Publications by authors named "Timothy W Tourville"

44 Publications

Articular cartilage thickness changes differ between males and females 4 years following anterior cruciate ligament reconstruction.

J Orthop Res 2021 Jul 20. Epub 2021 Jul 20.

Department of Rehabilitation and Movement Science, College of Nursing and Health Sciences, University of Vermont, Burlington, Vermont, USA.

Anterior cruciate ligament injury and reconstruction (ACLR) affects articular cartilage thickness profiles about the tibial, femoral, and patellar surfaces; however, it's unclear whether the magnitudes of change in cartilage thickness, as well as the locations and areas over which these changes occur, differ between males and females. This is important to consider as differences exist between the sexes with regard to knee biomechanics, patellofemoral pain, and anatomic alignment, which influence risk of an index and repeated injury. Subjects underwent ACLR with a bone-patella tendon-bone autograft. At 4-year follow-up, they had asymptomatic knees; however, significant ACL injured-to-contralateral normal knee differences in articular cartilage thickness values were observed. Both thickening and thinning of cartilage occurred about the tibiofemoral and patellofemoral joints, relative to matched control subjects with normal knees. Further, the location of the areas and magnitudes of thickening and thinning were different between females and males. Thickening (swelling) of articular cartilage is an early finding associated with the onset of posttraumatic osteoarthritis (PTOA). Therefore, the increases in cartilage thickness that were observed in this cohort may represent early signs of the onset of PTOA that occur prior to the patient developing symptoms and radiographic evidence of this disease. The different locations of areas that underwent a change in cartilage thicknesses between males and females suggest that each sex responds differently to knee ligament trauma, reconstruction, rehabilitation, and return to activity, and indicates that sex-specific analysis should be utilized in studies of PTOA.
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http://dx.doi.org/10.1002/jor.25142DOI Listing
July 2021

Skeletal muscle cellular contractile dysfunction after anterior cruciate ligament reconstruction contributes to quadriceps weakness at 6-month follow-up.

J Orthop Res 2021 May 10. Epub 2021 May 10.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA.

Muscle dysfunction following anterior cruciate ligament reconstruction (ACLR) may evolve from alterations in muscle contractility at the myofilament protein level. Using a prospective, within-subject case-control design, we evaluated cellular-level contractility, cross-sectional area (CSA), and myosin heavy chain (MHC) isoform expression on single muscle fibers 3 weeks post ACLR, and evaluated their relationship to whole muscle strength and patient-oriented outcomes 6 months post operation. Biopsies of the vastus lateralis were performed 3 weeks post ACLR in 11 subjects (5 females, mean age ± SD = 24.7 ± 6.5 years, height = 172.7 ± 8.2 cm, mass = 75.7 ± 12.5 kg) following first-time ACL rupture and whole muscle strength and self-reported pain, function, and quality of life assessed 6 months post ACLR. At 3 weeks post ACLR, force production was reduced (p < 0.01) in MHC I (-36%) and IIA (-48%) fibers compared with the non-injured leg. When force production was expressed relative to CSA to account for fiber atrophy, reductions remained in MHC IIA fibers (-40%; p < 0.001), but MHC I fibers showed only a trend toward being lower (-13%; p = 0.09). Finally, skeletal muscle fiber functional deficits at 3 weeks post ACLR were associated with whole muscle weakness and less favorable patient-reported outcomes at 6-month follow-up. Thus, ACLR promotes early cellular contractile dysfunction that may contribute to decreased whole muscle strength and patient function, and increased patient-reported symptoms, at 6-month follow-up.
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http://dx.doi.org/10.1002/jor.25065DOI Listing
May 2021

Utility of Neuromuscular Electrical Stimulation to Preserve Quadriceps Muscle Fiber Size and Contractility After Anterior Cruciate Ligament Injuries and Reconstruction: A Randomized, Sham-Controlled, Blinded Trial.

Am J Sports Med 2020 08 6;48(10):2429-2437. Epub 2020 Jul 6.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA.

Background: Anterior cruciate ligament (ACL) injuries and reconstruction (ACLR) promote quadriceps muscle atrophy and weakness that can persist for years, suggesting the need for more effective rehabilitation programs. Whether neuromuscular electrical stimulation (NMES) can be used to prevent maladaptations in skeletal muscle size and function is unclear.

Purpose: To examine whether early NMES use, started soon after an injury and maintained through 3 weeks after surgery, can preserve quadriceps muscle size and contractile function at the cellular (ie, fiber) level in the injured versus noninjured leg of patients undergoing ACLR.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Patients (n = 25; 12 men/13 women) with an acute, first-time ACL rupture were randomized to NMES (5 d/wk) or sham (simulated microcurrent electrical nerve stimulation; 5 d/wk) treatment to the quadriceps muscles of their injured leg. Bilateral biopsies of the vastus lateralis were performed 3 weeks after surgery to measure skeletal muscle fiber size and contractility. Quadriceps muscle size and strength were assessed 6 months after surgery.

Results: A total of 21 patients (9 men/12 women) completed the trial. ACLR reduced single muscle fiber size and contractility across all fiber types ( < .01 to < .001) in the injured compared with noninjured leg 3 weeks after surgery. NMES reduced muscle fiber atrophy ( < .01) through effects on fast-twitch myosin heavy chain (MHC) II fibers ( < .01 to < .001). NMES preserved contractility in slow-twitch MHC I fibers ( < .01 to < .001), increasing maximal contractile velocity ( < .01) and preserving power output ( < .01), but not in MHC II fibers. Differences in whole muscle strength between groups were not discerned 6 months after surgery.

Conclusion: Early NMES use reduced skeletal muscle fiber atrophy in MHC II fibers and preserved contractility in MHC I fibers. These results provide seminal, cellular-level data demonstrating the utility of the early use of NMES to beneficially modify skeletal muscle maladaptations to ACLR.

Clinical Relevance: Our results provide the first comprehensive, cellular-level evidence to show that the early use of NMES mitigates early skeletal muscle maladaptations to ACLR.

Registration: NCT02945553 (ClinicalTrials.gov identifier).
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http://dx.doi.org/10.1177/0363546520933622DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775613PMC
August 2020

A Cyber-Physical System for Near Real-Time Monitoring of At-Home Orthopedic Rehabilitation and Mobile-Based Provider-Patient Communications to Improve Adherence: Development and Formative Evaluation.

JMIR Hum Factors 2020 May 11;7(2):e16605. Epub 2020 May 11.

Department of Computer Science, University of Vermont, Burlington, VT, United States.

Background: Knee extensor muscle performance is reduced after lower extremity trauma and orthopedic surgical interventions. At-home use of neuromuscular electrical stimulation (NMES) may improve functional recovery, but adherence to at-home interventions is low. Greater benefits from NMES may be realized with closer monitoring of adherence to at-home prescriptions and more frequent patient-provider interactions.

Objective: This study aimed to develop a cyber-physical system to monitor at-home adherence to NMES prescription and facilitate patient-provider communications to improve adherence in near real time.

Methods: The RehabTracker cyber-physical system was developed to accomplish this goal and comprises four components: (1) hardware modifications to a commercially available NMES therapy device to monitor device use and provide Bluetooth functionality; (2) an iPhone Operating System-based mobile health (mHealth) app that enables patient-provider communications in near real time; (3) a clinician portal to allow oversight of patient adherence with device use; and (4) a back-end server to store data, enable adherence analysis, and send automated push notifications to the patient. These four elements were designed to be fully compliant with the Health Insurance Portability and Accountability Act. The system underwent formative testing in a cohort of patients following anterior cruciate ligament rupture (n=7) to begin to assess face validity.

Results: Compared with the NMES device software-tracked device use, the RehabTracker system recorded 83% (40/48) of the rehabilitation sessions, with 100% (32/32) of all sessions logged by the system in 4 out of 7 patients. In patients for whom tracking of automated push notifications was enabled, 100% (29/29) of the push notifications sent by the back-end server were received by the patient. Process, hardware, and software issues contributing to these inaccuracies are detailed.

Conclusions: RehabTracker represents a promising mHealth app for tracking and improving adherence with at-home NMES rehabilitation programs and warrants further refinement and testing.
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http://dx.doi.org/10.2196/16605DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248795PMC
May 2020

Effect of neuromuscular electrical stimulation on skeletal muscle size and function in patients with breast cancer receiving chemotherapy.

J Appl Physiol (1985) 2020 06 7;128(6):1654-1665. Epub 2020 May 7.

Department of Medicine, University of Vermont, Burlington, Vermont.

Exercise has numerous benefits for patients with cancer, but implementation is challenging because of practical and logistical hurdles. This study examined whether neuromuscular electrical stimulation (NMES) can serve as a surrogate for classic exercise by eliciting an exercise training response in skeletal muscle of women diagnosed with breast cancer undergoing chemotherapy. Patients ( = 22) with histologically confirmed stage I, II, or III breast cancer scheduled to receive neoadjuvant or adjuvant chemotherapy were randomized to 8 wk of bilateral neuromuscular electrical stimulation (NMES; 5 days/wk) to their quadriceps muscles or control. Biopsy of the vastus lateralis was performed at baseline and after 8 wk of intervention to assess muscle fiber size, contractility, and mitochondrial content. Seventeen patients (8 control/9 NMES) completed the trial and were included in analyses. NMES promoted muscle fiber hypertrophy ( < 0.001), particularly in fast-twitch, myosin heavy chain (MHC) IIA fibers ( < 0.05) and tended to induce fiber type shifts in MHC II fibers. The effects of NMES on single-muscle fiber contractility were modest, and it was unable to prevent declines in the function in MHC IIA fibers. NMES did not alter intermyofibrillar mitochondrial content/structure but was associated with reductions in subsarcolemmal mitochondria. Our results demonstrate that NMES induces muscle fiber hypertrophy and fiber type shifts in MHC II fibers but had minimal effects on fiber contractility and promoted reductions in subsarcolemmal mitochondria. Further studies are warranted to evaluate the utility of NMES as an exercise surrogate in cancer patients and other conditions. This is the first study to evaluate whether neuromuscular electrical stimulation (NMES) can be used as an exercise surrogate to improve skeletal muscle fiber size or function in cancer patients receiving treatment. We show that NMES promoted muscle fiber hypertrophy and fiber type shifts but had minimal effects on single-fiber contractility and reduced subsarcolemmal mitochondria.
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http://dx.doi.org/10.1152/japplphysiol.00203.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7311687PMC
June 2020

Open-Source Remote Gait Analysis: A Post-Surgery Patient Monitoring Application.

Sci Rep 2019 11 29;9(1):17966. Epub 2019 Nov 29.

M-Sense Research Group, University of Vermont, Burlington, VT, 05405, USA.

Critical to digital medicine is the promise of improved patient monitoring to allow assessment and personalized intervention to occur in real-time. Wearable sensor-enabled observation of physiological data in free-living conditions is integral to this vision. However, few open-source algorithms have been developed for analyzing and interpreting these data which slows development and the realization of digital medicine. There is clear need for open-source tools that analyze free-living wearable sensor data and particularly for gait analysis, which provides important biomarkers in multiple clinical populations. We present an open-source analytical platform for automated free-living gait analysis and use it to investigate a novel, multi-domain (accelerometer and electromyography) asymmetry measure for quantifying rehabilitation progress in patients recovering from surgical reconstruction of the anterior cruciate ligament (ACL). Asymmetry indices extracted from 41,893 strides were more strongly correlated (r = -0.87, p < 0.01) with recovery time than standard step counts (r = 0.25, p = 0.52) and significantly differed between patients 2- and 17-weeks post-op (p < 0.01, effect size: 2.20-2.96), and controls (p < 0.01, effect size: 1.74-4.20). Results point toward future use of this open-source platform for capturing rehabilitation progress and, more broadly, for free-living gait analysis.
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http://dx.doi.org/10.1038/s41598-019-54399-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884492PMC
November 2019

Combined Injury to the ACL and Lateral Meniscus Alters the Geometry of Articular Cartilage and Meniscus Soon After Initial Trauma.

J Orthop Res 2020 04 19;38(4):759-767. Epub 2019 Nov 19.

Department of Biomechanics, Hospital for Special Surgery, New York, New York.

Combined injury to the anterior cruciate ligament (ACL) and meniscus is associated with earlier onset and increased rates of post-traumatic osteoarthritis compared with isolated ACL injury. However, little is known about the initial changes in joint structure associated with these different types of trauma. We hypothesized that trauma to the ACL and lateral meniscus has an immediate effect on morphometry of the articular cartilage and meniscus about the entire tibial plateau that is more pronounced than an ACL tear without meniscus injury. Subjects underwent magnetic resonance imaging scanning soon after injury and prior to surgery. Those that suffered injury to the ACL and lateral meniscus underwent changes in the lateral compartment (increases in the posterior-inferior directed slopes of the articular cartilage surface, and the wedge angle of the posterior horn of the meniscus) and medial compartment (the cartilage-to-bone height decreased in the region located under the posterior horn of the meniscus, and the thickness of cartilage increased and decreased in the mid and posterior regions of the plateau, respectively). Subjects that suffered an isolated ACL tear did not undergo the same magnitude of change to these articular structures. A majority of the changes in morphometry occurred in the lateral compartment of the knee; however, change in the medial compartment of the knee with a normal appearing meniscus also occurred. Statement of clinical significance: Knee injuries that involve combined trauma to the ACL and meniscus directly affect both compartments of the knee, even if the meniscus and articular cartilage appears normal upon arthroscopic examination. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:759-767, 2020.
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http://dx.doi.org/10.1002/jor.24519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071961PMC
April 2020

Fiber typing human skeletal muscle with fluorescent immunohistochemistry.

J Appl Physiol (1985) 2019 12 7;127(6):1632-1639. Epub 2019 Nov 7.

Departments of Medicine and Molecular Physiology and Biophysics, College of Medicine and College of Nursing and Health Sciences, University of Vermont, Burlington, Vermont.

Skeletal muscle myosin heavy chain (MyHC) fiber type composition is a critical determinant of overall muscle function and health. Various approaches interrogate fiber type at the single cell, but the two most commonly utilized are single-muscle fiber sodium dodecyl sulfate-polyacrylamide gel electrophoresis (smfSDS-PAGE) and fluorescent immunohistochemistry (IHC). Although smfSDS-PAGE is generally considered the "gold standard," IHC is more commonly used because of its time-effectiveness and relative ease. Unfortunately, there is lingering inconsistency on how best to accurately and quickly determine fiber type via IHC and an overall misunderstanding regarding pure fiber type proportions, specifically the abundance of fibers exclusively expressing highly glycolytic MyHC IIX in humans. We therefore ) present information and data showing the low abundance of pure MyHC IIX muscle fibers in healthy human skeletal muscle and ) leverage this information to provide straightforward protocols that are informed by human biology and employ inexpensive, easily attainable antibodies for the accurate determination of fiber type.
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http://dx.doi.org/10.1152/japplphysiol.00624.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957370PMC
December 2019

Risk Factors Associated With a Noncontact Anterior Cruciate Ligament Injury to the Contralateral Knee After Unilateral Anterior Cruciate Ligament Injury in High School and College Female Athletes: A Prospective Study.

Am J Sports Med 2019 12 5;47(14):3347-3355. Epub 2019 Nov 5.

McClure Musculoskeletal Research Center, Department of Orthopedics and Rehabilitation, Robert Larner M.D. College of Medicine, University of Vermont, Burlington, Vermont, USA.

Background: The incidence of contralateral anterior cruciate ligament (CACL) injuries after recovery from a first-time anterior cruciate ligament (ACL) disruption is high in women; however, little is known about the risk factors associated with this trauma.

Hypothesis: Patient characteristics, strength, anatomic alignment, and neuromuscular characteristics of the contralateral uninjured leg at the time of the first ACL trauma are associated with risk of subsequent CACL injury, and these risk factors are distinct from those for a first-time ACL injury.

Study Design: Case-control study; Level of evidence, 3.

Methods: Sixty-one women who suffered a first-time noncontact ACL injury while participating in high school or college sports and underwent measurement of potential risk factors on their contralateral limb soon after the initial ACL injury and before reconstruction were followed until either a CACL injury or an ACL graft injury occurred, or until the last date of contact.

Results: Follow-up information was available for 55 (90.0%) of the 61 athletes and 11 (20.0%) suffered a CACL injury. Younger age, decreased participation in sport before the first ACL disruption, decreased anterior stiffness of the contralateral knee, and increased hip anteversion were associated with increases in the risk of suffering a CACL injury.

Conclusion: A portion of CACL injury risk factors were modifiable (time spent participating in sport and increasing anterior knee stiffness with bracing), while others were nonmodifiable (younger age and increased hip anteversion). The relationship between younger age at the time of an initial ACL injury and increased risk of subsequent CACL trauma may be explained by younger athletes having more years available to be exposed to at-risk activities compared with older athletes. A decrease of anterior stiffness of the knee is linked to decreased material properties and width of the ACL, and this may explain why some women are predisposed to bilateral ACL trauma while others only suffer the index injury. The risk factors for CACL injury are unique to women who suffer bilateral ACL trauma compared with those who suffer unilateral ACL trauma. This information is important for the identification of athletes who may benefit from risk reduction interventions.
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http://dx.doi.org/10.1177/0363546519886260DOI Listing
December 2019

Resistance training-induced gains in knee extensor strength are related to increased neural cell adhesion molecule expression in older adults with knee osteoarthritis.

BMC Res Notes 2019 Sep 18;12(1):595. Epub 2019 Sep 18.

Department of Medicine, College of Medicine, University of Vermont, Burlington, VT, USA.

Objective: Resistance training (RT) can improve whole muscle strength without increasing muscle fiber size or contractility. Neural adaptations, which lead to greater neural activation of muscle, may mediate some of these improvements, particularly in older adults, where motor neuron denervation is common. The purpose of this study was to explore the relationship of neural adaptations, as reflected by neural cell adhesion molecule (NCAM) expression, to improvements in (1) whole muscle strength and (2) muscle fiber size following RT in older adults with knee osteoarthritis. We performed whole muscle strength measurements and immunohistochemical analysis of fiber size, type, and NCAM expression before and after a 14-week RT program.

Results: RT increased whole-muscle strength as measured by 1-repetition maximum (1-RM) leg press (P = 0.01), leg extension (P = 0.03), and knee extensor peak torque (P = 0.050), but did not alter NCAM expression. Greater NCAM expression in myosin heavy chain (MHC) II fibers was associated with greater whole muscle strength gains (knee extensor peak torque r = 0.93; P < 0.01) and greater MHC II fiber size (r = 0.79; P < 0.01). Our results suggest that training-induced NCAM expression, and neural adaptations more generally, may be important for RT-induced morphological and functional improvements in older adults. Trial registration NCT01190046.
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http://dx.doi.org/10.1186/s13104-019-4642-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751848PMC
September 2019

Implementation of the FIFA 11+ Injury Prevention Program by High School Athletic Teams Did Not Reduce Lower Extremity Injuries: A Cluster Randomized Controlled Trial.

Am J Sports Med 2019 10 17;47(12):2844-2852. Epub 2019 Sep 17.

Department of Orthopaedics and Rehabilitation, Robert Larner, MD, College of Medicine, University of Vermont, Burlington, Vermont, USA.

Background: Lower extremity injuries are common in high school sports and are costly, and some have poor outcomes. The FIFA 11+ injury prevention program has been shown to decrease injuries in elite athletes by up to 72%.

Hypothesis: High schools in which coaches implement the FIFA 11+ injury prevention program in their athletic programs will have a decreased incidence of lower extremity injuries compared with schools using their usual prepractice warm-up.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Fourteen high schools that employed an athletic trainer were randomly assigned to either the FIFA 11+ group or control group (usual warm-up routine). Exposure to sports and injuries were recorded and used to determine the incidence rates of lower extremity injuries per athlete-exposure (AE). The FIFA 11+ program was implemented by coaches and complicance with the program recorded.

Results: There were 196 lower extremity injuries among 1825 athletes in the FIFA 11+ group and 172 injuries among 1786 athletes in the control group (1.59 and 1.47 injuries per 1000 AEs, respectively; = .771). The distribution of the types of injury in the 2 groups did not differ, but the body locations where the injuries occurred differed somewhat ( = .051). The FIFA 11+ group had larger proportions of thigh and foot injuries, while the control group had higher proportions of knee and ankle injuries. Group differences in injury rates varied with sport ( = .041 for interaction), but there were no significant differences in injury rates between the FIFA 11+ and control groups by sport, level of play, and sex. In the FIFA 11+ group, 62% of the coaches reported that their teams completed the full FIFA 11+ program at least once a week, and 32% reported that they completed it at least twice a week.

Conclusion: This study did not demonstrate a reduction in lower extremity injuries in schools randomized to use the FIFA 11+ program compared with schools using their usual prepractice warm-up program. Coach-reported compliance with performing the FIFA 11+ program at least twice a week was low.
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http://dx.doi.org/10.1177/0363546519873270DOI Listing
October 2019

Skeletal muscle atrophy and dysfunction in breast cancer patients: role for chemotherapy-derived oxidant stress.

Am J Physiol Cell Physiol 2018 11 12;315(5):C744-C756. Epub 2018 Sep 12.

Department of Medicine, College of Medicine, University of Vermont , Burlington, Vermont.

How breast cancer and its treatments affect skeletal muscle is not well defined. To address this question, we assessed skeletal muscle structure and protein expression in 13 women who were diagnosed with breast cancer and receiving adjuvant chemotherapy following tumor resection and 12 nondiseased controls. Breast cancer patients showed reduced single-muscle fiber cross-sectional area and fractional content of subsarcolemmal and intermyofibrillar mitochondria. Drugs commonly used in breast cancer patients (doxorubicin and paclitaxel) caused reductions in myosin expression, mitochondrial loss, and increased reactive oxygen species (ROS) production in C2C12 murine myotube cell cultures, supporting a role for chemotherapeutics in the atrophic and mitochondrial phenotypes. Additionally, concurrent treatment of myotubes with the mitochondrial-targeted antioxidant MitoQ prevented chemotherapy-induced myosin depletion, mitochondrial loss, and ROS production. In patients, reduced mitochondrial content and size and increased expression and oxidation of peroxiredoxin 3, a mitochondrial peroxidase, were associated with reduced muscle fiber cross-sectional area. Our results suggest that chemotherapeutics may adversely affect skeletal muscle in patients and that these effects may be driven through effects of these drugs on mitochondrial content and/or ROS production.
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http://dx.doi.org/10.1152/ajpcell.00002.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6293050PMC
November 2018

Geometric Characteristics of the Knee Are Associated With a Noncontact ACL Injury to the Contralateral Knee After Unilateral ACL Injury in Young Female Athletes.

Am J Sports Med 2017 Dec 13;45(14):3223-3232. Epub 2017 Oct 13.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA.

Background: Contralateral anterior cruciate ligament (CACL) injury after recovery from a first-time ACL rupture occurs at a high rate in young females; however, little is known about the risk factors associated with bilateral ACL trauma.

Hypothesis: The geometric characteristics of the contralateral knee at the time of the initial ACL injury are associated with risk of suffering a CACL injury in these female athletes.

Study Design: Case-control study; Level of evidence, 3.

Methods: Sixty-two female athletes who suffered their first noncontact ACL injury while participating in sports at the high school or college level were identified, and geometry of the femoral notch, ACL, tibial spines, tibial subchondral bone, articular cartilage surfaces, and menisci of the contralateral, uninjured, knee was characterized in 3 dimensions. We were unable to contact 7 subjects and followed the remaining 55 until either a CACL injury or an ACL graft injury occurred or, if they were not injured, until the date of last contact (mean, 34 months after their first ACL injury). Cox regression was used to identify risk factors for CACL injury.

Results: Ten (18.2%) females suffered a CACL injury. Decreases of 1 SD in femoral intercondylar notch width (measured at its outlet and anterior attachment of the ACL) were associated with increases in the risk of suffering a CACL injury (hazard ratio = 1.88 and 2.05, respectively). Likewise, 1 SD decreases in medial-lateral width of the lateral tibial spine, height of the medial tibial spine, and thickness of the articular cartilage located at the posterior region of the medial tibial compartment were associated with 3.59-, 1.75-, and 2.15-fold increases in the risk of CACL injury, respectively.

Conclusion: After ACL injury, subsequent injury to the CACL is influenced by geometry of the structures that surround the ACL (the femoral notch and tibial spines). This information can be used to identify individuals at increased risk for CACL trauma, who might benefit from targeted risk-reduction interventions.
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http://dx.doi.org/10.1177/0363546517735091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533631PMC
December 2017

Characterization of Prepractice Injury Prevention Exercises of High School Athletic Teams.

Sports Health 2017 Nov/Dec;9(6):511-517. Epub 2017 Oct 6.

Department of Orthopaedics & Rehabilitation, University of Vermont Larner College of Medicine, Burlington, Vermont.

Background: Static and dynamic exercises are performed before activity to decrease injury risk and increase performance. Although evidence supports using dynamic over static stretching and performing Fédération Internationale de Football Association (FIFA) 11+ as a dynamic prepractice routine, we do not know the frequency at which these exercises are utilized in high school populations.

Hypothesis: We hypothesize that there is a wide variety of preparticipation exercises performed by high school athletes, and that few high school teams perform FIFA 11+ as an injury prevention program in its entirety.

Study Design: Observational study.

Level Of Evidence: Level 4.

Methods: High school prepractice routines were observed for 185 teams (football, soccer, basketball, and lacrosse) over 1 season. The percentages of team warm-up routines that included components of FIFA 11+ were calculated, and the chi-square test was used to compare sex, sport, and level of competition.

Results: Of a total 644 warm-up observations, 450 (69.9%) included only non-FIFA 11+ exercises, 56 (8.7%) included at least 1 FIFA 11+ exercise, and 38 (5.9%) included only jogging; 69 (10.6%) consisted only of sport-specific activities. The type of warm-up differed significantly between males and females ( P = 0.002), sports ( P < 0.001), and level of competition ( P < 0.001). Static stretching and athletes stretching on their own were observed in 14% and 15% of all observations. No team performed the FIFA 11+ injury prevention routine in its entirety.

Conclusion: The type of warm-up differed by sex, sport, and level of competition. Static stretching was performed more frequently than anticipated, and an entire FIFA 11+ warm-up was never performed.

Clinical Relevance: We need to identify the exercises that decrease injury and increase performance and better inform the athletic population about the risks and benefits of static and dynamic warm-up programs.
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http://dx.doi.org/10.1177/1941738117733981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5665116PMC
November 2017

The Role of Athletic Trainers in Preventing and Managing Posttraumatic Osteoarthritis in Physically Active Populations: a Consensus Statement of the Athletic Trainers' Osteoarthritis Consortium.

J Athl Train 2017 Jun;52(6):610-623

University of North Carolina at Chapel Hill.

Objective:   To provide athletic trainers with a fundamental understanding of the pathogenesis and risk factors associated with the development of posttraumatic osteoarthritis (PTOA) as well as the best current recommendations for preventing and managing this condition.

Background:   Posttraumatic osteoarthritis, or osteoarthritis that develops secondary to joint injury, accounts for approximately 5.5 million US cases annually. A young athlete with a joint injury is at high risk for PTOA before the age of 40, which could lead to the patient living more than half of his or her life with a painful and disabling disorder. Given our frequent contact with physically active people who often sustain traumatic joint injuries, athletic trainers are in a unique position to help prevent and manage PTOA. We can, therefore, regularly monitor joint health in at-risk patients and implement early therapies as necessary.

Recommendations:   The recommendations for preventing and managing PTOA are based on the best available evidence. Primary injury prevention, self-management strategies, maintenance of a healthy body weight, and an appropriate level of physical activity should be encouraged among those at risk for PTOA after acute traumatic joint injury. Education of athletic trainers and patients regarding PTOA is also critical for effective prevention and management of this disease.
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http://dx.doi.org/10.4085/1062-6050-52.2.04DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5488853PMC
June 2017

Risk of Knee Osteoarthritis Over 24 Months in Individuals Who Decrease Walking Speed During a 12-Month Period: Data from the Osteoarthritis Initiative.

J Rheumatol 2017 08 1;44(8):1265-1270. Epub 2017 Jun 1.

From the Department of Epidemiology, Gillings School of Global Public Health, and the Injury Prevention Research Center, and the Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Division of Rheumatology, Tufts Medical Center, Boston, Massachusetts; Department of Sports Medicine, West Chester University, West Chester, Pennsylvania; Keller Army Community Hospital, West Point, New York; Department of Rehabilitation and Movement Science, University of Vermont, Burlington, Vermont, USA.

Objective: To assess the association between change in walking speed over a 12-month period and risk of developing radiographic knee osteoarthritis (rKOA) over a 24-month period.

Methods: We included participants without rKOA from the Osteoarthritis Initiative. Change in walking speed was determined from a 20-m walk assessment, calculated using walking speed at 12-month followup minus baseline speed and/or 24-month followup walking speed minus 12-month speed. Incident rKOA was defined as progressing to Kellgren-Lawrence arthritis grading scale ≥ 2 within 24 months (i.e., incidence between 12 and 36 mos or 24 and 48 mos). Self-reported significant knee injury during the exposure period, age, body mass index (BMI), and Physical Activity Scale for the Elderly (PASE) score were adjusted for analytically.

Results: We included 2638 observations among 1460 unique participants (58% women; aged 59 ± 9 yrs, range 45-79). The mean change in walking speed over 12 months was 0.001 ± 0.13 m/s (range -0.6271 to 1.4968). About 5% of the sample (n = 122) developed rKOA over a 24-month period. After controlling for significant knee injury, age, BMI, and PASE score, we found an 8% relative increase in risk of developing rKOA for every 0.1 m/s decrease in walking speed over a 12-month period (risk ratio 1.08, 95% CI 1.00-1.15, p = 0.05).

Conclusion: Evaluating change in speed over a 12-month period using a 20-m walk test may be useful in identifying individuals at increased risk of developing rKOA over the subsequent 24 months. Identification of patients at high risk for developing rKOA would allow medical providers to implement early interventions to maximize joint health.
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http://dx.doi.org/10.3899/jrheum.170093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6061917PMC
August 2017

Moderate-intensity resistance exercise alters skeletal muscle molecular and cellular structure and function in inactive older adults with knee osteoarthritis.

J Appl Physiol (1985) 2017 Apr 12;122(4):775-787. Epub 2017 Jan 12.

Department of Medicine, University of Vermont, Burlington, Vermont.

High-intensity resistance exercise (REX) training increases physical capacity, in part, by improving muscle cell size and function. Moderate-intensity REX, which is more feasible for many older adults with disease and/or disability, also increases physical function, but the mechanisms underlying such improvements are not understood. Therefore, we measured skeletal muscle structure and function from the molecular to the tissue level in response to 14 wk of moderate-intensity REX in physically inactive older adults with knee osteoarthritis ( = 17; 70 ± 1 yr). Although REX training increased quadriceps muscle cross-sectional area (CSA), average single-fiber CSA was unchanged because of reciprocal changes in myosin heavy chain (MHC) I and IIA fibers. Intermyofibrillar mitochondrial content increased with training because of increases in mitochondrial size in men, but not women, with no changes in subsarcolemmal mitochondria in either sex. REX increased whole muscle contractile performance similarly in men and women. In contrast, adaptations in single-muscle fiber force production per CSA (i.e., tension) and contractile velocity varied between men and women in a fiber type-dependent manner, with adaptations being explained at the molecular level by differential changes in myosin-actin cross-bridge kinetics and mechanics and single-fiber MHC protein expression. Our results are notable compared with studies of high-intensity REX because they show that the effects of moderate-intensity REX in older adults on muscle fiber size/structure and myofilament function are absent or modest. Moreover, our data highlight unique sex-specific adaptations due to differential cellular and subcellular structural and functional changes. Moderate-intensity resistance training causes sex-specific adaptations in skeletal muscle structure and function at the cellular and molecular levels in inactive older adult men and women with knee osteoarthritis. However, these responses were minimal compared with high-intensity resistance training. Thus adjuncts to moderate-intensity training need to be developed to correct underlying cellular and molecular structural and functional deficits that are at the root of impaired physical function in this mobility-limited population.
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http://dx.doi.org/10.1152/japplphysiol.00830.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407204PMC
April 2017

Geometric Risk Factors Associated With Noncontact Anterior Cruciate Ligament Graft Rupture.

Am J Sports Med 2016 Oct 11;44(10):2537-2545. Epub 2016 Aug 11.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA

Background: Anterior cruciate ligament (ACL) graft rupture occurs at a high rate, especially in young athletes. The geometries of the tibial plateau and femoral intercondylar notch are risk factors for first-time ACL injury; however, little is known about the relationship between these geometries and risk of ACL graft rupture.

Hypothesis: The geometric risk factors for noncontact graft rupture are similar to those previously identified for first-time noncontact ACL injury, and sex-specific differences exist.

Study Design: Case-control study; Level of evidence, 3.

Methods: Eleven subjects who suffered a noncontact ACL graft rupture and 44 subjects who underwent ACL reconstruction but did not experience graft rupture were included in the study. Using magnetic resonance imaging, the geometries of the tibial plateau subchondral bone, articular cartilage, meniscus, tibial spines, and femoral notch were measured. Risk factors associated with ACL graft rupture were identified using Cox regression.

Results: The following were associated with increased risk of ACL graft injury in males: increased posterior-inferior-directed slope of the articular cartilage in the lateral tibial plateau measured at 2 locations (hazard ratio [HR] = 1.50, P = .029; HR = 1.39, P = .006), increased volume (HR = 1.45, P = .01) and anteroposterior length (HR = 1.34, P = .0023) of the medial tibial spine, and increased length (HR = 1.18, P = .0005) and mediolateral width (HR = 2.19, P = .0004) of the lateral tibial spine. In females, the following were associated with increased risk of injury: decreased volume (HR = 0.45, P = .02) and height (HR = 0.46, P = .02) of the medial tibial spine, decreased slope of the lateral tibial subchondral bone (HR = 0.72, P = .01), decreased height of the posterior horn of the medial meniscus (HR = 0.09, P = .001), and decreased intercondylar notch width at the anterior attachment of the ACL (HR = 0.72, P = .02).

Conclusion: The geometric risk factors for ACL graft rupture are different for males and females. For females, a decreased femoral intercondylar notch width and a decreased height of the posterior medial meniscus were risk factors for ACL graft rupture that have also been found to be risk factors for first-time injury. There were no risk factors in common between ACL graft injury and first-time ACL injury for males.
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http://dx.doi.org/10.1177/0363546516657525DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6604045PMC
October 2016

Multivariate Analysis of the Risk Factors for First-Time Noncontact ACL Injury in High School and College Athletes: A Prospective Cohort Study With a Nested, Matched Case-Control Analysis.

Am J Sports Med 2016 Jun 29;44(6):1492-501. Epub 2016 Mar 29.

McClure Musculoskeletal Research Center, Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA

Background: Multivariate analysis that identifies the combination of risk factors associated with anterior cruciate ligament (ACL) trauma is important because it provides insight into whether a variable has a direct causal effect on risk or an indirect effect that is mediated by other variables. It can also reveal risk factors that might not be evident in univariate analyses; if a variable's effect is moderated by other variables, its association with risk may be apparent only after adjustment for the other variables. Most important, multivariate analyses can identify combinations of risk factors that are more predictive of risk than individual risk factors.

Hypothesis: A diverse combination of risk factors predispose athletes to first-time noncontact ACL injury, and these relationships are different for male and female athletes.

Study Design: Case-control study; Level of evidence, 3.

Methods: Athletes competing in organized sports at the high school and college levels participated in this study. Data from injured subjects (109 suffering an ACL injury) and matched controls (227 subjects) from the same athletic team were analyzed with multivariate conditional logistic regression to examine the effects of combinations of variables (demographic characteristics, joint laxity, lower extremity alignment, strength, and personality traits) on the risk of suffering their first ACL injury and to construct risk models.

Results: For male athletes, increases in anterior-posterior displacement of the tibia relative to the femur (knee laxity), posterior knee stiffness, navicular drop, and a decrease in standing quadriceps angle were jointly predictive of suffering an ACL injury. For female athletes the combined effects of having a parent who had suffered an ACL injury and increases in anterior-posterior knee laxity and body mass index were predictive of ACL injury.

Conclusion: Multivariate models provided more information about ACL injury risk than individual risk factors. Both male and female risk models included increased anterior-posterior knee laxity as a predictor of ACL injury but were otherwise dissimilar.
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http://dx.doi.org/10.1177/0363546516634682DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533630PMC
June 2016

Skeletal muscle fiber size and fiber type distribution in human cancer: Effects of weight loss and relationship to physical function.

Clin Nutr 2016 12 8;35(6):1359-1365. Epub 2016 Mar 8.

Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, USA.

Background & Aims: Cancer patients frequently experience weight loss, with negative consequences for functionality and prognosis. The extent to which muscle atrophy contributes to weight loss, however, is not clear, as few studies have directly measured muscle fiber morphology in cancer patients.

Methods: Whole body and regional tissue composition were measured, along with the cross-sectional area (CSA) and fiber type of mechanically-isolated, single muscle fibers, in 19 cancer patients (8 with a history of weight loss, 11 weight-stable) and 15 non-diseased controls.

Results: Whole body fat mass was reduced in cancer patients with a history of weight loss, but no differences in whole body or leg fat-free mass were apparent. In contrast, reductions (∼20%) in single muscle fiber CSA were found in both slow-twitch, myosin heavy chain (MHC) I and fast-twitch, MHC IIA fibers in both weight-stable patients and those with a history of weight loss. Fiber type distribution showed a shift towards a fast-twitch phenotype compared to controls, which may preserve muscle function in cancer patients despite atrophy, as positive relationships were found between the fractions of hybrid MHC IIAX and I/IIA fibers and 6-min walk performance.

Conclusions: Our results suggest that, although not apparent from whole body or regional measurements, cancer is associated with reduced skeletal muscle fiber size independent of weight loss history and a shift towards fast-twitch fibers, phenotypes that resemble adaptations to muscle disuse.
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http://dx.doi.org/10.1016/j.clnu.2016.02.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411286PMC
December 2016

Evaluation of an Algorithm to Predict Menstrual-Cycle Phase at the Time of Injury.

J Athl Train 2016 Jan 25;51(1):47-56. Epub 2016 Jan 25.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington.

Context: Women are 2 to 8 times more likely to sustain an anterior cruciate ligament (ACL) injury than men, and previous studies indicated an increased risk for injury during the preovulatory phase of the menstrual cycle (MC). However, investigations of risk rely on retrospective classification of MC phase, and no tools for this have been validated.

Objective: To evaluate the accuracy of an algorithm for retrospectively classifying MC phase at the time of a mock injury based on MC history and salivary progesterone (P4) concentration.

Design: Descriptive laboratory study.

Setting: Research laboratory.

Participants: Thirty-one healthy female collegiate athletes (age range, 18-24 years) provided serum or saliva (or both) samples at 8 visits over 1 complete MC.

Main Outcome Measure(s): Self-reported MC information was obtained on a randomized date (1-45 days) after mock injury, which is the typical timeframe in which researchers have access to ACL-injured study participants. The MC phase was classified using the algorithm as applied in a stand-alone computational fashion and also by 4 clinical experts using the algorithm and additional subjective hormonal history information to help inform their decision. To assess algorithm accuracy, phase classifications were compared with the actual MC phase at the time of mock injury (ascertained using urinary luteinizing hormone tests and serial serum P4 samples). Clinical expert and computed classifications were compared using κ statistics.

Results: Fourteen participants (45%) experienced anovulatory cycles. The algorithm correctly classified MC phase for 23 participants (74%): 22 (76%) of 29 who were preovulatory/anovulatory and 1 (50%) of 2 who were postovulatory. Agreement between expert and algorithm classifications ranged from 80.6% (κ = 0.50) to 93% (κ = 0.83). Classifications based on same-day saliva sample and optimal P4 threshold were the same as those based on MC history alone (87.1% correct). Algorithm accuracy varied during the MC but at no time were both sensitivity and specificity levels acceptable.

Conclusions: These findings raise concerns about the accuracy of previous retrospective MC-phase classification systems, particularly in a population with a high occurrence of anovulatory cycles.
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http://dx.doi.org/10.4085/1062-6050-51.3.01DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4851128PMC
January 2016

Relationship between synovial fluid biomarkers of articular cartilage metabolism and the patient's perspective of outcome depends on the severity of articular cartilage damage following ACL trauma.

J Orthop Res 2016 05 25;34(5):820-7. Epub 2015 Nov 25.

Department of Orthopaedics & Rehabilitation, University of Vermont College of Medicine, Burlington, Vermont.

Anterior cruciate ligament (ACL) trauma often occurs in combination with injury to the articular cartilage of the knee, this can result in earlier radiographic evidence of post traumatic osteoarthritis (OA) of the knee compared to the contralateral, ACL intact knee; however, the biomechanical and biological mechanisms associated with the onset and progression of this disease are not understood. We sought to gain insight into the mechanisms by determining the relationship between articular cartilage injury associated with ACL trauma and the expression of synovial fluid biomarkers of articular cartilage metabolism, and to evaluate the relationship between these biomarkers and the patient's perspective of the outcomes. Synovial fluid samples were acquired from 39 ACL injured subjects at an average of 10 weeks after injury, and 32 control subjects with normal knees (documented with clinical exam and MRI assessment). Subjects in the ACL-injured group were classified as low-risk for future OA if they displayed an International Cartilage Repair Society (ICRS) Grade 2 articular cartilage lesion or less and high-risk for future OA if they had an ICRS Grade 3A articular cartilage lesion. The patient's perspective of the injury was evaluated with the Knee Injury and Osteoarthritis Outcomes Score (KOOS). There were no significant differences in mean concentrations of the markers of type II collagen metabolism (CPII, C2C, and C1,2C) or the aggrecan breakdown Alanine-Arginine-Glycine-Serine (ARGS) -fragment between control subjects and the subjects in the low- and high-risk groups (p-value range: 0.80-0.43). Associations between ARGS-aggrecan concentration and KOOS subscales of symptoms and pain were significantly different between the low- and high-risk groups (p = 0.03 and p = 0.01, respectively). Likewise, there was strong evidence in support of an association between the markers of type II collagen metabolism (C1,2C and CPII concentrations) and the KOOS subscale of pain between the low- and high-risk groups (p = 0.051 and 0.077, correspondingly). In ACL injured subjects with concomitant Grade 3A articular cartilage injuries, concentrations of synovial fluid ARGS-aggrecan were directly associated with improvements in KOOS symptoms and pain. These findings suggest the possible involvement of ARGS-aggrecan in a localized tissue repair response involving an increase in aggrecan turnover following severe knee trauma. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:820-827, 2016.
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http://dx.doi.org/10.1002/jor.23084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533635PMC
May 2016

Reduced rate of knee extensor torque development in older adults with knee osteoarthritis is associated with intrinsic muscle contractile deficits.

Exp Gerontol 2015 Dec 3;72:16-21. Epub 2015 Sep 3.

Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, United States; Department of Orthopaedics and Rehabilitation, University of Vermont, College of Medicine, Burlington, VT, United States; Department of Molecular Physiology and Biophysics, University of Vermont, College of Medicine, Burlington, VT, United States. Electronic address:

We examined the effect of knee osteoarthritis on the rate of torque development (RTD) of the knee extensors in older adults with advanced-stage knee osteoarthritis (OA; n=15) and recreationally-active controls (n=15) of similar age, sex and health status, as well as the relationship between RTD and the size and contractility of single muscle fibers. OA participants had lower RTD when expressed in absolute terms (Nm/ms). There were sex differences in peak RTD (P<0.05), with greater RTD in men, but no group by sex interaction effects for any variables. The lower RTD in OA versus controls was not explained by variation between groups in the fiber type admixture of the muscle, and was mitigated when RTD was normalized to peak torque (PT). In knee OA volunteers, we found strong correlations between the RTD expressed relative to PT and the velocity of contraction of single myosin heavy chain (MHC) I and IIA/X muscle fibers (r=0.652 and 0.862; both P<0.05) and power output of MHC I fibers (r=0.642; P<0.05). In controls, RTD relative to PT was related to fiber cross-sectional area of MHC IIA/X fibers (r=0.707; P<0.05), but not measures of single fiber contractile performance. To our knowledge, these results represent the first demonstration that variation in whole muscle contractile kinetics in patients with advanced-stage knee osteoarthritis and healthy older adults is related, in part, to the size and function of single muscle fibers.
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http://dx.doi.org/10.1016/j.exger.2015.08.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4654635PMC
December 2015

Relationship between synovial fluid ARGS-aggrecan fragments, cytokines, MMPs, and TIMPs following acute ACL injury: A cross-sectional study.

J Orthop Res 2015 Dec 17;33(12):1796-803. Epub 2015 Jul 17.

Department of Orthopaedics and Rehabilitation, University of Vermont College of Medicine, Burlington, Vermont.

Severe knee trauma, such as an ACL disruption, produces aggrecan degradation as evidenced by elevated synovial fluid (SF) N-terminal (393) Alanine-Arginine-Glycine-Serine (ARGS) neoepitope (or ARGS-aggrecan) and is associated with inflammatory activity soon after injury. However, it is not known if this process persists for a substantial time interval following the initial trauma. The purpose of this study was to evaluate relationships between SF ARGS concentrations and an array of cytokines, matrix metalloproteases (MMPs), and tissue inhibitor of metalloproteases (TIMPs) during the initial 6 months following ACL rupture. SF samples from 67 ACL-injured subjects (29 women) were analyzed within 6 months of injury (18-155 days), immediately prior to surgical ACL reconstruction. Relationships between ARGS and individual analyte concentrations, as well as MMP/TIMP ratios were evaluated. Statistically significant relationships were found between ARGS and basic fibroblast growth factor (FGF2) (p=0.03) and TIMP-3 (p=0.01). Our findings suggest that FGF2, considered to be primarily catabolic in articular cartilage, is not downregulated as ARGS concentration declines over time since injury. In addition, these results support the hypothesis that an upregulation of TIMP-3, the primary aggrecanase inhibitor, is elicited in response to increased aggrecan degradation, which may inhibit further cleavage.
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http://dx.doi.org/10.1002/jor.22961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5508558PMC
December 2015

Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function.

Am J Physiol Cell Physiol 2015 Jun 25;308(11):C932-43. Epub 2015 Mar 25.

Department of Medicine, College of Medicine, University of Vermont, Burlington, Vermont; Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont, Burlington, Vermont; and

In older adults, we examined the effect of chronic muscle disuse on skeletal muscle structure at the tissue, cellular, organellar, and molecular levels and its relationship to muscle function. Volunteers with advanced-stage knee osteoarthritis (OA, n = 16) were recruited to reflect the effects of chronic lower extremity muscle disuse and compared with recreationally active controls (n = 15) without knee OA but similar in age, sex, and health status. In the OA group, quadriceps muscle and single-fiber cross-sectional area were reduced, with the largest reduction in myosin heavy chain IIA fibers. Myosin heavy chain IIAX fibers were more prevalent in the OA group, and their atrophy was sex-specific: men showed a reduction in cross-sectional area, and women showed no differences. Myofibrillar ultrastructure, myonuclear content, and mitochondrial content and morphology generally did not differ between groups, with the exception of sex-specific adaptations in subsarcolemmal (SS) mitochondria, which were driven by lower values in OA women. SS mitochondrial content was also differently related to cellular and molecular functional parameters by sex: greater SS mitochondrial content was associated with improved contractility in women but reduced function in men. Collectively, these results demonstrate sex-specific structural phenotypes at the cellular and organellar levels with chronic disuse in older adults, with novel associations between energetic and contractile systems.
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http://dx.doi.org/10.1152/ajpcell.00014.2015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4451348PMC
June 2015

Effects of balance-specific exercises on balance, physical activity and quality of life in adults with multiple sclerosis: a pilot investigation.

Disabil Rehabil 2015 4;37(24):2238-49. Epub 2015 Mar 4.

b Department of Orthopaedics and Rehabilitation , University of Vermont , Burlington , VT , USA.

Objective: To evaluate the efficacy of functional balance exercises on balance impairment, physical activity and quality of life (QOL) in adults with multiple sclerosis (MS).

Design: A multiple-baseline time-series design with an uncontrolled intervention.

Method: Ten subjects with MS completed assessments twice before and once after a 10-week balance intervention. ANOVA were used to evaluate the effects of testing session on the Brief-BESTest, instrumented stance and gait recordings by inertial motion sensors, lower-limb strength recorded by force transducers, accelerometry-based activity, the 12-item MS Walking Scale (MSWS-12), the Multiple Sclerosis Quality of Life-54 (MSQOL-54) questionnaire, the Modified Fatigue Impact scale (MFIS) and the Activity-specific Balance Confidence (ABC) scale.

Results: The intervention associated with significantly improved scores on the MSQOL-54 mental component, MFIS, MSWS-12 and Brief-BESTest. Sway amplitude significantly decreased and jerk significantly increased during instrumented standing on foam with eyes closed. Instrumented gait recordings of sagittal trunk range of motion also significantly decreased. ABC scores, strength measures and activity measures were not significantly changed.

Conclusions: Ten weeks of functional balance exercises provided a feasible intervention for individuals with MS that improved components of balance, mental well-being and perceived fatigue impact and ambulation disability. A future randomized, controlled clinical trial should confirm these preliminary findings. Implications for Rehabilitation A balance-specific exercise program is both safe and feasible for individuals with mild-to-moderate MS. Comprehensive exercise interventions that are conceptually driven and employ well-designed progressive exercise across multiple contexts of balance control can facilitate improvements in balance impairments associated with MS. Functional balance exercises can positively impact clinical and objective measures of balance control and favorably influence perceptions of ambulation disability and fatigue as well as perceived quality of life in people with MS.
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http://dx.doi.org/10.3109/09638288.2015.1019008DOI Listing
July 2016

Combined anatomic factors predicting risk of anterior cruciate ligament injury for males and females.

Am J Sports Med 2015 Apr 12;43(4):839-47. Epub 2015 Jan 12.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA

Background: Knee joint geometry has been associated with risk of suffering an anterior cruciate ligament (ACL) injury; however, few studies have utilized multivariate analysis to investigate how different aspects of knee joint geometry combine to influence ACL injury risk.

Hypotheses: Combinations of knee geometry measurements are more highly associated with the risk of suffering a noncontact ACL injury than individual measurements, and the most predictive combinations of measurements are different for males and females.

Study Design: Case-control study; Level of evidence, 3.

Methods: A total of 88 first-time, noncontact, grade III ACL-injured subjects and 88 uninjured matched-control subjects were recruited, and magnetic resonance imaging data were acquired. The geometry of the tibial plateau subchondral bone, articular cartilage, and meniscus; geometry of the tibial spines; and size of the femoral intercondylar notch and ACL were measured. Multivariate conditional logistic regression was used to develop risk models for ACL injury in females and males separately.

Results: For females, the best fitting model included width of the femoral notch at its anterior outlet and the posterior-inferior-directed slope of the lateral compartment articular cartilage surface, where a millimeter decrease in notch width and a degree increase in slope were independently associated with a 50% and 32% increase in risk of ACL injury, respectively. For males, a model that included ACL volume and the lateral compartment posterior meniscus to subchondral bone wedge angle was most highly associated with risk of ACL injury, where a 0.1 cm3 decrease in ACL volume (approximately 8% of the mean value) and a degree decrease in meniscus wedge angle were independently associated with a 43% and 23% increase in risk, correspondingly.

Conclusion: Combinations of knee joint geometry measurements provided more information about the risk of noncontact ACL injury than individual measures, and the aspects of geometry that best explained the relationship between knee geometry and the risk of injury were different between males and females. Consequently, a female with both a decreased femoral notch width and an increased posterior-inferior-directed lateral compartment tibial articular cartilage slope combined or a male with a decreased ACL volume and decreased lateral compartment posterior meniscus angle were most at risk for sustaining an ACL injury.
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http://dx.doi.org/10.1177/0363546514563277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6607022PMC
April 2015

Tibial articular cartilage and meniscus geometries combine to influence female risk of anterior cruciate ligament injury.

J Orthop Res 2014 Nov 6;32(11):1487-94. Epub 2014 Aug 6.

Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont.

Tibial plateau subchondral bone geometry has been associated with the risk of sustaining a non-contact ACL injury; however, little is known regarding the influence of the meniscus and articular cartilage interface geometry on risk. We hypothesized that geometries of the tibial plateau articular cartilage surface and meniscus were individually associated with the risk of non-contact ACL injury. In addition, we hypothesized that the associations were independent of the underlying subchondral bone geometry. MRI scans were acquired on 88 subjects that suffered non-contact ACL injuries (27 males, 61 females) and 88 matched control subjects that were selected from the injured subject's teammates and were thus matched on sex, sport, level of play, and exposure to risk of injury. Multivariate analysis of the female data revealed that increased posterior-inferior directed slope of the middle articular cartilage region and decreased height of the posterior horn of the meniscus in the lateral compartment were associated with increased risk of sustaining a first time, non-contact ACL injury, independent of each other and of the slope of the tibial plateau subchondral bone. No measures were independently related to risk of non-contact ACL injury among males.
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http://dx.doi.org/10.1002/jor.22702DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886124PMC
November 2014
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