Patients with patellar fractures present with focal tenderness and swelling, and usually with a loss of the extensor mechanism. Patients with femoral condyle fractures present with pain, swelling, deformity, rotation, shortening, and an inability to ambulate. Popliteal artery injury, deep peroneal nerve injury, ipsilateral hip dislocation or fracture, and quadriceps mechanism injury are associated with these fractures. Tibial spine fractures present with tenderness, swelling, inability to extend the knee, and a positive Lachman test. Patients with tibial plateau fractures have pain, swelling, and limited range of motion. Ligamentous instability is present in about one-third of these fractures. Patients with tibial shaft fractures present with pain, swelling, and crepitance. Distal tibial fractures involving the articular surface (tibial plaflond or Pilon fracture) present with pain, swelling, and tenderness about the ankle. The risk of compartment syndrome is high with these types of tibial fractures and mandates a thorough neurovascular examination. Proximal fibular fractures may be associated with ankle injuries. Patients with isolated fibular shaft fractures may be able to bear weight.
Diagnosis and Differential
The Ottawa Knee rules (Table 174-1) or the Pittsburgh Knee rules (Fig. 174-1) should be used to determine if radiography is needed for the knee. These rules have been validated in both children and adults. In suspected tibial and fibular injuries, radiographs of the ankle and knee also may be necessary to exclude associated fractures.
Table 174-1 Ottawa Knee Rules: Radiograph if 1 Criterion Is Met |Favorite Table|Download (.pdf)
Table 174-1 Ottawa Knee Rules: Radiograph if 1 Criterion Is Met
|Patient age >55 years (rules have been validated for children 2 to 16 years of age)|
|Tenderness at the head of the fibula|
|Isolated tenderness of the patella|
|Inability to flex knee to 90°|
|Inability to transfer weight for 4 steps both immediately after the injury and in the ED|
Pittsburgh Knee rules for radiography.
(Reproduced with permission from Seaberg DC, Yealy DM, Lukens T, et al: Multicenter comparison of two clinical decision rules for the use of radiography in acute, high-risk knee injuries. Ann Emerg Med
32: 8, 1998.)
Emergency Department Care and Disposition
Table 174-2 describes the mechanism and treatment for the various knee fractures. Most tibial fractures require emergent orthopedic consultation. Conditions for emergent operative repair include open fractures, vascular compromise, or compartment syndrome. Patients may be placed in long-leg immobilization and discharged home if they have a low-energy mechanism, have their pain well-controlled, and are not at risk for compartment syndrome. Treatment for isolated fibular shaft fractures includes splinting, ice, elevation, and orthopedic or primary care physician follow-up. Proximal fibular fractures associated with ankle injuries require surgical intervention and urgent orthopedic consult.