Eight knees with patellofemoral disorders following total knee arthroplasty had patellar revision surgery including proximal realignment of the extensor mechanism using the Insall procedure. The primary prosthesis was the Miller-Galante 1 (MG1) in seven knees and the Press Fit Condylar in one. Patellar dislocation occurred in three knees, patellar subluxation in two, patellar lateralization in two and patellar fractures in one. The MG1 prosthesis in four knees (2 subluxation and 2 lateralization), the metal-backed patellar implants failed because polyethylene wear or fracture exposed the metal backing.
Revision of a failed patellar prosthesis is difficult. Complications occurred in three of the eight patients. There was a patellar fracture in two patients and patellar subluxation in one.
With the current use of total condylar prosthesis that have improved design and instrumentation, patellofemoral complications following total knee arthroplasty can be best avoided by meticulous operative technique.
