Vibratory Stimuli, A Novel Rehabilitation Method for Preventing Post - Traumatic Knee Osteoarthritis

This study will evaluate the acute effects of vibration (whole body vibration and local muscle vibration) on quadriceps function, knee joint proprioception, and gait biomechanics linked to osteoarthritis development in individuals with anterior cruciate ligament reconstruction. Subjects will be randomly assigned to control (no vibration), whole body vibration, and local muscle vibration groups, and the aforementioned characteristics will be assessed prior to and following the respective interventions.

Quadriceps muscle dysfunction and proprioceptive deficits following knee injuries alter walking gait biomechanics in manners that contribute to development of knee osteoarthritis. Current rehabilitation techniques are minimally effective for addressing these complications and preventing knee osteoarthritis. Anterior cruciate ligament reconstruction dramatically increases the risk of knee osteoarthritis, and represents an ideal model for evaluating novel rehabilitation techniques for preventing knee osteoarthritis. Direct (local muscle vibration) and indirect (whole body vibration) vibratory stimuli enhance quadriceps function and proprioception, and may improve rehabilitation and reduce the risk of knee osteoarthritis. The purpose of this investigation is to determine and compare the acute effects of whole body vibration and local muscle vibration on quadriceps function, knee proprioception, and gait biomechanics in individuals with anterior cruciate ligament reconstruction. The investigators hypothesize that vibratory stimuli will enhance quadriceps function, knee proprioception, and gait biomechanics in manners that would reduce the risk of developing knee osteoarthritis, and that whole body vibration and local muscle vibration will produce equivalent improvements in these characteristics.

Subjects will receive whole body vibration (30Hz, 2g) applied continuously for 1 minute. This exposure will be repeated 6 times with 2 minutes of rest between exposures.

Subjects will receive local muscle vibration (30Hz, 2g) applied continuously for 1 minute. This exposure will be repeated 6 times with 2 minutes of rest between exposures.

Subjects will perform the same procedures as the experimental groups with the exception that no vibratory stimulus will be applied.

Change score (Post-Pre) for the ground reaction force during the first 50% of the stance phase calculated as the slope of the vertical ground reaction force time series curve from heelstrike to the first ground reaction force peak. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 8.5-9.5 multiples of body weight per second.

Change score (Post-Pre) for maximal isometric knee extension peak torque in Newton*meters/kilogram body mass. Though a "normal" value has not been established, typical values for the raw values (i.e. not changes scores) range 1.5-3.5 Newton*meters/kilogram body mass.

Change score (Post-Pre) for the absolute sagittal plane joint reposition error. This value, measured in degrees, represents the absolute difference between a target knee flexion angle and the angle the subject reproduces, and assesses how well the subject can perceive the position of his/her knee in space. Typical values for the raw scores (i.e. not change scores) range from 0.5 - 5 degrees.

Change score (Post-Pre) loading rate calculated as the peak of the first time derivative of the vertical ground reaction force time series curve during the first 50% of the stance phase. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 50-70 multiples of body weight per second.

Change score (Post-Pre) for the peak internal knee extension moment during the first 50% of the stance phase. This value reflects the internal (i.e. muscle and other soft tissue) response to external loading of the knee joint in the sagittal plane of motion, and is indicative of quadriceps muscle function during walking. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 2-4 % body weight x height.

Change score (Post-Pre) for the peak internal knee valgus moment during the first 50% of the stance phase. This value reflects the internal (i.e. muscle and other soft tissue) response to external loading of the knee joint in the frontal plane of motion, and is indicative of medial tibiofemoral joint loading during walking. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 2-4 % body weight x height.

Inclusion Criteria: age 18-35 years undergone unilateral ACLR within 5 years prior to participation at least 6 months post-ACLR Knee Injury and Osteoarthritis Outcome Score (KOOS) self-report survey Pain subscale score > 53.1 and Symptom subscale score > 44.9 cleared by a physician for return to physical activity, and currently participating in at least 20 minutes of physical activity 3x per week. Exclusion Criteria: central activation ratio (CAR) > 95% history of ACL graft rupture or revision surgery, neurological disorder, or injury to either leg within 6 months prior to participation (other than the initial ACLR)

Blackburn T, Padua DA, Pietrosimone B, Schwartz TA, Spang JT, Goodwin JS, Dewig DR, Johnston CD. Vibration improves gait biomechanics linked to posttraumatic knee osteoarthritis following anterior cruciate ligament injury. J Orthop Res. 2021 May;39(5):1113-1122. doi: 10.1002/jor.24821. Epub 2020 Aug 12.

Blackburn JT, Pietrosimone B, Spang JT, Goodwin JS, Johnston CD. Somatosensory Function Influences Aberrant Gait Biomechanics Following Anterior Cruciate Ligament Reconstruction. J Orthop Res. 2020 Mar;38(3):620-628. doi: 10.1002/jor.24495. Epub 2019 Oct 24.

Blackburn T, Pietrosimone B, Goodwin JS, Johnston C, Spang JT. Co-activation during gait following anterior cruciate ligament reconstruction. Clin Biomech (Bristol, Avon). 2019 Jul;67:153-159. doi: 10.1016/j.clinbiomech.2019.05.010. Epub 2019 May 9.