MiACLR: Michigan Initiative for Anterior Cruciate Ligament Rehabilitation

This clinical trial evaluates interventions to maximize muscle function and improve cartilage health following anterior cruciate ligament reconstruction. Improving muscle function may improve patient outcomes, improve joint mechanics, and potentially serve as a prevention approach for post-traumatic knee osteoarthritis. Knee osteoarthritis (OA) is a disabling disease that carries a substantial burden to society and to the individual affected.

Restoring quadriceps muscle strength following anterior cruciate ligament reconstruction (ACLR) may help prevent the post-traumatic knee osteoarthritis that affects over 50% of knees 10-20 years after surgical reconstruction. However, a fundamental gap exists in current understanding of how to maximize muscle strength following ACLR, as current rehabilitation fails to restore symmetrical quadriceps strength. The investigators pilot work shows that when patients return to activity, quadriceps strength is \~70% of the uninjured side, which is far below the recommended 90%. Further, these data suggest that embedding high-intensity neuromuscular electrical stimulation (NMES) and eccentric exercise into standard of care ACL rehabilitation leads to higher quadriceps strength when compared with standard of care alone. However, the true efficacy of these interventions is unknown, as controlled trials with adequate sample sizes are currently lacking. The absence of this information serves as the driving force and focus of the proposed trial. Therefore, the investigators propose a double-blind randomized controlled trial where ACLR patients will be randomized to 1 of 2 arms. Study arms will include: 1) 8 weeks of NMES+8 weeks of eccentric exercise; 2) 8 weeks of NMES placebo+8 weeks of eccentric placebo. All study arms will receive standard of care ACL rehabilitation in addition to the study interventions. The investigators hypothesize that subjects receiving NMES+eccentric exercise (Arm 1) will realize greater improvements in strength and biomechanical function at 6 months following ACLR than patients in the placebo study arm. Further, the investigators anticipate that patients in the NMES+eccentric exercise arm (Arm 1) will best eliminate negative changes in cartilage health at 18 months following ACLR. This study is innovative, because it employs interventions that directly target the primary mechanisms that result in strength loss following ACLR and will also evaluate whether improving muscle strength can minimize early changes in cartilage health, which may be indicative of future osteoarthritis. The proposed research is significant because it will identify evidence-based treatment approaches that can successfully counteract the muscle weakness which plagues ACLR patients for years after injury and contributes to the onset of post-traumatic osteoarthritis.

Eligibility Criteria:
Inclusion Criteria:

* Acute, complete ACL rupture
* ACL reconstruction with autograft
* Scheduled to undergo ACLR at U of Michigan
* Willingness to participate in testing and follow-up as outlined

Exclusion Criteria:

* Previous surgery to either knee
* Bony fracture accompanying ACL injury
* Patients who experienced a knee dislocation
* Female participants who are pregnant or planning pregnancy