No difference between mechanical perturbation training with compliant surface and manual perturbation training on knee functional performance after ACL rupture

Clinical and Biomechanical Efficacies of Mechanical Perturbation Training After Anterior Cruciate Ligament Rupture

CONTEXT

Manual perturbation training improves knee functional performance and mitigates abnormal gait in patients with anterior cruciate ligament (ACL) rupture. However, manual perturbation training is time- and labor-intensive for therapists.

OBJECTIVE

To investigate whether perturbation training administered using a mechanical device can provide effects similar to manual training on clinical measures and knee biomechanics after ACL rupture.

DESIGN

Prospective cohort (therapeutic) study. A 2 × 2 analysis of variance was used for statistical analysis.

SETTING

A clinical and biomechanical laboratory.

PATIENTS

Eighteen level I/II patients with acute ACL ruptures participated in this preliminary study.

INTERVENTION

Nine patients received mechanical perturbation training on an automated mechanical device (mechanical group), and 9 patients received manual perturbation training (manual group).

OUTCOME MEASURES

Patients completed performance-based testing (quadriceps strength and single-legged hop tests), patient-reported questionnaires (Knee Outcome Survey-Activities of Daily Living Scale, Global Rating Score, and International Knee Documentation Committee 2000), and 3-dimensional gait analysis before (pretesting) and after (posttesting) training.

RESULTS

There was no significant group-by-time interaction found for all measures (P ≥ .18). Main effects of time were found for International Knee Documentation Committee 2000 (pretesting: 69.10 [10.95], posttesting: 75.14 [7.19]), knee excursion during weight-acceptance (pretesting: 16.01° [3.99°]; posttesting: 17.28° [3.99°]) and midstance (pretesting: 14.78° [4.13°]; posttesting: 16.92° [4.53°]) and external knee-flexion moment (pretesting: 0.43 [0.11] N m/kg/m; posttesting: 0.48 [0.11] N m/kg/m) (P ≤ .04). After accounting for pretesting groups' differences, the mechanical group scored significantly higher on triple hops (mechanical: 96.73% [6.65%]; manual: 84.97% [6.83%]) and 6-m timed hops (mechanical: 102.07% [9.50%]; manual: 91.21 [9.42%]) (P ≤ .047) compared with manual group.

CONCLUSION

The clinical significance of this study is the mechanical perturbation training produced effects similar to manual training, with both training methods were equally  effective at improving patients' perception of knee function and increasing knee excursion and external flexion moment during walking after acute ACL rupture. Mechanical perturbation training is a potential treatment to improve patients' functional and biomechanical outcomes after ACL rupture.

THE EFFECT OF TRAINING ON A COMPLIANT SURFACE ON MUSCLE ACTIVATION AND CO-CONTRACTION AFTER ANTERIOR CRUCIATE LIGAMENT INJURY

BACKGROUND

Performing physical activities on compliant surfaces alters joints kinematics by decreasing joint motions. However, the effect of administering a training program on a compliant surface on muscle activities after anterior cruciate ligament (ACL) injury is unknown.

HYPOTHESIS/PURPOSE

To compare the effects of training on a compliant surface and manual perturbation training on individual muscle activation and muscle co-contraction indexes after an ACL injury. It was hypothesized that patients who received training on the compliant surface would demonstrate higher individual and combined muscle activities compared to the manual group.

METHOD

Sixteen patients (participated in level I/II sports) who sustained an ACL injury and had not undergone reconstructive surgery participated in this preliminary study. Eight patients received training on a compliant surface (Compliant group) and data of eight patients matched by age and sex from a previous study who received manual perturbation training were used as a control group (Manual group). Patients in both groups completed standard three-dimensional gait motion analysis with surface electromyography (EMG) of several lower extremity muscles during gait. Muscle co-contraction index and individual muscle activations were computed during weight acceptance (WA) and mid-stance (MS) intervals. A 2x2 analysis of variance (ANOVA) was used with an alpha level of p<0.10 to account for the high EMG variability.

RESULTS

The compliant group significantly increased muscle co-contraction of vastus lateralis-lateral hamstring (VL-LH), vastus medialis-gastrocnemius medialis (VM-MG), and vastus lateralis (VL) muscle activity during WA (p ≤ 0.035) and manual group significantly decreased VM-MG muscle co-contraction during WA (p=0.099) after training.

CONCLUSION

Administering training on a compliant surface provides different effects on muscle activation compared to manual perturbation training after an ACL injury. Training on a compliant surface caused increased muscle co-contraction indexes and individual muscle activation, while manual perturbation training decreased the VM-MG muscle co-contraction index.

LEVEL OF EVIDENCE

2b.