Whole patellar allograft for total knee arthroplasty after previous patellectomy.

UNLABELLED: We treated seven consecutive patients (nine knees) with previous total knee arthroplasties and patellectomies with whole patellar allograft reconstructions of the extensor mechanism. The patients' extensor mechanism soft tissue sleeve was intact, but the patella was not present. Deficient patellae were reconstructed using patellar ligament (whole patella) quadriceps tendon allograft. Six knees had previous patellectomies and underwent primary total knee arthroplasties. Three knees had previous patellectomies and underwent revision total knee arthroplasties. Two patients who had primary total knee arthroplasties had failed results; one from infection and one from aseptic allograft resorption and fragmentation. One patient in the revision total knee arthroplasty group had failed results from infection. After an average followup of 44 months (range, 39-48 months), the six intact knees had an increase in quadriceps strength of one grade. The average Knee Society knee and function scores increased from 59 and 63 points, respectively, to 85 and 67 points, respectfully. The average patellar thickness was 24 mm 6 weeks postoperatively, and 15 mm (38% decrease) at the most recent followup. Patellar allografting improved quadriceps function by restoring patellar height. However, a high risk of allograft complications can occur with this procedure. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series).