Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Health and Rehabilitation Sciences

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Birmingham, Trevor B.

2nd Supervisor

Bryant, Dianne M.

Co-Supervisor

Abstract

Aberrant landing biomechanics increase the risk of anterior cruciate ligament (ACL) injury and are a focus of rehabilitation after ACL reconstruction. The purpose of the present thesis was to develop and evaluate methods of assessing landing mechanics and investigate the effects of different rehabilitation strategies after ACL reconstruction. Three studies were conducted. The first study used a Delphi process to develop the content of a Clinician-Rated Drop Vertical Jump Scale to evaluate jump landing mechanics during rehabilitation after ACL reconstruction. Twenty experts participated in four rounds of questioning, resulting in 92% agreement for knee valgus collapse, lateral trunk lean, insufficient trunk and/or knee flexion, and asymmetry as undesirable movements included on the Scale. An instruction booklet to accompany the Scale was also developed and presented in the thesis.

The second study evaluated the reliability and sensitivity to change of several biomechanical parameters during a drop vertical jump measured using a motion capture system, completed by 46 patients after ACL reconstruction. Intraclass correlation coefficients ranged from 0.58-0.90 for peak knee flexion and abduction moments, 0.45-0.85 for knee flexion and abduction angles, 0.61-0.93 for forces and loading rate, and 0.42-0.61 for hip impulse. The standardized response mean for knee flexion angles were 0.38 (peak) and 0.35 (displacement), while other biomechanical measures on the drop vertical jump were ≤0.27. The present results support the interpretation of various landing biomechanics assessed during repeated assessments of patients undergoing rehabilitation after ACL reconstruction. A technical note on the determination of optimal filtering frequency of biomechanical analysis of jump landing was also completed to complement study two and is also presented in the thesis. Residual analysis resulted in a filtering frequency of 14 Hz for markers and 50 Hz for forces.

The third study was a randomized clinical trial comparing biomechanics of functional outcome measures in patients undergoing staged (home-based and in-clinic) rehabilitation after ACL reconstruction versus usual care. 125 patients completed a drop vertical jump at 6 and 12 months after ACL reconstruction. Results suggested the staged rehabilitation program can be effective for patients who have the motivation and resources to complete their exercises at home, when detailed instruction by a qualified therapist is provided beforehand.

Overall, the findings from this thesis provide an assessment tool to help guide rehabilitation after ACL reconstruction, describe the measurement properties of biomechanical measures in patients undergoing rehabilitation after ACL reconstruction, and supports the implementation of a novel Staged physiotherapy program.

Summary for Lay Audience

Anterior cruciate ligament (ACL) reconstruction knee surgery is a commonly used procedure to replace a torn ACL and regain stability and function in the knee. An assessment tool for evaluation of jump landing performance during the ACL rehabilitation process was developed by mimicking typical sporting maneuvers where ACL injuries frequently occur. This new tool can help clinicians identify and address faulty movements that increase the risk of ACL injury. The measurement properties of the biomechanical motion analysis assessment of jump landing were subsequently evaluated to ensure concise evaluation methods were possible and reproducible. Finally, a novel strategy for rehabilitation after ACL reconstruction that shifts focus to later rather than earlier phases of recovery was tested. Biomechanical and functional outcomes were assessed to compare a combined home followed by clinic rehabilitation strategy (Staged) to Usual Care. A series of biomechanical tests, including jump landing, over a 12-month period following surgery were carried out to evaluate stability, strength and function of the reconstructed knee. Biomechanical and functional outcomes between these two groups were similar, supporting the implementation of a Staged rehabilitation process. The information contained in this thesis will help improve rehabilitation strategies and optimize the care received.

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