Browsing by Author "Miller, Thomas K."

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    Development and Validation of Clinically Feasible Methods to Assess Landing Mechanics in Patients Following Anterior Cruciate Ligament Reconstruction
    Peebles, Alexander Thomas (Virginia Tech, 2020-06-09)
    Patients returning to sport after anterior cruciate ligament (ACL) reconstruction surgery currently have a high risk for sustaining a second ACL injury and having early signs of knee osteoarthritis. Assessing lower extremity kinetics and kinematics during landing can provide information about a patient's risk for sustaining a second ACL injury and having further joint trauma. However, currently accepted methods to assess kinetics and kinematics are not feasible to use in most non-research settings as they are expensive, time consuming, and take up a lot of space. The goal of this project was to identify methods to assess landing mechanics which are reliable and feasible to use in non-research settings. First, we found that the loadsol®, a wireless force sensing shoe insole, is valid relative to embedded force plates and repeatable between days for assessing kinetics and kinetic symmetry during bilateral and unilateral landing tasks. Second, we developed a new method to collect continuous kinematic data using a low-cost videocamera, disposable markers, and an automated point tracking program. This method was validated against a 3D motion capture system for measuring a fixed angle and for measuring sagittal plane running kinematics. Third, we found that the new video analysis method is valid relative to 3D motion capture and is repeatable between days for assessing frontal and sagittal plane knee kinematics during landing. Finally, we used the loadsol® and automated 2D video analysis to assess landing mechanics in both patients following ACL reconstruction and healthy uninjured control participants in a non-research setting. We found that, relative to controls, patients following ACL reconstruction had reduced kinetic symmetry during bilateral landing, where they offloaded their surgical limb and relied more heavily on their non-surgical limb. Additionally, patients following ACL reconstruction had reduced knee flexion range of motion symmetry during unilateral landing, where they had reduced knee flexion when landing on their surgical limb. Collectively, these projects developed methods to quantitatively assess landing mechanics that are feasible to use in non-research settings, documented the validity and between-day repeatability of these methods, and demonstrated that they could be used to identify kinetic and kinematic deficits in patients following ACL reconstruction. This project is an important step toward being able to assess landing mechanics in patients recovering from an ACL reconstruction.
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    Physical Performance Improves With Time and a Functional Knee Brace in Athletes After ACL Reconstruction
    Dickerson, Laura C.; Peebles, Alexander T.; Moskal, Joseph T.; Miller, Thomas K.; Queen, Robin M. (2020-08)
    Background: Athletes who return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) often have reduced physical performance and a high reinjury rate. Additionally, it is currently unclear how physical performance measures can change during the RTS transition and with the use of a functional knee brace. Purpose/Hypothesis: The purpose of this study was to examine the effects of time since surgery (at RTS and 3 months after RTS) and of wearing a brace on physical performance in patients who have undergone ACLR. We hypothesized that physical performance measures would improve with time and would not be affected by brace condition. Study Design: Controlled laboratory study. Methods: A total of 28 patients who underwent ACLR (9 males, 19 females) completed physical performance testing both after being released for RTS and 3 months later. Physical performance tests included the modified agilityttest (MAT) and vertical jump height, which were completed with and without a knee brace. A repeated-measures analysis of variance determined the effect of time and bracing on performance measures. Results: The impact of the knee brace was different at the 2 time points for the MAT side shuffle (P= .047). Wearing a functional knee brace did not affect any other physical performance measure. MAT times improved for total time (P< .001) and backpedal (P< .001), and vertical jump height increased (P= .002) in the 3 months after RTS. Conclusion: The present study showed that physical performance measures of agility and vertical jump height improved in the first 3 months after RTS. This study also showed that wearing a knee brace did not hinder physical performance.
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    Reduction of Risk Factors for ACL Re-injuries using an Innovative Biofeedback Approach: Rationale and Design
    Queen, Robin M.; Peebles, Alexander T.; Miller, Thomas K.; Savla, Jyoti S.; Ollendick, Thomas H.; Messier, Stephen P.; Williams, DS Blaise III (Elsevier, 2021-06)
    Nearly 1 in 60 adolescent athletes will suffer anterior cruciate ligament (ACL) injuries with 90% of these athletes electing to undergo an ACL reconstruction (ACLR) at an estimated annual cost of $3 billion. While ACLR and subsequent rehabilitation allow these athletes to return to sports, they have a 15-fold increased risk of second ACL injuries. The modification of post-operative rehabilitation to improve movement and loading symmetry using visual and tactile biofeedback could decrease the risk factors for sustaining a second ACL injury. Participants included 40 adolescent ACLR patients who were intending to return to full sport participation. This preliminary randomized controlled trial (RCT) examined the changes in knee extension moment symmetry, a known risk factor for second ACL injuries, during landing from a stop-jump task between the following time-points: pre-intervention, immediate post-intervention, and subsequent follow-up 6-weeks post-intervention. Participants met twice per week for six-weeks (12-session). The intervention included bilateral squat biofeedback (visual and tactile); the attention control group attended weekly educational sessions. This RCT enrolled and randomize 40 participants over a two-and-a-half-year period. All participants were greater than 4.5 months post-op from a primary, unilateral ACLR and were released to participate by their treating physician. The findings from this pilot biofeedback RCT will provide critical effect size estimates for use in subsequent larger clinical trials.