Allograft reconstruction of the extensor mechanism for progressive extensor lag after total knee arthroplasty and previous patellectomy: a 3-year follow-up.

Major extensor lag after total knee arthroplasty may follow operative damage to the patellar tendon or its insertion. It may also occur in a late progressive form postoperatively. A successful allograft reconstruction of the extensor mechanism for progressive extensor lag after total knee arthroplasty is described. Patellectomy had been carried out earlier on the same knee for patellofemoral osteoarthritis.