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Background: Chronic and recurrent shoulder dislocations prior to stabilization can increase the risk of glenoid bone loss. Glenoid bone loss exceeding critical levels can lead to further instability and decreased outcomes following arthroscopic labral repair. Indicators of low socioeconomic status (SES), such as high Area Deprivation Index (ADI) and non-commercial insurance, are related to generalized delays to orthopedic care, which can cause recurrent instability and increase glenoid bone loss., Hypothesis/purpose: Higher national ADI and non-commercial insurance would be associated with greater levels of radiographic glenoid bone loss after glenoid instability., Methods: A retrospective study was performed with patients who underwent anterior labral repair. Chart review included demographics, course of care data, preoperative instability data, national ADI, and insurance status. The Neighborhood Atlas Website and patients' home addresses were used to obtain national ADI. Glenoid bone loss was measured using the Best-fit circle Pico method on three-dimensionally aligned magnetic resonance images (MRIs). Researchers were blinded to SES indicators during radiographic analysis. Glenoid bone loss was compared between SES indicators using one-way ANOVAs., Results: 146 patients met inclusion criteria and had complete datasets (23.3% female; 22.4±7.0-years-old; national ADI=16.1±15.3). Patients experienced on average 9.12±6.63% glenoid bone loss. A curve fitting tool determined a quadratic non-linear regression best characterized the association of glenoid bone loss and ADI (R 2 = 0.392, p < 0.001). Individuals with commercial insurance experienced 8.58%±6.69% glenoid bone loss as compared to 11.78%±6.30% in individuals with Medicaid insurance (p=0.03). Critical bone loss at a threshold of 13.5% was more likely with higher national ADI (p<0.001) and Medicaid insurance (OR=2.49, CI=1.02-6.09). However, only national ADI was predictive of subcritical bone loss at a threshold of 10% (p<0.001)., Conclusion: Patients with greater national ADI and Medicaid insurance status had greater rates of critical preoperative glenoid bone loss at a threshold of 13.5%. Greater national ADI is also predictive of subcritical glenoid bone loss at a threshold of 10% and overall glenoid bone loss. Further study is needed to assess the postoperative implications of these findings in this population., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: The aim of this study was to examine demographic and surgical factors that influence patient-reported knee function in patients who undergo anterior crucial ligament reconstruction (ACLR) with concurrent bucket-handle meniscal tear (BHMT) procedures. We hypothesized that repair of BHMT in the setting of concomitant ACLR and shorter time from injury to surgery would lead to improved patient-reported outcomes., Methods: Forty-one patients (mean age: 28.0 ± 9.8 years, 72% male) with BHMT at the time of ACLR completed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) via online survey at an average of 15.2 months postop. Patient demographics and surgical characteristics, including time from injury to surgery, were compared between repair ( n  = 22) and meniscectomy ( n  = 19) groups using one-way analysis of variances; distributions of sex, graft source, BHMT compartment and zone were compared between groups using χ 2 tests. The association between IKDC-SKF score, demographics and surgical characteristics was evaluated using multivariable linear regression. A priori alpha level was p  < 0.05., Results: Meniscal repair and meniscectomy groups differed based on graft source and BHMT zone but not IKDC-SKF score ( p  = 0.085). Patients undergoing ACLR with autograft ( p  = 0.003) and with red-red zone BHMT ( p  < 0.001) more often underwent meniscal repair. The regression model demonstrated longer time from injury to surgery ( p  = 0.049), red-red tear zone ( p  = 0.04) and meniscectomy ( p  = 0.008); these were predictive of poorer IKDC-SKF scores., Conclusion: BHMT repair was more likely performed in ACL autograft and on red-red zone tears. Longer time from injury to surgery is an indicator of poorer IKDC-SKF score, as this may increase the risk of concomitant pathologies. White-white zone BHMTs are associated with better IKDC-SKF scores than red-red zone BHMTs, which may be due to the smaller volume of tissue removed during meniscectomy of white-white zone tears and the avoidance of iatrogenic complications of meniscal repair., Level of Evidence: Level III, therapeutic study., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Journal of Experimental Orthopaedics published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background: Lower socioeconomic status and public insurance lead to a longer delay to surgery and a higher likelihood of concomitant pathology before undergoing anterior cruciate ligament reconstruction (ACLR). However, few studies have examined the influence of community deprivation on ACLR timing and outcomes., Purpose/hypothesis: The primary aim of this study was to define the effect of the area deprivation index (ADI) and insurance classification on access to orthopaedic care after an ACL rupture, and the secondary aim was to determine whether these variables were associated with a second ACL injury after primary ACLR. It was hypothesized that patients with a greater national ADI percentile and Medicaid insurance would experience longer delays to care and an increased risk of reinjury after ACLR., Study Design: Cohort study; Level of evidence, 3., Methods: A retrospective study was performed to evaluate patients undergoing primary ACLR between 2016 and 2019. The national ADI percentile was obtained utilizing the Neighborhood Atlas website. The relationship between national ADI percentile and care characteristics (eg, time to specialized care) was investigated using the Spearman rho correlation coefficient ( r ). The association between patient and care characteristics and second ACL injury after the index procedure (ie, graft rerupture or contralateral ACL rupture) was investigated using binary logistic regression., Results: A total of 197 patients met the inclusion criteria. Longer times from injury to surgery ( r = 0.238; P < .001) and from specialized care to surgery ( r = 0.217; P = .002) were associated with a greater national ADI percentile. The second injury group reported significantly greater national ADI ( P = .026) and included a greater percentage of patients with Medicaid insurance (31.3%) compared with the no second injury group. Patients experienced 5.1% greater odds of a second ACL injury for each additional month between evaluation and surgery., Conclusion: Greater national ADI percentile and Medicaid insurance status were associated with adverse ACLR timing and outcomes. Patients with a greater national ADI percentile took significantly longer to obtain surgery after ACL injury. Those who sustained a second ACL injury after ACLR had an overall higher mean national ADI percentile and included a greater proportion of patients with Medicaid compared with those who did not sustain a second ACL injury. Future studies should critically investigate the underlying factors of these associations to reach equity in orthopaedic care., Competing Interests: The authors declared that they have the following conflicts of interest: A.J.C. has received education payments from Arthrex, Medwest Associates, Mid-Atlantic Surgical Systems LLC, Smith+Nephew, and Supreme Orthopedic Systems LLC; hospitality payments from Stryker; and a grant from Arthrex. B.M.B. has received education payments from Conetic Solutions, Arthrex, Smith+Nephew, and Medwest Associates; hospitality payments from Stryker, Smith+Nephew, Conetic Solutions, and Medical Device Business Services; honoraria from Encore Medical LP; and a grant from Arthrex. C.M.C. has received education payments from Liberty Surgical and hospitality payments from Medical Device Business Services. E.S.C. has received consulting fees from Avanos Medical; education payments from Arthrex and Supreme Orthopedic Systems LLC; and hospitality payments from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto. Ethical approval for this study was obtained from the Western Institutional Review Board-Copernicus Group (ref No. 20216925)., (© The Author(s) 2024.)

Objective: To determine the association between change in physical activity level, as defined as the change from pre-to post-operative Tegner Activity Scale, and quality of life (QOL) after anterior cruciate ligament reconstruction (ACLR), before patients are cleared for return to sport., Participants: 1198 participants (42.9% male; 18.7 ± 3.6 years; 7.1 ± 3.7 months post-ACLR)., Main Outcome Measures: Surveys included Knee Injury and Osteoarthritis Outcome Score QOL (KOOS-QOL) subscale and Tegner Activity Scale. KOOS-QOL score ≥62.5 is considered as meeting a previously established patient acceptable symptom state., Results: The acceptable KOOS-QOL group reported a significantly smaller decrease in activity level from pre-injury to time of data collection (median: 2.00, IQR: 2.00) than the unacceptable KOOS-QOL group (median: 3.00, IQR: 3.00). Across the full cohort, for every one-point larger decrease in Tegner score from pre-to post-ACLR, there is a 52% increase in the odds of having an unacceptable KOOS-QOL score. For adolescents, the odds increase to 60% while the odds for adults were lower at 39%., Conclusions: Following ACLR, greater decreases in physical activity level are associated with poorer QOL for both adolescents and adults at short-term follow-up, and this effect is larger amongst adolescents., Competing Interests: Declaration of competing interest There are no relevant declarations of interest for this manuscript., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

After an anterior cruciate ligament (ACL) injury, people need secondary prevention strategies to identify osteoarthritis at its earliest stages so that interventions can be implemented to halt or slow the progression toward its long-term burden. The Osteoarthritis Action Alliance formed an interdisciplinary Secondary Prevention Task Group to develop a consensus on recommendations to provide clinicians with secondary prevention strategies that are intended to reduce the risk of osteoarthritis after a person has an ACL injury. The group achieved consensus on 15 out of 16 recommendations that address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models. We hope this statement raises awareness among clinicians and researchers on the importance of taking steps to mitigate the risk of osteoarthritis after an ACL injury., (© by the National Athletic Trainers' Association, Inc.)

Context: The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury., Objective: Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps., Design: Consensus process., Setting: Virtual video conference calls and online voting., Patients or Other Participants: The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds., Main Outcome Measure(s): The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation., Results: The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models., Conclusions: This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury., (© by the National Athletic Trainers' Association, Inc.)

Context: Rehabilitation after anterior cruciate ligament reconstruction (ACLR) is challenging for adolescent patients concurrently experiencing growth and development, changes in attitudes and social interactions, and a gradual shift toward independence., Objective: To examine the perceptions of information sharing and interpersonal communication among adolescent patients going through ACLR, their parents, and physical therapists (PTs) treating adolescent patients with ACLR., Design: Cross-sectional study., Setting: University-affiliated sports medicine clinic., Patients or Other Participants: Nine adolescent patients who had recently completed physical rehabilitation after ACLR, one of their parents, and PTs who treated adolescent patients with ACLR were recruited and enrolled., Main Outcome Measure(s): Participants completed semistructured interviews. The interview scripts for patients, parents, and PTs intentionally addressed the same topics, with only minor modifications in wording as appropriate for each role. All interviews were recorded, transcribed verbatim, and analyzed using a hybrid of deductive and inductive coding by trained members of the study team., Results: Patients, parents, and PTs perceived that interpersonal dynamics (eg, communication, external motivation) and stakeholder knowledge (eg, understanding of the psychological consequences of injury) influenced intrapersonal experiences (eg, emotional response, intrinsic motivation) during rehabilitation after ACLR. Additionally, patients and parents indicated that a lack of information about the rehabilitation process hindered their ability to obtain additional information from the PT and surgeon., Conclusions: Participants from all stakeholder groups reported that orthopaedic surgeons and other members of the health care team may consider being more consistent when setting expectations, physical restrictions, and recovery timelines., (© by the National Athletic Trainers' Association, Inc.)

Context: Previously, the most common treatment for a concussion was prolonged physical and cognitive rest. Recently, researchers have suggested that earlier physical activity (PA) may be better at promoting recovery. Researchers have not evaluated the relationship between free-living PA (eg, walking) and symptom reporting or recovery duration., Objective: To assess the relationship between free-living PA participation and 2 recovery outcomes in college-aged adults with a concussion., Design: Prospective cohort., Setting: National Collegiate Athletic Association Division I and III universities., Patients or Other Participants: Thirty-two college-aged adults (68.8% female, age = 19.8 ± 1.4 years) with a concussion., Main Outcome Measure(s): Participants completed a postconcussion symptom evaluation at visits 1 (<72 hours from concussion) and 2 (8 days later). Between visits, each participant's PA was monitored using an Actigraph GT9X Link PA monitor and expressed as total PA (counts per minute) and percentage of PA time spent in moderate-to-vigorous intensity (%MVPA). Recovery time was the number of days from injury occurrence to medical clearance. With separate hierarchical multiple regressions, we evaluated the relationship between total PA and each recovery variable (visit 2 symptom severity, recovery time). Additionally, with separate exploratory hierarchical multiple regressions, we evaluated the relationship between %MVPA and each recovery variable. Statistical significance was set a priori at P ≤ .05., Results: Participants averaged 2446 ± 441 counts per minute and spent 12.1% ± 4.2% of their PA performing MVPA. Participants yielded median (interquartile) symptom severities of 28 (24) and 2 (8) for visit 1 and 2, respectively. Average recovery time was 14.7 ± 7.5 days. Total PA did not significantly contribute to the model for visit 2 symptom severity (P = .122) or recovery time (P = .301). Similarly, %MVPA had little contribution to the model for visit 2 symptom severity (P = .358) or recovery time (P = .276)., Conclusions: We suggest that free-living PA may not be enough to reduce symptoms or shorten recovery. Thus, clinicians may need to provide patients with more structured PA protocols mimicking findings from previous researchers., (© by the National Athletic Trainers' Association, Inc.)

Objectives: The purpose was to compare body composition, cardiorespiratory fitness, and physical activity (PA) engagement between women with ACLR and healthy controls., Design: Cross-sectional study., Setting: University laboratory., Participants: Ten women with ACLR (time since surgery = 33.0 ± 18.3 months; age = 21.4 ± 3.8 years) and 10 healthy women (age = 21.9 ± 3.1 years) matched based on age (±2 years) and Tegner Activity Level (±2) participated., Main Outcome Measures: Body fat percentage (%BF) was estimated using air displacement plethysmography, cardiorespiratory fitness was assessed via a graded cycle test, and PA was assessed using accelerometers worn for 7 days. Groups were compared using Mann-Whitney U tests. Time (minutes/week) spent in moderate-to-vigorous PA and step count (steps/day) were compared between groups using a one-way ANCOVA with 7-day total wear time as the only covariate. Statistical significance was established a priori as α ≤ 0.05., Results: Women with ACLR had significantly higher %BF than controls (ACLR = 32.7 ± 6.7%, healthy = 22.6 ± 4.9%; p < 0.01) and participated in less steps per day (ACLR = 6650 ± 3227 steps/day, healthy = 9361 ± 2626 steps/day; p = 0.02)., Conclusions: There may be persistent negative effects on body composition and PA engagement for women following ACLR. Low PA and high %BF have adverse consequences for premature mortality and morbidity; therefore, it is crucial to assess these characteristics and determine interventions to maintain PA and healthy body composition following ACLR., Competing Interests: Declaration of competing interest None declared., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Context: Female patients with anterior cruciate ligament reconstruction (ACLR) are less likely to return to sport than males. Psychological readiness predicts successful return to sport, but it is unclear if psychological experiences differ between males and females during recovery., Objective: To explore gender differences in psychological readiness factors of return to sport after ACLR., Design: Qualitative study., Setting: Laboratory., Patients or Other Participants: A total of 12 male (months since surgery = 6.2 ± 1.2) and 13 female (months since surgery = 6.4 ± 1.3) high school athletes with a history of ACLR., Data Collection and Analysis: Participants were interviewed before physician clearance to return to activity. Transcribed interviews were analyzed using deductive thematic coding of 5 themes identified from previous research (psychological distress, self-efficacy, locus of control, athletic identity, and fear of reinjury) and inductive secondary subthematic coding. Gender comparisons were generated within primary themes and secondary subthemes., Results: All deductive themes were consistently reinforced. Male and female participants reported fear of movement, loss of athletic identity, and motivational mindsets for return to sport and self-improvement. Males reported a stronger sense of internal locus of control using positive internal reinforcement, whereas females described balancing internal and external control and valuing external support systems. Male participants described mood changes influenced by physical and social limitations. Female participants closely monitored their emotions throughout recovery and were influenced by rehabilitation fluctuations., Conclusions: Male and female high school athletes described different psychological factors related to return to sport and locus of control as well as psychological distress. Gender-specific psychological interventions may be warranted to overcome psychological barriers after ACLR., (© by the National Athletic Trainers' Association, Inc.)

Context: Anterior cruciate ligament reconstruction (ACLR) and gait speed are risk factors for developing knee osteoarthritis (OA). Measuring minute-level cadence during free-living activities may aid in identifying individuals at elevated risk of developing slow habitual gait speed and, in the long term, OA., Objective: To assess differences in peak 1-minute cadence and weekly time in different cadence intensities between individuals with and without ACLR., Design: Cross-sectional study., Setting: Short-term, free-living conditions., Patients or Other Participants: A total of 57 participants with ACLR (34 women, 23 men; age = 20.9 ± 3.2 years, time since surgery = 28.7 ± 17.7 months) and 42 healthy control participants (22 women, 20 men; age = 20.7 ± 1.7 years)., Main Outcome Measure(s): Each participant wore a physical activity monitor for 7 days. Data were collected at 30 Hz, processed in 60-second epochs, and included in the analyses if the activity monitor was worn for at least 10 hours per day over 4 days. Mean daily steps, peak 1-minute cadence, and weekly minutes spent at 60 to 79 (slow walking), 80 to 99 (medium walking), 100 to 119 (brisk walking), ≥100 (moderate- to vigorous-intensity ambulation), and ≥130 (vigorous-intensity ambulation) steps per minute were calculated. One-way analyses of covariance were conducted to determine differences between groups, controlling for height and activity-monitor wear time., Results: Those with ACLR took fewer daily steps (8422 ± 2663 versus 10 033 ± 3046 steps; P = .005) and spent fewer weekly minutes in moderate- to vigorous-intensity cadence (175.8 ± 116.5 minutes versus 218.5 ± 137.1 minutes; P = .048) than participants without ACLR. We observed no differences in minutes spent at slow (ACLR = 77.4 ± 40.5 minutes versus control = 83.9 ± 34.3 minutes; P = .88), medium (ACLR = 71.6 ± 40.2 minutes versus control = 82.9 ± 46.8 minutes; P = .56), brisk (ACLR = 115.3 ± 70.3 minutes versus control = 138.3 ± 73.3 minutes; P = .18), or vigorous-intensity (ACLR = 24.3 ± 36.5 minutes versus control = 38.1 ± 60.9 minutes; P = .10) cadences per week., Conclusions: Participants with ACLR walked approximately 40 fewer minutes per week in moderate- to vigorous-intensity cadence than participants without ACLR. Increasing the time spent at cadence ≥100 steps per minute and overall volume of physical activity may be useful as interventional targets to help reduce the risk of early development of OA after ACLR., (© by the National Athletic Trainers' Association, Inc.)

Context: Patient-reported function is an important outcome in anterior cruciate ligament rehabilitation. Identifying which metrics of thigh-muscle function are indicators of normal patient-reported function can help guide treatment., Objective: To identify which metrics of thigh-muscle function discriminate between patients who meet and patients who fail to meet age- and sex-matched normative values for patient-reported knee function in the first 9 months after anterior cruciate ligament reconstruction (ACLR) and establish cutoffs for these metrics by covariate subgroups., Design: Cross-sectional retrospective study., Setting: Laboratory., Patients or Other Participants: A total of 256 patients (129 females, 128 males; age = 17.1 ± 3.0 years, height = 1.7 ± 0.1 m, mass = 74.1 ± 17.9 kg, months since surgery = 6.4 ± 1.4), 3 to 9 months after primary unilateral ACLR., Main Outcome Measure(s): We stratified the sample into dichotomous groups by the International Knee Documentation Committee (IKDC) score (IKDCMET, IKDCNOT MET) using sex- and age-matched normative values. We measured quadriceps and hamstrings isokinetic (60°/s) torque and power bilaterally. Normalized quadriceps and hamstrings peak torque (Nm/kg) and power (W/kg), limb symmetry indices (LSI, %), and hamstrings : quadriceps ratios were calculated. Logistic regression indicated which of these metrics could predict IKDC classification while controlling for age, graft type, and sex. Receiver operating characteristic curves established cutoffs for explanatory variables for both total cohort and covariate subgroups. Odds ratios (OR) determined the utility of each cutoff to discriminate IKDC status., Results: Quadriceps torque LSI (≥69.4%, OR = 3.6), hamstrings torque (≥1.11 Nm/kg, OR = 2.1), and quadriceps power LSI (≥71.4%, OR = 2.0) discriminated between IKDC classification in the total cohort. Quadriceps torque LSI discriminated between IKDC classification in the patellar-tendon graft (≥61.6%, OR = 5.3), hamstrings-tendon graft (≥71.8%, OR = 10.5), and age <18 years (≥74.3%, OR = 5.2) subgroups. Hamstrings torque discriminated between IKDC classifications in the age <18 years (≥1.10 Nm/kg, OR = 2.6) subgroup., Conclusions: Quadriceps torque LSI, hamstrings torque, and quadriceps power LSI were the most useful metrics for predicting normal patient-reported knee function early after ACLR. Further, cutoff values that best predicted normal patient-reported function differed by graft type and age., (© by the National Athletic Trainers' Association, Inc.)

Context: The sex-based differences in the structure and rules of boys' and girls' lacrosse result in very different styles of play, which may have significant implications for the rates and patterns of injuries., Objective: To compare the epidemiology of injuries sustained by boys' and girls' lacrosse players., Design: Descriptive epidemiology study., Setting: Web-based online surveillance system., Patients or Other Participants: The High School Reporting Information Online database was used to analyze injuries reported by certified athletic trainers from 2008-2009 through 2015-2016., Main Outcome Measure(s): Practice and competition injury rates, body site, diagnosis, and mechanism., Results: Boys had a higher injury rate than girls (20.9 versus 15.7 per 10 000 athlete-exposures, respectively; rate ratio = 1.3, 95% confidence interval = 1.2, 1.4). The most commonly injured body sites for boys and girls, respectively, were the lower extremities (38.0%, 56.4%) and the head/neck (28.3%, 29.8%). More specifically, the most frequently diagnosed injuries for both boys and girls, respectively, in competitions were concussions (23.1%, 25.6%), ankle ligament sprains (7.8%, 15.3%), upper leg strains (4.8%, 6.7%), and knee ligament sprains (4.2%, 6.7%). The most cited mechanism of injury overall was contact with another player (22.0%); among boys, it was contact with a stick (14.8%) and among girls, the most frequent mechanisms were overuse (25.0%) and contact with a stick (14.7%)., Conclusions: Injury rates and mechanisms of injuries differed between high school boys' and girls' lacrosse players. Boys had a higher rate of injury, with the most common mechanism of injury being contact with another player compared with overuse in girls. However, similarities were seen between sexes for the most frequently injured body sites and injury diagnoses. Future authors should continue to compare differences in injury rates, equipment upgrades, and rule changes in boys' and girls' lacrosse.

Context:: After anterior cruciate ligament reconstruction (ACLR), women have a greater risk of incurring a second anterior cruciate ligament injury and they display different landing movement patterns than men. It remains unclear if clinical movement-assessment tools, such as the Landing Error Scoring System (LESS), can detect sex differences in movement patterns after ACLR., Objective:: To compare total LESS scores and individual LESS errors between men and women with a history of ACLR., Design:: Cross-sectional study., Setting:: Laboratory., Patients or Other Participants:: A total of 168 individuals (41 men and 127 women; mean age: men = 20 years [range, 19-25 years], women = 19 years [range, 18-20 years]; mean time since surgery: men = 21 months [range, 12-36 months], women = 27.5 months [range, 17-39 months]) with a history of primary, unilateral ACLR., Main Outcome Measure(s):: Participants completed a minimum of 3 trials of a drop vertical-jump task scored using the LESS. The between-sexes difference in LESS score was assessed using analysis of covariance, whereas the associations between participant sex and errors on each LESS item were assessed using logistic or multinomial regression., Results:: Women displayed a greater number of total landing errors (men = 4.6 ± 2.3, women = 6.1 ± 2.3; P < .001) and were more likely to commit errors in trunk flexion at initial contact (men = 4.9%, women = 23.6%; odds ratio [OR] = 4.94), medial knee position at initial contact (men = 17.1%, women = 42.5%; OR = 6.01), medial knee displacement (men = 24.4%, women = 73.2%; OR = 7.88), total joint displacement (1 error: men = 58.5%, women = 71.7%, OR = 2.10; 2 errors: men = 7.3%, women = 14.2%, OR = 3.71), and overall impression (1 error: men = 75.6%, women = 84.3%, OR = 3.24; 2 errors: men = 2.4%, women = 10.2%, OR = 12.89) compared with men., Conclusions:: Women with ACLR displayed worse LESS scores and were more likely to commit errors related to medial knee displacement and overall landing quality than men with ACLR.

Objective:   To evaluate the current evidence concerning kinematic and kinetic strategies adopted during dynamic landing tasks by patients with anterior cruciate ligament reconstruction (ACLR)., Data Sources:   PubMed, Web of Science., Study Selection:   Original research articles that evaluated kinematics or kinetics (or both) during a landing task in those with a history of ACLR were included., Data Extraction:   Methodologic quality was assessed using the modified Downs and Black checklist. Means and standard deviations for knee or hip (or both) kinematics and kinetics were used to calculate Cohen d effect sizes and corresponding 95% confidence intervals between the injured limb of ACLR participants and contralateral or healthy matched limbs. Data were further stratified by landing tasks, either double- or single-limb landing. A random-effects-model meta-analysis was used to calculate pooled effect sizes and 95% confidence intervals., Data Synthesis:   The involved limbs of ACLR patients demonstrated clinically and significantly lower knee-extension moments during double-legged landing compared with healthy contralateral limbs and healthy control limbs (Cohen d range = -0.81 to -1.23) and decreased vertical ground reaction forces when compared with healthy controls, regardless of task (Cohen d range = -0.39 to -1.75)., Conclusions:   During single- and double-legged landing tasks, individuals with ACLR demonstrated meaningful reductions in injured-limb knee-extension moments and vertical ground reaction forces. These findings indicate potential unloading of the injured limb after ACLR, which may have significant implications for secondary ACL injury and long-term joint health.

Context:   The effect of unilateral cryotherapy-facilitated rehabilitation exercise on involved-limb quadriceps function and limb symmetry in individuals with quadriceps dysfunction after anterior cruciate ligament reconstruction (ACLR) remains unclear., Objective:   To measure the effect of a 2-week unilateral cryotherapy-facilitated quadriceps-strengthening program on knee-extension strength and quadriceps central activation ratio (CAR) in participants with ACLR., Design:   Controlled laboratory study., Setting:   Laboratory., Patients or Other Participants:   A total of 10 volunteers with unilateral ACLR (1 man, 9 women; age = 21.0 ± 2.8 years, height = 164.6 ± 5.0 cm, mass = 64.0 ± 6.1 kg, body mass index = 23.7 ± 2.7 kg/m 2 ) and 10 healthy volunteers serving as control participants (1 man, 9 women; age = 20.8 ± 2.5 years, height = 169.1 ± 6.2 cm, mass = 61.1 ± 6.4 kg, body mass index = 21.4 ± 2.3 kg/m 2 ) participated., Intervention(s):   Participants with ACLR completed a 2-week unilateral cryotherapy-facilitated quadriceps-strengthening intervention., Main Outcome Measure(s):   Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and quadriceps CAR (%) were assessed preintervention and postintervention. Limb symmetry index (LSI) was calculated at preintervention and postintervention testing. Preintervention between-groups differences in unilateral quadriceps function and LSI were evaluated using independent-samples t tests. Preintervention-to-postintervention differences in quadriceps function were evaluated using paired-samples t tests. Cohen d effect sizes (95% confidence interval [CI]) were calculated for each comparison., Results:   Preintervention between-groups comparisons revealed less knee-extension MVIC torque and quadriceps CAR for the ACLR limb (MVIC: P = .01, Cohen d = -1.31 [95% CI = -2.28, -0.34]; CAR: P = .004, Cohen d = -1.48 [95% CI = -2.47, -0.49]) and uninvolved limb (MVIC: P = .03, Cohen d = -1.05 [95% CI = -1.99, -0.11]; CAR: P = .01, Cohen d = -1.27 [95% CI = -2.23, -0.31]) but not for the LSI (MVIC: P = .46, Cohen d = -0.34 [95% CI = -1.22, 0.54]; CAR: P = .60, Cohen d = 0.24 [95% CI = -0.64, 1.12]). In the ACLR group, participants had improved knee-extension MVIC torque in the involved limb ( P = .04, Cohen d = 0.32 [95% CI = -0.56, 1.20]) and uninvolved limb ( P = .03, Cohen d = 0.29 [95% CI = -0.59, 1.17]); however, the improvement in quadriceps CAR was limited to the involved limb ( P = .02, Cohen d = 1.16 [95% CI = 0.21, 2.11]). We observed no change in the LSI with the intervention for knee-extension MVIC torque ( P = .74, Cohen d = 0.09 [95% CI = -0.79, 0.97]) or quadriceps CAR ( P = .61, Cohen d = 0.26 [95% CI = -0.62, 1.14])., Conclusions:   Two weeks of cryotherapy-facilitated exercise may improve involved-limb quadriceps function while preserving between-limbs symmetry in patients with a history of ACLR.

Context:   Anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) result in persistent alterations in lower extremity movement patterns. The progression of lower extremity biomechanics from the time of injury has not been described., Objective:   To compare the 3-dimensional (3D) lower extremity kinematics and kinetics of walking among individuals with ACL deficiency (ACLD), individuals with ACLR, and healthy control participants from 3 to 64 months after ACLR., Data Sources:   We searched PubMed and Web of Science from 1970 through 2013., Study Selection and Data Extraction:   We selected only articles that provided peak kinematic and kinetic values during walking in individuals with ACLD or ACLR and comparison with a healthy control group or the contralateral uninjured limb., Data Synthesis:   A total of 27 of 511 identified studies were included. Weighted means, pooled standard deviations, and 95% confidence intervals were calculated for the healthy control, ACLD, and ACLR groups at each reported time since surgery. The magnitude of between-groups (ACLR versus ACLD, control, or contralateral limb) differences at each time point was evaluated using Cohen d effect sizes and associated 95% confidence intervals. Peak knee-flexion angle (Cohen d = -0.41) and external knee-extensor moment (Cohen d = -0.68) were smaller in the ACLD than in the healthy control group. Peak knee-flexion angle (Cohen d range = -0.78 to -1.23) and external knee-extensor moment (Cohen d range = -1.39 to -2.16) were smaller in the ACLR group from 10 to 40 months after ACLR. Reductions in external knee-adduction moment (Cohen d range = -0.50 to -1.23) were present from 9 to 42 months after ACLR., Conclusions:   Reductions in peak knee-flexion angle, external knee-flexion moment, and external knee-adduction moment were present in the ACLD and ACLR groups. This movement profile during the loading phase of gait has been linked to knee-cartilage degeneration and may contribute to the development of osteoarthritis after ACLR.

It remains unclear what role reduced volume and cross-section area (CSA) of individual quadriceps muscles may play in persistent quadriceps weakness and more global dysfunction following ACL reconstruction (ACLR). The purpose of this investigation was to establish the relationship between cross-sectional area of the quadriceps muscle group and measures of knee related and quadriceps function following ACLR. Thirty participants with a history of primary, unilateral ACLR experiencing persistent quadriceps activation failure participated in this cohort study. Clinical factors including International Knee Documentation Committee (IKDC) score, normalized knee extension MVIC torque (Nm/kg) and quadriceps central activation ratio (CAR, %) were assessed in addition to CSA. Quadriceps CSA was measured via magnetic resonance imaging (MRI; Siemens Avanto 1.5T). Quadriceps CSA (cm(2) ) and quadriceps volume (cm(3) ) as well as individual muscle estimates were identified within a 10 cm mid-thigh capture area. Pearson's product-moment correlation coefficients (r) established relationships between CSA and all other variables. Stepwise linear regression established which CSA factors were able to successfully predict clinical factors. Knee extension MVIC torque was strongly correlated with Vastus Intermedius (VI; r =  0.857, p < 0.001) CSA as well as partial VI (r = 0.849, p < 0.001) and quadriceps (r = 0.830, p < 0.001) volume. Partial VI (r = 0.365, p = 0.047) volume was weakly correlated with IKDC score. Knee extension MVIC torque was strongly predicted using VI CSA alone (R(2)  = 0.725) or in combination with Vastus Medialis CSA (VM; R(2)  = 0.756). Statement of Clinical Significance: Atrophy of the VI and VM muscles negatively impacts knee extension strength following ACLR. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1656-1662, 2016., (© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Objectives: To compare the effects of power training (PWT) and a high-speed yoga program on physical performances in older patients with Parkinson disease (PD), and to test the hypothesis that both training interventions would attenuate PD symptoms and improve physical performance., Design: Randomized controlled trial., Setting: A laboratory of neuromuscular research and active aging., Participants: Patients with PD (N=41; mean age ± SD, 72.2 ± 6.5y)., Interventions: Two high-speed exercise interventions (specifically designed yoga program and PWT) were given for 12 weeks (twice a week), and 1 nonexercise control group., Main Outcome Measures: Unified Parkinson Disease Rating Scale motor score (UPDRSMS), Berg Balance Scale (BBS), Mini-Balance Evaluation Systems Test (Mini-BESTest), Timed Up and Go, functional reach, single leg stance (SLS), postural sway test, 10-m usual and maximal walking speed tests, 1 repetition maximum (RM), and peak power (PPW) for leg press., Results: For the posttests, both training groups showed significant improvements (P<.05) in all physical measurements except functional reach on the more affected side, SLS, and postural sway compared with the pretests, and significantly better scores for UPDRSMS, BBS, Mini-BESTest, Timed Up and Go, functional reach on the less affected side, 10-m usual and maximal walking speed tests, 1RM, and PPW than controls, with no differences detected between the yoga program and PWT., Conclusions: Both the specially designed yoga program and PWT programs can significantly improve physical performance in older persons with PD., (Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Background: After anterior cruciate ligament injury, patients have increased risk for developing degenerative osteoarthritis, potentially due to the kinematic changes that persist after surgical reconstruction. Current research only describes single joint kinematic differences rather than the way in which two joints behave concurrently, termed joint coupling. The purpose of this study was to compare knee motion relative to hip motion in anterior cruciate ligament reconstructed and healthy limbs during walking and jogging., Methods: Thirty-seven recreationally active volunteers (22 reconstructed, 15 healthy) walked and jogged at 4.83 km/h and 9.66 km/h respectively. Vector coding methods were used to calculate stride-to-stride variability, magnitude, and vector angle of 6 joint couples during walking and jogging: hip frontal-knee frontal planes, hip frontal-knee sagittal, hip frontal-knee transverse, hip sagittal-knee frontal, hip sagittal-knee transverse, and hip transverse-knee frontal planes., Findings: The hip sagittal-knee frontal and hip sagittal-knee transverse joint couples had decreased variability during mid-stance, and all other couples had increased variability during the stance phase in the reconstructed group. The reconstructed group had decreased magnitude of joint excursion in the hip frontal-knee sagittal couple during all phases of gait during walking. Vector angles of the hip frontal-knee transverse couple increased in the reconstructed group during the loading, middle, and terminal stance phases, and swing phase of gait during walking., Interpretation: The increased variability and decreased magnitude of joint excursion indicate that movement patterns were less consistent during walking gait despite employing a more constrained system during movement in the reconstructed limb compared to healthy controls., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The purpose of this study was to compare knee extension torque variability in patients with ACL reconstructed knees before and after exercise. Thirty two patients with an ACL reconstructed knee (ACL-R group) and 32 healthy controls (control group) completed measures of maximal isometric knee extension torque (90° flexion) at baseline and following a 30-min exercise protocol (post-exercise). Exercise included 30-min of repeated cycles of inclined treadmill walking and hopping tasks. Dependent variables were the coefficient of variation (CV) and raw-change in CV (ΔCV): CV = (torque standard deviation/torque mean x 100), ΔCV = (post-exercise - baseline). There was a group-by-time interaction (p = 0.03) on CV. The ACL-R group demonstrated greater CV than the control group at baseline (ACL-R = 1.07 ± 0.55, control = 0.79 ± 0.42, p = 0.03) and post-exercise (ACL-R = 1.60 ± 0.91, control = 0.94 ± 0.41, p = 0.001). ΔCV was greater (p = 0.03) in the ACL-R group (0.52 ± 0.82) than control group (0.15 ± 0.46). CV significantly increased from baseline to post-exercise (p = 0.001) in the ACL-R group, while the control group did not (p = 0.06). The ACL-R group demonstrated greater knee extension torque variability than the control group. Exercise increased torque variability more in the ACL-R group than control group., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Context: Individuals with a history of anterior cruciate ligament reconstruction (ACLR) are at greater risk of reinjury and developing early-onset osteoarthritis due to persistent abnormal joint loading. Real-time clinical assessment tools may help identify patients experiencing abnormal movement patterns after ACLR., Objective: To compare performance on the Landing Error Scoring System (LESS) between participants with ACLR and uninjured control participants and to determine the relationship between LESS score and knee-extension strength in these participants., Design: Controlled laboratory study., Setting: Research laboratory., Patients or Other Participants: Forty-six recreationally active participants, consisting of 22 with ACLR (12 men, 10 women; age = 22.5 ± 5.0 years, height = 172.8 ± 7.2 cm, mass = 74.2 ± 15.6 kg, body mass index = 24.6 ± 4.0) and 24 healthy control participants (12 men, 12 women; age = 21.7 ± 3.6 years, height = 168.0 ± 8.8 cm, mass = 69.2 ± 13.6 kg, body mass index = 24.3 ± 3.2) were enrolled., Main Outcome Measure(s): Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and LESS scores were measured during a single testing session. We compared LESS scores between groups using a Mann-Whitney U test and the relationships between LESS scores and normalized knee-extension MVIC torque using Spearman ρ bivariate correlations., Results: The ACLR participants had a greater number of LESS errors (6.0 ± 3.6) than healthy control participants (2.8 ± 2.2; t44 = -3.73, P = .002). In ACLR participants, lower normalized knee-extension MVIC torque in the injured limb (ρ = -0.455, P = .03) was associated with a greater number of landing errors., Conclusions: Participants with ACLR displayed more errors while landing. The occurrence of landing errors was negatively correlated with knee-extension strength, suggesting that weaker participants had more landing errors. Persistent quadriceps weakness commonly associated with ACLR may be related to a reduced quality of lower extremity movement during dynamic tasks.

Context: Return to activity in the presence of quadriceps dysfunction may predispose individuals with anterior cruciate ligament reconstruction (ACLR) to long-term joint degeneration. Asymmetry may manifest during movement and result in altered knee-joint-loading patterns; however, the underlying neurophysiologic mechanisms remain unclear., Objective: To compare limb symmetry of quadriceps neuromuscular function between participants with ACLR and participants serving as healthy controls., Design: Descriptive laboratory study., Setting: Research laboratory., Patients or Other Participants: A total of 22 individuals with ACLR (12 men, 10 women) and 24 individuals serving as healthy controls (12 men, 12 women)., Main Outcome Measure(s): Normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg), quadriceps central activation ratio (CAR) (%), quadriceps motor-neuron-pool excitability (Hoffmann reflex to motor wave ratio), and quadriceps active motor threshold (AMT) (% 2.0 T) were measured bilaterally and used to calculate limb symmetry indices for comparison between groups. We used analyses of variance to compare quadriceps Hoffmann reflex to motor wave ratio, normalized knee-extension MVIC torque, quadriceps CAR, and quadriceps AMT between groups and limbs., Results: The ACLR group exhibited greater asymmetry in knee-extension MVIC torque (ACLR group = 0.85 ± 0.21, healthy group = 0.97 ± 0.14; t44 = 2.26, P = .03), quadriceps CAR (ACLR group = 0.94 ± 0.11, healthy group = 1.00 ± 0.08; t44 = 2.22, P = .04), and quadriceps AMT (ACLR group = 1.13 ± 0.18, healthy group = 1.02 ± 0.11; t34 = -2.46, P = .04) than the healthy control group., Conclusions: Asymmetries in measures of quadriceps function and cortical excitability were present in patients with ACLR. Asymmetry in quadriceps strength, activation, and cortical excitability persisted in individuals with ACLR beyond return to recreational activity. Measuring the magnitude of asymmetry after ACLR represents an important step in understanding long-term reductions in self-reported function and increased rate of subsequent joint injury in otherwise healthy, active individuals after ACLR.

Context: Persistent muscle weakness after anterior cruciate ligament (ACL) reconstruction may be due to underlying activation failure and arthrogenic muscle inhibition (AMI). Knee-joint cryotherapy has been shown to improve quadriceps function transiently in those with AMI, thereby providing an opportunity to improve quadriceps muscle activation and strength in patients with a reconstructed ACL., Objective: To compare quadriceps muscle function in patients with a reconstructed ACL who completed a 2-week intervention including daily cryotherapy (ice bag), daily exercises, or both., Design: Cross-sectional study., Setting: Laboratory., Patients or Other Participants: A total of 30 patients with reconstructed ACLs who were at least 6 months post-index surgery and had measurable quadriceps AMI., Intervention(s): The patients attended 4 supervised visits over a 2-week period. They were randomly assigned to receive 20 minutes of knee-joint cryotherapy, 1 hour of therapeutic rehabilitation exercises, or cryotherapy followed by exercises., Main Outcome Measure(s): We measured quadriceps Hoffmann reflex, normalized maximal voluntary isometric contraction torque, central activation ratio using the superimposed-burst technique, and patient-reported outcomes before and after the intervention period., Results: After the 2-week intervention period, patients who performed rehabilitation exercises immediately after cryotherapy had higher normalized maximal voluntary isometric contraction torques (P = .002, Cohen d effect size = 1.4) compared with those who received cryotherapy alone (P = .16, d = 0.58) or performed exercise alone (P = .16, d = 0.30)., Conclusions: After ACL reconstruction, patients with AMI who performed rehabilitation exercises immediately after cryotherapy experienced greater strength gains than those who performed cryotherapy or exercises alone.

Context: Sex differences in lower extremity neuromuscular function have been reported after anterior cruciate ligament reconstruction (ACLR). Research evidence supports different levels of fatigability in men and women and between patients with ACLR and healthy controls. The influence of sex on the response to continuous exercise in patients with ACLR is not clear., Objective: To compare quadriceps neuromuscular function after exercise between men and women with ACLR., Design: Descriptive laboratory study., Setting: Laboratory., Patients or Other Participants: Twenty-six active volunteers (13 men [50%]: age = 24.1 ± 4.4 years, height = 179.1 ± 9.8 cm, mass = 80.1 ± 9.4 kg, months since surgery = 43.5 ± 37.0; 13 women [50%]: age = 24.2 ± 5.6 years, height = 163.0 ± 5.9 cm, mass = 62.3 ± 8.3 kg, months since surgery = 45.8 ± 42.7) with a history of unilateral primary ACLR at least 6 months earlier., Intervention(s): Thirty minutes of continuous exercise comprising 5 separate 6-minute cycles, including 5 minutes of uphill walking and 1 minute of body-weight squatting and step-ups., Main Outcome Measure(s): Normalized knee-extension maximal voluntary isometric contraction torque, quadriceps superimposed-burst torque, and quadriceps central activation ratio before and after exercise. We performed separate 2 (sex: men, women) × 2 (time: preexercise, postexercise) repeated-measures analyses of variance for the 3 variables. Separate, independent-samples t tests were calculated to compare preexercise with postexercise change in all dependent variables between sexes., Results: A significant group-by-time interaction was present for knee-extension torque (P = .04). The percentage reduction in knee-extension maximal voluntary isometric contraction torque (men = 1.94%, women = -10.32%; P = .02) and quadriceps central activation ratio (men = -1.45%, women = -8.69%; P = .03) experienced by men was less than that observed in women., Conclusions: In the presence of quadriceps dysfunction, female participants experienced greater-magnitude reductions in quadriceps function after 30 minutes of exercise than male participants. This indicates a reduced ability to absorb knee-joint loads, which may have significant implications for reinjury and joint osteoarthritis in women after ACLR.

Background. The purpose of this study was to compare outcomes of medial patellofemoral ligament (MPFL) repair or reconstruction. Methods. Fourteen knees that underwent MPFL repair and nine (F5, M4) knees that underwent reconstruction at our institution were evaluated for objective and subjective outcomes. The mean age at operation was 20.1 years for repair and 19.8 years for reconstruction. All patients had a minimum of 2 years of follow-up (range: 24-75 months). Patient subjective outcomes were obtained using the International Knee Documentation Committee (IKDC) and Kujala patellofemoral subjective evaluations, as well as Visual Analog (VAS) and Tegner Activity Scales. Bilateral isometric quadriceps strength and vastus medialis obliquus (VMO) and vastus lateralis (VL) surface EMG were measured during maximal isometric quadriceps contractions at 30° and 60° of flexion. Results. There were no redislocations in either group. There was no difference in IKDC (P = 0.16), Kujala (P = 0.43), Tegner (P = 0.12), or VAS (P = 0.05) scores at follow-up. There were no differences between repair and reconstruction in torque generation of the involved side at 30° (P = 0.96) and 60° (P = 0.99). In addition, there was no side to side difference in torque generation or surface EMG activation of VL or VMO. Conclusions. There were minimal differences found between patients undergoing MPFL repair and MPFL reconstruction for the objective and subjective evaluations in this study.

Purpose: This study aimed to compare the effects of 36 min of continuous exercise on postural control and joint reposition acuity in patients with anterior cruciate ligament reconstruction (ACL-R) and healthy controls., Methods: Twenty patients (10 women and 10 men; mean ± SD; age = 25.5 ± 5.5 yr, height = 1.75 ± 0.10 m, weight = 76.7 ± 14.4 kg) with a history of primary, uncomplicated ACL-R (5.0 ± 4.3 yr postsurgery) were matched to 20 healthy controls (10 women and 10 men, 24.6 ± 5.0 yr, 1.70 ± 0.09 m, 65.2 ± 12.1 kg). The center of pressure (COP) excursions in the medial-lateral (COP(ML-SD)) and anterior-posterior (COP(AP-SD)) directions and the velocity (COP(Vel)) and area (COP(Area)) were calculated during static, unipedal stance. Open-chain knee joint reposition acuity measures (absolute angular error [AAE] and relative angular error [RAE]) at 45° (AAE₄₅ and RAE₄₅) and 15° of knee flexion (AAE₁₅ and RAE₁₅) were recorded. Measures were recorded at baseline and after a 36-min exercise protocol. Exercise consisted of six repeating cycles of inclined treadmill walking (5 min) and jumping exercises (1 min)., Results: At baseline, the ACL-R group exhibited higher magnitude AAE₄₅ compared with controls. AAE₄₅ and COP(ML-SD) significantly increased after exercise in the control group; however, the ACL-R group did not experience a change in these measures., Conclusions: In a rested state, patients with a history of ACL-R have greater impairment in joint reposition acuity than healthy control. Exercise increased COP measurements and impaired joint reposition acuity. Healthy controls experienced impaired joint reposition acuity after exercise, whereas patients with a history of ACL-R did not.

Objective: To compare strength and quadriceps muscle activation in anterior cruciate ligament-deficient patients who underwent a two-week rehabilitation exercise program using TENS or cryotherapy., Design: Randomized, controlled study., Setting: Clinical research laboratory., Subjects: Thirty patients: 20 males, 10 females, 31.6 (13.0) years, 172.8 (10.0) cm, 75.8 (13.0) kg with diagnosed tear of the anterior cruciate ligament., Interventions: All patients attended four sessions of supervised quadriceps strengthening exercises over two weeks, prior to reconstruction surgery. Patients were randomly allocated (n = 10/group) to receive exercises alone, exercise while wearing a sensory transcutaneous electrical nerve stimulation (TENS) device on the knee joint for the duration of each daily session, or 20 minutes of knee joint cryotherapy immediately prior to each daily exercise session., Main Measures: Normalized knee extension force and quadriceps central activation ratio were measured before and after the first supervised treatment session and within 24 hours of the last session., Results: When accounting for differences in baseline measures, there were no statistically significant group differences immediately following the first exercise session for knee extension force (P = 0.10) or central activation ratio (P = 0.30) nor were there statistically significant group differences after the two-week intervention for knee extension force (P = 0.92) or central activation ratio (P = 0.94). Effect sizes for the change in knee extension force and central activation ratio after two weeks of therapy were all large., Conclusions: Quadriceps strength and central activation in anterior cruciate ligament deficient patients improved after two weeks of rehabilitaiton exercises, however, there were no significant differences between treatment groups.