Impaired neuromuscular control up to postoperative 1 year in operated and nonoperated knees after anterior cruciate ligament reconstruction

The current study was performed to assess serial changes in neuromuscular control until 1 year postoperatively in nonathletic patients undergoing anterior cruciate ligament reconstruction (ACLR). Ninety-six patients were included. Serial neuromuscular control tests were performed preoperatively, at 6 months, and 1 year postoperatively. Neuromuscular control was evaluated using acceleration time (AT) and dynamic postural stability (overall stability index, OSI). Functional activity levels were assessed using the Tegner activity-level scale. Preoperative AT of quadriceps and hamstrings in operated knees was 78.9 ± 6.4 and 86.5 ± 6.2 ms, respectively, which significantly reduced to 56.9 ± 2.0 and 62.5 ± 2.8 ms at 1 year (P = 0.006 and 0.002, respectively). In nonoperated knees, preoperative AT of quadriceps and hamstrings was 47.6 ± 1.7 and 56.5 ± 1.7 ms, respectively, which was significantly prolonged to 54.3 ± 2.0 and 67.9 ± 2.7 ms at 1 year (P = 0.02 and 0.001, respectively). Preoperative OSI of nonoperated knees was 1.2 ± 0.0°. It significantly increased to 1.5 ± 0.1° at 1 year (P < 0.001). In operated knees, preoperative OSI was 1.8 ± 0.1°. It significantly decreased to 1.4 ± 0.1° at 1 year (P = 0.001). Tegner scale at 6 months and 1 year were significantly lower than pre-operative scale (P < 0.001). AT and OSI on both knees showed significant negative correlation with Tegner scale at 6 months and 1 year. Neuromuscular control in both knees was not restored to preoperative levels of the nonoperated knees until 1 year after ACLR. Therefore, clinicians and physical therapists should attempt to enhance neuromuscular control in both nonoperated and operated knees.