Abstract: Background: Theoretically, the role of Posterior cruciate ligament in total knee replacement it has been suggested that PCL retaining knees can produce femoral rollback, which helps to increase the range of flexion and prevents posterior translation in the patients. However, this in effect, reduces loosening and excessive polyethylene wear by decreasing the shear stresses at the fixation surfaces. We conducted a prospective study to compare the retention of PCL using a standard PCL–retaining with cruciate sacrificing cemented total knee replacement and assesed the functional outcome of both using functional knee scores and WOMAC score during the period between December 2020 to December 2022.
Aim: The aim of the study is to prospectively compare the functional outcome of Primary Total Knee Replacement done in our hospital during the period of December 2020 to December 2022 between patients in whom Posterior cruciate ligament(PCL) was retained with those were it was sacrificed using Knee Society Knee Scoring and Functional Knee Score and WOMAC Questionnaire.
Methods: The study was done on 20 patients. Scoring systems such as 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. Preoperative full length radiograph from the hip to ankle was taken in all the patients who underwent knee replacement surgery and pre op mechanical axis was drawn and the amount of varus or valgus deformity was quantified. Radiological grading as advocated by Kellegren and Lawrence was used to evaluate the severity of the arthritis. PCL was retained in five patients who had minimal deformities with no flexion contracture pre operatively and PCL was sacrificed in rest of the patients.
Results: Analysing 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. Analysing 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 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.Statistically there was no significant difference. The WOMAC Score also showed a marked improvement. In CS groups it was 24.6 and in CR it was 27.4.Statistitical analysis showed a highly significant difference in favour 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.
