Patella clunk syndrome in posterior stabilised total knee arthroplasty

Patellofemoral complications (range from 5-55%) are probably the most common cause of unsatisfactory result after total knee replacement (TKR). From 2007 to 2009, 5patients (6 knees) were diagnosed, out of 418 operated, with patellar clunk syndrome (incidence of 1.4%). There were 3 women and 2 men whose average age was 63.5 years (range, 53-74 years). The patella clunks were reported at an average of 7.5 months (range, 3-12 months) after TKR. All patients were evaluated clinically using the knee society score. Preoperative and postoperative radiographs were reviewed. Joint line height was measured according to Figgie et al. Patellar height was evaluated using the Insall-Salvati ratio. All patients were followed up for one year. 2 patients who got operated and 1 conservatively treated patient were free of patellar clunk at 1-year follow up. The average preoperative and postoperative knee scores were 64 and 93 points respectively in operated and one conservatively treated patient. In other two conservative treated patients the average knee scores were 65 at the beginning of study and 70 points at 1-year follow up , they were advised for surgery. The etiology of patellar clunk is multifactorial and probably related to the design of the prosthesis, surgical trauma and component position.