Patellofemoral function in total condylar knee arthroplasty.

A series of 100 total condylar knee arthroplasties was studied to determine radiographic and clinical patellofemoral function. Before operation there was lateral patellar tilt in 31 cases and lateral displacement in 52. After operation tilt was present in 8 and displacement in 14. Only a few patients had medial patellar displacement. Dislocation or fracture of the patella was not encountered. Six patients had postoperative patellar pain. In one case there was a radiolucent zone at the bone-cement interface in the patella, without pain. Patellofemoral function before operation was good in 3, fair in 54, and poor in 43 cases. After operation it was good in 88 and fair in 12. Both tilt and displacement slightly reduced postoperative patellofemoral function. Patellar reconstruction with the total condylar prosthesis shows reasonably good tolerance of moderate malpositioning of the patellar prosthesis, affords sufficient stability and usually painless patellofemoral function.