Posterior Cruciate Retaining Versus Posterior Cruciate Sacrificing Total Knee Arthroplasty: A Comparitive study on Functional Outcome

INTRODUCTION: Total knee arthroplasty has evolved over the past decades into a very much reliable surgical treatment for advanced arthritis of knee Total knee replacement has been shown to restore patient function and relieve pain and deformity that results from knee arthrosis. The success of a total knee replacement is determined by many factors including pain relief, functional outcome, and range of motion, radiographic loosening or component revision.1 There have been numerous changes in the total condylar type of total knee arthroplasty during the past 20 years. These modifications include alterations in component geometry, understanding of the rotational alignment of the components, sizing options and modularity, accurate instrumentation for correcting deformity and improved cementation techniques. The best knee replacement is one, which the kinematics of the normal knee is reproduced. Amongst several factors affecting the kinematics, variations in surface geometry and the retention or sacrificing the posterior cruciate ligament is considered especially important. Yet, there is no clear evidence of how best to deal with the posterior cruciate ligament at the time of knee replacement surgery. There are four options available to the surgeon. AIM OF THE STUDY: The aim of the study is to “prospectively compare the functional outcome between posterior cruciate ligament retaining and posterior cruciate ligament sacrificing total knee arthroplasty.” at the Department of Orthopaedics and Traumatology, Government Kilpauk Medical College, Chennai between May 2005 and September 2007. MATERIALS AND METHODS: This is a prospective study, done in Kilpauk Medical College from June 2004 to November 2007. Who have undergone total knee arthroplasty for various indications, which includes varus as well as valgus knee. During this study period 26 knees were replaced in 18 patients. All patients were followed at 3weeks, 6weeks, 12weeks, thereafter every 6 months. Patients who did not turn up for follow-up and patients who had prior patellectomy were excluded. Age Group: Range 47years to 77years, Mean 60.11 years. RESULTS: The age of the patients who underwent total knee arthroplasty in our series ranged from 47 to 77 years; average was 60.11 years. More than 50% of the patients belong to sixth decade. The range in our series was from 150cms to 174cms. The mean was 158.11cms. The weight of the patients ranges from 48kgs to 80kgs. The average weight was 60.03kgs. Knee Society Score - All patients evaluated by scoring system proposed by The American Knee society. The average preoperative knee society score was 46.73. The average preoperative functional score was 48.46. Of the 20 patients entered into the study, 18 (26 total knee replacements) patients were available for review. Their mean age was 60 years. Total knee arthroplasty was performed on 18 knees for osteoarthritis and 4 for rheumatoid arthritis and 2 for posttraumatic arthritis. 20 varus and 6 valgus knees .Two patients lost follow-up. The mean pain score , range of movement , knee score , function score between the cruciate retained and the sacrificed groups shows that mean pain score for the retained group was 48.92 and 47.08 for the sacrificed group. CONCLUSION: In our short term analysis of this comparative study good results were obtained in both posterior cruciate retaining Total Knee Arthroplasty and posterior cruciate sacrificing Total Knee Arthroplasty. However, Posterior cruciate cruciate retaining Total Knee Arthroplasty had a marginally better outcome than the posterior cruciate sacrificing Total Knee Arthroplasty but it needs a long term analysis