Patella Maltracking in Posterior-stabilized Total Knee Arthroplasty

Maltracking of the patella component in total knee arthroplasty usually leads to complications such as subluxation, dislocation, fracture, excessive wear, or implant failure. After using a new posterior-stabilized total knee arthroplasty and a specific protocol for the patellofemoral articulation we determined the incidence of lateral retinacular release and patella complications. We retrospectively reviewed 255 consecutive primary posterior-stabilized total knee arthroplas- ties with an anatomic femoral component and a three-peg offset-dome patella. Component alignment was achieved using Whiteside’s lines for the femoral component, the medial border of the tubercle for the tibial component, and previously reported techniques for the patella. Lateral release was performed in 15 knees (6.2%), most of which had excessive preoperative valgus (mean, 15°). There were no reoperations for the patellofemoral joint at a mean followup of 3.7 years (range, 2-7 years). Two patients had asymptomatic osteonecrosis of the patella with complete radiolucent lines, and one patella fracture was treated with immobilization. We believe patella maltracking a largely avoidable problem in total knee arthroplasty. We found a low incidence of lateral retinacular release and patella complications using these components and this protocol for the patellofemoral articulation.

Level of Evidence: Level IV, therapeutic study (case series). See Guidelines for Authors for a complete description of levels of evidence.