Northwestern University Feinberg School of Medicine

Orthopedic Teaching

Leg/Knee Case 5 History/Physical Exam

Anterior Knee Dislocation

History and Physical Exam

A history of a significant mechanism of injury may be present. However, patients may also sustain this injury from less severe mechanisms, such as stepping in a hole and twisting. Patients will report immediate pain and inability to walk.

Physical exam will reveal obvious deformity. This may not be obvious in an obese patient, and will be absent if the injury reduced spontaneously. Exam should focus on assessing vascular status and identifying those patients who spontaneously reduced prior to evaluation.

The vascular assessment should check for pulse deficits and arterial pressure indices. A vascular exam should be performed before and after reduction attempts.

The knee exam should check for gross instability in more than one direction which may be the only finding in a reduced injury. Other findings reported to be suspicious for a reduced knee dislocation are large posterior ecchymosis and ACL tear with large effusion.