LAUSR

Abstract The purpose of this study was to compare muscle recovery in the lower extremities following the newly developed bi‐cruciate substituting (BCS) to posterior stabilized (PS) total knee arthroplasty (TKA) in the Asian population. Forty‐one knees in 41 patients undergoing BCS‐TKA (41 female, average age: 71 ± 8.8) and 34 knees in 34 patients undergoing PS‐TKA (33 female, average age: 73 ± 7.2) were included in this study. The maximum isometric power of the quadriceps and hamstring muscles was measured preoperatively, and at 1, 3, 6, and 12 months after surgery using a handheld dynamometer. Postoperative muscle recovery was calculated regarding preoperative muscle power as 100%. Pre‐ and postoperative range of knee motion, femorotibial angle, and clinical scores (Knee Society score and function score) were also compared. No significant difference in sex, age, preoperative quadriceps, or preoperative hamstring power was observed between the BCS and PS‐TKA groups. When regarding the preoperative muscle power as 100%, quadriceps power at 1, 3, 6, and 12 months following BCS‐TKA was 61.2 ± 22%, 86.3 ± 28.3%, 97 ± 27.4%, and 112.4 ± 30.8%, respectively. Quadriceps power at 1, 3, 6, and 12 months following PS‐TKA was 72.4 ± 20.8%, 84 ± 16.9%, 95 ± 20.7%, and 110.8 ± 27%, respectively. Hamstring power at 1, 3, 6, and 12 months following BCS‐TKA was 96.3 ± 30%, 111.4 ± 35%, 120 ± 37%, and 125 ± 31%, respectively. Hamstring power at 1, 3, 6, and 12 months following PS‐TKA was 95 ± 25%, 112.4 ± 27%, 117 ± 38.5%, and 120.4 ± 18.5%, respectively. No significant difference in muscle power recovery was observed at 3 (p = 0.995), 6 (p = 0.944), and 12 (p = 0.917) months after surgery between the two groups. No significant difference of the clinical score was observed between the groups (Knee Society score: p = 0.479, function score: p = 0.342). No significant difference in muscle recovery and clinical score were observed between the BCS and PS‐TKA groups. Longer follow‐up is needed for the evaluation of efficacy of BCS‐TKA in the Asian populations.