Evaluation of proprioception in patients who underwent ACL reconstruction: measurement in functional position

Background/aim: Anterior cruciate ligament (ACL) injuries cause mechanoreceptor loss in the joint; therefore, proprioceptive deficits are observed after injury. In particular, proprioceptive measurements made in the functional position give more accurate results, and this is an area that requires further studies. This study aimed to evaluate proprioception in patients who had undergone ACL reconstruction (ACLR) in functional positions used in daily life (closed kinetic chain position), according to joint angles where ACL injuries occur more frequently, in comparison with healthy controls. Materials and methods: Thirty-four participants who underwent ACLR using a hamstring tendon graft (aged 29.18 ± 8.16 years; body mass index (BMI), 26.58 ± 4.02 kg/cm2) and 31 healthy participants (aged 27.35 ± 5.74 years; BMI, 24.76 ± 2.98 kg/cm2) were included. Proprioception was assessed with an active angle repetition test, using an inclinometer in the closed kinetic chain position while standing. Participants were asked to perform single-leg squats until the angle at the knee joint was 30°. After the targeted angle was defined, the participants were asked to find the targeted angle. The difference between the targeted angle and the angle reached by the participants was calculated. Results: A statistically significant difference in the active joint position sense was found among the ACLR extremity, uninvolved extremity, and control extremity (p < 0.05). The proprioceptive sense between the two extremities in the ACLR group was similar, and the proprioceptive sense was worse than that of the control group. Conclusion: To our knowledge, this is the first study to evaluate closed kinetic chain position in patients who underwent ACLR, and it showed that proprioceptive sense was still poor in patients with ACLR compared with the control group, even if an average of 24 months have elapsed since surgery.