Long-term clinical result of posterior cruciate ligament retaining total knee arthroplasty: 15 years follow-up study

Abstract

To evaluate the long-term clinical result and reason of failure of posterior cruciate ligament(PCL) preserved prosthesis in a 15 years of follow-up study. A case series of 153 patients (178 knees) undergoing total knee arthroplasty (TKA) with PCL preserved prosthesis between September 1990 and March 1992 in Center Medico-Chirurgical du Cedre was reported. All cases were evaluated with postoperative roentgenogram and Keen Society Clinical Scale. Measurement of X-ray included average hip knee ankle angle (HKA), deviation of HKA, alpha angle, beta angle, index of patella (AP/AT), proximal tibia angle (PTA), et al. Thirty-one patients died and 4 patients were lost at the time follow-up. And 118 patients (125 knees) out of 153 patients were successfully followed-up. Fifteen years survival rate was 93.7%. And 11 knees were revised and the reasons were as follow: 9 aseptic loosening (7 knees with severe osteolysis, 2 knees with radiolucent line around tibial prosthesis); 1 recurvatum, 1 medial tibial plateau collapse. Postoperative score was 173 points. And 95.9% patients got good or excellent result. Comparing the clinical data of revised patients and un-revised patients, there were obvious difference between the following clinical data: varus and valgus angel of contralateral knee, beta angle of preoperative AP roentgenogram, preoperative and postoperative Knee Society Clinical Scale (P < 0.05). PCL preserved prosthesis could recover the knee function to good or excellent result. Survival rate over 15 years is good. The way to sterilize the prosthesis could be the main reason for surgery failure. Few failures are related to PCL rupture. High wear rate and patellofemoral syndrome could be avoided by correct PCL and soft tissue balancing. Varus and valgus deformity of un-surgical knee and tibial varus deformity of surgical knee could be important factors for prosthesis failure.