Superior dislocation of the patella with early onset patellofemoral arthritis: a case report and literature review.

Among the traumatic patellar dislocations, superior dislocation of patella without patellar ligament injury is very rare. We present in this article, a case of superior dislocation of the patella trapped by interlocked osteophytes in a 38-year-old female who had concurrent bilateral knee arthrosis. Successful reduction was achieved by closed manipulation without anesthesia. Neither redislocation nor symptoms of instability was seen after 36 months of follow-up, although some progression of arthritis was observed. A new classification including all traumatic patellar dislocation was also proposed.