Equivalence of clinical and radiological outcomes in cruciate-retaining and cruciate-substituting total knee arthroplasty with medial pivot knee: A comparative study

Introduction: Total knee arthroplasty (TKA) has been recognized as the most efficacious surgical intervention for individuals suffering from advanced arthritis; however, there is ongoing debate on the technical details of the procedure. It remains unknown whether preservation of the posterior cruciate ligament (PCL) significantly affects the mid-to long-term performance of ADVANCE® medial-pivotal (AMP) knee implants to enhance patient satisfaction. The hypothesis of this study was to investigate whether the preservation of the PCL has a substantial impact on the functional outcomes of medial pivot (MP) implants in patients undergoing TKA. Therefore, this study aimed to compare the midterm clinical and radiographic outcomes of cruciate-retaining (CR) and cruciate-substituting (CS) TKA using MP prostheses. Methods: We included 376 consecutive patients who underwent unilateral TKA between January 2011 and April 2014. Follow-up evaluations were conducted in April 2021. After propensity score matching analysis, clinical and radiological outcomes and complication rates were compared between patients in the CR and CS groups. Results: The postoperative outcomes in the two groups significantly improved the preoperative conditions of the patients (all p > 0.05). The postoperative outcomes (WOMAC score, p = 0.517; KSS, p = 0.107; KSFS, p = 0.240; ROM, p = 0.795; FJS, p = 0.822) and radiographic outcomes (preoperative FTA, p = 0.997; postoperative FTA, p = 0.646; aLDFA, p = 0.094; aMPTA, p = 0.970; PTS, p = 0.243) were comparable between the two groups. The complication and revision rates between the groups were not statistically significant (p = 0.34). The Kaplan–Meier cumulative survival of patients in the CRTKA and CSTKA groups was 100 % and 98.6 %, respectively. Conclusions: This study supports the hypothesis that when MP prostheses are used, both CR and CS procedures achieve equally good mid-to long-term clinical and radiographic outcomes and complication rates. These findings suggest that PCL preservation may not significantly affect the overall performance of MP implants in patients undergoing TKA.