Biomechanical Monitoring of Knee Stability and Recovery in Active Individuals Following Anterior Cruciate Ligament Reconstruction

Biomechanical Assessment and Feedback for Monitoring Recovery Following Anterior Cruciate Ligament (ACL) Reconstruction. What is the model-based approach? A computer model that combines data collected from video-based movement analysis, force plate measurements, and lower-limb strength testing to estimate knee function, assess movement mechanics, and monitor recovery progression following ACL reconstruction. Why: This study evaluates the use of repeated, non-invasive biomechanical assessments to monitor recovery following anterior cruciate ligament (ACL) reconstruction. The intervention aims to provide objective measures of knee stability, movement quality, limb symmetry, lower-limb strength, and functional performance throughout rehabilitation. Assessment results will be provided to the participant’s treating physiotherapist to support rehabilitation monitoring and return-to-play decision-making. Materials - Participants will complete biomechanical assessments using: 1. Dual-camera video capture system (iPhone frontal and lateral views) to assess movement patterns and knee joint kinematics. 2. Vernier force plate technology to measure ground reaction forces and loading characteristics during functional tasks. 3. Lower-limb strength testing equipment to assess quadriceps and hamstring strength (force frame or equivalent) 4.Reflective markers to support movement tracking and biomechanical analysis (if required) 5. Functional movement tasks appropriate to the participant’s rehabilitation stage. Procedures: 1. Participant demographics and rehabilitation information will be collected, including age, sex, height, weight, sport/activity level, injury history, surgical details, time since ACL reconstruction, and current rehabilitation stage. 2.Participants will complete an initial biomechanical assessment based on their current rehabilitation stage and physiotherapist recommendations. 3. Assessments may include: Single leg hop, single leg balance, forward and lateral hops, quadricep and hamstring strength testing. Both reconstructed and uninjured limbs will be assessed to evaluate recovery and limb symmetry. Participants will complete repeated assessments over a 12month period to monitor changes in knee stability, movement quality, strength, and functional performance. Assessment results will be analysed and summarised for feedback if deemed acceptable to the treating physiotherapist. 4. Participants will undergo repeated assessments over a 12-month period, with a minimum of one assessment every 4–6 weeks (approximately 8–12 assessments per participant). Additional assessments may be completed if requested by the treating physiotherapist or if a participant reaches a new stage of rehabilitation, provided they are clinically appropriate and the participant is available. 5. Assessment results will be analysed and summarised for feedback to the treating physiotherapist where the results are considered valid and clinically interpretable. Who Provided: Biomechanical assessments will be conducted by trained research staff experienced in motion analysis, force plate testing, and lower-limb strength assessment. The participant’s treating physiotherapist will guide progression of assessment tasks to ensure they are appropriate for the participant’s rehabilitation stage. How: 1. Individual, face-to-face assessment sessions. 2. Testing will be completed alongside the participant’s existing rehabilitation programme where possible. 3. Each assessment session will take approximately 2–5 minutes depending on the rehabilitation stage and selected tasks. 4. The assessment protocol will be adapted according to participant capability and physiotherapist recommendations. 5. Testing will not replace standard rehabilitation or clinical assessment. Location: Assessments will be completed at the participant’s rehabilitation facility or the University of Canterbury Sports Lab, Christchurch, New Zealand. Tailoring: 1. Assessment tasks will be selected according to rehabilitation stage and clinical clearance. 2. Early rehabilitation assessments will focus on balance, controlled movement, and strength. 3. Later rehabilitation assessments will progress to higher-demand activities such as jumping and hopping tasks. 4. Task difficulty will be adjusted according to participant ability and rehabilitation progression. Number and Duration of Intervention Sessions: 1. Participants will complete repeated biomechanical assessment sessions over a 12-month period. 2. Each assessment session will take approximately 2–5 minutes. 3. Participants will complete a minimum of one assessment every 4–6 weeks during rehabilitation (approximately 8–12 assessments over 12 months). Additional assessments may be completed at key rehabilitation milestones if approved by the treating physiotherapist and agreed to by the participant. Monitoring Strategies: 1. Research staff will record completed assessments and monitor participant attendance. 2. Data quality checks will be performed following each assessment. 3. Any incomplete assessments, technical issues, or deviations from the assessment protocol will be documented.