Postoperative limb alignment in total knee replacement. Conventional versus navigated versus robotic techniques.

BACKGROUND: Our objective was to compare the coronal mechanical axis after total knee replacement (TKR) obtained in three groups of patients subjected to conventional, navigated, and robotic surgery. METHODS: Retrospective analysis. RESULTS: 124 knees were included (36 conventional, 41 navigated, 47 robotic). No statistically significant differences were found between the postOp tibiofemoral angle of the conventional, navigated and robotic groups (p = 0.396). A repeated-measure analysis of preOp-to-postOp also found no significant differences (p = 0.387). There were no differences in the proportion of outliers (3-degree) found (p = 0.211). Nevertheless, a higher proportion of patients in the robotic group improved their mechanical alignment, as compared with conventional surgery (p = 0.023), although no differences were found when comparing with navigation (p = 0.121). CONCLUSIONS: No statistically significant differences were found with respect to the postOp alignment achieved. However, statistically significant differences were detected between robotic and conventional surgery when considering the percentage of patients with improved limb alignment.

Metaphyseal sleeves as the primary implant for the management of bone defects in total knee arthroplasty after post-traumatic knee arthritis.

BACKGROUND: Implantation of a prosthesis after post-traumatic knee arthritis poses challenges derived from the bone defects and soft tissue damage. The objective of this study was to evaluate the clinical and radiological results of the use of metaphyseal sleeves in primary total knee arthroplasty surgery after post-traumatic arthritis. METHODS: Clinical and radiological results of 25 patients undergoing surgery for post-traumatic knee arthritis were prospectively evaluated. A semi-constrained, mobile platform prosthesis with metaphyseal sleeves was implanted. American Knee Society scales, Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Short Form 12 Health Survey were used. Patients were evaluated at the baseline and at postoperative months three, 12, and annually until final follow-up. RESULTS: The mean follow-up was 79 months with a maximum of 10 years. Mean Knee Society Score (KSS) increased from 29 to 78, and functional KSS from 42 to 81. The average WOMAC pain index changed from 12 to three; average WOMAC stiffness improved from four to one, and WOMAC function score improved from 44 to 16. The mean physical SF12 varied from 30 to 46, while mental SF-12 varied from 45 to 55. Radiological osseointegration of the implants was considered optimal in all cases, with a survival of 100%. CONCLUSIONS: Metaphyseal sleeves in combination with varus-valgus constrained (VVC) components and a rotating platform, have shown good clinical and radiological results in patients with post-traumatic knee arthritis and constitute a reliable alternative for treatment of this disease when the epiphyseal zone is deteriorated and has bone defects.