Hewett, Timothy E.

Background: The association between quadriceps strength and functional outcomes after anterior cruciate ligament reconstruction (ACLR) is a focus of current research, while evaluations of hamstring strength are limited, despite the frequent use of hamstring autografts. Purpose/Hypothesis: The purpose of this study was to determine the relationship between changes in quadriceps and hamstring strength symmetry and self-reported outcomes before ACLR and at 12 and 24 weeks after surgery. We hypothesized that improvements in quadriceps and hamstring strength symmetry would be correlated with improvements in self-reported outcome measures within the first 6 months after ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: Thirty patients who underwent ACLR with a hamstring autograft were enrolled. Quadriceps and hamstring strength and Knee injury and Osteoarthritis Outcome Score (KOOS) values were assessed before and at 12 and 24 weeks after ACLR; limb symmetry indexes for strength were calculated at each time point. The Friedman and Wilcoxon signed-rank tests were used to analyze changes in KOOS values over time. Spearman rank-order correlations were used to test the relationship between changes in strength and KOOS values between each time point. Results: Hamstring and quadriceps limb symmetry significantly increased with time ( P ≤ .03). Fair correlations were observed between changes in the hamstring index and changes in the KOOS Symptoms subscore from before surgery to 12 weeks postoperatively ( r = 0.48; P ≤ .05). Changes in the quadriceps index (QI) were moderately correlated with changes in the KOOS Sport/Recreation subscore ( r = 0.60; P = .001), and fair correlations were seen between the QI and the KOOS Quality of Life subscore ( r = 0.39; P ≤ .04) from preoperatively to 12 weeks after surgery. Moderate correlations were seen between the QI and the KOOS Sport/Recreation subscore ( r = 0.57; P = .005) from 12 to 24 weeks after surgery. Conclusion: Improvements in quadriceps and hamstring strength symmetry were modestly associated with improvements in athletes’ perceived function in the first 6 months after ACLR. Specifically, improvements in hamstring symmetry were associated with improvements in knee symptoms within the first 12 weeks postoperatively, while improvements in quadriceps symmetry were associated with improvements in self-reported sport function throughout the first 6 months after ACLR. The restoration of strength symmetry within the first 6 months may be a critical component of rehabilitation aimed at maximizing function after ACLR. Further investigation is warranted to comprehensively evaluate whether the timing of strength gains predicts future function, including those who successfully return to their preinjury activity level after ACLR.

Background: Football has one of the highest injury rates (IRs) in sports, ranging from 4.1 to 8.6 per 1000 athlete-exposures (AEs). Previous research has reported that athletes may be at an increased risk of suffering lower extremity (LE) injuries after a concussion. Purpose/Hypothesis: The purpose of this study was to evaluate the rate of LE injuries in collegiate football athletes after a concussion. We predicted that the overall LE IR would increase after a concussion and that each position group would also demonstrate a similar increase in LE injuries after a concussion. Study Design: Cohort study; Level of evidence, 2. Methods: Daily attendance and injury records were prospectively collected by licensed team medical providers for the 2012 through 2016 college football regular seasons. Each injury report included the date of injury, position group, body part injured, and type of injury. IRs per 1000 AEs with 95% CIs were calculated to evaluate LE injuries at different time points after a concussion (remainder of season, next season, any additional seasons) and by months (<6 months, 6-12 months, >12 months). Mid- P exact tests were utilized to establish injury rate ratios (IRRs) to compare the IR between variables. Results: There was no significant difference in LE IRRs between the athletes post- versus preconcussion ( P = .20) or between the postconcussion and no concussion (control) athletes ( P = .08). There was an increased LE IR beyond 12 months in the postconcussion group (IR, 9.08 [95% CI, 3.68-18.89]) compared with the no concussion group (IR, 2.88 [95% CI, 2.04-3.96]) (IRR, 3.16 [95% CI, 1.21-7.15]; P = .02). Line position players had an increase in LE injuries after a concussion (IRR, 6.22 [95% CI, 1.31-23.68]; P = .03) compared with linemen with no concussion. Conclusion: There was no initial increase in LE IRs immediately after a concussion; however, there was an increased LE IR more than 12 months after a concussion. There was no increase in LE IRs demonstrated by skill and other position groups. Line position players experienced an increased LE IR the next season after a concussion or greater than 12 months after the injury.

Background: Database research is being used in orthopaedic literature with increased regularity. The main limitation of database research is the absence of diagnosis and treatment verification afforded by medical chart review. This absence may limit the accuracy of some conclusions and recommendations produced by database research. Hypothesis/Purpose: The purpose was to describe the accuracy of 1 database (Rochester Epidemiology Project) used in orthopaedic research to detect isolated anterior cruciate ligament (ACL) tears and to discuss the limitations of database research. It was hypothesized that diagnostic codes alone are unlikely to be accurate in identifying patients with ACL tears. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A population-based historical cohort study was performed with the Rochester Epidemiology Project database. All subjects had International Classification of Diseases, Ninth Revision, diagnosis codes consistent with ACL tears between January 1, 1990, and December 31, 2010. The medical records of all subjects were reviewed in detail to confirm the accuracy of diagnosis and gather data on injury type, laterality, associated meniscal injuries, magnetic resonance imaging findings, and treatment details. Results: A total of 3494 patients had codes consistent with ACL tears, and 2288 of them were confirmed through chart review to have an isolated ACL tear (65.5%). Among these were 1841 patients (52.7%) with an ACL tear within 1 year of injury and an additional 447 (12.8%) with an ACL tear >1 year from injury. Thirty-nine patients (1.1%) had a partial ACL tear diagnosed on magnetic resonance imaging, 48 (1.4%) had an isolated posterior cruciate ligament tear, and 22 (0.6%) had a combined ACL–posterior cruciate ligament injury. Twenty-four patients (0.7%) had ACL reconstruction before the study period. The remaining 1073 patients (30.7%) had diagnostic codes consistent with an ACL tear but did not have a cruciate ligament injury. Conclusion: This study demonstrates low accuracy with the use of diagnostic codes alone to identify an ACL tear. Database studies offer unique benefits to the medical literature, but the inherent limitations should be taken into account when these data are used to counsel patients, dictate clinical management, or make health care policy decisions. Information from a health care database is most accurate when accompanied by verification of diagnosis, treatment, and outcomes with medical chart review.

Background: The purpose of this study is to determine the effects of proximal hamate transfer for proximal pole scaphoid reconstruction upon carpal kinematics. Methods: Eight fresh-frozen cadaveric wrists underwent evaluation of their radiocarpal and midcarpal motion after proximal hamate osteotomy. A wrist simulator was used to apply cyclical tension to the flexor carpi ulnaris (FCU), flexor carpi radialis (FCR), extensor carpi ulnaris (ECU), and extensor carpi radialis longus and brevis stitched together (ECR). Kinematic motion was captured using Moiré Phase Tracking 3-dimensional motion-tracking sensors (MPT, Metria Innovation, Inc, Milwaukee, Wisconsin) to evaluate the lunocapitate and scapholunate angles for each condition. Results: During wrist flexion-extension and radial-ulnar deviation, there were no statistically significant differences about the lunocapitate or scapholunate axis between the intact and post-hamate osteotomy conditions. Conclusions: The harvest of the proximal hamate for proximal pole scaphoid reconstruction does not appear to adversely affect wrist kinematics.

Background: The efficacy of a neuromuscular training (NMT) program to ameliorate known hip biomechanical risk factors for athletes with anterior cruciate ligament reconstruction (ACLR) is currently unknown. Purpose/Hypothesis: The purpose was to quantify the effects of an NMT program on hip biomechanics among athletes with ACLR and to compare posttraining hip biomechanics with a control group. The hypotheses were that known hip biomechanical risk factors of anterior cruciate ligament (ACL) injury would be significantly reduced among athletes with ACLR after the NMT program and that posttraining hip biomechanics between the ACLR and control cohorts would not differ. Study Design: Controlled laboratory study. Methods: Twenty-eight athletes (n = 18, ACLR; n = 10, uninjured) completed a 12-session NMT program. Biomechanical evaluation of a jump-landing task was done before and after completion of the program. Repeated measures analysis of variance was performed to understand the effect of NMT within the ACLR cohort. Two-way analysis of variance was used to compare both groups. Post hoc testing was done for significant interactions. Hip biomechanical variables at initial contact are reported. Results: The athletes with ACLR who completed the NMT program had a significant session × limb interaction ( P = .01) for hip external rotation moment and a significant main effect of session for hip flexion angle ( P = .049) and moment ( P < .001). There was a significant change for the involved ( P = .04; 528% increase) and uninvolved ( P = .04; 57% decrease) limbs from pre- to posttraining for hip rotation moment. The ACLR cohort had an increase in hip flexion angle (14% change) and a decrease in hip flexion moment (65% change) from pre- to posttraining. Posttraining comparison for these same hip biomechanical variables of interest revealed no significant interactions ( P > .05) between the ACLR and control cohorts. There was a significant main effect of group ( P = .02) for hip flexion angle, as the ACLR cohort demonstrated greater hip flexion angle than that of the control group. Conclusion: For athletes with ACLR, hip biomechanical measures of ACL injury risk show significant improvements after completion of an NMT program. Clinical Relevance: Athletes with ACLR who are participating in an NMT program may ameliorate known hip biomechanical risk factors for an ACL injury.

Background: Clinical management of sport-related concussion typically involves a symptom checklist, clinical examination of mental status, and neurocognitive testing. However, recent studies have identified unresolved, impaired sensorimotor function after athletes return to sport. A review and meta-analysis of all current literature regarding risk of subsequent musculoskeletal (MSK) injury after concussion has yet to be published in the medical literature. Purpose/Hypothesis: To determine the odds that athletes will sustain MSK injury after concussion. It was hypothesized a priori that concussion would increase the risk for MSK injury. Study Design: Systematic review and meta-analysis. Methods: PubMed and Google Scholar were searched from January 2000 to November 2017. Reference lists of the included studies were manually searched. Two reviewers independently searched the literature for studies published in English that reported MSK injury after athletes returned to play following a concussion. Two independent reviewers completed data extraction using PRISMA guidelines and assessed study quality using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from the National Institutes of Health. Random effects meta-analyses were used to calculate odds ratio (OR) and incidence rate ratio (IRR) of MSK injury after concussion. The primary study outcome of interest was the number of athletes who sustained MSK injury after concussion. Results: Eight studies met inclusion criteria for meta-analysis. Meta-analysis results indicated that athletes who had a concussion had 2 times greater odds of sustaining a MSK injury than athletes without concussion (OR, 2.11; 95% CI, 1.46-3.06). In addition, athletes with concussion demonstrated a higher incidence of MSK injury after return to sport compared with nonconcussed athletes (IRR, 1.67; 95% CI, 1.42-1.96). Further analysis showed that both male and female athletes with concussion were at an increased risk of MSK injury compared with their respective same-sex, nonconcussed controls (OR > 1.56, P < .01). Conclusion: Based on the evidence of higher risk of MSK injuries after concussion, standard clinical assessments for athletes with concussion should include not only physical symptoms and cognitive function before return to sport but also neuromuscular risk factors associated with increased risk for MSK injuries.

Objectives: The incidence of 2nd anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) and return to sport (RTS) ranges from 25%-33% in young, active populations; with the greatest risk in the first 12 months after RTS. Recent data indicate that failure to successfully meet traditional RTS criteria, inclusive of strength, functional hop testing and patient reported outcome scores, may identify athletes at increased risk of future injury after ACLR. However, these studies have focused on adult populations and it is unknown if similar RTS criteria apply to young, adolescent, pivoting/cutting athletes. The purpose of this study was to determine if meeting all current, standard RTS criteria would identify young athletes at risk for future ACL injury after primary ACLR and RTS. The tested hypothesis was the likelihood of 2 nd ACL injury in the first 2 years after RTS would be lower in patients who met all RTS criteria prior to initiation of pivoting and cutting activity compared to patients who failed to meet all RTS criteria prior to RTS. Methods: One hundred fifty-nine subjects (112 female, 47 male) with a mean age of 17.2±2.6 years old (range: 13-25 y.o.) underwent ACLR and were released to return to pivoting/cutting sport. These patients were enrolled in a prospective, observational cohort study, completed a RTS assessment and were then tracked for occurrence of 2 nd ACL after ACLR for 24 months. The RTS assessment included 6 tests: isometric quadriceps strength, 4 functional hop tests and the International Knee Documentation Committee (IKDC) patient reported outcome survey. Limb symmetry index (LSI) was calculated for strength and hop test assessments [(involved/uninvolved)*100]. The IKDC was reported on a 0-100 scale with 100 representing a perfect score. Subjects were classified into groups that successfully passed all 6 RTS tests at a level of 90 and again at 95 compared to those that failed to meet all 6 criteria. Chi Square tests were used to determine if successfully passing all 6 RTS measures at various levels of symmetry resulted in a reduced risk of 2 nd ACL injury in the first 24 months after RTS. Results: Thirty-five (22.0%) patients suffered a 2 nd ACL injury, with 26 occurring in the first 12 months after RTS. At the time of RTS, 42 patients (26%) achieved LSI values of 90 or greater on all testing as well as an IKDC value of 90 or greater. The remaining 117 subjects (74%) scored below 90 on at least 1 of the 6 assessments. At this level, there was no difference in 2 nd ACL injury prevalence between patients who passed all RTS criteria (12/42; 28.6%) and those who failed at least 1 criteria (23/117; 19.7%) (p=0.23). When the passing criteria was elevated to 95 on all RTS testing, only 15 subjects (9%) successfully passed all 6 tests. There was no significant difference in 2 nd ACL injury prevalence between patients who passed all RTS criteria (5/15; 33%) and those who failed at least 1 test (30/144; 20.8%) (p=0.32). Sub-group analysis which evaluated the group by graft type, also indicated no significant differences between groups (p>0.05). Conclusion: Current criteria to evaluate readiness to return young athletes to pivoting and cutting sports, using quadriceps strength symmetry, functional hop performance symmetry and patient reported outcomes, may not identify young, active patients at high risk for 2 nd ACL injury. Future work must identify more appropriate criteria to assess readiness to RTS in the young, athletic population and incorporate these findings into practice.

ABSTRACT Several meta‐analyses have been published on the effectiveness of anterior cruciate ligament (ACL) injury prevention training programs to reduce ACL injury risk, with various degrees of risk reduction reported. The purpose of this research was to perform a systematic review and meta‐analysis of overlapping meta‐analyses evaluating the effectiveness of ACL injury prevention training programs so as to summarize the amount of reduction in risk for all ACL and non‐contact ACL injuries into a single source, and determine if there were sex differences in the relative efficacy of ACL injury prevention training programs. Five databases (Medline, PubMed, Embase, CINAHL, and Cochrane) were searched to identify meta‐analyses that evaluated the effectiveness of ACL injury prevention training programs on ACL injury risk. ACL injury data were extracted and the results from each meta‐analysis were combined using a summary meta‐analysis based on odds ratios (OR). Eight meta‐analyses met eligibility criteria. Six of the eight only included data for female athletes. Summary meta‐analysis showed an overall 50% reduction (OR = 0.5 [0.41–0.59]; I 2 = 15%) in the risk of all ACL injuries in all athletes and a 67% reduction (OR = 0.33 [0.27–0.41]; I 2 = 15%) for non‐contact ACL injuries in females. This paper combines all previous meta‐analyses into a single source and shows conclusive evidence that ACL injury prevention programs reduce the risk of all ACL injuries by half in all athletes and non‐contact ACL injuries by two‐thirds in female athletes. There is insufficient data to make conclusions as to the effectiveness of ACL injury prevention programs in male athletes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2696–2708, 2018.

Background: Anterior cruciate ligament (ACL) injuries are catastrophic events that affect athletic careers and lead to long-term degenerative knee changes. As injuries are believed to occur within the first 50 milliseconds after initial contact during a rapid deceleration task, impact simulators that rapidly deliver impulse loads to cadaveric specimens have been developed. However, no impactor has reproducibly and reliably created ACL injures in a distribution that mimics clinical observation. Purpose: To better understand ACL injury patterns through a cadaveric investigation that applied in vivo–measured external loads to the knee during simulated landings. Study Design: Controlled laboratory study. Methods: A novel mechanical impact simulator reproduced kinetics from in vivo–recorded drop landing tasks on 45 cadaveric knees. Specimens were exposed to a randomized order of variable knee abduction moment, anterior tibial shear, and internal tibial rotation loads before the introduction of an impulse load at the foot. This process was repeated until a hard or soft tissue injury was induced on the joint. Injuries were assessed by an orthopaedic surgeon, and ligament strain was recorded by implanted strain gauges. Results: The mechanical impact simulator induced ACL injuries in 87% of specimens, with medial collateral ligament (MCL) injuries in 31%. ACL tear locations were 71% femoral side, 21% midsubstance, and 9% tibial side. Peak strain before failure for ACL-injured specimens was 15.3% ± 8.7% for the ACL and 5.1% ± 5.6% for the MCL ( P < .001). Conclusion: The ACL injuries induced by the mechanical impact simulator in the present study have provided clinically relevant in vitro representations of in vivo ACL injury patterns as cited in the literature. Additionally, current ligament strains corroborate the literature to support disproportionate loading of the ACL relative to the MCL during athletic tasks. Clinical Relevance: These findings indicate that the mechanical impact simulator is an appropriate model for examining independent mechanical variables, treatment techniques, and preventive interventions during athletic tasks leading up to and including an ACL injury. Accordingly, this system can be utilized to further parse out contributing factors to an ACL injury as well as assess the shortcomings of ACL reconstruction techniques in a dynamic, simulated environment that is better representative of in vivo injury scenarios.