How to Choose the Appropriate Posterior Slope Angle Can Lead to Good Knee Joint Function Recovery in Total Knee Arthroplasty?

OBJECTIVE: In this study, we aim to examine the effects of osteotomy under varying posterior slope angles on knee joint function recovery following knee arthroplasty. METHODS: We conducted a retrospective analysis from September 2015 to September 2018 on 240 patients who underwent knee arthroplasty three years previously. The study participants were categorized based on changes in the angle of the posterior slope before and after surgery: Group 1, > 5°; Group 2, 3°–5°; Group 3, 0°–3°; Group 4, −3°–0°; Group 5, < −3°. All participants were affected with knee osteoarthritis. The Knee Society Clinical Rating System (KSS) knee function score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee function score, Visual Analogue Scale (VAS) pain score, and postoperative complications were measured 3 years after surgery. RESULTS: The level of pain experienced by the patients decreased significantly than before, with pain scores ranging from 1.0–3.0, and there was a statistical difference between groups (H = 93.400, P < 0.001). The KSS score increased, with group 5 having the lowest median score of 78.0 and group 2 having the highest median score of 97.0, and there was a statistical difference between groups (H = 164.460, P < 0.001). The WOMAC score was reduced, with the median score being 24.0, 11.0, 14.0, 20.0, and 26.0, in the five groups, respectively. Group 5 had the highest score, while Group 2 had the lowest score, and there was a statistically significant difference between groups (H = 164.223, P < 0.001). No symptoms such as periprosthetic femoral fracture, prosthetic loosening, or pad wear were detected in patients postoperatively. CONCLUSION: Osteotomy at various posterior slope angles in total knee arthroplasty impacts postoperative knee function rehabilitation. An excessive increase or decrease in angle can have an impact on the postoperative recovery of knee function.