Publications by authors named "Bruce D Beynnon"

116 Publications

Compliance and Fidelity With an Injury Prevention Exercise Program in High School Athletics.

Sports Health 2021 Sep 7:19417381211043120. Epub 2021 Sep 7.

McClure Musculoskeletal Research Center, Department of Orthopaedics and Rehabilitation, Larner College of Medicine, University of Vermont, Burlington, Vermont.

Background: Use of injury prevention programs (IPPs) by high school athletes has increased but their success in reducing injury depends on program compliance and fidelity of exercise performance.

Hypothesis: Compliance with the 11+ IPP and exercise performance fidelity by high school athletic teams depend on sex, sport, and level of play.

Study Design: Secondary analyses of data from a randomized controlled trial (RCT).

Level Of Evidence: Level 2.

Methods: The 11+ IPP was implemented by 100 male and female high school athletic teams (American football, soccer, basketball, and lacrosse). Team compliance and fidelity with the program were evaluated by direct observation of warm-up routines and a weekly online survey completed by coaches. Differences in compliance and fidelity due to sport, sex, and level of play were assessed by analysis of variance.

Results: Coaches reported that their teams performed the full IPP an average of 1.45 times per week, and 28% of observed warm-ups included all exercises in the IPP. Compliance differed by sport but not by level of play or the athletes' sex. At the end of the season, cueing was observed 19% of the time and differed by sport. Good technique was observed 66% of the time and varied by level of play.

Conclusion: Team compliance with the IPP varied by sport and was below the recommended number of sessions per week needed to reduce injury. Removal of implementation barriers and improved support from coaches are needed at all levels of play for IPPs to be effective.

Clinical Relevance: Clinical and sports practitioners intending to implement an IPP at the high school level should anticipate and address barriers that affect program compliance and fidelity of exercise performance. Frequent follow-up and instruction may be necessary for successful adoption of the IPP.
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http://dx.doi.org/10.1177/19417381211043120DOI Listing
September 2021

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

Association of Geometric Characteristics of Knee Anatomy (Alpha Angle and Intercondylar Notch Type) With Noncontact ACL Injury.

Am J Sports Med 2021 08 8;49(10):2624-2630. Epub 2021 Jul 8.

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

Background: The femoral intercondylar notch type and the alpha angle (the angle between the femoral notch roof and the long axis of the femur) are easily measured in clinical settings; however, their associations with anterior cruciate ligament (ACL) injury remain unclear.

Hypothesis/purpose: The purpose was to determine if the alpha angle and the femoral notch type are associated with noncontact ACL injury univariately and in combination with previously identified knee geometric risk factors. We hypothesized that the alpha angle and the femoral notch type are associated with noncontact ACL injury and that the association differs between men and women.

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

Methods: The alpha angle and the femoral notch type were measured via 3T magnetic resonance imaging (MRI) acquired from 61 women and 25 men with a first-time noncontact ACL injury. Each injured patient was matched with a control participant based on age, sex, and participation on the same sports team. A conditional logistic regression was used to assess univariate associations with ACL injury as well as multivariate associations using MRI-based risk factors of knee geometry identified in previous analyses: femoral intercondylar notch width at the anterior outlet, femoral intercondylar notch anteromedial ridge thickness, volume of the ACL, tibial plateau lateral compartment subchondral bone slope, lateral compartment middle articular cartilage slope, lateral compartment meniscus-cartilage height, lateral compartment meniscus-bone angle, and medial tibial spine volume.

Results: For female athletes, the alpha angle (odds ratio, [OR], 1.82 per 1-degree increase; = .001), the tibial lateral compartment articular cartilage slope (OR, 1.25 per 1-degree increase in the posterior-inferior directed slope; = .022), and the femoral notch anteromedial ridge thickness (OR, 3.36 per 1-mm increase; = .027) were independently associated with ACL disruption. For men, no other variables entered the models after the alpha angle was inputted as the first step (OR, 2.19 per 1-degree increase; = .010).

Conclusion: For women, ACL injury was most strongly associated with increased alpha angle, increased tibial plateau slope, and increased femoral notch ridge thickness. For men, increased alpha angle was the most significant factor associated with ACL injury. The mechanism of injury might be associated with a combination of impingement of the ACL against the bone and increased ligament loading.
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http://dx.doi.org/10.1177/03635465211023750DOI Listing
August 2021

Clinical-Grade MRI-Based Methods to Identify Combined Anatomic Factors That Predict ACL Injury Risk in Male and Female Athletes.

Am J Sports Med 2021 08 8;49(10):2615-2623. Epub 2021 Jul 8.

Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.

Background: Recently developed multivariate sex-specific statistical models can predict anterior cruciate ligament (ACL) injury risk using various knee anatomic factors. However, screening tools able to identify individuals at an increased injury risk are unlikely to be developed based on these models, given that sophisticated and time-consuming methods were used to measure those factors on research-grade resolution magnetic resonance images (MRIs).

Purpose: To determine whether simpler methods, amenable to using clinical-grade resolution MRIs, can identify the same knee anatomic factors previously found to contribute to ACL injury risk using sophisticated methods and research-grade resolution images.

Study Design: Cohort study (diagnosis); Level of evidence, 2.

Methods: High-resolution 3-dimensional MRIs previously acquired from 87 patients with primary, noncontact, grade III ACL injury and 87 uninjured matched control participants for a series of published studies were downgraded to clinical-grade resolution images. The 4 knee anatomic factors found to contribute to ACL injury risk in women and in men in these published studies-femoral intercondylar notch width at the anterior outlet of the ACL (NW_O), posterior-inferior directed slope of the middle region articular cartilage surface of the tibial plateau's lateral compartment (LTMCS), ACL volume, and tibial plateau's lateral compartment posterior meniscus to subchondral bone wedge angle (LTMBA)-were measured using clinical-grade resolution MRI-based methods. Stepwise multivariate conditional logistic regressions were used to identify the combinations of factors most highly associated with an ACL injury risk in women and men separately.

Results: The multivariate model that best predicted ACL injury risk in the female participants included the LTMCS and the NW_O. For the male participants, this model included the ACL volume and the LTMBA. These results corroborate the previously published results that reported models with the same knee anatomic factors to best predict injury risk in this group of young women and men.

Conclusion: Simpler methods using MRIs downgraded to a clinical-grade resolution can identify the same knee anatomic factors previously found to significantly contribute to ACL injury risk using sophisticated methods and research-grade resolution MRIs.
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http://dx.doi.org/10.1177/03635465211024249DOI Listing
August 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

Epidemiology of Anterior Cruciate Ligament Tears in the National Football League.

Am J Sports Med 2021 06 30;49(7):1786-1793. Epub 2021 Apr 30.

University of Michigan, Ann Arbor, Michigan, USA.

Background: Anterior cruciate ligament (ACL) tears are common in contact athletics and have a significant effect on the athletic performance and well-being of affected players. The prevalence, timing, and characteristics of ACL tears in National Football League (NFL) athletes are lacking.

Purpose: To define the epidemiology of ACL tears among NFL athletes.

Study Design: Descriptive epidemiology study.

Methods: This retrospective study includes all ACL injuries entered into the NFL injury database through the centralized leaguewide electronic health record system for the 2015-2019 seasons.

Results: A total of 314 ACL injuries occurred during the 5-year study period, with a mean of 62 per year. The overall 1-season injury risk of an NFL player sustaining an ACL injury was 1.9% (95% CI, 1.7%-2.1%). Most ACL injuries occurred during games (n = 199), with a higher rate observed in the preseason games as compared with the regular season games (6.1 vs 2.7 per 10,000 player-plays; < .01). NFL players with ≤3 of experience had a higher preseason injury rate (9.57 ACL tears per 1000 player-seasons) than those with ≥4 years of experience (5.12 ACL tears per 1000 player-seasons; < .01). NFL athletes playing on special teams had the highest rate of ACL injuries (7.6 per 10,000 player-plays) in comparison with all other player positions.

Conclusion: ACL injury incidence was fairly consistent across all years studied and occurred more frequently in players with ≤3 years of NFL experience. Tears were more common during games, special teams play, and the preseason.
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http://dx.doi.org/10.1177/03635465211010146DOI Listing
June 2021

Wrist Fractures in Skiers and Snowboarders: Incidence, Severity, and Risk Factors Over 40 Seasons.

J Hand Surg Am 2020 Nov 19;45(11):1037-1046. Epub 2020 Jul 19.

Department of Orthopedics and Rehabilitation, University of Vermont Larner College of Medicine, Burlington, VT. Electronic address:

Purpose: To determine and compare the incidence and severity of wrist fractures in skiers and snowboarders.

Methods: A university-run orthopedic clinic at the base of a major ski resort has maintained an injury database spanning the years 1972 to 2012. Demographic information, equipment type, ability level, trail type and conditions, number of falls, circumstances surrounding the injury, and radiographs were collected on participants sustaining wrist fractures and compared with uninjured control participants asked the same questions, but in reference to their last fall where no injury resulted. A risk factor model for wrist fracture and severity in alpine sports was developed.

Results: During the 40-year period, 679 wrist fractures were identified. The incidence of wrist fracture per 1,000 days was 0.447 in snowboarders and 0.024 in skiers. In comparison with a representative sample of uninjured skiers, bivariate analyses revealed that skiers who experienced fractures were less experienced, had a greater number of falls, were on green or double black trails, and were injured owing to jumping or other reason related to technique. A higher risk for fracture was found for beginners, males younger than age 16, women older than age 50, and 4 or fewer days skiing that season. Bivariate analyses found that injured snowboarders were more likely to be female, younger, less experienced and had received less instruction than uninjured snowboarders. Higher risk for wrist fracture among snowboarders was found to be associated with age younger than 18 and less experience.

Conclusions: Wrist fractures occur at an 18 times greater incidence in snowboarders than in skiers. Skiers with wrist fractures were beginners, males younger than 16, women older than 50, or those who had less participation. Snowboarders sustaining wrist fractures were younger than 18 or had less experience.

Type Of Study/level Of Evidence: Prognostic III.
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http://dx.doi.org/10.1016/j.jhsa.2020.05.008DOI Listing
November 2020

Comparison of Tip- Versus Hub-Oscillating Saw Blade Control in a Total Knee Arthroplasty Model.

J Arthroplasty 2020 11 15;35(11):3300-3304. Epub 2020 Jun 15.

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

Background: Oscillating saws are commonly used for bone preparation in total knee arthroplasty but can cause injury to the posterior neurovascular bundle during tibial resection. Tip-oscillating saw blades are a recent innovation that could improve saw control due to decreased excursion; however, the tactile feedback to the surgeon is different.

Methods: To compare traditional hub and new tip-oscillating saw blades, 16 participants of varying levels of experience were video-recorded during composite tibial bone model resections to measure posterior saw blade plunge. Subjective perceptions of saw control and preference were also surveyed.

Results: Saw blade design and level of surgical experience did not produce a significant difference in posterior saw blade plunge (P > .05). Independent of saw blade design, subjects with no previous saw experience had significantly decreased posterior tibial plunge over subsequent resections. Tip-oscillating saw blades were perceived to be easier to use and control by less experienced participants (P = .0163).

Conclusion: Tip-oscillating saw blades do not alter the risk of posterior tibial saw plunge compared with traditional saw blades.
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http://dx.doi.org/10.1016/j.arth.2020.06.019DOI Listing
November 2020

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

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

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

Assessment of Early Gait Recovery After Anterior Approach Compared to Posterior Approach Total Hip Arthroplasty: A Smartphone Accelerometer-Based Study.

J Arthroplasty 2020 02 26;35(2):465-470. Epub 2019 Sep 26.

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

Background: The influence of total hip arthroplasty surgical approach on postoperative recovery is not well understood and often debated. This study compares anterior and posterior approach (PA) gait and patient-reported Hip Osteoarthritis Outcome scores (HOOS) in the early phases of recovery.

Methods: A prospective study evaluated 20 control subjects, 35 direct anterior approach (DAA), and 34 PA total hip arthroplasty patients. Subjects were assessed preoperatively and at 1 and 4 months postoperatively with HOOS and smartphone gait assessments of gait speed, step length, cadence, step symmetry, and horizontal and vertical center of mass displacements.

Results: The DAA and PA groups were not different in baseline HOOS or gait characteristics except for less horizontal center of mass displacement in the DAA group. At 1 month postoperatively, the DAA group had significantly faster gait speed at self-selected (P = .02) and fastest possible gait (P = .01) and longer step length at self-selected (P = .047) and fastest gait (P = .003) compared to the PA. At 4 months, there were no differences in DAA and PA gait measures. At 1 month postoperatively there were no significant differences in HOOS, but after 4 months HOOS were significantly higher in the DAA group.

Conclusion: There were minimal differences between the two approaches in the recovery of gait mechanics with some gait parameters particularly gait speed and step length recovery favoring the DAA at 1 month postsurgery in this nonrandomized study.
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http://dx.doi.org/10.1016/j.arth.2019.09.030DOI Listing
February 2020

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

Radiographic-based measurement of tibiofemoral joint space width and magnetic resonance imaging derived articular cartilage thickness are not related in subjects at risk for post traumatic arthritis of the knee.

J Orthop Res 2019 05 28;37(5):1052-1058. Epub 2019 Mar 28.

Department Orthopedics and Rehabilitation, Robert Larner M.D. College of Medicine, University of Vermont, Burlington, Vermont.

Joint space width (JSW), measured as the distance between the femoral and tibial subchondral bone margins on two-dimensional weight-bearing radiographs, is the initial imaging modality used in clinical settings to diagnose and evaluate the progression of osteoarthritis (OA). While, JSW is the only structural outcome approved by the FDA for studying the treatment of this disease in phase III clinical trials, recent reports suggest that magnetic resonance imaging (MRI)-based measurements of OA changes are superior due to increased sensitivity and specificity to the structural changes associated with progression of this disease. In the current study, we examined the relationship between radiographic JSW and MRI-derived articular cartilage thickness in subjects 4 years post anterior cruciate ligament reconstruction (ACLR) who were at increased risk for the onset and early progression of post-traumatic OA, and in uninjured subjects with normal knees (Control). In both ACLR and Control groups, there were large measurement biases, wide limits of agreement, and poor correlation between the two measurement techniques. Clinical significance: The finding from this study suggest that the two methods of examining changes associated with the onset and early progression of PTOA either characterize different structures about the knee and should not be used interchangeably, or two-dimensional JSW measurements are not sensitive to small changes in articular cartilage thickness. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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http://dx.doi.org/10.1002/jor.24283DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6499682PMC
May 2019

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

Lift-off Test Results After Lesser Tuberosity Osteotomy Versus Subscapularis Peel in Primary Total Shoulder Arthroplasty.

J Am Acad Orthop Surg 2017 Apr;25(4):304-313

From the Department of Orthopaedics and Rehabilitation, University of Vermont Larner College of Medicine, Burlington, VT.

Background: The ideal method for management of the subscapularis tendon during anatomic total shoulder arthroplasty (TSA) remains controversial.

Methods: In a retrospective cohort study, primary anatomic TSA procedures performed with either a subscapularis peel or a lesser tuberosity osteotomy from 2002 to 2010 were reviewed at a minimum 1-year follow-up. The primary outcome measure was the performance of a normal lift-off test postoperatively. Multivariate logistic regression analysis was performed to determine if other covariates besides surgical technique correlated with an abnormal lift-off test result.

Results: Ninety TSA procedures were evaluated. Forty-six procedures were performed with subscapularis peel, and 44 were performed with lesser tuberosity osteotomy. Mean follow-up was 4 years. In the subscapularis peel group, 32 of 46 shoulders (69.6%) had a normal lift-off test, compared with 40 of 44 shoulders (90.9%) in the lesser tuberosity osteotomy group (P = 0.01). The results of multivariate logistic regression suggested that lesser tuberosity osteotomy was associated with a normal postoperative lift-off test 4.5 times more often than was subscapularis peel.

Conclusions: Our study suggests that the use of lesser tuberosity osteotomy as the surgical approach for anatomic TSA is a reliable option that provides the patient with a better chance of maintaining subscapularis function postoperatively than the subscapularis peel does.

Level Of Evidence: Level III retrospective cohort study.
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http://dx.doi.org/10.5435/JAAOS-D-16-00138DOI Listing
April 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

Relationship between geometry of the extensor mechanism of the knee and risk of anterior cruciate ligament injury.

J Orthop Res 2017 05 12;35(5):965-973. Epub 2016 Dec 12.

McClure Musculoskeletal Research Center, Department of Orthopedics and Rehabilitation, College of Medicine, University of Vermont, Burlington, Vermont.

The complex inter-segmental forces that are developed across an extended knee by body weight and contraction of the quadriceps muscle group transmits an anteriorly directed force on the tibia that strain the anterior cruciate ligament (ACL). We hypothesized that a relationship exists between geometry of the knees extensor mechanism and the risk of sustaining a non-contact ACL injury. Geometry of the extensor mechanism was characterized using MRI scans of the knees of 88 subjects that suffered their first non-contact ACL injury and 88 matched control subjects with normal knees that were on the same team. The orientation of the patellar tendon axis was measured relative to the femoral flexion-extension axis to determine the extensor moment arm (EMA), and relative to tibial long axis to measure coronal patellar tendon angle (CPTA) and sagittal patellar tendon angle (SPTA). Associations between these parameters and ACL injury risk were tested with and without adjustment for flexion and internal rotation position of the tibia relative to the femur during MRI data acquisition. After adjustment for internal rotation position of the tibia relative to the femur there were no associations between EMA, CPTA, and SPTA and risk of suffering an ACL injury. However, increased internal rotation position of the tibia relative to the femur was significantly associated with increased risk of ACL injury in female athletes both in univariate analysis (Odds Ratio = 1.16 per degree of internal rotation of the tibia, p = 0.002), as well as after adjustment for EMA, CPTA, and SPTA.: © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:965-973, 2017.
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http://dx.doi.org/10.1002/jor.23366DOI Listing
May 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

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
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