From the Gait Laboratory to the Rehabilitation Clinic: Translation of Motion Analysis and Modeling Data to Interventions That Impact Anterior Cruciate Ligament Loads in Gait and Drop Landing

Background and aim: It is unknown whether prophylactic knee braces can reduce the strain in the anterior cruciate ligament during dynamic activities. Technique: An athlete, who had characteristics of high anterior cruciate ligament injury risk, was chosen. A motion capture system (Optotrak Certus; Northern Digital, Waterloo, ON, Canada) was used to record dynamic trials during drop-landing activity of this subject with and without the knee brace being worn. A musculoskeletal model was used to estimate the muscle forces during this activity. A dynamic knee simulator then applied kinematics and muscle forces on a cadaver knee with and without the brace mounted on it. The anterior cruciate ligament strain was measured. Discussion: The peak strain in the anterior cruciate ligament was substantially lower for the braced (7%) versus unbraced (20%) conditions. Functional knee braces could decrease the strain in the anterior cruciate ligament during dynamic activities in a high-risk subject. However, the reduction seems to be a result of altered muscle firing pattern due to the brace. Clinical relevance Prophylactic knee brace could reduce the strain in the anterior cruciate ligament of high-risk subjects during drop-landing through altered muscle firing pattern associated with brace wear. This could help reduce the anterior cruciate ligament injury risk.

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Landing Kinematics and Kinetics at the Knee During Different Landing Tasks

Journal of Athletic Training ◽

10.4085/1062-6050-52.11.25 ◽

2017 ◽

Vol 52 (12) ◽

pp. 1101-1108 ◽

Cited By ~ 11

Author(s):

Nicholas R. Heebner ◽

Deirdre M. Rafferty ◽

Meleesa F. Wohleber ◽

Andrew J. Simonson ◽

Mita Lovalekar ◽

...

Keyword(s):

Anterior Cruciate Ligament ◽

Air Force ◽

Knee Flexion ◽

Cruciate Ligament ◽

Ligament Injuries ◽

Anterior Cruciate Ligament Injuries ◽

Drop Landing ◽

Us Air Force ◽

Peak Knee ◽

Anterior Cruciate

Context: Several tasks have been used to examine landing biomechanics for evaluation and rehabilitation, especially as related to anterior cruciate ligament injuries. However, comparing results among studies in which different tasks were used can be difficult, and it is unclear which task may be most appropriate. Objective: To compare lower extremity biomechanics across 5 commonly used landing tasks. Design: Descriptive laboratory study. Setting: University-operated US Air Force Special Operations Forces human performance research laboratory. Patients or Other Participants: A total of 65 US Air Force Special Tactics Operators (age = 27.7 ± 5.0 years, height = 176.5 ± 5.7 cm, mass = 83.1 ± 9.1 kg). Intervention(s): Kinematic and kinetic analysis of double- and single-legged drop landing, double- and single-legged stop jump, and forward jump to single-legged landing. Main Outcome Measure(s): Hip-, knee-, and ankle-joint kinematics; knee-joint forces and moments; and ground reaction forces (GRFs) were the dependent measures. We used repeated-measures analyses of variance or Friedman tests, as appropriate, to assess within-subject differences across tasks. Results: Peak vertical GRF and peak knee-flexion angle were different among all tasks (P < .001). Single-legged landings generated higher vertical GRF (χ2 = 244.68, P < .001) and lower peak knee-flexion values (F4,64 = 209.33, P < .001) except for forward jump to single-legged landing, which had the second highest peak vertical GRF and the lowest peak knee-flexion value. The single-legged drop landing generated the highest vertical (χ2 = 244.68, P < .001) and posterior (χ2 = 164.46, P < .001) GRFs. Peak knee-valgus moment was higher during the double-legged drop landing (χ2 = 239.63, P < .001) but similar for all others. Conclusions: Different landing tasks elicited different biomechanical responses; no single task was best for assessing a wide range of biomechanical variables related to anterior cruciate ligament injuries. Therefore, depending on the goals of the study, using multiple assessment tasks should be considered.

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