Bilateral neuromuscular control in patients one year after unilateral ACL rupture or reconstruction. A cross-sectional study

Objectives: To compare bilateral neuromuscular control in patients one year after anterior cruciate ligament reconstruction (ACL-R) or conservative treatment (ACL-C) to healthy controls (ACL-I). Design: Cross-sectional study. Setting: Electromyography of vastus medialis (VM) and lateralis (VL), biceps femoris (BF) and semitendinosus (ST) was recorded during stair descent and anterior tibial translation. Each step of stair descent was divided into pre-activity, weight-acceptance and push-off phase. Pre-activation, short, medium (MLR) and long latency responses (LLR) were defined for reflex activity. Participants: N = 38 patients one year after ACL reconstruction (ACL-R), N = 26 participants with conservative treatment one year after ACL rupture (ACL-C), N = 38 healthy controls with an intact ACL (ACL-I). Main outcome measures: Normalized root mean squares per muscle and phase (α = 0.05). Results: During stair descent, within-group leg differences were found for the quadriceps in ACL-R during all phases and for the BF in ACL-C during weight-acceptance. Between-group leg differences were found for BF in both patient groups compared to ACL-I during push-off.Between-group differences in pre-activation for VM between ACL-R and ACL-C, and between ACL-C and ACL-I were found, and as LLR between patients and ACL-R versus ACL-I. Pre-activation of BF and MLR of ST differed for each patient group compared to ACL-I. Conclusions: Bilateral neuromuscular alterations are still present one year after ACL rupture or reconstruction.