Occult knee ligament injuries associated with femoral shaft fractures.

Recognition of ligamentous injuries of the knee in the acute phase is essential for optimum treatment and prognosis. A multitraumatized patient with a fractured femur and occult knee ligament damage presents a difficult diagnostic challenge. This paper retrospectively reviews 52 patients with 54 midshaft femoral fractures. The high incidence (48%) of ipsilateral knee ligament damage, particularly of a severe nature (30%) evident at followup (mean 24.5 months) is alarming. In the 26 cases of knee ligament damage, the mean time from injury to documentation of instability is 12.8 months. Motor vehicle and athletic injuries and falls account for all of the injuries. The majority are dashboard impacts treated in balanced traction with subsequent case bracing. The anterior cruciate ligament (50%) is most often injured followed by the medial collateral ligament (31%), lateral collateral ligament (13%), and posterior cruciate ligament (6%). A Lachman test, aspiration of the effusions, examinations under anesthesia including stress films, and arthroscopy are recommended as diagnostic procedures. Acute ipsilateral knee instability is a strong relative indication for primary rigid immobilization of the fracture femur to allow early ligamentous repair.