Postural Adjustments Following ACL Rupture and Reconstruction: A Longitudinal Study

Abstract

Longitudinal changes in compensatory and anticipatory postural adjustments around the knee were investigated from rupture of ACL until return to play after reconstruction. Twelve ACL-injured participants (ACL-P) were asked to respond to unpredictable and predictable perturbations before (T1), 2 (T2) and 6 months after (T3) reconstruction. Twelve healthy participants served as controls. Compensatory and anticipatory latencies of vastus lateralis (VL) and medialis (VM) were measured with respect to the arrival of perturbations. ACL-P showed delayed compensatory latencies compared to controls at T1 for VL (101±32 ms vs 63±7 ms) and VM (117±36 ms vs 75±17 ms) and at T2 for VL (94±20 ms vs 63±7 ms) and VM (94±27 ms vs 71±11 ms). ACL-P showed earlier anticipatory latencies than controls for VL at T1 (-69±44 ms vs -12±12 ms) and T2 (-46±17 ms vs -16±12 ms). At T3, ACL-P showed delayed compensatory latencies for VL (91±18 ms vs 56±21 ms) and VM (95±13 ms vs 66±4 ms), whilst anticipatory latencies were restored. Rehabilitation should address delayed compensatory responses.

Quadriceps muscle compensatory activations are delayed following anterior cruciate ligament reconstruction using hamstring tendon graft

“…Moreover, in the same type of single knee joint task, earlier anticipatory muscle activations have been found in response to self-generated predictable perturbations in ACL-injured andreconstructed participants with respect to healthy subjects [9,10]. While following 6 months of rehabilitation anticipatory activations did not show any differences from healthy subjects, compensatory activations were still delayed at the time of return to sport activities.…”

“…Participants were asked to undertake a perturbation task featured by unpredictable and predictable perturbations in accordance with previous studies [9,10]. Perturbations were delivered to the dominant injured/operated limb of the ACL participants and to the dominant limb of healthy participants.…”

“…[19]. As EMG traces are strongly influenced by the distance between the electrodes and the innervations zone of the muscles [20], reproducibility of electrode positioning for the three testing sessions was ensured by marking the initial electrode position and skin characteristics on a transparent tracing sheet [10,21], which was then used to re-mark the same position for the second and third assessments. An electrogoniometer (Biometrics Ltd., Gwent, UK) was placed on the lateral side of the involved limb with the two arms aligning with the thigh and leg axes to record the knee joint angular displacement.…”

“…Abnormal responses, such as an earlier activity of both knee extensor and flexor muscles, have been found in late stages of the rehabilitation during weight-bearing tasks, such as stepping [6], squatting [7] or landing [8], following ACL reconstruction in comparison with uninjured subjects. In addition, it has been recently shown that delayed compensatory muscle activations occur following ACL injury and early after surgery in response to unexpected perturbations during an unweighted single knee joint task, in which ACL individuals were asked to suddenly stabilize the knee [9,10].…”

Postural stability during visual-based cognitive and motor dual-tasks after ACLR

“…These persistent deficits in postural stability may be due to changes in the neural control after injury including altered processing of somatosensory feedback and compensation in visual or motor cognitive processing. [9][10][11][12] These neural compensations may be the result of original mechanoreceptors and peripheral nerve connections that are not restored with reconstruction resulting in impaired motor control. 13 It has also been proposed that neurological deficits in ACLR patients can lead to motor performance deterioration, especially when under cognitive or visual stress that require quick reactions, processing speed, and visual or working memory.…”