Patellar resurfacing in total knee arthroplasty.

Technical errors in patellar resurfacing at the time of total knee arthroplasty (TKA) are responsible for many of the complications that affect the patellofemoral joint. Instability, patellar fracture, and wear of metal-backed patellar implants are significantly affected by errors of patellar resurfacing. A review of 50 TKAs using a condylar prosthesis and a standardized technique for patellar resurfacing was performed to evaluate the accuracy of the technique. The patients were evaluated at a mean of 2.5 years (range, two to five years) after surgery. The Hospital for Special Surgery Knee Score improved from a preoperative mean of 56 to 92 at the last evaluation. The Hospital for Special Surgery Knee Scores were excellent in 92% and good in 8%. The Knee Society Knee Score improved from a preoperative mean of 28 for pain and 49 for function to a last evaluation mean of 96 for pain and 85 for function. None of the patients had symptoms referable to the patellofemoral joint. There were no patellar fractures, dislocations, or instances of implant loosening of the patella. Roentgenograms revealed nine asymmetrically resurfaced patellae and five tilted patellae. There were no patellar subluxations. Patellar thickness was maintained at the preoperative level of 21 mm. Joint-line height was elevated 1 mm. The patellar height was decreased 2 mm from the preoperative height. Using a standard technique, satisfactory clinical results can be achieved, but minor errors in resurfacing and alignment will still occur.