Michigan Split-belt Treadmill Training Program to Improve Long-Term Knee Biomechanics After ACL Reconstruction (Mi-SPA)

University of Michigan

Status: Not yet enrolling

Conditions: ACL; ACL Injury; Anterior Cruciate Ligament

Treatments: Behavioral: Placebo Split-Belt Training; Behavioral: Split-Belt Training

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT06529692

HUM00221406_Aim3

1R21AR082643 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

The goal of this study is to gather pilot data to help inform a future clinical trial. As such, the investigators will employ a randomized clinical trial design, but data will only be collected on 9 total subjects. Nine subjects will be randomized to 2 split-belt intervention groups (one group where early stance loading is trained and the other where midstance loading is trained) and a placebo group.

The goal of this study is to explore the adaptations in knee loading from a 6-week split-belt training intervention.

The investigators' main question for this aim is:

1. Does knee loading, measured by the sagittal plane knee moment, change to a greater extent in the split-belt treadmill training groups compared to the placebo group?
2. Are there differences in training-related knee loading changes between individuals trained in the early stance vs. midstance loading split-belt training?

Full description

It is commonplace for individuals after anterior cruciate ligament (ACL) reconstruction to shift mechanical demands away from their surgical knee and limb. This manifests as diminished knee moments and vertical ground reaction forces in the ACL limb during everyday tasks (e.g., walking, running, standing, landing, etc.) and persists for as long as 2.5 years after surgery. This pattern of underloading is considered maladaptive, as it has been linked to re-injury and biological markers that are consistent with the development of post-traumatic osteoarthritis that affects over 50% of knees 10-20 years after surgical reconstruction.

Split-belt treadmill training is a gait retraining approach where treadmill belt speeds are decoupled (i.e., one belt is set to move at a faster or slower speed than the other belt) during walking. Split-belt training is based on well-established motor learning principles, such as error-based learning and variability of practice which can lead to locomotor adaptations. In healthy individuals, split-belt treadmill walking significantly increases (from baseline) knee moment impulses in the limb on the slow belt than on the fast belt during the braking and propulsive phases of gait. Split-belt treadmill training has also shown promise in individuals with neurological deficits, resulting in significant improvements in gait biomechanics after training.

To explore the adaptations in loading from a 6-week split-belt training intervention, the investigators will conduct a pilot randomized clinical trial design, but data will only be collected on 9 total subjects. Nine subjects will be randomized to one of 3 groups: 1) early stance split-belt treadmill training, 2) mid-stance split-belt treadmill training, or 3) placebo split-belt treadmill training. The primary outcome, sagittal plane knee moment, will be examined before, midway, & after the 6-weeks of training. Other outcomes, vertical ground reaction force, knee joint contact force, and the Knee Injury and Osteoarthritis Outcome Score, will be measured at the same timepoints. Medial and lateral knee cartilage thickness are additional outcomes that will only be assessed before and after training.

Enrollment: 9 estimated patients

Sex: All

Ages: 14 to 45 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• aged 14-45 years
• suffered an acute, complete ACL rupture as confirmed by MRI and physical exam
• have undergone ACL reconstruction w autograft within the past 10 months
• willingness to participate in testing and follow-up as outlined in the protocol
• English-speaking

Exclusion criteria

• inability to provide written informed consent
• female subjects who are pregnant or are planning to become pregnant (self-reported)
• previous ACL injury
• previous surgery to either knee
• bony fracture accompanying ACL injury
• patients who experienced a knee dislocation
• patients who had their ACL reconstructed with an allograft
• patients who underwent a multi-ligamentous and/or staged ACL reconstruction

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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9 participants in 3 patient groups, including a placebo group

Early Stance Training

Experimental group

Description:

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at 150-170% of 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Treatment:

Behavioral: Split-Belt Training

Mid-Stance Training

Experimental group

Description:

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at 30-50% of 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Treatment:

Behavioral: Split-Belt Training

Placebo Split-Belt Training

Placebo Comparator group

Description:

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at a speed that is 10% different from 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Treatment:

Behavioral: Placebo Split-Belt Training