Superior Patellar Dislocation Reduced by Intra-articular Injection: A Case Report and Review of Literature

A 53-year-old woman presented with a locked knee after an atraumatic hyperextension episode. Imaging showed an anterior tilt of the patella hinging over the superior trochlear margin, consistent with a superior patellar dislocation. The patella spontaneously reduced on an intra-articular injection with 15 mL of lidocaine in normal saline, after which she was able to actively range her knee.

Superior patellar dislocations are rare and usually result from a sudden forced contraction of the quadriceps, trapping the patella over superior trochlear osteophytes. Reduction is possible through an intra-articular local anesthetic injection, without manipulation of the patella.