A PROSPECTIVE STUDY ON FUNCTIONAL OUTCOME IN POSTERIOR CRUCIATE RETAINING VERSUS POSTERIOR CRUCIATE SACRIFICING TOTAL KNEE ARTHROPLASTY

Abstract

Background: 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 arthritis. The success of a total knee replacement is determined by many factors like degree of pain relief and functional outcome. The role of Posterior cruciate ligament in total knee replacement is controversial. The first is to retain the ligament and to preserve as much as possible of the normal anatomy and function of the knee. Preservation of the ligament is thought to enhance stability, femoral rollback, mechanical advantage of the quadriceps muscle and proprioceptive properties. Theoretically it has been suggested that PCL retaining can increases the range of flexion and prevents posterior translation which reduces loosening and excessive polyethylene wear by decreasing the shear stresses at the fixation surfaces. We conducted a prospective study to compare resection with retention of PCL using a standard PCL–retaining cemented total knee replacement and assessed the functional outcome using functional knee scores and WOMAC score. Aims and Objectives: 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. Materials and Methods: The study was done on 20 patients admitted to Hi-Tech Medical College & Hospital, Bhubaneswar. Scoring system formulated by the WOMAC Score, Knee Society Knee Score and Functional Knee Score were used to evaluate the patients before and after surgery. Both knee scores and functional scores are calculated with each amounting to a total of 100 points and WOMAC Score with max of 96 points. All patients were evaluated postoperatively and followed up. Results: Analyzing the functional outcome it was found that all the patients in both the groups had significant improvement in their knee score and the functional knee score. Analyzing the total Knee Scores, the average Knee Society Score for the PS group was 85.80 and that of CR group was 75.60 and statistical analysis revealed a significant difference in the the p-value in favour of Cruciate Sacrificing Prosthesis signifying that Cruciate Sacrificing Prosthesis has better functional outcome. The functional knee society also showed a marked improvement in all patients, for CS group FKS was 99.6 and for CR group it was 91.6.The WOMAC Score also showed a marked improvement. In CS groups it was 24.6 and in CR it was 27.4. Statistical analysis showed a highly significant difference in favor of cruciate sacrificing prosthesis. Conclusions:Total Knee Arthroplasty in patients in whom posterior cruciate ligament was sacrificed was found to have a better functional outcome as compared to the retaining group, which can be mainly attributed to the persistence of flexion deformity in cruciate retaining group. In Indian scenario where knee replacement is done at a late stage of osteoarthritis, sacrificing the contracted posterior cruciate ligament has better outcomes as compared to retaining it.