ABSTRACT
Aim For a successful total knee arthroplasty (TKA), bone cuts and soft tissue envelope must be balanced to ensure equal flexion and extension gaps. The study aims to assess if preoperative computed tomography (CT) scans and planning software reduce soft tissue release. Methodology A retrospective analysis was conducted for the first 100 consecutive robotic-assisted (RA) TKA (RA-TKA) patients between March 2022 and May 2023. All patients underwent preoperative leg CT scans utilizing a fully automated Cuvis Joint robot. Planning software determined implant sizes and bone resections to achieve a 180° hip-knee-ankle axis. A posterior-stabilized knee design was implanted during surgery by the same surgical team using a medial parapatellar approach. The study hypothesis was, that RA-TKA with preoperative CT scans and planning does not reduce soft tissue release incidence, comparing it with the historical control cohort using chi-square tests (P < 0.05 considered significant). Results The study consisted of 89 women and 11 males, with an average age of 65.3 ± 12 years. The average body mass index of the patients was 27.4 ± 5.2 kg/m2. Ninety-four individuals had varus knees, while six had valgus knee deformity. Varus deformity ranged between 7° and 18°, and valgus knee deformity ranged from 6° to 14° preoperatively. Twelve patients (12.77%) of 94 varus knees (versus historic control 29%, P-value = 0.0047) and one out of 6 (16.67%) valgus knees (versus historic control 84%, P < 0.0001) required posteromedial and posterolateral release for appropriate knee balance. Conclusions The study negates the null hypothesis and indicates that RA-TKA with preoperative CT scans and planning reduces the incidence of soft tissue releases to achieve a well-balanced knee.
ABSTRACT
Background The conventional total knee arthroplasty (TKA) for grade 4 knee arthritis lacks individualized strategies for determining femur component rotation, contributing to suboptimal clinical outcomes and heightened patient dissatisfaction. Methods One hundred consecutive active robotic-assisted TKA (RA-TKA) patients were retrospectively evaluated. The control group is the patients undergoing conventional TKA for grade 4 arthritis of the knee joint, where the femoral component is placed in a fixed 3-degree external rotation. The study aimed to explore the relationships between the posterior femoral axis of the functionally aligned TKA (FAA), the trans-epicondylar axis (TEA), and the posterior condylar axis (PCA). Specifically, it investigated whether there is a statistically significant difference in femoral component rotation between the functionally aligned TKA (FTKA) and the conventional 3-degrees of external rotation of the femoral component used in traditional TKA (C-TKA). Internal rotation is indicated by a negative value for the femur component. A student's t-test was employed to compare mean rotation values between FTKA and C-TKA, with a p-value below 0.05 considered statistically significant. Results A total of 100 patients (male: female, 11:89) were studied. The FAA was externally rotated in relation to the TEA (mean 1.451°, SD 1.023°, p-value <0.0001). As regards the PCA, the FAA was externally rotated (mean 2.36°, SD 2.221°, p-value 0.0002). These findings demonstrate a statistically significant difference in femoral component rotation between FTKA and C-TKA. Clinically, no patellofemoral complications or premature loosening were observed at one-year follow-up. Conclusion Functional alignment TKA technique resulted in external rotation of the femur component with respect to TEA and PCA. This negates the null hypothesis, indicating a statistically significant difference amongst the femur component rotation implanted according to the FTKA concept with robotic assisted technology and C-TKA.