Measuring the force perception in knee flexor/ extensor muscles in patients with anterior cruciate ligament injury and healthy subjects

Abstract

BACKGROUND: Force perception as a contributor to the neuromuscular control of the knee joint may be altered after anterior cruciate ligament (ACL) injury. OBJECTIVE: This study aimed to compare the force perception accuracy in the knee joints of patients with ACL injury and healthy subjects. METHODS: Twenty-six patients with ACL injury and 26 healthy subjects participated in this case-control study. Participants were asked to produce 50% of the maximum voluntary isometric contraction of the knee muscles as a target force and reproduce it in their limbs in flexion and extension directions. RESULTS: There were significant interactions between group and condition as well as group, condition, and limb in the force perception error respectively (P< 0.05). The highest amount of error was seen in the contralateral limb of the ACL injury group when the reference force was produced in the injured limb (P< 0.05). CONCLUSION: The findings revealed that the force perception accuracy in the knee flexor/extensor muscles of individuals with ACL injury is impaired. Moreover, error is most evident when the patient produces force in the injured limb and replicates it in the uninjured limb in both flexion and extension directions. Therefore, the rehabilitation programs should encompass neuromuscular training in both quadriceps and hamstrings after ACL injury.