Open Access Publications

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Open access publications by faculty, staff, postdocs, and graduate students from the Biomechanics & Movement Science Program.


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Now showing 1 - 5 of 8
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    Challenging the assumption of uniformity in patellar tendon structure: Regional patellar tendon morphology and mechanical properties in vivo
    (Journal of Orthopaedic Research, 2023-04-08) Ito, Naoaki; Scattone Silva, Rodrigo; Sigurðsson, Haraldur B.; Cortes, Daniel H.; Silbernagel, Karin Grävare
    Patellar tendons are assumed to be uniform in morphology and mechanical properties despite a higher prevalence of tendinopathies observed in the medial region. The purpose of this study was to compare the thickness, length, viscosity, and shear modulus of the medial, central, and lateral regions of healthy patellar tendons of young males and females in vivo. B-mode ultrasound and continuous shear wave elastography were performed on 35 patellar tendons (17 females, 18 males) over three regions of interest. A linear mixed-effects model (α = 0.05) was used to determine differences between the three regions and sexes followed by pairwise comparisons for significant findings. The lateral region (mean [95% confidence interval] = 0.34 [0.31–0.37] cm) was thinner compared with the medial (0.41 [0.39–0.44] cm, p < 0.001), and central (0.41 [0.39–0.44] cm, p < 0.001) regions regardless of sex. Viscosity was lower in the lateral (19.8 [16.9–22.7] Pa-s) versus medial region (27.4 [24.7–30.2] Pa-s, p = 0.001). Length had a region-by-sex interaction (p = 0.003) characterized by a longer lateral (4.83 [4.54–5.13] cm) versus medial (4.42 [4.12–4.72] cm) region in males (p < 0.001), but not females (p = 0.992). Shear modulus was uniform between regions and sexes. The thinner, and less viscous lateral patellar tendon may reflect the lower load the tendon experiences explaining the differences in regional prevalence of developing tendon pathology. Statement of Clinical Significance: Healthy patellar tendons are not uniform in morphology or mechanical properties. Considering regional tendon properties may help guide targeted interventions for patellar tendon pathologies.
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    Clinically relevant subgroups exist among athletes who have ruptured their anterior cruciate ligaments: A Delaware-Oslo Cohort Study
    (Arthritis Care & Research, 2023-03-01) Arhos, Elanna K.; Pohlig, Ryan T.; Di Stasi, Stephanie; Risberg, May Arna; Snyder-Mackler, Lynn; Grävare Silbernagel, Karin
    Objective: To identify subgroups of individuals with anterior cruciate ligament (ACL) injuries based on patient characteristics, self-reported outcomes, and functional performance at baseline, and to associate subgroups with long-term outcomes after ACL rupture. Methods: A total of 293 participants (45.7% male, mean ± SD age 26.2 ± 9.4 years, days from injury 58 ± 35) were enrolled after effusion, pain, and range of motion impairments were resolved and quadriceps strength was at least 70% of the uninvolved limb. Mixture modeling was used to uncover latent subgroups without a prior group classification using probabilistic assignment. Variables include demographics, functional testing, and self-reported outcome measures. Radiographic evidence of osteoarthritis (OA; i.e., Kellgren/Lawrence grade of ≥1) in the involved knee at 5 years after injury was the primary outcome of interest. Chi-square tests assessed differences in the presence of radiographic OA in the involved knee between subgroups at 5 years after ACL rupture. Secondary outcomes of interest included radiographic OA in the uninvolved knee, return to preinjury sport by 2 years, operative status, and clinical OA (classified using Luyten et al criteria) at 5 years. Results: Four distinct subgroups exist after ACL rupture (younger good self-report, younger poor self-report, older poor self-report, older good self-report) with 30%, 31%, 47%, and 53%, respectively, having involved knee OA. The percentage of radiographic OA was not significantly different between the groups (P = 0.059). Conclusion: The prevalence of OA in all subgroups is highly concerning. These results suggest there are unique subgroupings of individuals that may guide treatment after ACL rupture and reconstruction by providing support for developing a patient-centered approach.
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    Comparing an Expanded Versus Brief Telehealth Physical Therapist Intervention for Knee Osteoarthritis: Study Protocol for the Delaware PEAK Randomized Controlled Trial
    (Physical Therapy & Rehabilitation Journal, 2023-02-01) Jakiela, Jason T.; Voinier, Dana; Hinman, Rana S.; Copson, Jennifer; Schmitt, Laura A.; Leonard, Tara R.; Aily, Jéssica B; Bodt, Barry A.; White, Daniel K.
    Objective The purpose of this study is to investigate whether a remotely delivered physical therapist intervention increases physical activity (PA) over 12 weeks, compared with existing web-based resources, in adults with knee osteoarthritis (OA). Methods This will be a single-center, randomized controlled trial with 2 parallel arms: (1) the Expanded Intervention (Delaware PEAK [Physical Exercise and Activity for Knee osteoarthritis]), which includes five 45- to 60-minute video conference-based sessions of supervised exercise (strengthening exercises, step goals) that are remotely delivered over 12 weeks by a physical therapist; or (2) the Brief Intervention (control group), a website that includes prerecorded videos directing participants to web-based resources for strengthening, PA, and pain management for knee OA that are freely available. The trial will enroll 100 participants who meet the National Institute for Health and Care Excellence OA clinical criteria (≥45 years old, have activity-related knee pain, and have no morning stiffness or it lasts ≤30 minutes), reside in the contiguous United States (excluding Alaska and Hawaii), and are seeking to be more physically active. Outcomes include PA (time in moderate-to-vigorous and light PA, steps per day), sedentary behaviors, treatment beliefs, and self-efficacy for exercise. Our primary outcome is moderate-to-vigorous PA. Outcomes will be measured at baseline, 12 weeks, and 24 weeks. Impact This protocol focuses on the remote delivery of physical therapy via telehealth to adults with knee OA and comes at a critical time, because the burden of inactivity is of particular concern in this population. If successful, the findings of this work will provide strong support for the broad implementation of Delaware PEAK, highlight the utility of telehealth in physical therapy, and address the critical need to utilize exercise to manage adults with knee OA through physical therapists.
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    Markerless motion capture: What clinician-scientists need to know right now
    (Journal of Science and Medicine in Sport Plus, 2022-11-14) Ito, Naoaki; Sigurðsson, Haraldur B.; Seymore, Kayla D.; Arhos, Elanna K.; Buchanan, Thomas S.; Snyder-Mackler, Lynn; Gravare Silbernagel, Karin
    Markerless motion capture (mocap) could be the future of motion analysis. The purpose of this report was to describe our team of clinicians and scientists’ exploration of markerless mocap (Theia 3D) and share data for others to explore (link: Simultaneous mocap was performed using markerless and marker-based systems for walking, squatting, and forward hopping. Segment lengths were more variable between trials using markerless mocap compared to marker-based mocap. Sagittal plane angles were most comparable between systems at the knee joint followed by the ankle and hip. Frontal and transverse plane angles were not comparable between systems. The data collection experience using markerless mocap was simpler, faster, and user friendly. The ease of collection was in part offset by the added data transfer and processing times, and the lack of troubleshooting flexibility. If used selectively with proper understanding of limitations, markerless mocap can be exciting technology to advance the field of motion analysis.
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    Reliability of Continuous Shear Wave Elastography in the Pathological Patellar Tendon
    (Journal of Ultrasound in Medicine, 2022-10-27) Ito, Naoaki; Sigurðsson, Haraldur B.; Pohlig, Ryan T.; Cortes, Daniel H.; Grävare Silbernagel, Karin; Sprague, Andrew L.
    Objectives Patellar tendon injuries occur via various mechanisms such as overuse, or due to surgical graft harvest for anterior cruciate ligament reconstruction (ACLR). Quantified patellar tendon stiffness after injury may help guide clinical care. Continuous shear wave elastography (cSWE) allows for the assessment of viscosity and shear modulus in tendons. The reliability of the measure, however, has not been established in the patellar tendon. The purpose of this study was to investigate the interrater reliability, intrarater reliability, and between-day stability of cSWE in both healthy and pathological patellar tendons. Methods Participants with patellar tendinopathy (n = 13), history of ACLR using bone-patellar tendon-bone autograft (n = 9), and with no history of patellar tendon injury (n = 13) were recruited. cSWE was performed 4 times by multiple raters over 2 days. Intraclass correlations (ICC) and minimum detectable change (MDC95%) were calculated. Results Good to excellent between-day stability were found for viscosity (ICC = 0.905, MDC95% = 8.3 Pa seconds) and shear modulus (ICC = 0.805, MDC95% = 27.4 kPa). The interrater reliability measures, however, were not as reliable (ICC = 0.591 and 0.532). Conclusions cSWE is a reliable assessment tool for quantifying patellar tendon viscoelastic properties over time. It is recommended, however, that a single rater performs the measure as the interrater reliability was less than ideal.
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