ACL Injury, Muscle Weakness, Neuromuscular Manifestations
Conditions
Keywords
Eccentric exercise, Hamstrings
Brief summary
Anterior cruciate ligament (ACL) injuries constitute a significant portion of major knee joint injuries sustained by young, active individuals, and significantly increase risk for long-term disability. Yet the recommended solution to restore joint stability following injury--ACL reconstruction (ACLR)--does not prevent post-traumatic knee osteoarthritis (PTOA). Post-traumatic quadriceps (dys)function is a hallmark characteristic following ACLR, reported to accelerate the onset of PTOA after ACL injury, making the recovery of muscle function a primary concern to clinicians. However, hamstrings muscle function is drastically underrepresented relative to the quadriceps in the context of recovery from ACLR, which impedes the ability to develop targeted treatment approaches. Persistent hamstrings weakness is widely reported in patients who undergo ACLR with a hamstring tendon (HT) autograft, which increases ACL strain, and may contribute to higher graft failure rates in this population. To effectively treat muscular impairments, underlying neuromuscular adaptations known to occur in response to ACLR must be targeted. Eccentric exercise is uniquely suited to enhance neuromuscular function. The Nordic hamstring exercise (NHE) is a specific form of eccentric exercise that is clinically relevant and easy to implement, but has not been explored as an intervention for hamstrings neuromuscular dysfunction in patients who undergo ACLR with HT. To establish an evidence-based treatment model, the investigators will use a single-blind, randomized controlled clinical trial to establish the feasibility and efficacy of a 4-week NHE protocol in patients who undergo ACLR with HT. Separate factorial ANOVAs will be used to assess the effects of group (NHE, control) and time (baseline, 4 weeks) on selected outcomes. Effect sizes will be calculated for within- and between-group comparisons. The investigators expect to observe improvements in hamstrings neuromuscular function following the NHE protocol, and that those improvements will be greater than the control group. Additionally, the investigators expect the protocol to be feasible in terms of intervention adherence and patient retention. This study will identify specific barriers to the implementation of NHE in patients who undergo ACLR with HT, and will provide support for the application of an easy to implement clinical intervention able to address a complex neurophysiological problem.
Interventions
A 4-week (10 session), progressive, NHE protocol will be used for this study. Immediately following the completion of study visit 1, patients will be informed about the nature of the NHE protocol. Those available and willing to participate will be randomized to an intervention group (NHE, control). Patients randomized to NHE will receive formal instruction about how to correctly perform the exercise, and will be asked to perform several repetitions to familiarize themselves with the exercise and verify proper technique. At this time, patients will be dismissed from study visit 1, and return visits 2-11 will be scheduled to complete the NHE protocol. Patients will return for a final study visit (12) to record post-intervention measurements within 7 days of completing the NHE protocol. A minimum of 48 hours will be used to separate study visits. To accurately assess patients' ability to perform the NHE, all exercise will be performed on a NordBord Hamstring Testing System.
Sponsors
University of Toledo
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
* Age 18-35 * History of primary, unilateral ACL reconstruction (ACLR) with hamstrings tendon autograft
Exclusion criteria
* Lower extremity orthopedic surgery prior to ACLR * Post-surgical complication (e.g. infection, delayed healing) * Multiple ligament knee injury * Treated articular cartilage lesion * Known history of knee osteoarthritis * Concussion within 6 months * History of neurological disorder * Currently taking prescription medication that may alter neural excitability (e.g. stimulants, depressants)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in peak eccentric torque | Baseline, 4 weeks | Hamstrings |
| Change in peak isometric torque | Baseline, 4 weeks | Hamstrings |
| Change in peak isokinetic torque | Baseline, 4 weeks | Hamstrings |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in torque coefficient of variation | Baseline, 4 weeks | Hamstrings |
| Change in central activation ratio | Baseline, 4 weeks | Hamstrings |
| Change in short-interval cortical inhibition | Baseline, 4 weeks | Transcranial magnetic stimulation (TMS) derived outcome in semitendinosus |
| Change in active motor threshold | Baseline, 4 weeks | Transcranial magnetic stimulation (TMS) derived outcome in semitendinosus |
| Change in cortical silent period | Baseline, 4 weeks | Transcranial magnetic stimulation (TMS) derived outcome in semitendinosus |
| Change in single leg hop | Baseline, 4 weeks | Hop for distance |
| Change in intracortical facilitation | Baseline, 4 weeks | Transcranial magnetic stimulation (TMS) derived outcome in semitendinosus |
| Change in rate of torque development | Baseline, 4 weeks | Hamstrings |
Other
| Measure | Time frame | Description |
|---|---|---|
| Average rating of perceived exertion | 4 weeks (intervention group only) | Subjective perception of effort/difficulty during exercise questionnaire (range: 6 \[light effort\] to 20 \[high effort\]), completed during each intervention session |
| Change in visual analog scale | Baseline, 4 weeks | Current knee pain questionnaire (range: 0 \[no pain\] to 10 \[high pain\]) |
| Average visual analog scale | 4 weeks (intervention group only) | Average pain or discomfort questionnaire (range: 0 \[no pain/discomfort\] to 10 \[high pain/discomfort\]), completed during each intervention session |
| Change in Tampa Scale of Kinesiophobia 11-item | Baseline, 4 weeks | Fear of pain-related movement and reinjury questionnaire (range: 11 \[low fear\] to 44 \[high fear\]) |
| Change in ACL Return to Sport after Injury | Baseline, 4 weeks | Psychological readiness questionnaire (range: 0 \[low readiness\] to 100 \[high readiness\]) |
| Change in International Knee Documentation Committee Subjective Knee Evaluation | Baseline, 4 weeks | Subjective knee function questionnaire (range: 0 \[low function\] to 100 \[high function\]) |
| Change in Knee Injury and Osteoarthritis Outcome Score | Baseline, 4 weeks | Subjective knee function questionnaire (range: 0 \[low function\] to 100 \[high function\]) |
| Veterans RAND 12-Item Health Survey | Baseline, 4 weeks | Global health questionnaire (range: 0 \[low global health\] to 100 \[high global health\]) |
| Change in Tegner Activity Scale | Baseline, 4 weeks | Subjective activity level questionnaire (range: 0 \[low activity\] to 10 \[high activity\]) |
| Change in International Physical Activity Questionnaire | Baseline, 4 weeks | Subjective activity level (higher values = higher activity level) |
| Time spent in moderate-to-vigorous physical activity | 4 weeks | Objectively monitored physical activity |
| Global Rating of Change | 4 weeks | Subjective perception of change in knee function following intervention (range: -7 \[worse knee function\] to 7 \[better knee function\]) |
| Intrinsic Motivation Inventory | 4 weeks (intervention group only) | Interest/enjoyment and value/usefulness subscale questionnaires (range: 7 \[no interest/enjoyment or value/usefulness\] to 49 \[high interest/enjoyment or value/usefulness\]) |
Countries
United States
Outcome results
None listed