Total knee arthroplasty for neglected permanent post-traumatic patellar dislocation--case report.

Permanent post-traumatic patellar dislocation is a rare entity resulting from recurrent trauma. This uncommon condition is often confused clinically with congenital dislocation of the patella. Treatment options, although not well defined, include observation, various soft tissue and bony procedures for realigning the patella and patellectomy. To our knowledge, this is the first case reporting the use of conventional non-constrained total knee arthroplasty with patellar resurfacing and soft tissue realignment procedure for long-standing patellar dislocation in a single stage. An interesting feature of this case was the patient's ability to function reasonably well for nearly 40 years with a dislocated patella until the development of secondary osteoarthritis, and the surprisingly good recovery after total knee replacement.