# MiACLR: Michigan Initiative for Anterior Cruciate Ligament Rehabilitation

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2021 · $594,256

## Abstract

ABSTRACT
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 our understanding of how to maximize muscle strength
following ACLR, as current rehabilitation fails to restore symmetrical quadriceps strength. Our 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, our 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 we currently lack controlled trials with adequate sample sizes. The absence of
this information serves as the driving force and focus of the proposed trial. Therefore, we propose a double-
blind randomized controlled trial where ACLR patients will be randomized to 1 of 4 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 exercise; 3) 8 weeks of NMES+8 weeks of eccentric placebo; and 4) 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. We 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
other 3 study arms. Further, we 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.

## Key facts

- **NIH application ID:** 9905543
- **Project number:** 5R01HD093626-03
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Riann Marie Palmieri-Smith
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $594,256
- **Award type:** 5
- **Project period:** 2018-09-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9905543

## Citation

> US National Institutes of Health, RePORTER application 9905543, MiACLR: Michigan Initiative for Anterior Cruciate Ligament Rehabilitation (5R01HD093626-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9905543. Licensed CC0.

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