Comparison of Step-Based Metrics Under Laboratory and Free-Living Conditions in Femoroacetabular Impingement Syndrome.

CONTEXT: Femoroacetabular impingement syndrome (FAIS) causes pain and functional limitations. Little is known regarding walking characteristics, volume and intensity evaluated in laboratory and free-living conditions and whether these measures differ between those with FAIS and uninjured individuals. OBJECTIVE: To examine the differences in laboratory gait measures and free-living step-based metrics between individuals with FAIS and uninjured control participants. DESIGN: Comparative, cross-sectional study. PATIENTS OR OTHER PARTICIPANTS: We enrolled 25 participants with FAIS and 14 uninjured controls. MAIN OUTCOME MEASURES: We evaluated laboratory spatiotemporal gait measures (cadence, velocity, step length, stride length) during self-selected and fast walking speeds using an instrumented walkway. Participants then wore an accelerometer around the waist during waking hours for 7 consecutive days. Free-living step-based metrics included average daily steps, peak 1- and 30-minute cadence, and average daily time spent in walking cadence bands. We compared laboratory gait measures and step-based metrics between groups. RESULTS: The groups did not differ in laboratory spatiotemporal gait measures during both speeds (all p>0.05). The FAIS group took fewer daily steps (5,346±2,141 vs. 7,338±2,787 steps/day; p=0.030) and had a lower peak 1-minute (92.9±23.9 vs. 119.6±16.3 steps/min; p<0.001) and 30- minute cadences (60.9±27.1 vs. 86.8±22.4 steps/min; p=0.003) compared with uninjured controls, respectively. The FAIS group also spent less time in slow (6.0±3.6 vs. 10.3±3.4 min/day; p=0.001), medium (4.5 + 4.2 vs. 8.9±4.4 min/day; p=0.005), and brisk/moderate (4.5±6.2 vs. 12.2±10.3; p=0.020) cadence bands compared with uninjured controls. CONCLUSIONS: Considering only clinical/laboratory gait measures may not be representative of real- world walking-related PA behavior in individuals with FAIS.

Fat-free mass mediates the association between body mass and jump height in healthy young adults.

BACKGROUND: The countermovement jump (CMJ) is a reliable and valid test of lower-extremity (LE) muscle power and neuromuscular performance. Body mass is positively associated with CMJ performance in young adults, warranting the examination of the influence of body composition on jump height (JH). This study examined the mediation effects of body composition on CMJ performance in young adults. The hypothesis was that fat-free mass and percent fat mass would significantly mediate the association between body mass with JH in young adults. METHODS: Healthy young adults (N.=81; 47 female; mean age 25.1±3.4) completed this study and underwent body composition assessment using a bioelectrical impedance analysis device. Participants performed three CMJ trials to measure average JH using an electronic jump mat. Mediation analysis models were performed to examine the hypothesis of this study. RESULTS: The mediation analyses indicated that the indirect effects of fat-free mass on the association between body mass with JH were significant (indirect effect [IE]=-0.23, 95% CI -0.315, 0.767; IE=0.76, 95% CI 0.334, 1.272; respectively), after controlling for sex and percent fat mass. CONCLUSIONS: The association between body mass with JH in young adults with normal BMI was mediated by fat-free mass. Clinicians, trainers, and coaches should potentially target increasing fat-free mass when improving LE power and neuromuscular performance in rehabilitation and sports settings in this population, but further studies are needed.

Outcomes and Proportions of Subsequent Contralateral Sports Hernia Repair Following Primary Unilateral Repair.

BACKGROUND: In the event that nonoperative treatment for sports hernia fails, surgical repair may be warranted. Bilateral repair can occur in up to 45% of surgically treated patients. PURPOSE: To investigate the clinical outcomes of athletes who underwent unilateral sports hernia repair and determine the proportion of patients who required contralateral sports hernia repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We identified patients at our institution who underwent primary unilateral sports hernia repair (rectus abdominis-adductor longus aponeurotic plate repair and adductor lengthening) with a single surgeon between 2015 and 2020. We assessed patient-reported outcomes using the Hip Outcome Score-Sport (HOS-Sport), the Numeric Pain Rating Scale, and an internally developed return-to-play questionnaire. We further collected data regarding subsequent sports hernia procedures on the ipsilateral or contralateral side. We calculated summary statistics for outcomes and examined the association between preinjury patient characteristics and the HOS-Sport score at follow-up or successful return to preinjury sport using linear and logistic regression, respectively. RESULTS: A total of 104 of 128 (81.3%) eligible patients (mean age at surgery, 23.0 ± 6.2 years; 94.2% male; 51.9% American football athletes) completed follow-up at a mean time of 4.4 ± 1.5 years. Overall, 79.8% of athletes (n = 83) were able to return to their preinjury sport/activity, but 90.2% (83/92) who attempted to return were able to do so. When examining reasons for not returning to preinjury sport, only 9 patients reported not returning to preinjury sport because of limitations or persistent symptoms from their original injury. Only 4 patients underwent subsequent sports hernia procedures (3 contralateral, 1 ipsilateral revision) after their index unilateral sports hernia repair. At follow-up, the mean HOS-Sport score was high (94.0 ± 10.8), and the mean Numeric Pain Rating Scale score was low (0.31 ± 1.26). There were no preinjury patient characteristics associated with either the HOS-Sport score at follow-up or the successful return to preinjury sport. CONCLUSION: Patients with unilateral sports hernia symptoms can undergo repair and return to sport at the preinjury level with little concern for injuries to the contralateral groin. In our cohort, patient-reported hip function and pain outcomes at follow-up were excellent.

Technique and Outcomes of Posterior Cruciate Ligament Repair With Augmentation.

Background: Posterior cruciate ligament (PCL) injuries to the knee are uncommon, and ideal surgical management of these injuries is unclear. Current surgical techniques include PCL reconstruction with remnant debridement, remnant-preserving techniques, and primary PCL repair. Augmentation of PCL repairs and reconstructions has been proposed to protect repairs or grafts in the postoperative period. Purpose: To describe PCL repair with the hamstring autograft augmentation technique and examine our preliminary midterm outcomes from a sequential cohort of patients. Study Design: Case series; Level of evidence, 4. Methods: The authors identified patients at their institution who underwent remnant-preserving primary PCL repair with hamstring autograft augmentation for both isolated tears and tears associated with multiligament knee injury (MLKI). Patient-reported outcomes were evaluated at a minimum 2-year follow-up using the International Knee Documentation Committee (IKDC) subjective knee form, the 12-item Short Form Survey, and a custom return-to-play questionnaire. Patient-reported outcomes data were summarized, and the predictors of outcomes from the descriptive data and clinical measures were further examined. Results: A total of 23 patients with a mean follow-up of 5.3 years met the inclusion criteria. Of these patients, 87% were associated with MLKI. The mean IKDC score was 87.7. Approximately 83% of patients were able to successfully return to their sport or occupation. Among 19 athletes, only 2 reported being unable to return to their preinjury level of sport because of limitations from their PCL surgery. Patient-reported outcome scores and return to sport or occupation did not have a statistically significant association with age, sex, body mass index, time from injury to surgery, or follow-up time. Conclusion: Outcomes of our cohort with remnant-preserving primary PCL repairs with hamstring autograft augmentation demonstrated comparable clinical outcomes to previously published PCL data. The advantages of remnant preservation, primary repair, and augmentation with an independent hamstring autograft reconstruction are combined within this technique.

Outcomes of Double-Row Rotator Cuff Repair Using a Novel All-Suture Soft Anchor Medial Row.

Background: Few studies have examined the short-term clinical outcomes of rotator cuff repair (RCR) with all-suture anchors for medial row anchor fixation. Purpose: To evaluate clinical outcomes of double-row suture bridge RCR using a novel all-suture medial row anchor. Study Design: Case series; Level of evidence, 4. Methods: We enrolled 179 patients before double-row suture bridge RCR (mean age at surgery, 60.0 years; 63% male patients) at a single institution. All patients underwent RCR with all-suture anchor fixation for the medial row and solid anchor fixation for the lateral row. Preoperative (baseline) and follow-up (minimum follow-up time of 2 years; mean, 2.5 years) clinical outcomes were compared using the American Shoulder and Elbow Surgeons (ASES) score and a 10-point numeric pain rating scale (NPRS). We calculated the proportions of patients meeting previously published Patient Acceptable Symptom State (PASS) thresholds for the ASES (≥78.0) and NPRS (≤1.7). We further compared baseline and follow-up outcome scores and the proportions of patients meeting PASS thresholds using paired t tests and McNemar tests, respectively, and calculated effect size to quantify the magnitude of change from baseline to follow-up. Results: Values significantly improved from baseline to follow-up for ASES (from 45.3 ± 19.8 to 87.3 ± 17.1) and NPRS (from 5.2 ± 2.5 to 1.4 ± 2.1). The proportion of patients meeting PASS thresholds also significantly improved for the ASES (from 6% to 77%) and the NPRS (from 7% to 72%). The magnitude of baseline to follow-up change for all measures was large (all effect sizes ≥1.5). Conclusion: Our study demonstrated excellent short-term clinical outcomes and substantial improvements for patients undergoing double-row suture bridge RCR with all-suture anchors for medial row fixation.

Demographic and Clinical Correlates of Device-Measured Physical Activity Levels in Individuals with Femoroacetabular Impingement Syndrome.

Objective: To compare physical activity (PA) levels between individuals with femoroacetabular impingement syndrome (FAIS) and uninjured controls and determine correlates of moderate to vigorous physical activity (MVPA). Design: Cross-sectional, comparative study. Setting: University laboratory. Participants: A total number of 25 individuals with FAIS (15 female; age, 31.0±9.2 years; symptom duration, 4.7±7.1 years) and 14 uninjured controls (9 female; age, 28.0±9.1 years) (N=39). Interventions: Not applicable. Main Outcome Measures: All individuals wore an accelerometer around the waist during waking hours for 7 days. We compared demographic, clinical data, and PA levels between groups using independent samples t tests and compared the proportions of those meeting the PA guideline cutoff (150min/wk) using a chi-square test. Additionally, we examined correlates of mean daily MVPA using linear regression in both groups. Results: Individuals with FAIS spent less time in MVPA (controls, 52.1±25.6min/d; FAIS, 26.9±19.1min/d; P=.001) and took fewer steps (controls, 8428±2931 steps/d; FAIS, 6449±2527 steps/d; P=.033) than uninjured controls. A lower proportion of individuals with FAIS met the PA cutoff (40.0%) compared with uninjured controls (78.6%; P=.020). Higher body mass index (BMI) values and lower (worse) Hip Disability and Osteoarthritis Outcome Score (HOOS)-Quality of Life subscale scores were associated with lower mean daily MVPA in those with FAIS (R 2=21.2%, P=.021; R 2=22.0%, P=.018; respectively) but not in uninjured controls. Conclusions: Individuals with FAIS spent less time in daily MVPA, took fewer daily steps, and met recommended PA guideline cutoffs at lower proportions compared with uninjured controls. Higher BMI and lower HOOS-Quality of Life scores were associated with lower mean daily MVPA. Interventions should be developed for individuals with FAIS to increase PA engagement to potentially lessen the risk of future comorbidities associated with decreased PA and increased BMI.

30-Second Chair Stand Test Predicts Countermovement Jump Performance in Young Adults.

BACKGROUND: The countermovement jump (CMJ) is a valid and reliable test of lower extremity (LE) muscle power. However, the CMJ may not be appropriate during early-stage rehabilitation of injuries. Functional muscle strength tests (FMSTs) could evaluate LE muscle power with lower joint reaction forces. HYPOTHESIS: The lateral step-up test (LSUT), 5 times sit to stand (5×STS), and 30-s chair stand test (30CST) could predict CMJ jump height (JHt) and jump peak power (JPow). STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 2. METHODS: Eighty-one young adults performed 3 CMJs to measure JHt and JPow using an electronic jump mat and speed analyzer. Participants also performed three FMSTs: 1 trial of the LSUT and a modified trial of LSUT touching the ground with the heel only (MLSUT); 2 trials of the 5×STS; and 2 trials of the 30CST, in a randomized order. Spearman rho correlations and hierarchal multiple linear regressions were used to determine whether FMST performances predicted JHt and JPow, after controlling for sex, body height, and body mass. RESULTS: 30CST, LSUT, MLSUT, sex, body mass, and body height were significantly associated with JHt (P < 0.05). LSUT, sex, body height, and body mass were significantly associated with JPow (P < 0.05). Hierarchical regression analyses showed that the 30CST significantly predicted JHt (P < 0.01) and JPow (P = 0.03), independent of sex, body height, and body mass. CONCLUSION: 30CST performance predicted JHt and JPow in young adults. CLINICAL RELEVANCE: The 30CST is easy to perform, requires equipment found readily in clinics, and predicts LE muscle power. This test could be used to track progress during the early stages of LE injury rehabilitation.

Intra-rater Reliability of a Qualitative Landing Scale for the Single-Hop Test: A Pilot Study.

Background: The test battery classically used for return-to-sport (RTS) decision-making after anterior cruciate ligament (ACL) reconstruction (ACLR) may not be sufficient, as it does not include a qualitative analysis of movement. Therefore, the Landing Error Scoring System (LESS) scale was adapted to a primary functional test in the typical RTS test battery: the single leg hop for distance (SHD). Hypothesis/ Purpose: The aim of this study was to determine the intra-rater reliability of the LESS scale adapted to the SHD (SHD-LESS scale) in healthy young athletes. Study Design: Reliability analysis. Methods: Nineteen healthy individuals (14 men, 5 women; mean age: 22.4 years) participated in the study. Participants performed the SHD tasks on both limbs (dominant and non-dominant) using a standardized protocol in two sessions that were one week apart (single reviewer; 2-dimensional video). Intra-class correlation coefficients (ICC2,1) were used to measure the reproducibility of the scale in the dominant (dom) and non-dominant (nondom) limbs. Additionally, limb data (dom and nondom) were pooled and evaluated collectively with intra-class correlation coefficients. The Kappa coefficient was used to assess the reproducibility of each individual item of SHD-LESS scale. Results: The intra-rater reliability was good (ICCdom = 0.77; ICCnondom = 0.87; ICCpooled = 0.87) for the overall SHD-LESS scale scores. Agreement of SHD-LESS individual items ranged from 62% to 100%. Dorsiflexion at initial contact (97% agreement; kappa value=0.79) and knee valgus after landing (88% agreement; kappa value=0.65) had excellent agreement and kappa values. Conclusion: The newly-adapted SHD-LESS scale showed good intra-rater reliability overall. Further studies should evaluate the impact of using the SHD-LESS scale within the RTS test battery on outcomes in patients after ACLR. Level of Evidence: 3.

Few young athletes meet newly derived age- and activity-relevant functional recovery targets after ACL reconstruction.

PURPOSE: National registry data have established Knee injury and Osteoarthritis Outcome Score (KOOS) functional recovery target values for adults after anterior cruciate ligament (ACL) reconstruction. However, the specificity of these target values for young athletes after ACL reconstruction is unclear. The purpose of this analysis was to (1) derive age- and activity-relevant KOOS functional recovery target values from uninjured young athlete data and (2) determine clinical measures at the time of RTS clearance associated with meeting the newly-derived functional recovery target values in young athletes following ACLR. METHODS: Two hundred and twenty-two young athletes (56 uninjured controls, 17.2 ± 2.4 years, 73% female; 166 after ACL reconstruction, 16.9 ± 2.2 years, 68% female) were included in this cross-sectional analysis from a larger cohort study. Uninjured control participants completed the KOOS, and functional recovery target values were defined as the lower bound of the 95% confidence interval for KOOS subscales. ACL reconstruction participants completed testing within 4 weeks of return-to-sport clearance, including the KOOS, single-leg hop tests, and isometric quadriceps strength. In ACL reconstruction participants, logistic regression was used to determine predictors of meeting all KOOS functional recovery target values (primary outcome) among demographic/injury, hop, and strength data (α ≤ 0.05). RESULTS: KOOS functional recovery target values for each subscale from uninjured athlete data were: Pain ≥ 94, Symptoms ≥ 92, Activities of Daily Living ≥ 97, Sport ≥ 92, and Quality-of-Life ≥ 92. At the time of return-to-sport clearance, ACL reconstruction participants met the KOOS functional recovery targets in the following proportions: Pain, 63%; Symptoms, 42%; Activities of Daily Living, 80%; Sport, 45%; Quality-of-Life, 24%; overall functional recovery (met all subscale targets), 17%. In ACL reconstruction participants, significant predictors of overall functional recovery (primary outcome) were: younger age, hamstring graft, pediatric ACL reconstruction, quadriceps strength limb-symmetry index > 90%, single-hop limb-symmetry index > 90%, and crossover-hop limb-symmetry index > 90%. CONCLUSIONS: KOOS functional recovery target values derived from uninjured young athletes were higher than those previously reported. Small proportions of young athletes following recent RTS clearance after ACLR met these newly-derived functional recovery target values, and factors associated with meeting functional recovery target values included younger age, hamstring autograft and pediatric ACLR, and having > 90% LSI for quadriceps strength and single-leg hop tests. LEVEL OF EVIDENCE: I.

Passing return-to-sport criteria and landing biomechanics in young athletes following anterior cruciate ligament reconstruction.

We sought to evaluate the sagittal plane knee joint loading patterns during a double-leg landing task among young athletes who passed or failed return-to-sport (RTS) criteria following anterior cruciate ligament reconstruction reconstruction (ACLR), and in uninjured athletes. Participants completed quadriceps strength testing, a hop test battery, and the International Knee Documentation Committee subjective form following medical RTS clearance. ACLR participants "passed" RTS criteria (RTS-PASS) if they met ≥90 limb symmetry (%) or score on all measures and were categorized as "failing" (RTS-FAIL) if not. All participants completed three-dimensional motion analysis testing. Sagittal plane kinematic and kinetic variables were calculated during a double-leg drop vertical jump task. Mean limb values and limb symmetry indices (LSI; %) were calculated and compared using a one-way analysis of variance (ANOVA) (for LSI) and mixed between-within ANOVA (for group × limb differences). A total of 205 participants were included, with 39 in the RTS-PASS group, 109 in the RTS-FAIL group, and 57 control groups (CTRLs). The RTS-FAIL group demonstrated lower symmetry values for peak vertical ground reaction force, peak internal knee extension moment, and peak knee flexion angle. Group × limb interactions were observed for peak vertical ground reaction force and peak internal knee extension moment. Involved limb values were reduced in the RTS-PASS and RTS-FAIL groups compared to CTRLs, while the RTS-PASS groups had lower uninvolved limb values compared to the RTS-FAIL and CTRLs. Clinical Significance: Young athletes who pass RTS criteria after ACLR land symmetrically during a double-leg task, but symmetry was achieved by reducing loading on both limbs.

Return-to-sport quadriceps strength symmetry impacts 5-year cartilage integrity after anterior cruciate ligament reconstruction: A preliminary analysis.

Quadriceps femoris strength asymmetry at the time of return to sports participation after anterior cruciate ligament (ACL) reconstruction contributes to worse function and asymmetric landing patterns, but the impact on longitudinal outcomes is not known. This study determined if young athletes after ACL reconstruction with quadriceps femoris strength asymmetry at a return to sports clearance would demonstrate markers of knee cartilage degeneration 5 years later compared to those with symmetric quadriceps femoris strength at return to sports. Participants (n = 27) were enrolled at the time of medical clearance for sports participation (baseline testing) and followed for 5 years. At baseline, quadriceps femoris strength was measured bilaterally and a limb symmetry index was used to divide the cohort into two groups: return to sport clearance with high quadriceps femoris strength (RTS-HQ; limb symmetry index ≥ 90%) and return to sport clearance with low quadriceps femoris strength (RTS-LQ; limb symmetry index < 85%). At 5 years post-baseline, quantitative magnetic resonance imaging (T2 relaxation times (ms): involved knee medial/lateral femoral condyle and tibial plateau) data were collected. Group differences were evaluated with independent samples t tests. At 5 years post-return to sports, the RTS-LQ strength group (n = 14) demonstrated elevated T2 relaxation times at the anterior region of the lateral femoral condyle compared to the RTS-HQ strength group (n = 13). Clinical Significance: Just over 50% of this cohort was cleared for sports participation with involved limb quadriceps femoris strength deficits that may contribute to early markers of knee cartilage degeneration within the subsequent 5 years.

Movement Patterns and Their Associations With Pain, Function, and Hip Morphology in Individuals With Femoroacetabular Impingement Syndrome: A Scoping Review.

OBJECTIVE: The purpose of the study was to synthesize studies of movement patterns and their association with hip pain, function/activity, and morphology in individuals with femoroacetabular impingement syndrome (FAIS). METHODS: PubMed, SPORTDiscus, CINAHL, Embase, and Scopus databases were searched using predefined terms. Two authors independently reviewed abstracts and full texts. Studies were included if they enrolled individuals with FAIS, reported kinematic or kinetic data during movement tasks, and tested the data's associations with hip pain, function/activity, or morphology. Exclusion criteria were studies that did not evaluate associations between movement patters and pain, function/activity, or hip morphology. Additionally, studies with hip conditions other than FAIS, case reports, conference proceedings, review articles, and non-English studies were excluded. Descriptive consolidation and qualitative synthesis were performed for the included studies. RESULTS: Of the 1155 potential studies, 5 studies met all eligibility criteria. Movement patterns were evaluated during walking (n = 4) and squatting (n = 1). Studies reported multiple associations between variables of interest. Statistically significant associations were identified between movement patterns and hip pain (n = 2), function/activity (n = 2), or morphology (n = 3). Significant associations included increased hip flexion moment impulse during walking was associated with worse pain, increased hip flexion moment during walking was associated with worse hip function, decreased hip external rotation during gait and hip internal rotation during squat were associated with larger cam deformity, and increased hip flexion moment impulse during walking was also associated with more severe acetabular cartilage abnormalities. CONCLUSIONS: Very little current evidence has evaluated the associations between altered movement patterns and hip pain, function/activity, or morphology in individuals with FAIS, and only low-intensity tasks have been tested. These studies found some preliminary associations between altered hip biomechanics and higher hip pain, worse hip function, and specific measures of hip morphology in individuals with FAIS. IMPACT: This review is a first step in gaining a better understanding of movement patterns and their associations with hip pain, function/activity, and morphology, which could ultimately assist with the development of movement retraining interventions and potentially improve rehabilitation outcomes for those with FAIS.

Young athletes after ACL reconstruction with asymmetric quadriceps strength at the time of return-to-sport clearance demonstrate drop-landing asymmetries two years later.

BACKGROUND: Quadriceps strength asymmetry at the time of return-to-sport (RTS) after anterior cruciate ligament reconstruction (ACLR) contributes to altered landing mechanics. However, the impact of RTS quadriceps strength on longitudinal alterations in landing mechanics, a risk factor for poor knee joint health over time, is not understood. The purpose of this study was to test the hypothesis that young athletes with quadriceps strength asymmetry at the time of RTS clearance after ACLR would demonstrate asymmetric landing mechanics 2 years later compared to those without quadriceps strength asymmetry. METHODS: We followed 57 young athletes (age at RTS = 17.6 ± 3.0 years; 77% females) with primary, unilateral ACLR for 2 years following RTS clearance. At RTS, we measured isometric quadriceps strength bilaterally and calculated limb-symmetry indices [LSI = (involved/uninvolved)×100%]. Using RTS quadriceps LSI, we divided participants into High-Quadriceps (HQ; LSI ≥ 90%) and Low-Quadriceps (LQ; LSI < 85%) groups. Two years later, we assessed landing mechanics during a drop-vertical jump (DVJ) task using three-dimensional motion analysis. We compared involved/uninvolved limb values and LSI between the HQ and LQ groups using Mann-Whitney U tests. RESULTS: The LQ group (n = 26) demonstrated greater asymmetry (lower LSI) during landing at 2 years post-RTS for knee flexion excursion (p = 0.016) and peak vertical ground reaction force (p = 0.006) compared to the HQ group (n = 28). There were no group differences in uninvolved or involved limb values for all variables (all p > 0.093). CONCLUSION: Young athletes after ACLR with quadriceps strength asymmetry at the time of RTS favored the uninvolved limb during DVJ landing 2 years later. These landing asymmetries may relate to long-term knee joint health after ACLR.

Mobility-related outcomes for periacetabular osteotomy in persons with acetabular dysplasia: setting the stage for measurement of real-world outcomes.

Periacetabular osteotomy (PAO) is a surgery for persons with symptomatic acetabular dysplasia (AD) that increases acetabular coverage of the femoral head for reducing hip pain and improving function. Patient-reported outcomes (PROs) are significantly improved following PAO, yet little is known regarding mobility-related outcomes. This narrative review provides a synthesis of evidence regarding PROs and mobility-related outcomes in persons with AD following PAO. We further identified important future research directions, chiefly the need for measurement of real-world outcomes. We searched PubMed using comprehensive predefined search terms. We included studies that (i) enrolled persons with AD undergoing PAO, (ii) included PROs and/or mobility-related outcomes and (iii) were written in English. We synthesized and summarized study characteristics and findings. Twenty-three studies were included in this review. Commonly evaluated PROs included pain (n = 14), hip function (n = 19) and quality of life (n = 9). Mobility-related outcomes included self-reported physical activity (PA; n = 11), walking speed and cadence (n = 4), device-measured PA (n = 2), and sit-to-stand, four-square-step and timed stair ascent tests (n = 1). Persons with AD had significant improvements in PROs following PAO, yet mobility-related outcomes (e.g. walking speed and device-measured PA levels) did not change over 1 year following PAO. Few studies have evaluated mobility-related outcomes following PAO, and these studies were of a low methodological quality. Future research might include experience sampling data collection approaches and body-worn devices as free-living, technology-driven methodologies to evaluate mobility and other outcomes in persons with AD undergoing PAO.

Reduced 2-D Frontal Plane Motion During Single-Limb Landing Is Associated With Risk of Future Anterior Cruciate Ligament Graft Rupture After Anterior Cruciate Ligament Reconstruction and Return to Sport: A Pilot Study.

OBJECTIVES: To evaluate the association between 2-D frontal plane movement and second anterior cruciate ligament (ACL) injury risk in young athletes at return to sport (RTS) after ACL reconstruction. DESIGN: Prospective cohort. METHODS: Forty-nine participants who had ACL reconstruction (mean ± SD age, 16.5 ± 3.0 years) performed a single-leg drop landing from a 31-cm box at the time of their RTS. Frontal plane trunk, pelvis, and knee angles were measured using 2-D video analysis at the point of maximum depth during landing. Summated frontal plane angles were calculated by adding trunk, pelvis, and knee angles. Participants were grouped based on whether or not they sustained an ACL graft rupture over the 24 months after RTS. RESULTS: Seven participants (14%) sustained an ipsilateral graft rupture within 24 months after RTS. Participants who suffered a second ACL injury had a significant reduction in the summated frontal plane angle of the trunk, pelvis, and knee (P = .018) and of the trunk and knee (P = .02) compared to those who did not suffer a second injury. For every 5° increase in the summated trunk, pelvis, and knee angle (odds ratio [OR] = 0.54; 95% confidence interval [CI]: 0.31, 0.94) and the summated trunk and knee angle (OR = 0.48; 95% CI: 0.25, 0.94), the athletes were 46% to 52% less likely to sustain a graft rupture. CONCLUSION: Athletes who suffered an ACL graft rupture within 24 months of RTS had a more rigid posture when landing compared to their uninjured peers. The results of this pilot study should be replicated in a larger sample to determine whether this method has merit as a screening tool to identify athletes at high risk for second ACL injury. J Orthop Sports Phys Ther 2021;51(2):82-87. Epub 25 Dec 2020. doi:10.2519/jospt.2021.9302.

Quadriceps and Hamstring Strength Symmetry After Anterior Cruciate Ligament Reconstruction: A Prospective Study.

OBJECTIVES: To evaluate change in involved and uninvolved quadriceps and hamstring strength and limb symmetry indices (LSI) in regular intervals over the first 6 months following anterior cruciate ligament reconstruction (ACLR). DESIGN: Prospective cohort study. PARTICIPANTS: Thirty-eight male participants (mean age: 24.2 [6.4] y, mean body mass index: 23.6 [4.2] kg/m2), who underwent ACLR were included. MAIN OUTCOME MEASURES: Isometric strength testing of the quadriceps and hamstring muscles was performed at 1, 2, 3, and 6 months after ACLR. Quadriceps and hamstring peak torques for each limb and LSI were calculated. Repeated-measures analysis of covariance and paired t tests were used to evaluate changes in strength over time and between limbs, respectively. RESULTS: Quadriceps and hamstring peak torques of the involved limb consistently increased between each time point from 1 to 6 months (P < .001 and P = .01, respectively), whereas the uninvolved limb values did not change after ACLR (P > .05). In addition, uninvolved limb peak torque values were higher than involved limb values at each time point after ACLR for both the quadriceps and hamstrings (all P < .01). At 6 months after ACLR, 28.9% of participants demonstrated LSI greater than 90% for quadriceps strength, 36.8% demonstrated LSI greater than 90% for hamstring strength, and 15.8% of participants demonstrated greater than 90% LSI for both quadriceps and hamstring strength. CONCLUSIONS: Participants demonstrated a consistent increase in quadriceps and hamstring strength of the involved limb, with no notable change in uninvolved limb strength over the 6 months after ACLR. However, at 6 months after ACLR, only approximately 16% of participants demonstrated both quadriceps and hamstring strength LSI greater than 90%, the typically recommended cutoff value for return to sport.

Change in Drop-Landing Mechanics Over 2 Years in Young Athletes After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: While between-limb landing asymmetries after anterior cruciate ligament reconstruction (ACLR) are linked with poor function and risk of additional injury, it is not currently understood how landing symmetry changes over time after ACLR. PURPOSE/HYPOTHESIS: The purpose was to investigate how double-legged drop vertical jump (DVJ) landing and single-legged drop-landing symmetry changed from the time of return-to-sport (RTS) clearance to 2 years later in a prospective cohort of young athletes after ACLR. It was hypothesized that double-legged DVJ landing and single-legged drop-landing symmetry would improve from the time of RTS to 2 years later. STUDY DESIGN: Descriptive laboratory study. METHODS: The authors followed 64 young athletes with primary, unilateral ACLR for 2 years after RTS clearance. At the time of RTS and 2 years later, between-limb symmetry values for biomechanical variables of interest (VOIs) were calculated with 3-dimensional motion analysis during double-legged DVJ and single-legged drop-landing tasks. VOIs included knee flexion excursion, peak internal knee extension moment, peak vertical ground-reaction force, and peak trunk flexion (for single-legged task only). Symmetry values and proportions of participants meeting 90% symmetry cutoffs were compared between time points. RESULTS: For double-legged DVJ landing, symmetry values for all VOIs and the proportions meeting 90% cutoffs for peak internal knee extension moment and peak vertical ground-reaction force were higher at 2 years after RTS as compared with RTS. For single-legged drop-landing, symmetry values were higher for knee flexion excursion and lower for peak trunk flexion at 2 years after RTS as compared with RTS, but the proportions meeting 90% cutoffs for all VOIs did not differ between time points. CONCLUSION: Double-legged DVJ landing symmetry improved across VOIs over the 2 years after RTS following ACLR, while single-legged drop-landing did not improve as consistently. The implications of longitudinal landing asymmetry after ACLR should be further studied.

Strength and Function Across Maturational Levels in Young Athletes at the Time of Return to Sport After ACL Reconstruction.

BACKGROUND: The impact of maturation on lower extremity strength and function after anterior cruciate ligament reconstruction (ACLR) may help guide future studies of age-specific rehabilitation. HYPOTHESIS: Pediatric ACLR patients would demonstrate higher thigh strength symmetry and knee-related function at return to sport (RTS) compared with adolescent and young adult participants who underwent traditional ACLR. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 144 young athletes at the time of RTS clearance post-ACLR were classified into 3 maturational groups (pediatric, n = 16 with physeal-sparing ACLR [mean age = 12.3 years; range = 9.2-14.6 years]; adolescent, n = 113 [mean age = 16.5 years; range = 14.1-19.8 years]; young adult, n = 15 [mean age = 22.0 years; range = 20.5-24.9 years]). Quadriceps and hamstring strength were measured using an electromechanical dynamometer. Knee-related function was measured using the International Knee Documentation Committee (IKDC) subjective form and single-leg hop tests. The Limb symmetry Index (LSI) was used in calculations for hop and strength tests. Group differences were compared with Kruskal-Wallis tests and Mann-Whitney U post hoc tests. Proportions of participants meeting literature-recommended RTS criterion cutoffs were compared among the groups using chi-square tests. RESULTS: The pediatric group demonstrated higher quadriceps LSI (P = 0.01), IKDC scores (P < 0.01), single-hop LSI (P < 0.01), and crossover-hop LSI (P = 0.02) compared with the young adult group. In addition, the pediatric group demonstrated higher IKDC scores (P < 0.01) and single-hop LSI (P = 0.02) compared with the adolescent group. The adolescent group demonstrated higher IKDC scores (P < 0.01), single-hop LSI (P = 0.02), and crossover-hop LSI (P = 0.03) compared with the young adult group. The proportions of participants meeting all RTS criterion cutoffs were highest in the pediatric group and lowest in the young adult group (P = 0.03). CONCLUSION: Young athletes at RTS clearance after pediatric ACLR demonstrated higher quadriceps strength symmetry and knee-related function than adolescents and young adults after traditional ACLR. CLINICAL RELEVANCE: These findings demonstrate the need for further study regarding the impact of these group differences on longitudinal outcomes after ACLR, including successful RTS and risk of second ACL injury.

Knee Function, Strength, and Resumption of Preinjury Sports Participation in Young Athletes Following Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Following anterior cruciate ligament reconstruction (ACLR), young athletes demonstrate deficits in knee function and strength whose association with successful return to preinjury sports participation is not well understood. OBJECTIVES: To examine differences in knee function and strength at the time of return-to-sport clearance between young athletes who successfully resumed preinjury sports participation, those who did not resume preinjury sports participation, and those who sustained a second anterior cruciate ligament (ACL) injury by 1 year following return-to-sport clearance. METHODS: This prospective cohort study collected data in 124 young athletes (mean ± SD age, 17.1 ± 2.4 years) at the time of return-to-sport clearance post ACLR. Measures included the Knee injury and Osteoarthritis Outcome Score (KOOS), single-leg hop tests, isokinetic quadriceps and hamstring strength, and limb symmetry during hop tests and strength tests. Participants were allocated to 3 groups: resumed preinjury sports participation (Tegner score), did not resume preinjury sports participation, or sustained a second ACL injury. Group differences were compared using Kruskal-Wallis tests and Mann-Whitney U post hoc tests. RESULTS: Seventy (56%) participants successfully resumed preinjury sports participation and 26 (21%) sustained a second ACL injury by 1 year post return-to-sport clearance. Participants who successfully resumed preinjury sports participation demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .007 and P = .004, respectively) and the crossover hop (P = .033 and P = .037, respectively), and in the involved limb on the single hop (P = .043), compared to those who did not (n = 28). Participants who sustained a second ACL injury demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .034 and P = .027, respectively) compared to those who did not resume preinjury sports participation. There were no group differences between those who successfully resumed preinjury levels of sports participation and those who sustained a second ACL injury. CONCLUSION: Following ACLR, the small proportion of young athletes who successfully resumed preinjury levels of sports participation 1 year after return to sport demonstrated greater absolute functional performance at the time of return-to-sport clearance. No differences were identified between those who successfully resumed preinjury sports participation and those who sustained a second ACL injury. Measures of limb symmetry did not differ among any of the groups. LEVEL OF EVIDENCE: Prognosis, level 2b. J Orthop Sports Phys Ther 2019;49(3):145-153. doi:10.2519/jospt.2019.8624.

Clinical measures associated with knee function over two years in young athletes after ACL reconstruction.

PURPOSE: The purpose of this study was to investigate how patient-reported knee function changed over a two-year period in young athletes after anterior cruciate ligament reconstruction (ACLR) and return-to-sport (RTS), and to determine the impact of clinical measures, after controlling for demographic and surgical covariates. METHODS: At the time of RTS after primary, unilateral ACLR, the following data were collected in 67 young athletes: Quadriceps (QF), hamstring (HS), and hip abduction (HA) strength; knee range-of-motion, effusion, and anterior laxity; and patient-reported function using the Knee injury and Osteoarthritis Outcome Score (KOOS). At two years post-RTS, patient-reported function was reevaluated using the KOOS. Absolute KOOS scores and proportions of participants meeting functional recovery cutoffs were compared between time-points. Multivariable linear regression was used to determine clinical measures at RTS associated with two-year post-RTS KOOS scores. RESULTS: KOOS scores for all subscales were higher at two years post-RTS (all p < 0.003), and the proportions of participants demonstrating functional recovery were higher at two years post-RTS for the KOOS-Symptoms, KOOS-Sport, KOOS-QOL, and all KOOS subscales combined (all p < 0.03). After controlling for graft type, clinical measures at RTS associated with higher two-year post-RTS KOOS scores were: KOOS-Pain (lower HA peak torque); KOOS-Symptoms (higher QF strength symmetry and higher QF peak torque); and KOOS-ADL (lower HA peak torque). CONCLUSIONS: In this cohort, after controlling for graft type, higher QF strength symmetry, higher involved-limb QF peak torque, and lower involved-limb HA peak torque from the time of RTS were associated with higher function at two years post-RTS.