Patellofemoral crepitation and clunk following modern, fixed-bearing total knee arthroplasty.

Patellar crepitation and clunk (PCC) is an important and modifiable complication of total knee arthroplasty (TKA). We calculated the incidence of PCC using a modern fixed-bearing TKA prosthesis, assessed whether PCC is associated with knee range of motion, and determined if there were any radiographic variables associated with the development of PCC in this prosthetic design. Five hundred seventy primary TKAs were evaluated after a mean follow-up of 24 months (range 12-81). Thirty-four knees developed PCC (6%); 6 required arthroscopic debridement. With each degree increase in the flexion angle, the likelihood of developing PCC increased by 4.2%. The incidence of PCC was low but increased with postoperative flexion ≥ 110°. No radiographic parameters were associated with the development of PCC.