Risk Factors for Concomitant Meniscal Injury With Sport-Related Anterior Cruciate Ligament Injury.

Background: Previous studies of concomitant meniscal injury in athletes with anterior cruciate ligament (ACL) injury have examined age, sex, body mass index (BMI), injury mechanism, and time from injury to surgery as potential risk factors. Purpose: To identify additional risk factors for concomitant meniscal injury, including preinjury joint laxity and lower extremity alignment, in athletes with sport-related ACL injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study included 180 participants aged 13 to 26 years who underwent ACL reconstruction (ACLR) after a first-time ACL injury sustained during participation in sport. Contralateral lower extremity alignment and joint laxity were used as surrogate measures for the injured knee before trauma. Concomitant meniscal tear patterns were identified at the time of ACLR. Sex-specific analyses were conducted. Results: Concomitant meniscal injury was observed in 60.6% of the subjects. The prevalence of concomitant injury was higher in male than female participants (69.9% vs 54.2%; P = .035) due to a higher prevalence of lateral meniscal injuries (56.2% vs 38.3%; P = .018). Among male patients, there was a significant difference in the prevalence of concomitant lateral meniscal tear according to sport participation (≥9 vs <9 h/week: 67.4% vs 35.7%; P = .032). Among male patients, the likelihood of concomitant injury to both the lateral and medial menisci increased by 28.8% for each 1-mm decrease in navicular drop. Among female patients, the likelihood of concomitant injury to the lateral meniscus increased by 15% per degree increase in genu recurvatum and 14% per degree decrease in standing quadriceps angle, with similar effects on the likelihood of concurrent injury to both the lateral and medial menisci. Conclusion: Measures of lower extremity alignment and genu recurvatum previously identified as risk factors for ACL injury were also associated with concomitant meniscal injury in female patients while other risk factors, including BMI and joint laxity, were not. Increased time spent participating in sport and navicular drop were associated with concomitant meniscal injury in male patients.

The Duration of Thigh Tourniquet Use Associated With Anterior Cruciate Ligament Reconstruction Does Not Produce Cellular-Level Contractile Dysfunction of the Quadriceps Muscle at 3 Weeks After Surgery.

BACKGROUND: Anterior cruciate ligament (ACL) trauma and ACL reconstruction (ACLR) are associated with the loss of strength and function of the muscles that span the knee joint. The underlying mechanism associated with this is not completely understood. PURPOSE: To determine whether the duration of tourniquet use during ACLR has an effect on knee extensor muscle contractile function and size at the cellular (ie, fiber) level 3 weeks after surgery and at the whole-muscle level at 6 months after surgery. STUDY DESIGN: Descriptive laboratory study and case series; Level of evidence, 4. METHODS: Study participants sustained an acute, first-time ACL injury. All participants underwent ACLR with the use of a tourniquet placed in a standardized location on the thigh; the tourniquet was inflated (pressure range, 250-275 mm Hg), and the time of tourniquet use during surgery was documented. Participants were evaluated 1 week before surgery (to measure patient function, strength, and subjective outcome with the Knee injury and Osteoarthritis Outcome Score [KOOS] and International Knee Documentation Committee [IKDC] score), at 3 weeks after ACLR surgery (to obtain muscle biopsy specimens of the vastus lateralis and assess muscle fiber cross-sectional area, contractile function, and mitochondrial content and morphometry), and at 6 months after ACLR (to evaluate patient function, strength, and subjective outcomes via KOOS and IKDC scores). Data were acquired on both the injured/surgical limb and the contralateral, normal side to facilitate the use of a within-subjects study design. Results are based on additional analysis of data acquired from previous research that had common entry criteria, treatments, and follow-up protocols. RESULTS: At 3 weeks after ACLR, the duration of tourniquet use at the time of surgery did not explain the variation in single-muscle fiber contractile function or cross-sectional area (myosin heavy chain [MHC] I and II fibers) or subsarcolemmal and intermyofibrillar mitochondrial content or morphometry. At 6 months after ACLR, the duration of tourniquet use was not associated with the peak isometric and isokinetic torque measurements, patient function, or patient-reported outcomes. CONCLUSION: The duration of tourniquet use at the time of ACLR surgery did not explain variation in muscle fiber size, contractile function, or mitochondrial content at 3 weeks after surgery or strength of the quadriceps musculature or patient-reported function or quality of life at 6-month follow-up.

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

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.

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

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.

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.

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 (P < .01 to P < .001) in the injured compared with noninjured leg 3 weeks after surgery. NMES reduced muscle fiber atrophy (P < .01) through effects on fast-twitch myosin heavy chain (MHC) II fibers (P < .01 to P < .001). NMES preserved contractility in slow-twitch MHC I fibers (P < .01 to P < .001), increasing maximal contractile velocity (P < .01) and preserving power output (P < .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).

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.

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.

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

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.

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

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; P = .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 (P = .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 (P = .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.

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

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.