Patellar Clunk Syndrome After Posterior Stabilized Total Knee Replacement

Abstract

Two hundred and thirty six posterior stabilized total knee arthroplasties were performed consecutively. Twenty seven patellar clunk syndromes were identified in 25 patients. Insall-Salvati ratio, position of joint line, postoperative patellar height and anterior-posterior position of tibial tray were measured. We found that post-operative low-lying patella (p<0.001) and anterior placement of tibial tray (p=0.011) was associated with patellar clunk syndrome. Thirteen patients had bilateral total knee replacements of the same prosthesis (5 bilateral AMK and 8 bilateral IB) but unilateral patellar clunk syndrome. The non-clunk sides were used as control for comparison with the clunk sides. The congruency and tilting of the patellar button in the skyline view were documented. We observed that the congruency of the patella button was less satisfactory in the clunk side (p=0.019).