Protocol and validity testing of femoroacetabular posterior translation with dynamic hip ultrasonography.

OBJECTIVE: To describe femoroacetabular posterior translation (FAPT) using dynamic hip ultrasonography (DHUS), and to determine the inter- and intra-rater reliability of hip ultrasound measurements of FAPT. MATERIALS AND METHODS: The study design was a feasibility study of 13 healthy young adults (26 hips) using test-retest analysis. The data was collected prospectively over a 2-week time period. Three DHUS measurements (posterior neutral (PN), flexion, adduction, and internal rotation (PFADIR), and stand and load (PStand) were measured by four independent raters (2 senior who divided the cohort, 1 intermediate, 1 junior) at two time points for bilateral hips of each participant. Reliability was assessed by calculating the intraclass correlation coefficient (ICC) along with 95% confidence intervals (CIs) for each rater and across all raters. RESULTS: A total of 468 US scans were completed. The mean age of the cohort was 25.7 years (SD 5.1 years) and 54% were female. The inter-rater reliability was excellent for PFADIR (ICC 0.85 95% CI 0.76-0.91), good for PN (ICC 0.69 95% CI 0.5-0.81), and good for PStand (ICC 0.72 95% CI 0.55-0.83). The intra-rater reliability for all raters was good for PFADIR (ICC 0.60 95% CI 0.44-0.73), fair for PN (ICC 0.42 95% CI 0.21-0.59), and fair for PStand (ICC 0.42 95% CI 0.22-0.59). CONCLUSION: This is the first study to present a protocol using dynamic ultrasonography to measure FAPT. DHUS measure for FAPT was shown to be reliable across raters with varying levels of ultrasound experience.

Running Biomechanics and Clinical Features Among Adolescent Athletes With Lower Leg Chronic Exertional Compartment Syndrome.

OBJECTIVE: To compare clinical measures between patients with chronic exertional compartment syndrome (CECS) and healthy controls and evaluate running biomechanics, physical measurements, and exertional intracompartmental (ICP) changes in adolescent athletes with lower leg CECS. DESIGN: Cross-sectional case-control study. SETTING: Large tertiary care hospital and affiliated injury prevention center. PARTICIPANTS: Forty-nine adolescents with CECS (39 F, 10 M; age: 16.9 ± 0.8 years; body mass index (BMI): 23.1 ± 2.9 kg/m 2 ; symptom duration: 8 ± 12 months) were compared with 49 healthy controls (39 F, 10 M; age: 6.9 ± 0.8 years; BMI: 20.4 ± 3.7 kg/m 2 ). INTERVENTIONS: All participants underwent gait analyses on a force plate treadmill and clinical lower extremity strength and range of motion testing. Patients with chronic exertional compartment syndrome underwent Stryker monitor ICP testing. MAIN OUTCOME MEASURES: Symptoms, menstrual history, and ICP pressures of the patients with CECS using descriptive statistics. Mann-Whitney U and χ 2 analyses were used to compare CECS with healthy patients for demographics, clinical measures, and gait biomechanics continuous and categorical outcomes, respectively. For patients with CECS, multiple linear regressions analyses were used to assess associations between gait biomechanics, lower extremity strength and range of motion, and with ICP measures. RESULTS: The CECS group demonstrated higher mass-normalized peak ground reaction force measures (xBW) compared with controls (0.21 ± 0.05 xBW ( P < 0.001) and were more likely to have impact peak at initial contact ( P = 0.04). Menstrual dysfunction was independently associated with higher postexertion ICP (ß = 14.6; P = 0.02). CONCLUSIONS: The CECS group demonstrated increased total force magnitude and vertical impact transient peaks. In women with CECS, menstrual dysfunction was independently associated with increased postexertion ICP. These biomechanical and physiological attributes may play a role in the development of CECS.

Outpatient Runners Clinic Visit Trends and Injury Characteristics Among 392 Child and Adolescent Patients: A 10-year Chart Review.

OBJECTIVE: To evaluate clinic visits and running-related injury (RRI) characteristics among child and adolescent runners seeking care at an outpatient clinic over a 10-year time frame. DESIGN: Retrospective chart review. SETTING: Outpatient hospital-affiliated Injured Runners Clinic. PATIENTS: Children and adolescent runners (6-17 years) with RRIs. INDEPENDENT VARIABLES: We examined electronic medical records (EMRs) among child and adolescent patients in the hospital database from 2011 to 2021 to obtain RRI characteristics and key demographic factors. MAIN OUTCOME MEASURES: We assessed volume and frequency of patient visits to the clinic by RRI characteristics. Chi square analyses were used to compare the proportion of clinic visits over time and injury trends by body region and diagnosis. RESULTS: There were 392 patients (sex: 277 F; mean age: 16.1 ± 1.3 years) and an average of 5 clinic visits per diagnosis (5 ± 4 visits; min: 1 visit, max: 31 visits). Number of visits generally increased over time up to 2016 but declined most drastically during the years of the pandemic (2020-2021; χ 2 = 644, P < 0 .001). Of the 654 new injury diagnoses, 77.68% were attributed to repetitive stress. Bone stress injuries to the tibia were the most common RRI (χ 2 = 1940, P < 0 .001; N = 132; 20.2% of all injuries) and constituted most of the clinic visits (χ 2 = 9271, P < 0 .001; N = 591; 25.4% of all visits). CONCLUSION: We identified that adolescents with overuse injuries, particularly bone stress injuries to the tibia, constituted most of the visits to the outpatient healthcare setting. Clinicians should emphasize injury prevention efforts in clinical practice to reduce RRI burden.

Generalized Joint Laxity Is Associated With Dynamic Hip Ultrasonography Measures in Female Athlete Patients Who Are Not Hypermobile.

OBJECTIVES: To investigate ultrasound (US) femoroacetabular translation measurements in female athlete patients. METHODS: A prospective cross-sectional study was conducted in female athlete patients <50 years. Demographic data, Beighton score/hypermobility status, and sport participation were collected. Hip dysplasia was determined using radiographic measurements (lateral center edge angle, anterior center edge angle, Tönnis angle); femoral version angles were measured with CT or MR. Femoroacetabular translation US measures included neutral (N), neutral flexed (NF), extension external rotation/apprehension (EER) positions. Maximal difference (delta) between US measures was calculated. RESULTS: 206/349 female hips were analyzed (median age 21.2 years [range, 12-49.5]). The primary sport group was performing arts (45%, 92/206). Mean Beighton score was 5.2 (SD, 2.5) with 61% (129/206) of hips exhibiting hypermobility (Beighton score ≥5). For each additional unit of Beighton score, N US measurement increased by 0.7 mm (ß = 0.7; 95% confidence interval [CI] = 0.22-1.25; P < .001), NF by 1 mm ( ß = 0.9; 95% CI = 0.3-1.43; P = .002) and EER by 0.8 mm ( ß = 0.8; 95% CI = 0.27-1.37; P < .001) when adjusting for age and dysplasia status. A positive correlation was detected between NF (r = 0.19; 95% CI = 0.05-0.33; P = .007) and EER (r = 0.19; 95% CI = 0.05-0.32; P = .01) with Tönnis angle and a negative correlation between the delta and femoral version (r = -0.20; 95% CI = -0.35 to 0.03; P = .02). No difference in US measures was detected across sport groups (N [P = .24], NF [P = .51], EER [P = .20], delta [P = .07]). CONCLUSION: Beighton score was independently associated with dynamic US measures in female athlete patients who are not hypermobile when controlling for other factors.

Running gait biomechanics in female runners with sacroiliac joint pain.

[Purpose] To identify running gait biomechanics associated with sacroiliac (SI) joint pain in female runners compared to healthy controls. [Participants and Methods] In this case-control study, treadmill running gait biomechanics of female runners diagnosed SI joint pain, (by ultrasound-guided diagnostic SI joint injection and/or ≥2 positive SI physical exam maneuvers) were compared with age, height, mass, and BMI matched healthy female runners. Sagittal and coronal plane treadmill running video angles were measured and compared. [Results] Eighteen female runners with SI pain, and 63 matched controls, were analyzed. There was no difference in age, height, mass, or BMI between groups. At the point of initial contact, runners with SI joint pain demonstrated less knee flexion, greater tibial overstride, and greater ankle dorsiflexion, compared to controls. In midstance, runners with SI pain had greater contralateral pelvic drop compared to controls. For unilateral SI joint pain cases (N=15), greater contralateral pelvic drop was observed when loading their affected side compared to the unaffected side. [Conclusion] Female runners with SI joint pain demonstrated greater contralateral pelvic drop during midstance phase; along with less knee flexion, greater "tibial overstride", and greater ankle dorsiflexion at initial contact compared to controls.

Youth running consensus statement: minimising risk of injury and illness in youth runners.

Despite the worldwide popularity of running as a sport for children, relatively little is known about its impact on injury and illness. Available studies have focused on adolescent athletes, but these findings may not be applicable to preadolescent and pubescent athletes. To date, there are no evidence or consensus-based guidelines identifying risk factors for injury and illness in youth runners, and current recommendations regarding suitable running distances for youth runners at different ages are opinion based. The International Committee Consensus Work Group convened to evaluate the current science, identify knowledge gaps, categorise risk factors for injury/illness and provide recommendations regarding training, nutrition and participation for youth runners.

Qualitative Assessment of a Medical Protocols Mobile Application at the Boston Marathon 2016.

OBJECTIVE: To examine the creation of a medical protocols mobile application for the Boston Marathon and its use by medical volunteers for the 2016 Boston Marathon. DESIGN: Anonymous questionnaire. SETTING: 2016 Boston Marathon. PARTICIPANTS: Two hundred ninety-four marathon medical volunteers. MAIN OUTCOME MEASURES: Responses regarding ease of use, acceptability, and usefulness of the International Institute of Race Medicine mobile application. RESULTS: In total, 88% of medical volunteers who participated in the study felt that the medical protocols mobile application was easy to use. Approximately 72% would use the app again, and 79% would recommend the app to others. However, only 15% of volunteers consistently used the app during the event, and 37% felt like it contributed to clinical decision-making. CONCLUSIONS: A medical protocols app was found to be useful and well accepted among medical volunteers who reported using the app, but only a minority of respondents used the app on marathon day or felt like it contributed to clinical care. Although new, mobile apps in race medicine should continue to be an area of development as providers increasingly integrate their use into clinical practice.

Short-term Effect of Ultrasound-Guided Iliopsoas Peritendinous Corticosteroid Injection.

OBJECTIVES: Treatment for iliopsoas tendinopathy includes ultrasound (US)-guided iliopsoas peritendinous corticosteroid injection. Evidence is lacking regarding US-guided iliopsoas injection efficacy in patients with iliopsoas tendinopathy and intra-articular (IA) hip abnormalities. The purpose of this study was to examine the efficacy of US-guided iliopsoas corticosteroid injection for iliopsoas tendinopathy in patients with and without IA hip abnormalities. METHODS: This work was a prospective study evaluating patients aged 12 to 50 years with iliopsoas tendinopathy. Participants completed a Hip Disability and Osteoarthritis Outcome Score (HOOS) questionnaire before and 6 weeks after injection. The main outcome measure was the change in HOOS subcategory scores. Independent variables included time and hip status. Normal hips were compared to abnormal hips with IA abnormalities. A 2-way repeated measures analysis of covariance with effect size (η2 ) was used to determine injection effects on HOOS scores before and 6 weeks after injection. RESULTS: A total of 178 patients (154 female and 24 male) were analyzed. Time effects were found for both normal and abnormal hips in all HOOS subcategories: symptoms (P = .041; η2 = 0.050), pain (P = .001; η2 = 0.184), activities of daily living (P = .011; η2 = 0.076), function in sports and recreation (P = .001; η2 = 0.151), and quality of life (QOL; P = .001; η2 = 0.193). Significant differences between normal versus abnormal hips were found in the sports and recreation (P = .032; η2 = 0.056) and QOL scores (P = .001; η2 = 0.135). CONCLUSIONS: In patients with iliopsoas tendinopathy, US-guided iliopsoas corticosteroid injection improved outcomes regardless of coexisting IA hip abnormalities. Patients without IA hip abnormalities showed greater improvement in sports and recreation and QOL scores compared to patients with IA hip abnormalities. Ultrasound-guided iliopsoas injection for iliopsoas tendinopathy may advance short-term care and help continue with nonsurgical treatment regimens.

Can Dynamic Ultrasonography of the Hip Reliably Assess Anterior Femoral Head Translation?

BACKGROUND: Hip microinstability has gained attention recently as a potential cause of hip pain. Currently there is a lack of evidence-based objective diagnostic criteria surrounding this diagnosis. Previous studies have shown translation of the femoral head during extreme hip positions. However, reliable assessment of femoral head translation is lacking. QUESTIONS/PURPOSES: (1) How precise is musculoskeletal ultrasound for measuring anterior femoral head translation during the hip anterior apprehension test? (2) What is the intra- and interrater reliability of dynamic ultrasonography in assessing anterior femoral head translation? METHODS: We recruited 10 study participants (20 hips) between the ages of 22 and 50 years with no history of hip pain or functional limitations. Test-retest methodology was used. Seven females and three males were enrolled. The mean age of study participants was 27 years (SD 8.7 years); mean body mass index was 22.6 kg/m (SD 2.2 kg/m). All study participants underwent dynamic hip ultrasonography by three different physicians 1 week apart. Each hip was visualized in two neutral positions (neutral and neutral with the contralateral hip flexed [NF]) and two dynamic positions, which sought to replicate the apprehension test, although notably study participants had no known hip pathology and therefore no apprehension. The first maintained the hip in extension and external rotation off to the side of the examination table (EER1), and the second held the hip off of the bottom of the examination table (EER2). One hundred twenty ultrasound scans (480 images) were performed. Mean and SD were calculated using absolute values of the difference in ultrasound measurements (mm) between positions NF and EER1 and NF and EER2 calculated for each physician as well as an average of all three physicians. Intraclass correlation coefficient (ICC) analysis was used to examine intra- and interrater reliability. RESULTS: The mean absolute difference for NF and EER1 was 0.84 mm (SD 0.93 mm) and for NF and EER2 0.62 mm (SD 0.40 mm) on Study Day 1. Similarly, on Study Day 2, the mean absolute difference for NF and EER1 position was 0.90 mm (SD 0.74 mm) and for NF and EER2 1.03 mm (SD 1.18 mm). Cumulative values of ICC analysis indicated excellent intrarater reliability in all four positions: neutral 0.794 (95% confidence interval [CI], 0.494-0.918), NF 0.927 (95% CI, 0.814-0.971), EER1 0.929 (95% CI, 0.825-0.972), and EER2 0.945 (95% CI, 0.864-0.978). Similarly, interrater ICC analysis cumulative values were excellent for NF, EER1, and EER2 and fair to good for the neutral position: neutral 0.725 (95% CI, 0.526-0.846), NF 0.846 (95% CI, 0.741-0.913), EER1 0.812 (95% CI, 0.674-0.895), and EER2 0.794 (95% CI, 0.652-0.884). CONCLUSIONS: This study offers the first ultrasound protocol of which we are aware for measuring anterior femoral head translation. Hip dynamic ultrasound may assist in providing precise objective clinical-based diagnostic evidence when evaluating complex hip pain and suspected microinstability. Musculoskeletal ultrasound is a reliable office-based method of measuring anterior femoral head translation that can be utilized by physicians with varying experience levels. Future studies are needed to investigate ultrasound anterior femoral head translation taking into account sex, prior hip surgery, hip osseous morphology, and ligamentous laxity. LEVEL OF EVIDENCE: Level III, diagnostic study.

Medical encounters (including injury and illness) at mass community-based endurance sports events: an international consensus statement on definitions and methods of data recording and reporting.

Mass participation endurance sports events are popular but a large number of participants are older and may be at risk of medical complications during events. Medical encounters (defined fully in the statement) include those traditionally considered 'musculoskeletal' (eg, strains) and those due to 'illness' (eg, cardiac, respiratory, endocrine). The rate of sudden death during mass endurance events (running, cycling and triathlon) is between 0.4 and 3.3 per 100 000 entrants. The rate of other serious medical encounters (eg, exertional heat stroke, hyponatraemia) is rarely reported; in runners it can be up to 100 times higher than that of sudden death, that is, between 16 and 155 per 100 000 race entrants. This consensus statement has two goals. It (1) defines terms for injury and illness-related medical encounters, severity and timing of medical encounters, and diagnostic categories of medical encounters, and (2) describes the methods for recording data at mass participation endurance sports events and reporting results to authorities and for publication. This unifying consensus statement will allow data from various events to be compared and aggregated. This will inform athlete/patient management, and thus make endurance events safer.

Youth Distance Running: Strategies for Training and Injury Reduction.

Running is a popular sport for children in the United States. However, review of available literature on health effects and safety recommendations for youth running has not been previously conducted. Unique factors for injury include periods of growth during puberty and potential for growth plate injury. Youth runners may benefit from activities that incorporate high-impact loading and multidirectional movement for optimal bone maturation, exercises to strengthen tendons and muscles, and strategies aimed at improving running biomechanics to reduce risk of injury. In addition, addressing lifestyle factors, including nutrition and sleep is essential for a runner's general health. Similar to other sports, sports specialization should not be encouraged in youth runners. Reducing running-related injury in growing children and assessing readiness for running should be based on a combination of physical, emotional, psychological, social, and cognitive factors. Youth runners require individualized training and competition to safely participate in the sport.

The Young Injured Gymnast: A Literature Review and Discussion.

Gymnastics is a sport requiring grace, strength, and flexibility, resulting in a wide variety of injuries. This article is an overview of the sport of gymnastics and associated injury trends in the artistic gymnastics population. Injury rates in gymnastics range from 1.08 to 50.3 per 1000 h of exposure. More injuries occur in competition versus practice. Fewer injuries occur in recreational gymnastics than competitive gymnastics. The most common injury in gymnastics occurs in the lower extremity, and is an ankle sprain, followed by knee internal derangement. However, in men's gymnastics the most common gymnastics injury occurs in the upper body (specifically the shoulder). The most common skills causing injury to a gymnast are front/back handsprings and saltos/flips. Unique injuries commonly seen when caring for the young gymnast include spondylolysis, ostoechondritis dissecans of the capetillium and talus, Gymnast wrist, Grip lock, Osgood-Schlatter, patellofemoral syndrome, Sever's disease, and ankle sprains. Research efforts should focus on injury rates after the 2006 rule change, injury prevention, men's gymnastics injury patterns, concussions, hip injuries, and ACL injuries in gymnasts.

Running mechanics of females with bilateral compartment syndrome.

[Purpose] Primary purpose was to compare running mechanics between healthy runners and runners with chronic exertional compartment syndrome (CECS) including overstride angles, ankle dorsiflexion (DF) angles, and foot strike patterns. The secondary purpose was to analyze the association between the overstride angles and ankle DF angles. [Participants and Methods] Running images of 7 female runners with bilateral CECS patients were captured at a time of the medical examination. Their running images were compared with gender, age, and body mass index matched 31 healthy control runners. [Results] The bilateral CECS female runners have a propensity of running with significantly greater overstride and ankle DF angles than the healthy female runners. There were no foot strike differences between the two cohorts. There were a non-significant, poor relationship between overstride and ankle DF angles in the healthy female runners while a significant, strong association was found between overstride and ankle DF angles in the bilateral CECS female runners. [Conclusion] Compared to healthy female runners, bilateral CECS female runners demonstrated different running mechanics including greater overstride and ankle DF angles. The two variables were strongly associated with each other in bilateral CECS female runners, but not in healthy female runners. This may potentially contribute to the mechanism of CECS development.

Cardiac arrest during long-distance running races.

BACKGROUND: Approximately 2 million people participate in long-distance running races in the United States annually. Reports of race-related cardiac arrests have generated concern about the safety of this activity. METHODS: We assessed the incidence and outcomes of cardiac arrest associated with marathon and half-marathon races in the United States from January 1, 2000, to May 31, 2010. We determined the clinical characteristics of the arrests by interviewing survivors and the next of kin of nonsurvivors, reviewing medical records, and analyzing postmortem data. RESULTS: Of 10.9 million runners, 59 (mean [±SD] age, 42-13 years; 51 men) had cardiac arrest (incidence rate, 0.54 per 100,000 participants; 95% confidence interval [CI], 0.41 to 0.70). Cardiovascular disease accounted for the majority of cardiac arrests. The incidence rate was significantly higher during marathons (1.01 per 100,000; 95% CI, 0.72 to 1.38) than during half-marathons (0.27; 95% CI, 0.17 to 0.43) and among men (0.90 per 100,000; 95% CI, 0.67 to 1.18) than among women (0.16; 95% CI, 0.07 to 0.31). Male marathon runners, the highest-risk group, had an increased incidence of cardiac arrest during the latter half of the study decade (2000-2004, 0.71 per 100,000 [95% CI, 0.31 to 1.40]; 2005-2010, 2.03 per 100,000 [95% CI, 1.33 to 2.98]; P=0.01). Of the 59 cases of cardiac arrest, 42 (71%) were fatal (incidence, 0.39 per 100,000; 95% CI, 0.28 to 0.52). Among the 31 cases with complete clinical data, initiation of bystander-administered cardiopulmonary resuscitation and an underlying diagnosis other than hypertrophic cardiomyopathy were the strongest predictors of survival. CONCLUSIONS: Marathons and half-marathons are associated with a low overall risk of cardiac arrest and sudden death. Cardiac arrest, most commonly attributable to hypertrophic cardiomyopathy or atherosclerotic coronary disease, occurs primarily among male marathon participants; the incidence rate in this group increased during the past decade.

Youth Sport Specialization: Current Concepts and Clinical Guides.

The concept of youth sport specialization has evolved over the past decade, from a focus on the risk of overuse injury to a broader awareness of its effects on mental health, social well-being, quality of life, growth and maturation, sport performance, and long-term athletic success. This review article considers a recently revised definition of youth sport specialization, as well as guidelines and consensus statements from various sports medicine organizations, with practical applications for young athletes.

Biomechanical changes identified during a marathon race among high-school aged runners.

BACKGROUND: Despite the increasing popularity of endurance running competitions among adolescent runners, there is currently limited information regarding expected biomechanical changes across the duration of a long-distance running event, and the relationship between young runners' biomechanics and running performance. Wearable technology offers an ecological means to continuously assess runners' biomechanical data during outdoor running competitions. RESEARCH QUESTION: Do adolescent athletes adopt changes in sensor-derived biomechanics throughout a marathon race, and are there relationships between race performance and biomechanical features among young marathoners? METHODS: Fourteen high-school aged runners (9 M, 5 F; age: 16 ± 1 years, height: 170.8 ± 7.5 cm; mass: 63.6 ± 9.4 kg) wore lace-mounted sensors to record step-by-step biomechanics during a marathon race. Official race segment completion times were extracted across 5 race segments (5-K, 15-K, Half Marathon [21.1-K], 35-K, Marathon [42.2-K]). Within-participant repeated measures of covariance (pace) were conducted to assess changes in biomechanics across the race, with Bonferroni post-hoc comparisons. Pearson's r correlations were performed to assess the relationship between race finish times and biomechanics. RESULTS: Pace was significantly slower (p-range: 0.002-0.005), contact times significantly longer, and stride lengths significantly shorter in the final segment compared to middle segments (p-range: 0.003-0.004). The rate of shock accumulation was significantly higher in the final race segment compared to the first three segments (p-range: 0.001-0.002). Moderate relationships existed between finish times and pace (r = -0.63), stride length (r = -0.62), and contact time (r = 0.51). SIGNIFICANCE: Adolescent runners altered their gait patterns in the final marathon segment compared to earlier segments. Spatiotemporal measures were moderately correlated with race finish times, suggesting a link between faster run pace, increased stride lengths, and reduced contact time for improved running performance during an endurance race.

Surgical management of popliteal artery entrapment syndrome.

Introduction: Popliteal artery entrapment syndrome (PAES) is a rare condition in which the popliteal artery becomes compressed by adjacent soft tissue structures causing progressive claudication. Due to its low incidence, this disorder and its surgical management is poorly described in the literature. This study presents our institutional data surrounding PAES management to further optimize care of this syndrome. Methods: This retrospective study gathered demographic, surgical, and outcome data of all patients with PAES who underwent surgical decompression at our institution from 2015 to 2022. Patients were identified using CPT and ICD-9/10 codes. Summary statistics were calculated, with Chi-squared and T-test used for subgroup analysis. Results: 50 surgical patients with PAES were identified. On average, they were young (mean age: 20.7 years), mostly female (78 %), and predominately white (68 %). The vast majority were physically active, with 13 of the 50 patients being runners (26 %). Medically, the cohort was otherwise healthy, with 74 % reporting no comorbidities. Diagnosis was often delayed, with patients on average seeing 4.5 physicians over 2.0 years prior to arriving at our institution for care. In addition to popliteal artery release, the second most performed procedure was fasciotomy (82 %). Postoperatively, there was significant long-term subjective improvement, with 91 % of patients reporting they would repeat the operation and 65 % reporting improved activity. Conclusion: PAES is a rare condition affecting the lower limb that requires a nuanced surgical approach. From diagnosis to outcome, we hope to better inform surgeons of PAES so that these patients may receive the highest quality care.

Detection of pars injury by SPECT in patients younger than age 10 with low back pain.

BACKGROUND: Evaluation of extension-based low back pain in young athletes with suspected pars injury may include a referral for skeletal single photon emission computed tomography (SPECT). However, the diagnostic yield of this technique in children with low back pain before the age of 10 years remains uncertain. We examined a series of consecutive SPECT scans to address this question. MATERIALS AND METHODS: A retrospective review of department databases revealed 107 consecutive skeletal Tc-99m MDP SPECT scans performed between January 1, 2007 and December 31, 2009 in children less than 10 years of age. Of these, 72 studies were performed for a referral diagnosis of back pain. There were 43 girls (44 studies) and 28 boys (28 studies). The mean age was 7.2 years (range, 1.9 to 9.9 y). All SPECT scans were reviewed and positive findings documented. In addition, all available anatomic imaging, imaging reports (computed tomography, magnetic resonance, and x-ray) and clinical notes were reviewed, and results were compared with those of SPECT studies. RESULTS: Of the 72 SPECT studies, 35 (49%) identified a focal area in the spine of abnormal increased uptake, with 17 in the region of the pars interarticularis. With additional imaging, 1 case was demonstrated not to be a pars injury (computed tomography showed a transverse process fracture) and 2 patients with negative SPECT scans were shown to have pars injuries that SPECT scan had not detected, for a total of 18 pars injuries (25%) in this cohort. Reported participation in gymnastics or football was related to pars injury (odds ratio 4.3, P=0.04). CONCLUSIONS: Pars injury was found in 25% of children referred for SPECT scan with back pain below 10 years of age. SPECT scan was highly sensitive for this injury as well as in identifying other potential sites of pathology, and should be considered in the workup of persistent low back pain in young children. LEVEL OF EVIDENCE: Level II, diagnostic study.

Adolescent and young adult hip and knee strength profiles relate to running gait biomechanics.

OBJECTIVES: Compare and assess relationships between strength and running biomechanics among healthy adolescents and young adult males and females. DESIGN: Retrospective cohort. SETTING: Clinic. PARTICIPANTS: 802 healthy participants (570 F, 232 M; 16.6 ± 2.3 years). MAIN OUTCOME MEASURES: Mass-normalized knee flexor and extensor strength, hip adductor and abductor strength, hamstrings-to-quadriceps (H:Q), and abductor-to-adductor (Abd:Add) ratios were obtained using hand-held dynamometry. Mass-normalized peak vertical ground reaction force (vGRF), %stance, cadence, and stride length were obtained using an instrumented treadmill. Multivariate analyses of variance were used to compare strength and biomechanics across ages and sexes. Linear regressions were used to assess the relationships between strength and biomechanics, accounting for speed, age, and sex. Independent t-tests were used to compare strength between strength ratio profiles. RESULTS: Strength and running biomechanics significantly differed between sexes (p-range: <0.001-0.05) and age groups (p-range: <0.001-0.02). Strength and strength ratios were significantly associated with increased cadence (p-range:0.001-0.04) and stride lengths (p-range:0.004-0.03), and decreased vGRF (p < 0.001). Lower H:Q ratios had significantly lower strength measures (p < 0.001). Higher Abd:Add ratios had significantly increased abductor strength (p < 0.001). CONCLUSIONS: Strength and running biomechanics differed by sexes and ages. Hip and knee strength and strength ratios were related to select spatiotemporal and kinetic biomechanical features.