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

ABSTRACT

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.