gms | German Medical Science

Objective: To study the biomechanical and electrophysiological changes in the lower limbs after rehabilitation in patients who underwent anterior cruciate ligament (ACL) reconstruction using either closed kinetic chain (CKC) exercises alone or combined closed and open kinetic chain (OKC) exercises.

Material/Methods: The study included 40 patients who were assigned to two groups; group A which carried out CKC exercises and group B which performed combined CKC and OKC exercises. Both groups carried out proprioceptive exercises as well. Before rehabiliation they underwent bilateral knee examination which included thigh girth measurement, range of motion (ROM) assessment, detection of effusion as well as muscle strength assessment for the quadriceps and hamstrings. The biomechanical and posturographic parameters which were determined were the limits of stability (LOS) as well as the vertical projection of the center of gravity (COG) over the base of support. A modified single-legged hop test was performed and the different response parameters were recorded (force, velocity and power). Computerized dynamic posturography was carried out to study the pattern of reflex muscle activity in response to forward and backward translation perturbations and the postural restoration strategy adopted was determined. All the patients underwent re-assessment after completion of the rehabilitation program which lasted for 12 weeks.

Results: Both groups showed a significant increase in knee ROM and thigh girth, however there was no statistically significant difference between the two groups. There was a significant reduction in effusion in both groups. Both groups showed a significant increase in quadriceps and hamstrings muscle strength which was also significantly greater in group B. On performing the modified hop test, the force, velocity and power showed a statistically significant increase in both groups, however there was no statistically significant difference between the two groups. LOS increased significantly in both groups; however it was significantly greater in group B. The COG was centrally projected in 75% of patients in group A and in 50% of patients in group B. There was a statistically significant difference between the 2 groups. In both groups, reflex EMG results showed an improvement which was especially prominent in the tibialis anterior and the gastrocnemius. This reflected its effect on the postural restoration strategy adopted by the patients which generally showed a shift towards ankle strategy rather than hip strategy in both groups with no statistically significant difference between the two groups.

Conclusion: The addition of OKC exercises in rehabilitation programs after ACL reconstruction is essential in restoring adequate muscle strength and postural stability, and is safe when performed in a controlled and supervised manner.