitive movements and manual work can exacerbate triggering.⁴

Presentation and exam. Patients report pain at the metacarpal head or metacarpophalangeal (MCP) joint, difficulty grasping objects, and, possibly, clicking and catching of the digit and locking of the digit in flexion.^3,5

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.

On exam, there might be tenderness at the level of the A1 pulley over the volar MCP joint or a palpable nodule. In severe cases, the proximal interphalangeal (PIP) joint or entire finger can be fixed in flexion.⁵ Repeated compound finger flexion (eg, closing and opening a fist) or holding a fist for as long as 1 minute and then slowly opening it might provoke triggering.

More than 60% of patients with trigger finger also have carpal tunnel syndrome.⁵ This makes it important to assess for (1) sensory changes in the distribution of the median nerve and (2) nerve compression, by eliciting Phalen and Tinel signs.^4,5

Continue to: Imaging

Imaging. Trigger finger is a clinical diagnosis. Imaging is therefore unnecessary for diagnosis or treatment.⁵

Treatment. Trigger finger resolves spontaneously in 52% of cases.³ Most patients experience relief in 8 to 12 months.³

First-line treatment is injection of a corticosteroid into the flexor tendon sheath, which often alleviates symptoms.^4,5 Injection is performed at the level of the A1 pulley on the palmar surface, just proximal to the MCP joint at the level of the distal palmar crease⁶ (FIGURE 1). The needle is inserted at an oblique angle until there is an increase in resistance. The needle is then slightly withdrawn to reposition it in the tendon sheath; 0.5 to 1 mL of 50% corticosteroid and 50% local anesthetic without epinephrine is then injected.⁶

JFP07106206_f1.JPG

The cure rate of trigger finger is 57% to 70% with 1 injection and 82% to 86% after 2 injections.^3,4,19

Many patients experience symptom relief in 1 to 4 weeks after a corticosteroid injection; however, as many as 56% experience repeat triggering within 6 months—often making multiple injections (maximum, 3 per digit) necessary.^19,20 Patients who have a longer duration of symptoms, more severe symptoms, and multiple trigger fingers are less likely to experience relief with injections.^3,5

Continue to: Splinting is an effective treatment...

Splinting is an effective treatment for patients who cannot undergo corticosteroid injection or surgery. The MCP or PIP joint is immobilized in extension while movement of the distal interphalangeal (DIP) joint is maintained. Instruct the patient that the splint must be worn day and night; splinting is continued for ≥ 6 weeks.²¹ Splinting relieves symptoms in 47% to 70% of cases and is most effective in patients whose symptoms have been present for < 6 months.^3,7

Patients whose trigger finger is locked in flexion and those who have not experienced improvement after 2 or 3 corticosteroid injections should be referred for surgery.⁴ The surgical cure rate is nearly 100%; only 6% of patients experience repeat triggering 6 to 12 months postoperatively.^4,7,22

Jersey finger

Causes and incidence. Jersey finger is caused by avulsion injury to the flexor digitorum profundus (FDP) tendon at its insertion on the distal phalanx.^8,9 It occurs when a flexed finger is forced into extension, such as when a football or rugby player grabs another player’s jersey during a tackle.^9,10 This action causes the FDP tendon to detach from the distal phalanx, sometimes with a bony fragment.^9,11 Once detached, the tendon might retract proximally within the finger or to the palm, with consequent loss of its blood supply.⁹

Although jersey finger is not as common as the other conditions discussed in this article,⁹ it is important not to miss this diagnosis because of the risk of chronic disability when it is not treated promptly. Seventy-five percent of cases occur in the ring finger, which is more susceptible to injury because it extends past the other digits in a power grip.^8,9

Presentation and exam. On exam, the affected finger lies in slight extension compared to the other digits; the patient is unable to actively flex the DIP joint.^8,9 There may be tenderness to palpation over the volar distal phalanx. The retracted FDP tendon might be palpable more proximally in the digit.

Continue to: Imaging

Imaging. Anteroposterior (AP), oblique, and lateral radiographs, although unnecessary for diagnosis, are recommended to assess for an avulsion fragment, associated fracture, or dislocation.^9,11 Ultrasonography or magnetic resonance imaging is useful in chronic cases to quantify the degree of tendon retraction.⁹

Treatment. Refer acute cases of jersey finger for surgical management urgently because most cases require flexor tendon repair within 1 or 2 weeks for a successful outcome.⁹ Chronic jersey finger, in which injury occurred > 6 weeks before presentation, also requires surgical repair, although not as urgently.⁹

Complications of jersey finger include flexion contracture at the DIP joint and the so-called quadriga effect, in which the patient is unable to fully flex the fingers adjacent to the injured digit.⁸ These complications can cause chronic disability in the affected hand, making early diagnosis and referral key to successful treatment.⁹

Mallet finger

Also called drop finger, mallet finger is a result of loss of active extension at the DIP joint.^12,13

Causes and incidence. Mallet finger is a relatively common injury that typically affects the long, ring, or small finger of the dominant hand in young to middle-aged men and older women.^12,14,23 The condition is the result of forced flexion or hyperextension injury, which disrupts the extensor tendon.^6,14

Continue to: Sudden forced flexion...

Sudden forced flexion of an extended DIP joint during work or sports (eg, catching a ball) is the most common mechanism of injury.^12,15 This action causes stretching or tearing of the extensor tendon as well as a possible avulsion fracture of the distal phalanx.¹³ Mallet finger can also result from a laceration or crush injury of the extensor tendon (open mallet finger) or hyperextension of the DIP joint, causing a fracture at the dorsal base of the distal phalanx.¹²

Presentation. Through any of the aforementioned mechanisms, the delicate balance between the flexor and extensor tendons is disrupted, causing the patient to present with a flexed DIP joint that can be passively, but not actively, extended.^6,12 The DIP joint might also be painful and swollen. Patients whose injury occurred > 4 weeks prior to presentation (chronic mallet finger) might also have a so-called swan-neck deformity, with hyperextension of the PIP joint in the affected finger.¹²

Imaging. AP, oblique, and lateral radiographs are recommended to assess for bony injury.

Treatment. Splinting is the first-line treatment for almost all mallet finger injuries that are not the result of a laceration or crush injury. Immobilize the DIP joint in extension for 6 to 8 weeks, with an additional 2 to 4 weeks of splinting at night.^6,12 The splint must be worn continuously in the initial 6 to 8 weeks, and the DIP joint should remain in extension—even when the patient is performing daily hygiene.¹² It is imperative that patients comply with that period of continuous immobilization; if the DIP joint is allowed to flex, the course of treatment must be restarted.¹³

Many different types of splints exist; functional outcomes are equivalent across all of them.^24,25 In our practice, we manage mallet finger with a volar-based splint (FIGURE 2), which is associated with fewer dermatologic complications and has provided the most success for our patients.²³

JFP07106206_f2.JPG

Continue to: Surgical repair of mallet finger injury...

Surgical repair of mallet finger injury is indicated in any of these situations^12,14:

• injury is caused by laceration
• there is volar subluxation of the DIP joint
• more than one-third of the articular surface is involved in an avulsion fracture.

Patients who cannot comply with wearing a splint 24 hours per day or whose occupation precludes wearing a splint at all (eg, surgeons, dentists, musicians) are also surgical candidates.¹²

Surgical and conservative treatments have similar clinical and functional outcomes, including loss of approximately 5° to 7° of active extension and an increased risk of DIP joint osteoarthritis.^12,14,24 Patients with chronic mallet finger can be managed with 6 weeks of splinting initially but will likely require surgery.^6,12,13

Skier’s thumb

This relatively common injury is a tear of the ulnar collateral ligament (UCL) at the MCP joint of the thumb.¹⁶

Causes and incidence. Skier’s thumb occurs when a valgus force hyperabducts the thumb,¹⁶ and is so named because the injury is often seen in recreational skiers who fall while holding a ski pole.^15-17 It can also occur in racquet sports when a ball or racquet strikes the ulnar side of thumb.¹⁶

Continue to: In chronic cases...

In chronic cases, the UCL can be injured by occupational demands and is termed gamekeeper’s thumb because it was first described in this population, who killed game by breaking the animal's neck between the thumb and index finger against the ground.^16,18 A UCL tear causes instability at the thumb MCP joint, which affects a person’s ability to grip and pinch.^2,16,18

Presentation. On exam, the affected thumb is swollen and, possibly, bruised. There might be radial deviation and volar subluxation of the proximal phalanx. The ulnar side of the MCP joint is tender to palpation.¹⁶ If the distal UCL is torn completely, it can displace proximally and present as a palpable mass over the ulnar side of the MCP joint, known as a Stener lesion.¹⁶

Symptoms of trigger finger are pain at the metacarpal head or in the MCP joint, difficulty grasping objects, clicking and catching of the digit, and locking of the digit in flexion.

Stress testing of the MCP joint is the most important part of the physical exam for skier’s thumb. Stabilize the metacarpal neck and apply a valgus stress on the proximal phalanx at both 0° and 30° of MCP flexion (FIGURE 3), which allows for assessment of both the proper and accessory bands of the UCL.^2,16 (A common pitfall during stress testing is to allow the MCP joint to rotate, which can mimic instability.²) Intra-articular local anesthesia might be necessary for this exam because it can be painful.^16,18,26 A stress exam should assess for laxity and a soft or firm endpoint; the result should be compared to that of a stress exam on the contralateral side.^16,17

JFP07106206_f3.JPG

Imaging. AP, oblique, and lateral radiographs of the thumb should be obtained to assess for instability, avulsion injury, and associated fracture. Subluxation (volar or radial) or supination of the proximal phalanx relative to the metacarpal on imaging suggests MCP instability of the MCP joint.^16,17

If the stress exam is equivocal, magnetic resonance imaging is recommended for further assessment.^2,18

Continue to: Stress radiographs...

Stress radiographs (ie, radiographs of the thumb with valgus stress applied at the MCP joint) can aid in diagnosis but are controversial. Some experts think that these stress views can further damage the UCL; others recommend against them because they carry a false-negative rate ≥ 25%.^15,16 If you choose to perform stress views, order standard radiographs beforehand to rule out bony injury.¹⁷

Treatment. UCL tears are classified as 3 tiers to guide treatment.

• Grade 1 injury (a partial tear) is characterized by pain upon palpation but no instability on the stress exam.
• Grade 2 injury (also a partial tear) is marked by laxity on the stress exam with a firm endpoint.
• Grade 3 injury (complete tear) shows laxity and a soft endpoint on a stress exam^16,17; Stener lesions are seen only in grade 3 tears.^16,17

Grades 1 and 2 UCL tears without fracture or with a nondisplaced avulsion fracture can be managed nonoperatively by immobilizing the thumb in a spica splint or cast for 4 to 6 weeks.^16,18 The MCP joint is immobilized and the interphalangeal joint is allowed to move freely.^2,16,17

Grade 3 injuries should be referred to a hand specialist for surgical repair.¹⁶ Patients presenting > 12 weeks after acute injury or with a chronic UCL tear should also be referred for surgical repair.¹⁶

CORRESPONDENCE
Caitlin A. Nicholson, MD, 1611 West Harrison Street, Suite 300, Chicago, IL 60612; Caitlin.nicholson@gmail.com

Finger injuries are often seen in the primary care physician’s office. The evidence—and our experience in sports medicine—indicates that many of these injuries can be managed conservatively with bracing or injection; a subset, however, requires surgical referral. In this article, we provide a refresher on finger anatomy (see “A guide to the anatomic structures of the digits of the hand”^1,2) and review the diagnosis and management of 4 common soft-tissue finger and thumb injuries in adults: trigger finger, jersey finger, mallet finger, and skier’s thumb (TABLE^2-18).

JFP07106206_B1.JPG

JFP07106206_t1.JPG

Trigger finger

Also called stenosing flexor tenosynovitis, trigger finger is caused by abnormal flexor tendon movement that results from impingement at the level of the A1 pulley.

Causes and incidence. Impingement usually occurs because of thickening of the A1 pulley but can also be caused by inflammation or a nodule on the flexor tendon.^3,4 The A1 pulley at the metacarpal head is the most proximal part of the retinacular sheath and therefore experiences the greatest force upon finger flexion, making it the most common site of inflammation and constriction.⁴

JFP07106206_f.JPG

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.⁵ The condition typically affects the long and ring fingers of the dominant hand; most cases occur in women in the sixth and seventh decades.^3-5

Multiple systemic conditions predispose to trigger finger, including endocrine disorders (eg, diabetes, hypothyroidism), inflammatory arthropathies (gout, ­pseudogout), and autoimmune disorders (rheumatoid arthritis, sarcoidosis).^3,5 Diabetes commonly causes bilateral hand and multiple digit involvement, as well as more severe disease.^3,5 Occupation is also a risk factor for trigger finger because repetitive movements and manual work can exacerbate triggering.⁴

Presentation and exam. Patients report pain at the metacarpal head or metacarpophalangeal (MCP) joint, difficulty grasping objects, and, possibly, clicking and catching of the digit and locking of the digit in flexion.^3,5

Trigger finger occurs in 2% to 3% of the general population and in as many as 10% of people with diabetes.

On exam, there might be tenderness at the level of the A1 pulley over the volar MCP joint or a palpable nodule. In severe cases, the proximal interphalangeal (PIP) joint or entire finger can be fixed in flexion.⁵ Repeated compound finger flexion (eg, closing and opening a fist) or holding a fist for as long as 1 minute and then slowly opening it might provoke triggering.

More than 60% of patients with trigger finger also have carpal tunnel syndrome.⁵ This makes it important to assess for (1) sensory changes in the distribution of the median nerve and (2) nerve compression, by eliciting Phalen and Tinel signs.^4,5

Continue to: Imaging

Imaging. Trigger finger is a clinical diagnosis. Imaging is therefore unnecessary for diagnosis or treatment.⁵

Treatment. Trigger finger resolves spontaneously in 52% of cases.³ Most patients experience relief in 8 to 12 months.³

First-line treatment is injection of a corticosteroid into the flexor tendon sheath, which often alleviates symptoms.^4,5 Injection is performed at the level of the A1 pulley on the palmar surface, just proximal to the MCP joint at the level of the distal palmar crease⁶ (FIGURE 1). The needle is inserted at an oblique angle until there is an increase in resistance. The needle is then slightly withdrawn to reposition it in the tendon sheath; 0.5 to 1 mL of 50% corticosteroid and 50% local anesthetic without epinephrine is then injected.⁶

JFP07106206_f1.JPG

The cure rate of trigger finger is 57% to 70% with 1 injection and 82% to 86% after 2 injections.^3,4,19

Many patients experience symptom relief in 1 to 4 weeks after a corticosteroid injection; however, as many as 56% experience repeat triggering within 6 months—often making multiple injections (maximum, 3 per digit) necessary.^19,20 Patients who have a longer duration of symptoms, more severe symptoms, and multiple trigger fingers are less likely to experience relief with injections.^3,5

Continue to: Splinting is an effective treatment...

Splinting is an effective treatment for patients who cannot undergo corticosteroid injection or surgery. The MCP or PIP joint is immobilized in extension while movement of the distal interphalangeal (DIP) joint is maintained. Instruct the patient that the splint must be worn day and night; splinting is continued for ≥ 6 weeks.²¹ Splinting relieves symptoms in 47% to 70% of cases and is most effective in patients whose symptoms have been present for < 6 months.^3,7

Patients whose trigger finger is locked in flexion and those who have not experienced improvement after 2 or 3 corticosteroid injections should be referred for surgery.⁴ The surgical cure rate is nearly 100%; only 6% of patients experience repeat triggering 6 to 12 months postoperatively.^4,7,22

Jersey finger

Causes and incidence. Jersey finger is caused by avulsion injury to the flexor digitorum profundus (FDP) tendon at its insertion on the distal phalanx.^8,9 It occurs when a flexed finger is forced into extension, such as when a football or rugby player grabs another player’s jersey during a tackle.^9,10 This action causes the FDP tendon to detach from the distal phalanx, sometimes with a bony fragment.^9,11 Once detached, the tendon might retract proximally within the finger or to the palm, with consequent loss of its blood supply.⁹

Although jersey finger is not as common as the other conditions discussed in this article,⁹ it is important not to miss this diagnosis because of the risk of chronic disability when it is not treated promptly. Seventy-five percent of cases occur in the ring finger, which is more susceptible to injury because it extends past the other digits in a power grip.^8,9

Presentation and exam. On exam, the affected finger lies in slight extension compared to the other digits; the patient is unable to actively flex the DIP joint.^8,9 There may be tenderness to palpation over the volar distal phalanx. The retracted FDP tendon might be palpable more proximally in the digit.

Continue to: Imaging

Imaging. Anteroposterior (AP), oblique, and lateral radiographs, although unnecessary for diagnosis, are recommended to assess for an avulsion fragment, associated fracture, or dislocation.^9,11 Ultrasonography or magnetic resonance imaging is useful in chronic cases to quantify the degree of tendon retraction.⁹

Treatment. Refer acute cases of jersey finger for surgical management urgently because most cases require flexor tendon repair within 1 or 2 weeks for a successful outcome.⁹ Chronic jersey finger, in which injury occurred > 6 weeks before presentation, also requires surgical repair, although not as urgently.⁹

Complications of jersey finger include flexion contracture at the DIP joint and the so-called quadriga effect, in which the patient is unable to fully flex the fingers adjacent to the injured digit.⁸ These complications can cause chronic disability in the affected hand, making early diagnosis and referral key to successful treatment.⁹

Mallet finger

Also called drop finger, mallet finger is a result of loss of active extension at the DIP joint.^12,13

Causes and incidence. Mallet finger is a relatively common injury that typically affects the long, ring, or small finger of the dominant hand in young to middle-aged men and older women.^12,14,23 The condition is the result of forced flexion or hyperextension injury, which disrupts the extensor tendon.^6,14

Continue to: Sudden forced flexion...

Sudden forced flexion of an extended DIP joint during work or sports (eg, catching a ball) is the most common mechanism of injury.^12,15 This action causes stretching or tearing of the extensor tendon as well as a possible avulsion fracture of the distal phalanx.¹³ Mallet finger can also result from a laceration or crush injury of the extensor tendon (open mallet finger) or hyperextension of the DIP joint, causing a fracture at the dorsal base of the distal phalanx.¹²

Presentation. Through any of the aforementioned mechanisms, the delicate balance between the flexor and extensor tendons is disrupted, causing the patient to present with a flexed DIP joint that can be passively, but not actively, extended.^6,12 The DIP joint might also be painful and swollen. Patients whose injury occurred > 4 weeks prior to presentation (chronic mallet finger) might also have a so-called swan-neck deformity, with hyperextension of the PIP joint in the affected finger.¹²

Imaging. AP, oblique, and lateral radiographs are recommended to assess for bony injury.

Treatment. Splinting is the first-line treatment for almost all mallet finger injuries that are not the result of a laceration or crush injury. Immobilize the DIP joint in extension for 6 to 8 weeks, with an additional 2 to 4 weeks of splinting at night.^6,12 The splint must be worn continuously in the initial 6 to 8 weeks, and the DIP joint should remain in extension—even when the patient is performing daily hygiene.¹² It is imperative that patients comply with that period of continuous immobilization; if the DIP joint is allowed to flex, the course of treatment must be restarted.¹³

Many different types of splints exist; functional outcomes are equivalent across all of them.^24,25 In our practice, we manage mallet finger with a volar-based splint (FIGURE 2), which is associated with fewer dermatologic complications and has provided the most success for our patients.²³

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Continue to: Surgical repair of mallet finger injury...

Surgical repair of mallet finger injury is indicated in any of these situations^12,14:

• injury is caused by laceration
• there is volar subluxation of the DIP joint
• more than one-third of the articular surface is involved in an avulsion fracture.

Patients who cannot comply with wearing a splint 24 hours per day or whose occupation precludes wearing a splint at all (eg, surgeons, dentists, musicians) are also surgical candidates.¹²

Surgical and conservative treatments have similar clinical and functional outcomes, including loss of approximately 5° to 7° of active extension and an increased risk of DIP joint osteoarthritis.^12,14,24 Patients with chronic mallet finger can be managed with 6 weeks of splinting initially but will likely require surgery.^6,12,13

Skier’s thumb

This relatively common injury is a tear of the ulnar collateral ligament (UCL) at the MCP joint of the thumb.¹⁶

Causes and incidence. Skier’s thumb occurs when a valgus force hyperabducts the thumb,¹⁶ and is so named because the injury is often seen in recreational skiers who fall while holding a ski pole.^15-17 It can also occur in racquet sports when a ball or racquet strikes the ulnar side of thumb.¹⁶

Continue to: In chronic cases...

In chronic cases, the UCL can be injured by occupational demands and is termed gamekeeper’s thumb because it was first described in this population, who killed game by breaking the animal's neck between the thumb and index finger against the ground.^16,18 A UCL tear causes instability at the thumb MCP joint, which affects a person’s ability to grip and pinch.^2,16,18

Presentation. On exam, the affected thumb is swollen and, possibly, bruised. There might be radial deviation and volar subluxation of the proximal phalanx. The ulnar side of the MCP joint is tender to palpation.¹⁶ If the distal UCL is torn completely, it can displace proximally and present as a palpable mass over the ulnar side of the MCP joint, known as a Stener lesion.¹⁶

Symptoms of trigger finger are pain at the metacarpal head or in the MCP joint, difficulty grasping objects, clicking and catching of the digit, and locking of the digit in flexion.

Stress testing of the MCP joint is the most important part of the physical exam for skier’s thumb. Stabilize the metacarpal neck and apply a valgus stress on the proximal phalanx at both 0° and 30° of MCP flexion (FIGURE 3), which allows for assessment of both the proper and accessory bands of the UCL.^2,16 (A common pitfall during stress testing is to allow the MCP joint to rotate, which can mimic instability.²) Intra-articular local anesthesia might be necessary for this exam because it can be painful.^16,18,26 A stress exam should assess for laxity and a soft or firm endpoint; the result should be compared to that of a stress exam on the contralateral side.^16,17

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Imaging. AP, oblique, and lateral radiographs of the thumb should be obtained to assess for instability, avulsion injury, and associated fracture. Subluxation (volar or radial) or supination of the proximal phalanx relative to the metacarpal on imaging suggests MCP instability of the MCP joint.^16,17

If the stress exam is equivocal, magnetic resonance imaging is recommended for further assessment.^2,18

Continue to: Stress radiographs...

Stress radiographs (ie, radiographs of the thumb with valgus stress applied at the MCP joint) can aid in diagnosis but are controversial. Some experts think that these stress views can further damage the UCL; others recommend against them because they carry a false-negative rate ≥ 25%.^15,16 If you choose to perform stress views, order standard radiographs beforehand to rule out bony injury.¹⁷

Treatment. UCL tears are classified as 3 tiers to guide treatment.

• Grade 1 injury (a partial tear) is characterized by pain upon palpation but no instability on the stress exam.
• Grade 2 injury (also a partial tear) is marked by laxity on the stress exam with a firm endpoint.
• Grade 3 injury (complete tear) shows laxity and a soft endpoint on a stress exam^16,17; Stener lesions are seen only in grade 3 tears.^16,17

Grades 1 and 2 UCL tears without fracture or with a nondisplaced avulsion fracture can be managed nonoperatively by immobilizing the thumb in a spica splint or cast for 4 to 6 weeks.^16,18 The MCP joint is immobilized and the interphalangeal joint is allowed to move freely.^2,16,17

Grade 3 injuries should be referred to a hand specialist for surgical repair.¹⁶ Patients presenting > 12 weeks after acute injury or with a chronic UCL tear should also be referred for surgical repair.¹⁶

CORRESPONDENCE
Caitlin A. Nicholson, MD, 1611 West Harrison Street, Suite 300, Chicago, IL 60612; Caitlin.nicholson@gmail.com

CASE

A 19-year-old college football player presents to your outpatient family practice clinic after suffering a right ankle injury during a football game over the weekend. He reports having his right ankle planted on the turf with his foot externally rotated when an opponent fell onto his posterior right lower extremity. He reports having felt immediate pain in the area of the right ankle and requiring assistance off of the field, as he had difficulty walking. The patient was taken to the emergency department where x-rays of the right foot and ankle did not show any signs of acute fracture or dislocation. The patient was diagnosed with a lateral ankle sprain, placed in a pneumatic ankle walking brace, and given crutches.

A high ankle sprain, or distal tibiofibular syndesmotic injury, can be an elusive diagnosis and is often mistaken for the more common lateral ankle sprain. Syndesmotic injuries have been documented to occur in approximately 1% to 10% of all ankle sprains.^1-3 The highest number of these injuries occurs between the ages of 18 and 34 years, and they are more frequently seen in athletes than in nonathletes, particularly those who play collision sports, such as football, ice hockey, rugby, wrestling, and lacrosse.^1-9 In one study by Hunt et al,¹⁰ syndesmotic injuries accounted for 24.6% of all ankle injuries in National Collegiate Athletic Association (NCAA) football players. Incidence continues to grow as recognition of high ankle sprains increases among medical professionals.^1,5 Identification of syndesmotic injury is critical, as lack of detection can lead to extensive time missed from athletic participation and chronic ankle dysfunction, including pain and instability.^2,4,6,11

Back to basics: A brief anatomy review

Stability in the distal tibiofibular joint is maintained by the syndesmotic ligaments, which include the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), the transverse ligament, and the interosseous ligament.^3-6,8 This complex of ligaments stabilizes the fibula within the incisura of the tibia and maintains a stable ankle mortise.^1,4,5,11 The deep portion of the deltoid ligament also adds stability to the syndesmosis and may be disrupted by a syndesmotic injury.^2,5-7,11

Mechanisms of injury: From most common to less likely

The distal tibiofibular syndesmosis is disrupted when an injury forces apart the distal tibiofibular joint. The most commonly reported means of injury is external rotation with hyper-dorsiflexion of the ankle.^1-3,5,6,11 With excessive external rotation of the forefoot, the talus is forced against the medial aspect of the fibula, resulting in separation of the distal tibia and fibula and injury to the syndesmotic ligaments.^2,3,5,6 Injuries associated with external rotation are commonly seen in sports that immobilize the ankle within a rigid boot, such as skiing and ice hockey.^1,2,5 Some authors have suggested that a planovalgus foot alignment may place athletes at inherent risk for an external rotation ankle injury.^5,6

Trauma causing ankle syndesmotic injuries may be associated with Weber B or Weber C distal fibula fractures or a Maisonneuve fracture.

Syndesmotic injury may also occur with hyper-dorsiflexion, as the anterior, widest portion of the talus rotates into the ankle mortise, wedging the tibia and fibula apart.^2,3,5 There have also been reports of syndesmotic injuries associated with internal rotation, plantar flexion, inversion, and eversion.^3,5,11 Therefore, physicians should maintain a high index of suspicion for injury to the distal tibiofibular joint, regardless of the mechanism of injury.

Presentation and evaluation

Observation of the patient and visualization of the affected ankle can provide many clues. Many patients will have difficulty walking after suffering a syndesmotic injury and may require the use of an assistive device.⁵ The inability to bear weight after an ankle injury points to a more severe diagnosis, such as an ankle fracture or syndesmotic injury, as opposed to a simple lateral ankle sprain. Patients may report anterior ankle pain, a sensation of instability with weight bearing on the affected ankle, or have persistent symptoms despite a course of conservative treatment. Also, they can have a variable amount of edema and ecchymosis associated with their injury; a minimal extent of swelling or ecchymosis does not exclude syndesmotic injury.³

A large percentage of patients will present with a concomitant sprain of the lateral ligaments associated with lateral swelling and bruising. One study found that 91% of syndesmotic injuries involved at least 1 of the lateral collateral ligaments (anterior talofibular ligament [ATFL], calcaneofibular ligament [CFL], or posterior talofibular ligament [PTFL]).¹² Patients may have pain or a sensation of instability when pushing off with the toes,⁵ and patients with syndesmotic injuries often have tenderness to palpation over the distal anterolateral ankle or syndesmotic ligaments.⁷

Continue to: A thorough examination...

A thorough examination of the ankle, including palpation of common fracture sites, is important. Employ the Ottawa Ankle Rules (see http://www.theottawarules.ca/ankle_rules) to investigate for: tenderness to palpation over the posterior 6 cm of the posterior aspects of the distal medial and lateral malleoli; tenderness over the navicular; tenderness over the base of the fifth metatarsal; and/or the inability to bear weight on the affected lower extremity immediately after injury or upon evaluation in the physician’s office. Any of these findings should raise concern for a possible fracture (see “Adult foot fractures: A guide”) and require an x-ray(s) for further evaluation.¹³

Perform range-of-motion and strength testing with regard to ankle dorsiflexion, plantar flexion, abduction, adduction, inversion, and eversion. Palpate the ATFL, CFL, and PTFL for tenderness, as these structures may be involved to varying degrees in lateral ankle sprains. An anterior drawer test (see https://www.youtube.com/watch?v=vAcBEYZKcto) may be positive with injury to the ATFL. This test is performed by stabilizing the distal tibia with one hand and using the other hand to grasp the posterior aspect of the calcaneus and apply an anterior force. The test is positive if the talus translates forward, which correlates with laxity or rupture of the ATFL.¹³ The examiner should also palpate the Achilles tendon, peroneal tendons just posterior to the lateral malleolus, and the tibialis posterior tendon just posterior to the medial malleolus to inspect for tenderness or defects that may be signs of injury to these tendons.

An associated Weber B or C fracture? Trauma causing ankle syndesmosis injuries may be associated with Weber B or Weber C distal fibula fractures.⁷ Weber B fractures occur in the distal fibula at the level of the ankle joint (see FIGURE 1). These types of fractures are typically associated with external rotation injuries and are usually not associated with disruption of the interosseous membrane.

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Weber C fractures are distal fibular fractures occurring above the level of the ankle joint. These fractures are also typically associated with external ankle rotation injuries and include disruption of the syndesmosis and deltoid ligament.¹⁴

Also pay special attention to the proximal fibula, as syndesmotic injuries are commonly associated with a Maisonneuve fracture, which is a proximal fibula fracture associated with external rotation forces of the ankle (see FIGURE 1).^{1,2,4,11,14,15} Further workup should occur in any patient with the possibility of a Weber- or Maisonneuve-type fracture.

Continue to: Multiple tests...

Multiple tests are available to investigate the possibility of a syndesmotic injury and to assess return-to-sport readiness, including the External Rotation Test, the Squeeze Test, the Crossed-Leg Test, the Dorsiflexion Compression Test, the Cotton Test, the Stabilization Test, the Fibular Translation Test, and the Single Leg Hop Test (see TABLE^{1-3,5,6,16,17}). The External Rotation Test is noted by some authors to have the highest interobserver reliability, and is our preferred test.² The Squeeze Test also has moderate interobserver reliability.² There is a significant degree of variation among the sensitivity and specificity of these diagnostic tests, and no single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury. Therefore, it is recommended to use multiple physical exam maneuvers, the history and mechanism of injury, and findings on imaging studies in conjunction to make the diagnosis of a syndesmotic injury.^1,16

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Imaging: Which modes and when?

The initial workup should include ankle x-rays when evaluating for the possibility of a distal tibiofibular syndesmosis injury. While the Ottawa Ankle Rules are helpful in providing guidance with regard to x-rays, suspicion of a syndesmotic injury mandates x-rays to determine the stability of the joint and rule out fracture. The European Society of Sports Traumatology, Knee Surgery and Arthroscopy–European Foot and Ankle Associates (ESSKA-AFAS) recommend, at a minimum, obtaining anteroposterior (AP)- and mortise-view ankle x-rays to investigate the tibiofibular clear space, medial clear space, and tibiofibular overlap.⁷ Most physicians also include a lateral ankle x-ray.

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If possible, images should be performed while the patient is bearing weight to further evaluate stability. Radiographic findings that support the diagnosis of syndesmotic injury include a tibiofibular clear space > 6 mm on AP view, medial clear space > 4 mm on mortise view, or tibiofibular overlap < 6 mm on AP view or < 1 mm on mortise view (see FIGURES 2 and 3).^1,3,5,8 Additionally, if you suspect a proximal fibular fracture, obtain an x-ray series of the proximal tibia and fibula to investigate the possibility of a Maisonneuve injury.^1,2,4,11

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The External Rotation Test is noted by some authors to have the highest interobserver reliability.

If you continue to suspect a syndesmotic injury despite normal x-rays, obtain stress x-rays, in addition to the AP and mortise views, to ensure stability. These x-rays include AP and mortise ankle views with manual external rotation of the ankle joint, which may demonstrate abnormalities not seen on standard x-rays. Bilateral imaging can also be useful to further assess when mild abnormalities vs symmetric anatomic variants are in question.^1,7

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If there is concern for an unstable injury, refer the patient to a foot and ankle surgeon, who may pursue magnetic resonance imaging (MRI) or standing computed tomography (CT).^1,2,5,7 MRI is the recommended choice for further evaluation of a syndesmotic injury, as it is proven to be accurate in evaluating the integrity of the syndesmotic ligaments (see FIGURES 4 and 5).¹⁸ MRI has demonstrated 100% sensitivity for detecting AITFL and PITFL injuries, as well as 93% and 100% specificity for AITFL and PITFL tears, respectively.⁸ A weight-bearing CT scan, particularly axial views, can also be a useful adjunct, as it is more sensitive than standard x-rays for assessing for mild diastasis. Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.^1,7

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Continue to: Although not the standard of care...

Although not the standard of care, ultrasonography (US) is gaining traction as a means of investigating the integrity of the syndesmotic ligaments. US is inexpensive, readily available in many clinics, allows for dynamic testing, and avoids radiation exposure.⁷ However, US requires a skilled sonographer with experience in the ankle joint for an accurate diagnosis. If the workup with advanced imaging is inconclusive, but a high degree of suspicion remains for an unstable syndesmotic injury, consider arthroscopy to directly visualize and assess the syndesmotic structures.^1,2,5,7,8

Grading the severity of the injury and pursuing appropriate Tx

Typically, the severity of a syndesmotic injury is classified as fitting into 1 of 3 categories: Grade I and II injuries are the most common, each accounting for 40% of syndesmotic injuries, while 20% of high ankle sprains are classified as Grade III.¹²

No single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury.

A Grade I injury consists of a stable syndesmotic joint without abnormal radiographic findings. There may be associated tenderness to palpation over the distal tibiofibular joint, and provocative testing may be subtle or normal. These injuries are often minor and able to be treated conservatively.

A Grade II injury is associated with a partial syndesmotic disruption, typically with partial tearing of the AITFL and interosseous ligament. These injuries may be stable or accompanied by mild instability, and provocative testing is usually positive. X-rays are typically normal with Grade II injuries, but may display subtle radiographic findings suggestive of a syndesmotic injury. Treatment of Grade II injuries is somewhat controversial and should be an individualized decision based upon the patient’s age, activity level, clinical exam, and imaging findings. Therefore, treatment of Grade II syndesmotic injuries may include a trial of conservative management or surgical intervention.

A Grade III injury represents inherent instability of the distal tibiofibular joint with complete disruption of all syndesmotic ligaments, with or without involvement of the deltoid ligament. X-rays will be positive in Grade III syndesmotic injuries because of the complete disruption of syndesmotic ligaments. All Grade III injuries require surgical intervention with a syndesmotic screw or other stabilization procedure.^1,6-8,15

Continue to: A 3-stage rehabilitation protocol

When conservative management is deemed appropriate for a stable syndesmotic sprain, a 3-stage rehabilitation protocol is typically utilized.

The acute phase focuses on protection, pain control, and decreasing inflammation. The patient’s ankle is often immobilized in a cast or controlled ankle movement (CAM) boot. The patient is typically allowed to bear weight in the immobilizer during this phase as long as he/she is pain-free. If pain is present with weight bearing despite immobilization, non-weight bearing is recommended. The patient is instructed to elevate the lower extremity, take anti-inflammatory medication, and ice the affected ankle. Additionally, physical therapy modalities may be utilized to help with edema and pain. Joint immobilization is typically employed for 1 to 3 weeks post-injury. In the acute phase, the patient may also work with a physical therapist or athletic trainer on passive range of motion (ROM), progressing to active ROM as tolerated.^1,5,7,8,19

The patient can transition from the CAM boot to a lace-up ankle brace when he/she is able to bear full weight and can navigate stairs without pain, which typically occurs around 3 to 6 weeks post-injury.^1,5,7 A pneumatic walking brace may also be used as a transition device to provide added stabilization.

In the sub-acute phase, rehabilitation may progress to increase ankle mobility, strengthening, neuromuscular control, and to allow the patient to perform activities of daily living.^5-7

The advanced training phase includes continued neuromuscular control, increased strengthening, plyometrics, agility, and sports-specific drills.⁵ Athletes are allowed to return to full participation when they have regained full ROM, are able to perform sport-specific agility drills without pain or instability, and have near-normal strength.^5-7 Some authors also advocate that a Single Leg Hop Test should be included in the physical exam, and that it should be pain free prior to allowing an athlete to return to competition.²⁰ Both progression in physical rehabilitation and return to sport should be individualized based upon injury severity, patient functionality, and physical exam findings.

Continue to: Outcomes forecast

Outcomes forecast: Variable

The resolution of symptoms and return to competition after a syndesmotic injury is variable. In one cohort study of cadets (N = 614) at the United States Military Academy, the average time lost from a syndesmotic ankle sprain was 9.82 days (range 3-21 days).⁹ In a retrospective review of National Hockey League players, average time to return to competition after a syndesmotic ankle injury sprain (n = 14) was 45 days (range 6-137 days) vs 1.4 days (range 0-6 days) for lateral ankle sprains (n = 5).²¹ In another study, National Football League players with syndesmotic sprains (n = 36) had a mean time loss from play of 15.4 days (± 11.1 days) vs 6.5 days (± 6.5 days) of time loss from play in those with lateral ankle sprains (n = 53).²²

Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.

Although there is a fair amount of variability among studies, most authors agree that the average athlete can expect to return to sport 4 to 8 weeks post-injury with conservative management.¹⁹ At least 1 study suggests that the average time to return to sport in patients with Grade III syndesmotic injuries who undergo surgical treatment with a syndesmotic screw is 41 days (range 32-48).²³ The differences in return to sport may be related to severity of injury and/or type of activity.

Persistent symptoms are relatively common after conservative management of syndesmotic injuries. One case series found that 36% of patients treated conservatively had complaints of persistent mild-to-moderate ankle stiffness, 23% had mild-to-moderate pain, and 18% had mild-to-moderate ankle swelling.²⁴ Despite these symptoms, 86% of the patients rated their ankle function as good after conservative treatment.²⁴ In patients with persistent symptoms, other possible etiologies should be considered including neurologic injury, complex regional pain syndrome, osteochondral defect, loose body, or other sources that may be contributing to pain, swelling, or delayed recovery.

At least 1 randomized controlled trial (RCT) investigated the utility of platelet rich plasma (PRP) injections around the injured AITFL in the setting of an acute syndesmotic injury. The study showed promising results, including quicker return to play, restabilization of the syndesmotic joint, and less residual pain;²⁵ however, the study population was relatively small (N = 16), and the authors believed that more research is required on the benefits of PRP therapy in syndesmotic injuries before recommendations can be made.

An ounce of preventionis worth a pound of cure

Although injury is not always avoidable, there are measures that can help prevent ankle sprains and facilitate return to play after injury. As previously mentioned, athletes should be able to demonstrate the ability to run, cut, jump, and perform sport-specific activities without limitations prior to being allowed to return to sport after injury.^5-7,26 Additionally, issues with biomechanics and functional deficits should be analyzed and addressed. By targeting specific strength deficits, focusing on proprioceptive awareness, and working on neuromuscular control, injury rates and recurrent injuries can be minimized. One RCT showed a 35% reduction in the recurrence rate of lateral ankle sprains with the use of an unsupervised home-based proprioceptive training program.²⁷

Continue to: Strength training...

Although not the standard of care, ultrasonography is gaining traction as a means of investigating the integrity of the syndesmotic ligaments.

Strength training, proprioceptive and neuromuscular control activities, and low-risk activities such as jogging, biking, and swimming do not necessarily require the use of prophylactic bracing. However, because syndesmotic injuries are associated with recurrent ankle injuries, prophylactic bracing should be used during high-risk activities that involve agility maneuvers and jumping. Substantial evidence demonstrates that the use of ankle taping or ankle bracing decreases the incidence of ankle injuries, particularly in those who have had previous ankle injuries.²⁶ In one study (N = 450), only 3% of athletes with a history of prior ankle injuries suffered a recurrent ankle sprain when using an ankle orthosis compared with a 17% injury rate in the control group.²⁸

More recently, 2 separate studies by McGuine et al demonstrated that the use of lace-up ankle braces led to a reduction in the incidence of acute ankle injuries by 61% among 2081 high-school football players, and resulted in a significant reduction in acute ankle injuries in a study of 1460 male and female high-school basketball players, compared with the control groups.^29,30

CASE

Ten days after injuring himself, the patient returns for a follow-up exam. Despite using the walking brace and crutches, he is still having significant difficulty bearing weight. He reports a sensation of instability in the right ankle. On exam, you note visible edema of the right ankle and ecchymosis over the lateral ankle, as well as moderate tenderness to palpation over the area of the ATFL and deltoid ligament. Tenderness over the medial malleolus, lateral malleolus, fifth metatarsal, and navicular is absent. Pain is reproducible with external rotation, and a Squeeze Test is positive. There is no tenderness over the proximal tibia or fibula. The patient is neurovascularly intact.

You order stress x-rays, which show widening of the medial clear space. The patient is placed in a CAM boot, instructed to continue non–weight-bearing on the ankle, and referred to a local foot and ankle surgeon for consideration of surgical fixation.

CORRESPONDENCE
John T. Nickless, MD, Division of Primary Care Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, 1611 W. Harrison Street, Suite 200, Chicago, IL, 60612; jack.nickless@rushortho.com.

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CASE

A 19-year-old college football player presents to your outpatient family practice clinic after suffering a right ankle injury during a football game over the weekend. He reports having his right ankle planted on the turf with his foot externally rotated when an opponent fell onto his posterior right lower extremity. He reports having felt immediate pain in the area of the right ankle and requiring assistance off of the field, as he had difficulty walking. The patient was taken to the emergency department where x-rays of the right foot and ankle did not show any signs of acute fracture or dislocation. The patient was diagnosed with a lateral ankle sprain, placed in a pneumatic ankle walking brace, and given crutches.

A high ankle sprain, or distal tibiofibular syndesmotic injury, can be an elusive diagnosis and is often mistaken for the more common lateral ankle sprain. Syndesmotic injuries have been documented to occur in approximately 1% to 10% of all ankle sprains.^1-3 The highest number of these injuries occurs between the ages of 18 and 34 years, and they are more frequently seen in athletes than in nonathletes, particularly those who play collision sports, such as football, ice hockey, rugby, wrestling, and lacrosse.^1-9 In one study by Hunt et al,¹⁰ syndesmotic injuries accounted for 24.6% of all ankle injuries in National Collegiate Athletic Association (NCAA) football players. Incidence continues to grow as recognition of high ankle sprains increases among medical professionals.^1,5 Identification of syndesmotic injury is critical, as lack of detection can lead to extensive time missed from athletic participation and chronic ankle dysfunction, including pain and instability.^2,4,6,11

Back to basics: A brief anatomy review

Stability in the distal tibiofibular joint is maintained by the syndesmotic ligaments, which include the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), the transverse ligament, and the interosseous ligament.^3-6,8 This complex of ligaments stabilizes the fibula within the incisura of the tibia and maintains a stable ankle mortise.^1,4,5,11 The deep portion of the deltoid ligament also adds stability to the syndesmosis and may be disrupted by a syndesmotic injury.^2,5-7,11

Mechanisms of injury: From most common to less likely

The distal tibiofibular syndesmosis is disrupted when an injury forces apart the distal tibiofibular joint. The most commonly reported means of injury is external rotation with hyper-dorsiflexion of the ankle.^1-3,5,6,11 With excessive external rotation of the forefoot, the talus is forced against the medial aspect of the fibula, resulting in separation of the distal tibia and fibula and injury to the syndesmotic ligaments.^2,3,5,6 Injuries associated with external rotation are commonly seen in sports that immobilize the ankle within a rigid boot, such as skiing and ice hockey.^1,2,5 Some authors have suggested that a planovalgus foot alignment may place athletes at inherent risk for an external rotation ankle injury.^5,6

Trauma causing ankle syndesmotic injuries may be associated with Weber B or Weber C distal fibula fractures or a Maisonneuve fracture.

Syndesmotic injury may also occur with hyper-dorsiflexion, as the anterior, widest portion of the talus rotates into the ankle mortise, wedging the tibia and fibula apart.^2,3,5 There have also been reports of syndesmotic injuries associated with internal rotation, plantar flexion, inversion, and eversion.^3,5,11 Therefore, physicians should maintain a high index of suspicion for injury to the distal tibiofibular joint, regardless of the mechanism of injury.

Presentation and evaluation

Observation of the patient and visualization of the affected ankle can provide many clues. Many patients will have difficulty walking after suffering a syndesmotic injury and may require the use of an assistive device.⁵ The inability to bear weight after an ankle injury points to a more severe diagnosis, such as an ankle fracture or syndesmotic injury, as opposed to a simple lateral ankle sprain. Patients may report anterior ankle pain, a sensation of instability with weight bearing on the affected ankle, or have persistent symptoms despite a course of conservative treatment. Also, they can have a variable amount of edema and ecchymosis associated with their injury; a minimal extent of swelling or ecchymosis does not exclude syndesmotic injury.³

A large percentage of patients will present with a concomitant sprain of the lateral ligaments associated with lateral swelling and bruising. One study found that 91% of syndesmotic injuries involved at least 1 of the lateral collateral ligaments (anterior talofibular ligament [ATFL], calcaneofibular ligament [CFL], or posterior talofibular ligament [PTFL]).¹² Patients may have pain or a sensation of instability when pushing off with the toes,⁵ and patients with syndesmotic injuries often have tenderness to palpation over the distal anterolateral ankle or syndesmotic ligaments.⁷

Continue to: A thorough examination...

A thorough examination of the ankle, including palpation of common fracture sites, is important. Employ the Ottawa Ankle Rules (see http://www.theottawarules.ca/ankle_rules) to investigate for: tenderness to palpation over the posterior 6 cm of the posterior aspects of the distal medial and lateral malleoli; tenderness over the navicular; tenderness over the base of the fifth metatarsal; and/or the inability to bear weight on the affected lower extremity immediately after injury or upon evaluation in the physician’s office. Any of these findings should raise concern for a possible fracture (see “Adult foot fractures: A guide”) and require an x-ray(s) for further evaluation.¹³

Perform range-of-motion and strength testing with regard to ankle dorsiflexion, plantar flexion, abduction, adduction, inversion, and eversion. Palpate the ATFL, CFL, and PTFL for tenderness, as these structures may be involved to varying degrees in lateral ankle sprains. An anterior drawer test (see https://www.youtube.com/watch?v=vAcBEYZKcto) may be positive with injury to the ATFL. This test is performed by stabilizing the distal tibia with one hand and using the other hand to grasp the posterior aspect of the calcaneus and apply an anterior force. The test is positive if the talus translates forward, which correlates with laxity or rupture of the ATFL.¹³ The examiner should also palpate the Achilles tendon, peroneal tendons just posterior to the lateral malleolus, and the tibialis posterior tendon just posterior to the medial malleolus to inspect for tenderness or defects that may be signs of injury to these tendons.

An associated Weber B or C fracture? Trauma causing ankle syndesmosis injuries may be associated with Weber B or Weber C distal fibula fractures.⁷ Weber B fractures occur in the distal fibula at the level of the ankle joint (see FIGURE 1). These types of fractures are typically associated with external rotation injuries and are usually not associated with disruption of the interosseous membrane.

JFP06804e5_f1.JPG

Weber C fractures are distal fibular fractures occurring above the level of the ankle joint. These fractures are also typically associated with external ankle rotation injuries and include disruption of the syndesmosis and deltoid ligament.¹⁴

Also pay special attention to the proximal fibula, as syndesmotic injuries are commonly associated with a Maisonneuve fracture, which is a proximal fibula fracture associated with external rotation forces of the ankle (see FIGURE 1).^{1,2,4,11,14,15} Further workup should occur in any patient with the possibility of a Weber- or Maisonneuve-type fracture.

Continue to: Multiple tests...

Multiple tests are available to investigate the possibility of a syndesmotic injury and to assess return-to-sport readiness, including the External Rotation Test, the Squeeze Test, the Crossed-Leg Test, the Dorsiflexion Compression Test, the Cotton Test, the Stabilization Test, the Fibular Translation Test, and the Single Leg Hop Test (see TABLE^{1-3,5,6,16,17}). The External Rotation Test is noted by some authors to have the highest interobserver reliability, and is our preferred test.² The Squeeze Test also has moderate interobserver reliability.² There is a significant degree of variation among the sensitivity and specificity of these diagnostic tests, and no single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury. Therefore, it is recommended to use multiple physical exam maneuvers, the history and mechanism of injury, and findings on imaging studies in conjunction to make the diagnosis of a syndesmotic injury.^1,16

JFP06804e5_t1.JPG

Imaging: Which modes and when?

The initial workup should include ankle x-rays when evaluating for the possibility of a distal tibiofibular syndesmosis injury. While the Ottawa Ankle Rules are helpful in providing guidance with regard to x-rays, suspicion of a syndesmotic injury mandates x-rays to determine the stability of the joint and rule out fracture. The European Society of Sports Traumatology, Knee Surgery and Arthroscopy–European Foot and Ankle Associates (ESSKA-AFAS) recommend, at a minimum, obtaining anteroposterior (AP)- and mortise-view ankle x-rays to investigate the tibiofibular clear space, medial clear space, and tibiofibular overlap.⁷ Most physicians also include a lateral ankle x-ray.

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If possible, images should be performed while the patient is bearing weight to further evaluate stability. Radiographic findings that support the diagnosis of syndesmotic injury include a tibiofibular clear space > 6 mm on AP view, medial clear space > 4 mm on mortise view, or tibiofibular overlap < 6 mm on AP view or < 1 mm on mortise view (see FIGURES 2 and 3).^1,3,5,8 Additionally, if you suspect a proximal fibular fracture, obtain an x-ray series of the proximal tibia and fibula to investigate the possibility of a Maisonneuve injury.^1,2,4,11

JFP06804e5_f3.JPG

The External Rotation Test is noted by some authors to have the highest interobserver reliability.

If you continue to suspect a syndesmotic injury despite normal x-rays, obtain stress x-rays, in addition to the AP and mortise views, to ensure stability. These x-rays include AP and mortise ankle views with manual external rotation of the ankle joint, which may demonstrate abnormalities not seen on standard x-rays. Bilateral imaging can also be useful to further assess when mild abnormalities vs symmetric anatomic variants are in question.^1,7

JFP06804e5_f4.JPG

If there is concern for an unstable injury, refer the patient to a foot and ankle surgeon, who may pursue magnetic resonance imaging (MRI) or standing computed tomography (CT).^1,2,5,7 MRI is the recommended choice for further evaluation of a syndesmotic injury, as it is proven to be accurate in evaluating the integrity of the syndesmotic ligaments (see FIGURES 4 and 5).¹⁸ MRI has demonstrated 100% sensitivity for detecting AITFL and PITFL injuries, as well as 93% and 100% specificity for AITFL and PITFL tears, respectively.⁸ A weight-bearing CT scan, particularly axial views, can also be a useful adjunct, as it is more sensitive than standard x-rays for assessing for mild diastasis. Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.^1,7

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Continue to: Although not the standard of care...

Although not the standard of care, ultrasonography (US) is gaining traction as a means of investigating the integrity of the syndesmotic ligaments. US is inexpensive, readily available in many clinics, allows for dynamic testing, and avoids radiation exposure.⁷ However, US requires a skilled sonographer with experience in the ankle joint for an accurate diagnosis. If the workup with advanced imaging is inconclusive, but a high degree of suspicion remains for an unstable syndesmotic injury, consider arthroscopy to directly visualize and assess the syndesmotic structures.^1,2,5,7,8

Grading the severity of the injury and pursuing appropriate Tx

Typically, the severity of a syndesmotic injury is classified as fitting into 1 of 3 categories: Grade I and II injuries are the most common, each accounting for 40% of syndesmotic injuries, while 20% of high ankle sprains are classified as Grade III.¹²

No single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury.

A Grade I injury consists of a stable syndesmotic joint without abnormal radiographic findings. There may be associated tenderness to palpation over the distal tibiofibular joint, and provocative testing may be subtle or normal. These injuries are often minor and able to be treated conservatively.

A Grade II injury is associated with a partial syndesmotic disruption, typically with partial tearing of the AITFL and interosseous ligament. These injuries may be stable or accompanied by mild instability, and provocative testing is usually positive. X-rays are typically normal with Grade II injuries, but may display subtle radiographic findings suggestive of a syndesmotic injury. Treatment of Grade II injuries is somewhat controversial and should be an individualized decision based upon the patient’s age, activity level, clinical exam, and imaging findings. Therefore, treatment of Grade II syndesmotic injuries may include a trial of conservative management or surgical intervention.

A Grade III injury represents inherent instability of the distal tibiofibular joint with complete disruption of all syndesmotic ligaments, with or without involvement of the deltoid ligament. X-rays will be positive in Grade III syndesmotic injuries because of the complete disruption of syndesmotic ligaments. All Grade III injuries require surgical intervention with a syndesmotic screw or other stabilization procedure.^1,6-8,15

Continue to: A 3-stage rehabilitation protocol

When conservative management is deemed appropriate for a stable syndesmotic sprain, a 3-stage rehabilitation protocol is typically utilized.

The acute phase focuses on protection, pain control, and decreasing inflammation. The patient’s ankle is often immobilized in a cast or controlled ankle movement (CAM) boot. The patient is typically allowed to bear weight in the immobilizer during this phase as long as he/she is pain-free. If pain is present with weight bearing despite immobilization, non-weight bearing is recommended. The patient is instructed to elevate the lower extremity, take anti-inflammatory medication, and ice the affected ankle. Additionally, physical therapy modalities may be utilized to help with edema and pain. Joint immobilization is typically employed for 1 to 3 weeks post-injury. In the acute phase, the patient may also work with a physical therapist or athletic trainer on passive range of motion (ROM), progressing to active ROM as tolerated.^1,5,7,8,19

The patient can transition from the CAM boot to a lace-up ankle brace when he/she is able to bear full weight and can navigate stairs without pain, which typically occurs around 3 to 6 weeks post-injury.^1,5,7 A pneumatic walking brace may also be used as a transition device to provide added stabilization.

In the sub-acute phase, rehabilitation may progress to increase ankle mobility, strengthening, neuromuscular control, and to allow the patient to perform activities of daily living.^5-7

The advanced training phase includes continued neuromuscular control, increased strengthening, plyometrics, agility, and sports-specific drills.⁵ Athletes are allowed to return to full participation when they have regained full ROM, are able to perform sport-specific agility drills without pain or instability, and have near-normal strength.^5-7 Some authors also advocate that a Single Leg Hop Test should be included in the physical exam, and that it should be pain free prior to allowing an athlete to return to competition.²⁰ Both progression in physical rehabilitation and return to sport should be individualized based upon injury severity, patient functionality, and physical exam findings.

Continue to: Outcomes forecast

Outcomes forecast: Variable

The resolution of symptoms and return to competition after a syndesmotic injury is variable. In one cohort study of cadets (N = 614) at the United States Military Academy, the average time lost from a syndesmotic ankle sprain was 9.82 days (range 3-21 days).⁹ In a retrospective review of National Hockey League players, average time to return to competition after a syndesmotic ankle injury sprain (n = 14) was 45 days (range 6-137 days) vs 1.4 days (range 0-6 days) for lateral ankle sprains (n = 5).²¹ In another study, National Football League players with syndesmotic sprains (n = 36) had a mean time loss from play of 15.4 days (± 11.1 days) vs 6.5 days (± 6.5 days) of time loss from play in those with lateral ankle sprains (n = 53).²²

Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.

Although there is a fair amount of variability among studies, most authors agree that the average athlete can expect to return to sport 4 to 8 weeks post-injury with conservative management.¹⁹ At least 1 study suggests that the average time to return to sport in patients with Grade III syndesmotic injuries who undergo surgical treatment with a syndesmotic screw is 41 days (range 32-48).²³ The differences in return to sport may be related to severity of injury and/or type of activity.

Persistent symptoms are relatively common after conservative management of syndesmotic injuries. One case series found that 36% of patients treated conservatively had complaints of persistent mild-to-moderate ankle stiffness, 23% had mild-to-moderate pain, and 18% had mild-to-moderate ankle swelling.²⁴ Despite these symptoms, 86% of the patients rated their ankle function as good after conservative treatment.²⁴ In patients with persistent symptoms, other possible etiologies should be considered including neurologic injury, complex regional pain syndrome, osteochondral defect, loose body, or other sources that may be contributing to pain, swelling, or delayed recovery.

At least 1 randomized controlled trial (RCT) investigated the utility of platelet rich plasma (PRP) injections around the injured AITFL in the setting of an acute syndesmotic injury. The study showed promising results, including quicker return to play, restabilization of the syndesmotic joint, and less residual pain;²⁵ however, the study population was relatively small (N = 16), and the authors believed that more research is required on the benefits of PRP therapy in syndesmotic injuries before recommendations can be made.

An ounce of preventionis worth a pound of cure

Although injury is not always avoidable, there are measures that can help prevent ankle sprains and facilitate return to play after injury. As previously mentioned, athletes should be able to demonstrate the ability to run, cut, jump, and perform sport-specific activities without limitations prior to being allowed to return to sport after injury.^5-7,26 Additionally, issues with biomechanics and functional deficits should be analyzed and addressed. By targeting specific strength deficits, focusing on proprioceptive awareness, and working on neuromuscular control, injury rates and recurrent injuries can be minimized. One RCT showed a 35% reduction in the recurrence rate of lateral ankle sprains with the use of an unsupervised home-based proprioceptive training program.²⁷

Continue to: Strength training...

Although not the standard of care, ultrasonography is gaining traction as a means of investigating the integrity of the syndesmotic ligaments.

Strength training, proprioceptive and neuromuscular control activities, and low-risk activities such as jogging, biking, and swimming do not necessarily require the use of prophylactic bracing. However, because syndesmotic injuries are associated with recurrent ankle injuries, prophylactic bracing should be used during high-risk activities that involve agility maneuvers and jumping. Substantial evidence demonstrates that the use of ankle taping or ankle bracing decreases the incidence of ankle injuries, particularly in those who have had previous ankle injuries.²⁶ In one study (N = 450), only 3% of athletes with a history of prior ankle injuries suffered a recurrent ankle sprain when using an ankle orthosis compared with a 17% injury rate in the control group.²⁸

More recently, 2 separate studies by McGuine et al demonstrated that the use of lace-up ankle braces led to a reduction in the incidence of acute ankle injuries by 61% among 2081 high-school football players, and resulted in a significant reduction in acute ankle injuries in a study of 1460 male and female high-school basketball players, compared with the control groups.^29,30

CASE

Ten days after injuring himself, the patient returns for a follow-up exam. Despite using the walking brace and crutches, he is still having significant difficulty bearing weight. He reports a sensation of instability in the right ankle. On exam, you note visible edema of the right ankle and ecchymosis over the lateral ankle, as well as moderate tenderness to palpation over the area of the ATFL and deltoid ligament. Tenderness over the medial malleolus, lateral malleolus, fifth metatarsal, and navicular is absent. Pain is reproducible with external rotation, and a Squeeze Test is positive. There is no tenderness over the proximal tibia or fibula. The patient is neurovascularly intact.

You order stress x-rays, which show widening of the medial clear space. The patient is placed in a CAM boot, instructed to continue non–weight-bearing on the ankle, and referred to a local foot and ankle surgeon for consideration of surgical fixation.

CORRESPONDENCE
John T. Nickless, MD, Division of Primary Care Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, 1611 W. Harrison Street, Suite 200, Chicago, IL, 60612; jack.nickless@rushortho.com.

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CASE

A 19-year-old college football player presents to your outpatient family practice clinic after suffering a right ankle injury during a football game over the weekend. He reports having his right ankle planted on the turf with his foot externally rotated when an opponent fell onto his posterior right lower extremity. He reports having felt immediate pain in the area of the right ankle and requiring assistance off of the field, as he had difficulty walking. The patient was taken to the emergency department where x-rays of the right foot and ankle did not show any signs of acute fracture or dislocation. The patient was diagnosed with a lateral ankle sprain, placed in a pneumatic ankle walking brace, and given crutches.

A high ankle sprain, or distal tibiofibular syndesmotic injury, can be an elusive diagnosis and is often mistaken for the more common lateral ankle sprain. Syndesmotic injuries have been documented to occur in approximately 1% to 10% of all ankle sprains.^1-3 The highest number of these injuries occurs between the ages of 18 and 34 years, and they are more frequently seen in athletes than in nonathletes, particularly those who play collision sports, such as football, ice hockey, rugby, wrestling, and lacrosse.^1-9 In one study by Hunt et al,¹⁰ syndesmotic injuries accounted for 24.6% of all ankle injuries in National Collegiate Athletic Association (NCAA) football players. Incidence continues to grow as recognition of high ankle sprains increases among medical professionals.^1,5 Identification of syndesmotic injury is critical, as lack of detection can lead to extensive time missed from athletic participation and chronic ankle dysfunction, including pain and instability.^2,4,6,11

Back to basics: A brief anatomy review

Stability in the distal tibiofibular joint is maintained by the syndesmotic ligaments, which include the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), the transverse ligament, and the interosseous ligament.^3-6,8 This complex of ligaments stabilizes the fibula within the incisura of the tibia and maintains a stable ankle mortise.^1,4,5,11 The deep portion of the deltoid ligament also adds stability to the syndesmosis and may be disrupted by a syndesmotic injury.^2,5-7,11

Mechanisms of injury: From most common to less likely

The distal tibiofibular syndesmosis is disrupted when an injury forces apart the distal tibiofibular joint. The most commonly reported means of injury is external rotation with hyper-dorsiflexion of the ankle.^1-3,5,6,11 With excessive external rotation of the forefoot, the talus is forced against the medial aspect of the fibula, resulting in separation of the distal tibia and fibula and injury to the syndesmotic ligaments.^2,3,5,6 Injuries associated with external rotation are commonly seen in sports that immobilize the ankle within a rigid boot, such as skiing and ice hockey.^1,2,5 Some authors have suggested that a planovalgus foot alignment may place athletes at inherent risk for an external rotation ankle injury.^5,6

Trauma causing ankle syndesmotic injuries may be associated with Weber B or Weber C distal fibula fractures or a Maisonneuve fracture.

Syndesmotic injury may also occur with hyper-dorsiflexion, as the anterior, widest portion of the talus rotates into the ankle mortise, wedging the tibia and fibula apart.^2,3,5 There have also been reports of syndesmotic injuries associated with internal rotation, plantar flexion, inversion, and eversion.^3,5,11 Therefore, physicians should maintain a high index of suspicion for injury to the distal tibiofibular joint, regardless of the mechanism of injury.

Presentation and evaluation

Observation of the patient and visualization of the affected ankle can provide many clues. Many patients will have difficulty walking after suffering a syndesmotic injury and may require the use of an assistive device.⁵ The inability to bear weight after an ankle injury points to a more severe diagnosis, such as an ankle fracture or syndesmotic injury, as opposed to a simple lateral ankle sprain. Patients may report anterior ankle pain, a sensation of instability with weight bearing on the affected ankle, or have persistent symptoms despite a course of conservative treatment. Also, they can have a variable amount of edema and ecchymosis associated with their injury; a minimal extent of swelling or ecchymosis does not exclude syndesmotic injury.³

A large percentage of patients will present with a concomitant sprain of the lateral ligaments associated with lateral swelling and bruising. One study found that 91% of syndesmotic injuries involved at least 1 of the lateral collateral ligaments (anterior talofibular ligament [ATFL], calcaneofibular ligament [CFL], or posterior talofibular ligament [PTFL]).¹² Patients may have pain or a sensation of instability when pushing off with the toes,⁵ and patients with syndesmotic injuries often have tenderness to palpation over the distal anterolateral ankle or syndesmotic ligaments.⁷

Continue to: A thorough examination...

A thorough examination of the ankle, including palpation of common fracture sites, is important. Employ the Ottawa Ankle Rules (see http://www.theottawarules.ca/ankle_rules) to investigate for: tenderness to palpation over the posterior 6 cm of the posterior aspects of the distal medial and lateral malleoli; tenderness over the navicular; tenderness over the base of the fifth metatarsal; and/or the inability to bear weight on the affected lower extremity immediately after injury or upon evaluation in the physician’s office. Any of these findings should raise concern for a possible fracture (see “Adult foot fractures: A guide”) and require an x-ray(s) for further evaluation.¹³

Perform range-of-motion and strength testing with regard to ankle dorsiflexion, plantar flexion, abduction, adduction, inversion, and eversion. Palpate the ATFL, CFL, and PTFL for tenderness, as these structures may be involved to varying degrees in lateral ankle sprains. An anterior drawer test (see https://www.youtube.com/watch?v=vAcBEYZKcto) may be positive with injury to the ATFL. This test is performed by stabilizing the distal tibia with one hand and using the other hand to grasp the posterior aspect of the calcaneus and apply an anterior force. The test is positive if the talus translates forward, which correlates with laxity or rupture of the ATFL.¹³ The examiner should also palpate the Achilles tendon, peroneal tendons just posterior to the lateral malleolus, and the tibialis posterior tendon just posterior to the medial malleolus to inspect for tenderness or defects that may be signs of injury to these tendons.

An associated Weber B or C fracture? Trauma causing ankle syndesmosis injuries may be associated with Weber B or Weber C distal fibula fractures.⁷ Weber B fractures occur in the distal fibula at the level of the ankle joint (see FIGURE 1). These types of fractures are typically associated with external rotation injuries and are usually not associated with disruption of the interosseous membrane.

JFP06804e5_f1.JPG

Weber C fractures are distal fibular fractures occurring above the level of the ankle joint. These fractures are also typically associated with external ankle rotation injuries and include disruption of the syndesmosis and deltoid ligament.¹⁴

Also pay special attention to the proximal fibula, as syndesmotic injuries are commonly associated with a Maisonneuve fracture, which is a proximal fibula fracture associated with external rotation forces of the ankle (see FIGURE 1).^{1,2,4,11,14,15} Further workup should occur in any patient with the possibility of a Weber- or Maisonneuve-type fracture.

Continue to: Multiple tests...

Multiple tests are available to investigate the possibility of a syndesmotic injury and to assess return-to-sport readiness, including the External Rotation Test, the Squeeze Test, the Crossed-Leg Test, the Dorsiflexion Compression Test, the Cotton Test, the Stabilization Test, the Fibular Translation Test, and the Single Leg Hop Test (see TABLE^{1-3,5,6,16,17}). The External Rotation Test is noted by some authors to have the highest interobserver reliability, and is our preferred test.² The Squeeze Test also has moderate interobserver reliability.² There is a significant degree of variation among the sensitivity and specificity of these diagnostic tests, and no single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury. Therefore, it is recommended to use multiple physical exam maneuvers, the history and mechanism of injury, and findings on imaging studies in conjunction to make the diagnosis of a syndesmotic injury.^1,16

JFP06804e5_t1.JPG

Imaging: Which modes and when?

The initial workup should include ankle x-rays when evaluating for the possibility of a distal tibiofibular syndesmosis injury. While the Ottawa Ankle Rules are helpful in providing guidance with regard to x-rays, suspicion of a syndesmotic injury mandates x-rays to determine the stability of the joint and rule out fracture. The European Society of Sports Traumatology, Knee Surgery and Arthroscopy–European Foot and Ankle Associates (ESSKA-AFAS) recommend, at a minimum, obtaining anteroposterior (AP)- and mortise-view ankle x-rays to investigate the tibiofibular clear space, medial clear space, and tibiofibular overlap.⁷ Most physicians also include a lateral ankle x-ray.

JFP06804e5_f2.JPG

If possible, images should be performed while the patient is bearing weight to further evaluate stability. Radiographic findings that support the diagnosis of syndesmotic injury include a tibiofibular clear space > 6 mm on AP view, medial clear space > 4 mm on mortise view, or tibiofibular overlap < 6 mm on AP view or < 1 mm on mortise view (see FIGURES 2 and 3).^1,3,5,8 Additionally, if you suspect a proximal fibular fracture, obtain an x-ray series of the proximal tibia and fibula to investigate the possibility of a Maisonneuve injury.^1,2,4,11

JFP06804e5_f3.JPG

The External Rotation Test is noted by some authors to have the highest interobserver reliability.

If you continue to suspect a syndesmotic injury despite normal x-rays, obtain stress x-rays, in addition to the AP and mortise views, to ensure stability. These x-rays include AP and mortise ankle views with manual external rotation of the ankle joint, which may demonstrate abnormalities not seen on standard x-rays. Bilateral imaging can also be useful to further assess when mild abnormalities vs symmetric anatomic variants are in question.^1,7

JFP06804e5_f4.JPG

If there is concern for an unstable injury, refer the patient to a foot and ankle surgeon, who may pursue magnetic resonance imaging (MRI) or standing computed tomography (CT).^1,2,5,7 MRI is the recommended choice for further evaluation of a syndesmotic injury, as it is proven to be accurate in evaluating the integrity of the syndesmotic ligaments (see FIGURES 4 and 5).¹⁸ MRI has demonstrated 100% sensitivity for detecting AITFL and PITFL injuries, as well as 93% and 100% specificity for AITFL and PITFL tears, respectively.⁸ A weight-bearing CT scan, particularly axial views, can also be a useful adjunct, as it is more sensitive than standard x-rays for assessing for mild diastasis. Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.^1,7

JFP06804e5_f5.JPG

Continue to: Although not the standard of care...

Although not the standard of care, ultrasonography (US) is gaining traction as a means of investigating the integrity of the syndesmotic ligaments. US is inexpensive, readily available in many clinics, allows for dynamic testing, and avoids radiation exposure.⁷ However, US requires a skilled sonographer with experience in the ankle joint for an accurate diagnosis. If the workup with advanced imaging is inconclusive, but a high degree of suspicion remains for an unstable syndesmotic injury, consider arthroscopy to directly visualize and assess the syndesmotic structures.^1,2,5,7,8

Grading the severity of the injury and pursuing appropriate Tx

Typically, the severity of a syndesmotic injury is classified as fitting into 1 of 3 categories: Grade I and II injuries are the most common, each accounting for 40% of syndesmotic injuries, while 20% of high ankle sprains are classified as Grade III.¹²

No single test is sufficiently reliable or accurate to diagnose a syndesmotic ankle injury.

A Grade I injury consists of a stable syndesmotic joint without abnormal radiographic findings. There may be associated tenderness to palpation over the distal tibiofibular joint, and provocative testing may be subtle or normal. These injuries are often minor and able to be treated conservatively.

A Grade II injury is associated with a partial syndesmotic disruption, typically with partial tearing of the AITFL and interosseous ligament. These injuries may be stable or accompanied by mild instability, and provocative testing is usually positive. X-rays are typically normal with Grade II injuries, but may display subtle radiographic findings suggestive of a syndesmotic injury. Treatment of Grade II injuries is somewhat controversial and should be an individualized decision based upon the patient’s age, activity level, clinical exam, and imaging findings. Therefore, treatment of Grade II syndesmotic injuries may include a trial of conservative management or surgical intervention.

A Grade III injury represents inherent instability of the distal tibiofibular joint with complete disruption of all syndesmotic ligaments, with or without involvement of the deltoid ligament. X-rays will be positive in Grade III syndesmotic injuries because of the complete disruption of syndesmotic ligaments. All Grade III injuries require surgical intervention with a syndesmotic screw or other stabilization procedure.^1,6-8,15

Continue to: A 3-stage rehabilitation protocol

When conservative management is deemed appropriate for a stable syndesmotic sprain, a 3-stage rehabilitation protocol is typically utilized.

The acute phase focuses on protection, pain control, and decreasing inflammation. The patient’s ankle is often immobilized in a cast or controlled ankle movement (CAM) boot. The patient is typically allowed to bear weight in the immobilizer during this phase as long as he/she is pain-free. If pain is present with weight bearing despite immobilization, non-weight bearing is recommended. The patient is instructed to elevate the lower extremity, take anti-inflammatory medication, and ice the affected ankle. Additionally, physical therapy modalities may be utilized to help with edema and pain. Joint immobilization is typically employed for 1 to 3 weeks post-injury. In the acute phase, the patient may also work with a physical therapist or athletic trainer on passive range of motion (ROM), progressing to active ROM as tolerated.^1,5,7,8,19

The patient can transition from the CAM boot to a lace-up ankle brace when he/she is able to bear full weight and can navigate stairs without pain, which typically occurs around 3 to 6 weeks post-injury.^1,5,7 A pneumatic walking brace may also be used as a transition device to provide added stabilization.

In the sub-acute phase, rehabilitation may progress to increase ankle mobility, strengthening, neuromuscular control, and to allow the patient to perform activities of daily living.^5-7

The advanced training phase includes continued neuromuscular control, increased strengthening, plyometrics, agility, and sports-specific drills.⁵ Athletes are allowed to return to full participation when they have regained full ROM, are able to perform sport-specific agility drills without pain or instability, and have near-normal strength.^5-7 Some authors also advocate that a Single Leg Hop Test should be included in the physical exam, and that it should be pain free prior to allowing an athlete to return to competition.²⁰ Both progression in physical rehabilitation and return to sport should be individualized based upon injury severity, patient functionality, and physical exam findings.

Continue to: Outcomes forecast

Outcomes forecast: Variable

The resolution of symptoms and return to competition after a syndesmotic injury is variable. In one cohort study of cadets (N = 614) at the United States Military Academy, the average time lost from a syndesmotic ankle sprain was 9.82 days (range 3-21 days).⁹ In a retrospective review of National Hockey League players, average time to return to competition after a syndesmotic ankle injury sprain (n = 14) was 45 days (range 6-137 days) vs 1.4 days (range 0-6 days) for lateral ankle sprains (n = 5).²¹ In another study, National Football League players with syndesmotic sprains (n = 36) had a mean time loss from play of 15.4 days (± 11.1 days) vs 6.5 days (± 6.5 days) of time loss from play in those with lateral ankle sprains (n = 53).²²

Although CT can provide an assessment of bony structures, it is not able to evaluate soft tissue structures, limiting its utility in evaluation of syndesmotic injuries.

Although there is a fair amount of variability among studies, most authors agree that the average athlete can expect to return to sport 4 to 8 weeks post-injury with conservative management.¹⁹ At least 1 study suggests that the average time to return to sport in patients with Grade III syndesmotic injuries who undergo surgical treatment with a syndesmotic screw is 41 days (range 32-48).²³ The differences in return to sport may be related to severity of injury and/or type of activity.

Persistent symptoms are relatively common after conservative management of syndesmotic injuries. One case series found that 36% of patients treated conservatively had complaints of persistent mild-to-moderate ankle stiffness, 23% had mild-to-moderate pain, and 18% had mild-to-moderate ankle swelling.²⁴ Despite these symptoms, 86% of the patients rated their ankle function as good after conservative treatment.²⁴ In patients with persistent symptoms, other possible etiologies should be considered including neurologic injury, complex regional pain syndrome, osteochondral defect, loose body, or other sources that may be contributing to pain, swelling, or delayed recovery.

At least 1 randomized controlled trial (RCT) investigated the utility of platelet rich plasma (PRP) injections around the injured AITFL in the setting of an acute syndesmotic injury. The study showed promising results, including quicker return to play, restabilization of the syndesmotic joint, and less residual pain;²⁵ however, the study population was relatively small (N = 16), and the authors believed that more research is required on the benefits of PRP therapy in syndesmotic injuries before recommendations can be made.

An ounce of preventionis worth a pound of cure

Although injury is not always avoidable, there are measures that can help prevent ankle sprains and facilitate return to play after injury. As previously mentioned, athletes should be able to demonstrate the ability to run, cut, jump, and perform sport-specific activities without limitations prior to being allowed to return to sport after injury.^5-7,26 Additionally, issues with biomechanics and functional deficits should be analyzed and addressed. By targeting specific strength deficits, focusing on proprioceptive awareness, and working on neuromuscular control, injury rates and recurrent injuries can be minimized. One RCT showed a 35% reduction in the recurrence rate of lateral ankle sprains with the use of an unsupervised home-based proprioceptive training program.²⁷

Continue to: Strength training...

Although not the standard of care, ultrasonography is gaining traction as a means of investigating the integrity of the syndesmotic ligaments.

Strength training, proprioceptive and neuromuscular control activities, and low-risk activities such as jogging, biking, and swimming do not necessarily require the use of prophylactic bracing. However, because syndesmotic injuries are associated with recurrent ankle injuries, prophylactic bracing should be used during high-risk activities that involve agility maneuvers and jumping. Substantial evidence demonstrates that the use of ankle taping or ankle bracing decreases the incidence of ankle injuries, particularly in those who have had previous ankle injuries.²⁶ In one study (N = 450), only 3% of athletes with a history of prior ankle injuries suffered a recurrent ankle sprain when using an ankle orthosis compared with a 17% injury rate in the control group.²⁸

More recently, 2 separate studies by McGuine et al demonstrated that the use of lace-up ankle braces led to a reduction in the incidence of acute ankle injuries by 61% among 2081 high-school football players, and resulted in a significant reduction in acute ankle injuries in a study of 1460 male and female high-school basketball players, compared with the control groups.^29,30

CASE

Ten days after injuring himself, the patient returns for a follow-up exam. Despite using the walking brace and crutches, he is still having significant difficulty bearing weight. He reports a sensation of instability in the right ankle. On exam, you note visible edema of the right ankle and ecchymosis over the lateral ankle, as well as moderate tenderness to palpation over the area of the ATFL and deltoid ligament. Tenderness over the medial malleolus, lateral malleolus, fifth metatarsal, and navicular is absent. Pain is reproducible with external rotation, and a Squeeze Test is positive. There is no tenderness over the proximal tibia or fibula. The patient is neurovascularly intact.

You order stress x-rays, which show widening of the medial clear space. The patient is placed in a CAM boot, instructed to continue non–weight-bearing on the ankle, and referred to a local foot and ankle surgeon for consideration of surgical fixation.

CORRESPONDENCE
John T. Nickless, MD, Division of Primary Care Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, 1611 W. Harrison Street, Suite 200, Chicago, IL, 60612; jack.nickless@rushortho.com.

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