Patellofemoral problems following total knee arthroplasty.

We reviewed 350 knee arthroplasties performed between 1977 and 1984 for patellar problems. Seventeen knees with four types of patellofemoral complications were found. The diagnosis in both the group of 350 and the study group of 17 knees was evenly distributed between rheumatoid arthritis and osteoarthritis. The complication rate was 4.9%. Follow-up ranged from one to nine years post-complication. Two knees had two different complications, providing a total of 19 complications with five loosenings, three fractures of the patella, one fracture of the patellar component, and ten subluxations or dislocations. Sixteen revision surgical procedures were performed on 11 knees. Six knees were managed nonoperatively. In the four knees with multiple surgeries, one of the complications was patellar subluxation or dislocation. Only one patient was dissatisfied with his result; however, this included both knees. Patellar complications continue to be recognized as a frequent cause of problems after total knee arthroplasty. We recommend nonoperative management of patellar fractures, revision of implant with loosening or component fracture, and careful selection of realignment procedures.