Browsing by Author "Spritzer, Charles E"

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    In Vivo Assessment of Exercise-Induced Glenohumeral Cartilage Strain.
    (Orthopaedic journal of sports medicine, 2018-07-13) Zhang, Hanci; Heckelman, Lauren N; Spritzer, Charles E; Owusu-Akyaw, Kwadwo A; Martin, John T; Taylor, Dean C; Moorman, CT; Garrigues, Grant E; DeFrate, Louis E
    The human shoulder joint is the most mobile joint in the body. While in vivo shoulder kinematics under minimally loaded conditions have been studied, it is unclear how glenohumeral cartilage responds to high-demand loaded exercise.A high-demand upper extremity exercise, push-ups, will induce compressive strain in the glenohumeral articular cartilage, which can be measured with validated magnetic resonance imaging (MRI)-based techniques.Descriptive laboratory study.High-resolution MRI was used to measure in vivo glenohumeral cartilage thickness before and after exercise among 8 study participants with no history of upper extremity injury or disease. Manual MRI segmentation and 3-dimensional modeling techniques were used to generate pre- and postexercise thickness maps of the humeral head and glenoid cartilage. Strain was calculated as the difference between pre- and postexercise cartilage thickness, normalized to the pre-exercise cartilage thickness.Significant compressive cartilage strains of 17% ± 6% and 15% ± 7% (mean ± 95% CI) were detected in the humeral head and glenoid cartilage, respectively. The anterior region of the glenoid cartilage experienced a significantly higher mean strain (19% ± 6%) than the posterior region of the glenoid cartilage (12% ± 8%). No significant regional differences in postexercise humeral head cartilage strain were observed.Push-ups induce compressive strain on the glenohumeral joint articular cartilage, particularly at the anterior glenoid. This MRI-based methodology can be applied to further the understanding of chondral changes in the shoulder under high-demand loading conditions.These results improve the understanding of healthy glenohumeral cartilage mechanics in response to loaded upper extremity exercise. In the future, these methods can be applied to identify which activities induce high glenohumeral cartilage strains and deviations from normal shoulder function.
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    In vivo cartilage strain increases following medial meniscal tear and correlates with synovial fluid matrix metalloproteinase activity
    (JOURNAL OF BIOMECHANICS, 2015-06-01) Carter, Teralyn E; Taylor, Kevin A; Spritzer, Charles E; Utturkar, Gangadhar M; Taylor, Dean C; Moorman, Claude T; Garrett, William E; Guilak, Farshid; McNulty, Amy L; DeFrate, Louis E
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    Lumbar intervertebral disc diurnal deformations and T2 and T1rho relaxation times vary by spinal level and disc region.
    (European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2022-03) Martin, John T; Oldweiler, Alexander B; Kosinski, Andrzej S; Spritzer, Charles E; Soher, Brian J; Erickson, Melissa M; Goode, Adam P; DeFrate, Louis E

    Purpose

    Magnetic resonance imaging (MRI) is routinely used to evaluate spine pathology; however, standard imaging findings weakly correlate to low back pain. Abnormal disc mechanical function is implicated as a cause of back pain but is not assessed using standard clinical MRI. Our objective was to utilize our established MRI protocol for measuring disc function to quantify disc mechanical function in a healthy cohort.

    Methods

    We recruited young, asymptomatic volunteers (6 male/6 female; age 18-30 years; BMI < 30) and used MRI to determine how diurnal deformations in disc height, volume, and perimeter were affected by spinal level, disc region, MRI biomarkers of disc health (T2, T1rho), and Pfirrmann grade.

    Results

    Lumbar discs deformed by a mean of -6.1% (95% CI: -7.6%, -4.7%) to -8.0% (CI: -10.6%, -5.4%) in height and -5.4% (CI: -7.6%, -3.3%) to -8.5% (CI: -11.0%, -6.0%) in volume from AM to PM across spinal levels. Regional deformations were more uniform in cranial lumbar levels and concentrated posteriorly in the caudal levels, reaching a maximum of 13.1% at L5-S1 (CI:-16.1%, -10.2%). T2 and T1rho relaxation times were greatest in the nucleus and varied circumferentially within the annulus. T2 relaxation times were greatest at the most cranial spinal levels and decreased caudally. In this young healthy cohort, we identified a weak association between nucleus T2 and the diurnal change in the perimeter.

    Conclusions

    Spinal level is a key factor in determining regional disc deformations. Interestingly, deformations were concentrated in the posterior regions of caudal discs where disc herniation is most prevalent.
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    Quantifying the biochemical state of knee cartilage in response to running using T1rho magnetic resonance imaging.
    (Scientific reports, 2020-02-05) Heckelman, Lauren N; Smith, Wyatt AR; Riofrio, Alexie D; Vinson, Emily N; Collins, Amber T; Gwynn, Olivia R; Utturkar, Gangadhar M; Goode, Adam P; Spritzer, Charles E; DeFrate, Louis E
    Roughly 20% of Americans run annually, yet how this exercise influences knee cartilage health is poorly understood. To address this question, quantitative magnetic resonance imaging (MRI) can be used to infer the biochemical state of cartilage. Specifically, T1rho relaxation times are inversely related to the proteoglycan concentration in cartilage. In this study, T1rho MRI was performed on the dominant knee of eight asymptomatic, male runners before, immediately after, and 24 hours after running 3 and 10 miles. Overall, (mean ± SEM) patellar, tibial, and femoral cartilage T1rho relaxation times significantly decreased immediately after running 3 (65 ± 3 ms to 62 ± 3 ms; p = 0.04) and 10 (69 ± 4 ms to 62 ± 3 ms; p < 0.001) miles. No significant differences between pre-exercise and recovery T1rho values were observed for either distance (3 mile: p = 0.8; 10 mile: p = 0.08). Percent decreases in T1rho relaxation times were significantly larger following 10 mile runs as compared to 3 mile runs (11 ± 1% vs. 4 ± 1%; p = 0.02). This data suggests that alterations to the relative proteoglycan concentration of knee cartilage due to water flow are mitigated within 24 hours of running up to 10 miles. This information may inform safe exercise and recovery protocols in asymptomatic male runners by characterizing running-induced changes in knee cartilage composition.