Evidence supports what family physicians know to be true: Knee pain is an exceedingly common presenting problem in the primary care office. Estimates of lifetime incidence reach as high as 54%,1 and the prevalence of knee pain in the general population is increasing.2 Knee disability can result from acute or traumatic injuries as well as chronic, degenerative conditions such as osteoarthritis (OA). The decision to pursue orthopedic consultation for a particular injury or painful knee condition can be challenging. To address this, we highlight specific knee diagnoses known to cause pain, with the aim of describing which conditions likely will necessitate surgical consultation—and which won’t.
Acute or nondegenerative knee injuries and pain
Acute knee injuries range in severity from simple contusions and sprains to high-energy, traumatic injuries with resulting joint instability and potential neurovascular compromise. While conservative treatment often is successful for many simple injuries, surgical management—sometimes urgently or emergently—is needed in other cases, as will be detailed shortly.
Neurovascular injury associated with knee dislocations
Acute neurovascular injuries often require emergent surgical intervention. Although rare, tibiofemoral (knee) dislocations pose a significant challenge to the clinician in both diagnosis and management. The reported frequency of popliteal artery injury or rupture following a dislocation varies widely, with rates ranging from 5% to 64%, according to older studies; more recent data, however, suggest the rate is actually as low as 3.3%.3 Vascular injury can lead to irreversible tissue damage and even limb loss if not promptly identified. Identifying a knee dislocation can prove challenging, as spontaneous joint reduction occurs in as many as 50% of cases, potentially shrouding the severity of the injury on initial evaluation.4
Immediate immobilization and emergency department transport for monitoring, orthopedics consultation, and vascular studies or vascular surgery consultation is recommended in the case of a suspected knee dislocation. In one cross-sectional cohort study, the surgical management of knee dislocations yielded favorable outcomes in > 75% of cases.5
Tibial plateau fracture
This fracture often occurs as a result of high-energy trauma, such as contact sports or motor vehicle accidents, and is characterized by a proximal tibial fracture line with extension to the articular surface. X-rays often are sufficient for initial diagnosis. Computed tomography can help rule out a fracture line when clinical suspicion is high and x-rays are nondiagnostic. As noted earlier, any suggestion of neurovascular compromise on physical exam requires an emergent orthopedic surgeon consultation for a possible displaced and unstable (or more complex) injury (FIGURE 1).6-8
Nondisplaced tibial plateau fractures without supraphysiologic ligamentous laxity on valgus or varus stress testing can be managed safely with protection and early mobilization, gradual progression of weight-bearing, and serial x-rays to ensure fracture healing and stability. Surgical management and fixation are required emergently for open fractures or gross joint instability with vascular or neurologic compromise. Suspicion of these complications is raised by distal neuropathic symptoms of paresthesia or skin anesthesia, progressively worsening pain distal to the knee, or vascular signs of pallor, delayed or lost capillary refill, or decreased or absent distal pulses.
Gross joint instability identified by positive valgus or varus stress testing, positive anterior or posterior drawer testing, or patient inability to tolerate these maneuvers due to pain similarly should raise suspicion for a more significant fracture at risk for concurrent neurovascular injury. Acute compartment syndrome also is a known complication of tibial plateau fractures and similarly requires emergent operative management. Urgent surgical consultation is recommended for fractures with displaced fracture fragments, tibial articular surface step-off or depression, fractures with concurrent joint laxity, or medial plateau fractures.6-8
Continue to: Patella fractures