vch.ca The extensor mechanism (EM) of the knee comprises the quadriceps muscles and tendon, the patella, patellar tendon and supporting retinaculum (figure 1). Injuries of the EM are common and may be ...

The diagnosis is usually clear from the history. Examination may disclose the patella still lying lateral to the joint, but more usually the dislocation has been reduced and there is a swollen knee ...