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PURPOSE: To establish prevalence of lumbar and lumbosacral pathologies in patients with hip abductor tendon disorders. METHODS: A retrospective review of patients' charts was conducted over a 5-year period, January 2013 to October 2018, using the S76 and M76 International Classification of Diseases Tenth Revision (ICD-10) codes. Patients with symptomatic and radiologically confirmed hip abductor tendon disorders (partial and full-thickness tear of the gluteus medius tear with or without gluteus minimus tearing) were included in the study. No exclusion criteria were applied. Patient medical history was examined for concurrent diagnoses of lumbar and lumbosacral pathologies (radiculopathy, lumbar stenosis, degenerative disc disease, and neurogenic claudication). RESULTS: One-hundred and three patients with hip abductor tendon disorders were identified. Forty-seven (45.6%) patients had low-grade partial abductor tears, while 56 (54.4%) of patients had a high-grade partial or complete abductor tear. Fifty (48.5%) patients carried a concomitant lumbosacral diagnosis, with 20 (19.4%) patients being diagnosed with lumbar stenosis and 45 (43.7%) being diagnosed with degenerative disc disease. CONCLUSION: Patients with hip abductor tendon disorders were associated with a high prevalence of underlying lumbar and lumbosacral pathologies. Nevertheless, a causal relationship between these conditions cannot be established. LEVEL OF EVIDENCE: Level IV. Retrospective Case Series.

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BACKGROUND: Sports-related fractures of the fifth metatarsal are common in professional athletes. Data regarding outcomes of surgical management including refracture, complications, and return-to-play statistics are available for other professional American sports with a notable exception of soccer. PURPOSE: To quantify the burden of operative fifth metatarsal fractures in Major League Soccer (MLS) athletes, to compare outcomes as well as refracture and complication rates with other professional sports, to analyze factors that may contribute to treatment failure, and to report on return-to-play characteristics for affected players. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We searched all injuries in the prospectively collected HealtheAthlete database for MLS for operative fifth metatarsal fractures for seasons 2013 to 2017. Additional information regarding each fracture including demographics, treatment, postoperative course, and return-to-play statistics were compiled from HealtheAthlete and supplemented by teams' chief medical officers, coaches, trainers, and online sources. RESULTS: There were 21 fractures in 18 players during the study period. Mean time to radiographic healing was 8.5 weeks (n = 17). Mean time to return to play was 11.1 weeks (n = 19). Of 21 fractures, 20 (95%) players returned to sport. Of 18 players, 4 (22.2%) experienced refracture. Of 18 players, 5 (27.8%) and 2 (11.1%) reported previous stress injuries on the contralateral and ipsilateral limb, respectively. Player performance characteristics showed small declines in the first year of return that improved by the second year. CONCLUSION: MLS athletes who sustain a sports-related fifth metatarsal fracture can expect a high rate of return to sport with time to radiographic healing and return to play as well as risk of refracture similar to other professional cohorts.

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PURPOSE: To compare the area of visualization, capsular stiffness, and strength between the pie-crusting capsulotomy technique and the T-capsulotomy technique following repair. METHODS: Eight matched pairs of fresh-frozen cadaveric hips (n = 16) were divided to either T-capsulotomy or pie-crusting capsulotomy followed by subsequent repair. The area of visualization was measured for all capsulotomy states using a digitizing probe. Hips were then distracted along the iliofemoral ligament in the intact, extended capsulotomy, and repair states. Afterwards, specimens were externally rotated to failure. RESULTS: An average force of 250.1 ± 16.1 N was required to distract intact hips to 6 mm. Both extended capsulotomy techniques reduced the force required to distract the hip 6 mm with no statistical difference between the two (T-capsulotomy [T-cap] = 114.3 ± 63.4 N vs pie-capsulotomy [Pie-cap] = 170.1 ± 38.8 N), P = .07. Subsequent repair of the extended capsulotomies demonstrated the pie-crust capsulotomy required significantly greater force to reach 6 mm of distraction than those with a repaired T-capsulotomy (T-cap = 165.04 ± 40.43N vs Pie-cap = 204.43 ± 10.13N), P = .03. There was no significant difference in ultimate torque to failure between the 2 techniques (T-cap = 22.0 ± 7.41 N·m vs Pie-cap = 27.01 ± 11.13 N·m), P = .28. Visualization significantly increased with each extended capsulotomy, with an average increase of 62% (P < .001) and 48% (P < .001) for the pie- and T-capsulotomies, respectively. CONCLUSIONS: The pie-crusting technique maintained similar strength and increased stiffness to the T-capsulotomy following repair while using less suture. Both techniques provided similar visualization. Clinically, the pie-crusting technique provides an alternative to the T-capsulotomy with similar biomechanical and visual outcomes. CLINICAL RELEVANCE: Visualization during hip arthroscopy can be difficult with large cam morphology. Techniques to improve visualization while restoring the native biomechanics of the hip as best as possible are important.

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PURPOSE: To define the topographic anatomy of the footprint of the adductor longus origin on the pubis and its underlying bony morphology to better inform surgical repair of adductor longus tendon injuries. METHODS: Five cadaveric pelvis specimens were dissected, making 10 adductor footprints available for analysis. The adductor longus tendon origin was isolated and the surrounding tissue debrided. The circumference of the tendinous attachment to the pubic crest was marked before excising the tendon and fibrocartilage enthesis from the pubis. Radiopaque paint was prepared by mixing 30 mL of all-purpose acrylic paint (Anita's no. 11150 Island Blue; Rust-Oleum Corp, Vernon Hills, IL) with 15g of E-Z-HD 98% w/w barium sulfate (Bracco Diagnostics Inc., Anjou Quebec, Canada) and applied to the marked footprint. The specimens underwent a 1.0-mm slice computed tomographic scan with 3-dimensional reconstructions. Synapse PACS (FujiFilm, Valhalla, NY) software for measurements of the tendon footprint and underlying bone. RESULTS: Average age and weight of the specimens at the time of death was 37 years and 204.6 ± 48.7 lbs, respectively. The width and length of the tendon origin was 12.0 ± 1.1 mm and 10.9 ± 1.1 mm, respectively. The distance of the center of the footprint from the center of the pubic tubercle was 8.5 ± 1.4 mm lateral and 12.2 ± 0.4 mm caudal. The osseous thickness underlying the footprint was 18.7 ± 3.7 mm at an angle of 34.5 ± 1.5° in relation to the sagittal plane. The correlation between specimen body weight and the thickness of the bone underlying the footprint was strongly positive (r = 0.92). CONCLUSIONS: We found that there is a consistent angle from the center of the adductor longus tendon footprint to the point of maximal underlying bony thickness, as well as a positive correlation between body mass index and osseous thickness, which may inform anatomic reattachment of this tendon. CLINICAL RELEVANCE: Our findings will assist surgeons in identifying the footprint of the adductor longus tendon and safely perform anatomic repair of adductor longus tendon avulsions.

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Intra-articular injections are commonly used in the treatment algorithm for osteoarthritis of the hip. A number of different adjuvants can be used, such as corticosteroids, hyaluronic acid, and platelet-rich plasma, but there is no consensus regarding indications for or anticipated outcomes of each of these interventions. Recent data suggest that corticosteroids provide the best relief in the short term whereas platelet-rich plasma may be more beneficial in the mid term, but the results are variable. Ultimately, more rigorous studies are needed to evaluate these adjuvants, in particular biologics, while remaining fastidious with our indications for injection therapy.

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To determine the outcomes of a limited surgical intervention, consisting of neurolysis, inguinal wall repair and/or adductor debridement of adhesions based on intraoperative findings. Retrospective case series. Outpatient orthopedic/general surgery clinic. Fifty-one athletes treated surgically for inguinal-related groin pain from 2009 to 2015. Limited surgical intervention, consisting of neurolysis, inguinal wall repair and/or adductor debridement based on intra-operative findings. Ability to return to sport at the same level, time to return to play. Fifty-one athletes were included in the study with an average follow-up of 4.42 years (range 2.02-7.01). The average age was 24.2 years (range 16-49) and consisted of 94.0% males and 6.0% females. Nerve entrapment was demonstrated in 96.2% of cases with involvement of the ilioinguinal in 92.5%, the iliohypogastric in 30.8% and the genitofemoral in 13.2%. Attenuation of the posterior inguinal wall was present and repaired in 79.3% of cases. Scar tissue was present around the adductor origin and required debridement in 56.7% of cases. Forty-nine (96.1%) athletes returned to sport at the same level of play at an average of 5.9 weeks. Two athletes required a revision surgery. High rates of return to sport were achieved after surgery for inguinal-related groin pain that addresses the varying pathology and associated nerve entrapment.

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Water polo places significant stress on the hip joint requiring repetitive hip flexion and rotation to elevate the body out of water for passing, shooting and blocking. Femoroacetabular impingement (FAI) is common in water polo athletes; however, no study to date has investigated the results of hip arthroscopy in this patient population. The purpose of this study was to determine return to play rates and satisfaction following hip arthroscopy for FAI in a cohort of elite level water polo players. A retrospective review of our surgical database was performed. Collegiate water polo players with clinical and radiographic FAI who underwent hip arthroscopy were identified. Pre- and post-operative modified Harris hip scores (mHHSs) were obtained. Patient surveys were administered to determine return to play rates, level of return to play, timing of return and patient satisfaction. A Wilcoxon ranked sum test was performed to compare pre- and post-operative outcome scores. Ten patients met inclusion criteria. Average age was 19.5 years old (SD ±1.08). All patients were male Division 1 collegiate water polo players. Median mHHS improved from 66.0 (SD ±7.9) pre-operatively to 89.5 (SD ±3.2) at average 1.6 years (range: 0.4-3.6 years) post-operatively. Patient survey responses demonstrated a 100% return to water polo and 100% return to the same level of play (NCAA Division 1) at mean 5.75 months (SD ±1.8). All patients (10/10) reported being satisfied with their surgical result. Our study results, suggest that return to sport rates and patient satisfaction are high in water polo players who undergo hip arthroscopy for FAI.

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BACKGROUND: Artificial playing surfaces are becoming more common due to decreased cost of maintenance and increased field usability across different environmental conditions. The Fédération Internationale de Football Association (FIFA) has approved newer generation artificial turf for soccer competition at the elite level, but many elite-level athletes prefer to play on natural grass surfaces due to a perceived increase in injury rate, discomfort, and fatigability on artificial turf. HYPOTHESIS: Injury rates and rates of individually categorized types of injury experienced on artificial turf are noninferior to rates of injury on the standard comparator, natural grass, in elite-level Major League Soccer athletes. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Over the course of 4 Major League Soccer seasons (2013-2016), athlete injury data were recorded electronically. Injury data recorded in matches between 2 Major League Soccer teams were then analyzed. Playing surface was known for each venue, and all artificial turf surfaces were rated as 2-star according to FIFA criteria. Incidence rate ratios (Artificial Turf ÷ Natural Grass) were calculated with a 95% CI (α = .05) for both overall injury incidence and individual injury subgroups. A noninferiority margin (δ) of 0.15 was used to determine noninferiority of injury incidence rates. RESULTS: A total of 2174 in-game injuries were recorded during the study period, with 1.54 injuries per game on artificial turf and 1.49 injuries per game on natural grass (incidence rate ratio, 1.033; 95% CI, 0.937-1.139). Within injury subgroups, overall ankle injury, Achilles injury, and ankle fracture were found to have a statistically higher incidence on artificial turf. Artificial turf was found to be noninferior to natural grass for overall foot injury and forefoot injury. No statistically significant differences were found in knee injuries between the 2 surfaces. CONCLUSION: The overall rate of injury on artificial turf was noninferior to that on natural grass. Within individual injury categories, a higher rate of ankle injury was found on artificial turf. No other injury subgroup demonstrated statistically significant differences between surfaces. CLINICAL RELEVANCE: FIFA 2-star rated artificial turf is a viable alternative to natural grass in elite-level soccer competition. Innovative research methods for comparing artificial turf versus natural grass may elucidate relative advantages with respect to player safety.

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There is a growing understanding of the relation between femoroacetabular impingement (FAI) and injury to adjacent structures. Patients with proximal hamstring pathology appear to have a high prevalence of underlying FAI. The kinetic chain phenomenon is a potential explanation of the high correlation between proximal hamstring injury and underlying FAI of the hip.

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Hip arthroscopy is commonly performed for the treatment of femoroacetabular impingement and labral pathology. When arthroscopy for femoroacetabular impingement is performed, a capsulotomy is often utilized to maximize access and allow for improved visualization. When an extended interportal or T capsulotomy is performed, the iliofemoral ligament is transected, which can lead to micro or gross instability. The purpose of this Technical Note is to describe an alternative approach to the standard T capsulotomy using a pie crusting technique, which provides improved visualization of the femoral head-neck junction during the femoroplasty without the need for an extended capsulotomy and can also serve to create venting holes that prevent hematoma formation within the capsule.

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BACKGROUND: Despite an abundance of literature regarding construct strength for a myriad of anchors and anchor configurations in the shoulder, there remains a paucity of biomechanical studies detailing the efficacy of these implants for proximal hamstring repair. PURPOSE: To biomechanically evaluate the ultimate failure load and failure mechanism of knotless and knotted anchor configurations for hamstring repair. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 17 cadaveric specimens divided into 3 groups composed of intact hamstring tendons as well as 2 different anchor configurations (all-knotted and all-knotless) underwent first cyclic loading and subsequent maximal loading to failure. This protocol entailed a 10-N preload, followed by 100 cycles incrementally applied from 20 to 200 N at a frequency of 0.5 Hz, and ultimately followed by a load to failure with a loading rate of 33 mm/s. The ultimate failure load and mechanism of failure were recorded for each specimen, as was the maximal displacement of each bone-tendon interface subsequent to maximal loading. Analysis of variance was employed to calculate differences in the maximal load to failure as well as the maximal displacement between the 3 study groups. Holm-Sidak post hoc analysis was applied when necessary. RESULTS: The all-knotless suture anchor construct failed at the highest maximal load of the 3 groups (767.18 ± 93.50 N), including that for the intact tendon group (750.58 ± 172.22 N). There was no statistically significant difference between the all-knotless and intact tendon groups; however, there was a statistically significant difference in load to failure when the all-knotless construct was compared with the all-knotted technique (549.56 ± 20.74 N) (P = .024). The most common mode of failure in both repair groups was at the suture-tendon interface, whereas the intact tendon group most frequently failed via avulsion of the tendon from its insertion site. CONCLUSION: Under biomechanical laboratory testing conditions, proximal hamstring repair using all-knotless suture anchors outperformed the all-knotted suture anchor configuration with regard to elongation during cyclic loading and maximal load to failure. Failure in the all-knotted repair group was at the suture-tendon interface in most cases, whereas the all-knotless construct failed most frequently at the musculotendinous junction. CLINICAL RELEVANCE: No biomechanical studies have clearly identified the optimal anchor configuration to avert proximal hamstring repair failure. Delineating this ideal suture anchor construct and its strength compared with an intact hamstring tendon may alter the current standards for postoperative rehabilitation, which remain extremely conservative and onerous for these patients.

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BACKGROUND: Proximal hamstring avulsions cause considerable morbidity. Operative repair results in improved pain, function, and patient satisfaction; however, outcomes remain variable. PURPOSE: To evaluate the predictors of clinical outcomes after proximal hamstring repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We retrospectively reviewed proximal hamstring avulsions repaired between January 2014 and June 2017 with at least 1-year follow-up. Independent variables included patient demographics, medical comorbidities, tear characteristics, and repair technique. Primary outcome measures were the Single Assessment Numerical Evaluation (SANE), International Hip Outcome Tool-12 (iHOT-12), and Kerlan-Jobe Orthopaedic Clinic (KJOC) Athletic Hip score. Secondary outcome measures included satisfaction, visual analog scale for pain, Tegner score, and timing of return to sports. RESULTS: Of 102 proximal hamstring repairs, 86 were eligible, 58 were enrolled and analyzed (67%), and patient-reported outcomes were available for 45 (52%), with a mean 29-month follow-up. The mean patient age was 51 years, and 57% were female. Acute tears accounted for 66%; 78% were complete avulsions. Open repair was performed on 90%. Overall satisfaction was 94%, although runners were less satisfied compared with other athletes (P = .029). A majority of patients (88%) returned to sports by 7.6 months, on average, with 72% returning at the same level. Runners returned at 6.3 months, on average, but to the same level 50% of the time and at a decreased number of miles per week compared to nonrunners (15.7 vs 7.8, respectively; P < .001). Postoperatively, 78% had good/excellent SANE Activity scores, but the mean Tegner score decreased (from 5.5 to 5.1). Acute tears had higher SANE Activity scores. The mean iHOT-12 and KJOC scores were 99 and 77, respectively. Endoscopic repairs had equivalent outcome scores to open repairs, although conclusions were limited given the small number of patients in the endoscopic group. Greater satisfaction was noted in patients older than 50 years (P = .024), although they were less likely to return to running (P = .010). CONCLUSION: Overall, patient satisfaction and functionality were high. With the numbers available, we were unable to detect any significant differences in functional outcome scores based on patient age, sex, body mass index, smoking status, medical comorbidities, tear grade, activity level, or open versus endoscopic technique. Acute tears had better SANE Activity scores. Runners should be cautioned that they may be unable to return to the same preinjury activity level after proximal hamstring repair. CLINICAL RELEVANCE: When counseling patients with proximal hamstring tears, runners and those with chronic tears should set appropriate expectations.

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Soccer is the most popular sport in the world and has the fourth highest number of sports injuries. Hip and groin injuries account for 14% of soccer injuries and can be difficult to recognize and treat as they often require a high level of suspicion and advanced imaging. Groin pain can be separated into 3 categories: (1) defined clinical entities for groin pain (adductor-related, iliopsoas-related, inguinal-related [sports hernias/athletic pubalgia], and pubic-related groin pain), (2) hip-related groin pain (hip morphologic abnormalities, labral tears, and chondral injuries), and (3) other causes of groin pain. Conservative approaches are typically the first line of treatment, but operative intervention has been reported to result in higher rates of return to sport in athletes with hip-related and inguinal-related groin pain injuries. In patients with concurrent hip-related and inguinal-related groin pain, the failure to recognize the relationship and treat both conditions may result in lower rates of return to sport. Preseason screening programs can identify high-risk athletes, who may benefit from a targeted prevention program. Further study on exercise therapy, early surgical intervention, and potential biologic intervention are needed to determine the most effective methods of preventing groin injuries in athletes.

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BACKGROUND: Surveillance programs are vital to analyze the cause and nature of lesions and ultimately establish protocols of action to lower injury rates. PURPOSE: To evaluate the adherence of team doctors to an electronic surveillance system and determine the incidence and characteristics of injuries among soccer players participating in the 2017 Gold Cup. STUDY DESIGN: Descriptive epidemiological study. METHODS: All data were collected from the electronic medical reports submitted during each match of the 2017 Gold Cup. Twelve teams participated in the tournament (each with 23 players), for a total of 276 players. A 19-question online survey was filled out by the team physician after each injury. Each report contained the player's number, the exact time of injury (minute of play), the location and diagnosis of injury as indicated by a previously defined code, and its severity in terms of the number of days of absence from training and match play. RESULTS: The electronic reporting system had a response rate of 100.0%, with 97.2% of questions answered completely. The mean age of injured players was 27 years (range, 21-35 years) and was not statistically significantly different from the overall mean player age (P > .05). There were no significant differences in the frequency of injuries when analyzed by player position (P = .743). The overall rate of injuries was 1.04 per match, with the most common injuries being contusions (42.3%), sprains (7.7%), strains (7.7%), and fractures (7.7%). These injuries were more commonly the result of contact (75.0%) than noncontact (25.0%) mechanisms (P < .001). Injuries most commonly occurred between the 60th and 75th minute of play when comparing all 15-minute time intervals (P = .004). CONCLUSION: This study supports the use of electronic injury reporting, which demonstrated a high level of adherence among an international cohort of team physicians and has significant potential for improving injury surveillance and tracking responses to prevention programs. Injury rates in the Gold Cup were similar to those in previous studies and demonstrated the highest rates late in the second half of the game, specifically between the 60th and 75th minute of play.

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We conducted a study to assess 30 expert hip arthroscopists' ability to identify common surface landmarks used during hip arthroscopy. Thirty hip arthroscopists independently performed a blinded examination of an awake supine human volunteer for identification of 5 surface landmarks: anterior superior iliac spine (ASIS), tip of greater trochanter (GT), rectus origin (RO), superficial inguinal ring (SIR), and psoas tendon (PT). The examiners applied the labels ASIS, GT, RO, SIR, and PT to the landmarks. An ultrasonographer performed a musculoskeletal ultrasound examination and applied labels as well, and a photographer documented the examiner labels after obtaining overhead and lateral digital images with use of fixed camera mounts. Digital overlay composite images of arthroscopist and ultrasonographer labels were analyzed. Direction and distance of inaccurately placed labels were compared with known values for neurovascular structures previously reported for common arthroscopic portals. Average distance from examiner-applied labels to ultrasonographer-applied labels was 31 mm for ASIS, 24 mm for GT, 26 mm for RO, 19 mm for SIR, and 35 mm for PT. Interobserver variability of examiner-applied labels was recorded as areas of 95% predictive interval: 65 cm2 for ASIS, 16 cm2 for GT, 221 cm2 for RO, 38 cm2 for SIR, and 29 cm2 for PT. Examiner labels demonstrated the highest potential for injury because of anterior portal inaccuracy. Expert hip arthroscopists varied in their ability to accurately and precisely identify common surface landmarks about the hip, using only manual palpation.

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BACKGROUND: Previous studies have indicated that hip and pelvis kinematics may be altered during functional tasks in persons with femoroacetabular impingement. The purpose of this study was to compare hip and pelvis kinematics and kinetics during a deep squat task between persons with cam femoroacetabular impingement and pain-free controls. METHODS: Fifteen persons with cam femoroacetabular impingement and 15 persons without cam femoroacetabular impingement performed a deep squat task. Peak hip flexion, abduction, and internal rotation, and mean hip extensor, adductor, and external rotator moments were quantified. Independent t-tests (α<0.05) were used to evaluate between group differences. FINDINGS: Compared to the control group, persons with cam femoroacetabular impingement demonstrated decreased peak hip internal rotation (15.2° (SD 9.5°) vs. 9.4° (SD 7.8°); P=0.041) and decreased mean hip extensor moments (0.56 (SD 0.12) Nm/kg vs. 0.45 (SD 0.15) Nm/kg; P=0.018). In addition persons in the cam femoroacetabular impingement group demonstrated decreased posterior pelvis tilt during squat descent compared to the control group, resulting in a more anteriorly tilted pelvis at the time peak hip flexion (12.5° (SD 17.1°) vs. 23.0° (SD 12.4°); P=0.024). INTERPRETATION: The decreased hip internal rotation observed in persons with cam femoroacetabular impingement may be the result of bony impingement. Furthermore, the decrease in posterior pelvis tilt may contribute to impingement by further approximating the femoral head-neck junction with the acetabulum. Additionally, decreased hip extensor moments suggest that diminished hip extensor muscle activity may contribute to decreased posterior pelvis tilt.

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Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

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PURPOSE: To survey surgeons who perform a high volume of hip arthroscopy procedures regarding their operative technique, type of procedure, and postoperative management. METHODS: We conducted a cross-sectional survey of 27 high-volume orthopaedic surgeons specializing in hip arthroscopy to report their preferences and practices related to their operative practice and postoperative rehabilitation protocol. All participants completed the survey in person in an anonymous fashion during a meeting of the American Hip Institute. RESULTS: All surgeons perform hip arthroscopy with the patient in the supine position, accessing the central compartment of the hip initially, using intraoperative fluoroscopy. All surgeons perform labral repair (100%), with the majority performing labral reconstructions (77.8%) and gluteus medius repairs (81.5%). There is variability in the type of anchors used during labral repair. Most surgeons perform capsular closure in most cases (88.9%), inject either intra-articular cortisone or platelet-rich plasma at the conclusion of the procedure (59%), and prescribe a postoperative hip brace for some or all patients (59%). There is considerable variability in rehabilitation protocols. All surgeons routinely prescribe postoperative heterotopic ossification prophylaxis to their patients, with most surgeons (88.9%) prescribing a nonsteroidal anti-inflammatory medication for 3 weeks. Forty percent of the respondents use the modified Harris Hip Score as the most important outcome measure. CONCLUSIONS: Consistent practices such as use of intraoperative fluoroscopy, heterotopic ossification prophylaxis, and labral repair skills were identified by surveying 27 hip arthroscopy surgeons at high-volume centers. Most of the surgeons performed routine capsular closure unless underlying conditions precluded capsular release or plication. The survey identified higher variability between surgeons regarding postoperative rehabilitation protocols and use of intra-articular pharmacologic injections at the end of the procedure. These data may provide surgeons with a set of aggregate trends that may help guide training, clinical practice, and research in the evolving field of hip arthroscopy.

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PURPOSE: To define the topographic anatomy of the footprint of the hamstrings origin on the ischium. METHODS: Dissection of the hamstrings origin in 6 cadaveric pelvises was performed. The hamstrings origin was isolated with sharp dissection, and it was noted whether the semimembranosus had a separate attachment or whether there was one confluent tendon attached at the footprint. The common hamstrings tendon was then sharply dissected from the ischium, and the footprint was outlined with surgical marker followed by radiopaque paint. Paint was prepared by mixing 0.25 g Daler-Rowney acrylic artists ink scarlet no. 567 (Daler-Rowney, Bracknell, England) per gram of EZ-HD 98% v/w barium sulfate (E-Z-EM Inc, Lake Success, NY). The paint was then applied to the area of the footprint, and the specimen underwent a 0.5-mm-slice computed tomographic (CT) scan of the pelvis with 3-dimensional (3D) reconstructions. Vitrea (Vital Images, Minnetonka, MN) software was used to determine the surface area of the ligament footprint as well as the distance from the ischial tuberosity to the center of the footprint. The thickness of the bone underlying the footprint was measured. Data are presented as means ± standard error. RESULTS: Five of 6 specimens had a common hamstrings tendon, whereas one had a separate attachment for the semimembranosus. The semimembranosus joined the common hamstrings tendon 2.33 ± 0.61 cm distal to the footprint. The average surface area of the hamstrings footprint measured 10.19 ± 0.75 cm(2). The distance from the tip of the ischial tuberosity to the center of the hamstrings footprint measured 3.73 ± 0.22 cm. The average thickness of the bone deep to the footprint was 3.77 ± 0.9 cm. CONCLUSIONS: This study provides a topographic description of the origin of the hamstrings footprint and may assist surgeons in performing anatomic reattachment of this tendon. CLINICAL RELEVANCE: Our data will assist surgeons in performing anatomic repair of proximal hamstrings avulsions.

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As the fraction of electricity generation from intermittent renewable sources--such as solar or wind--grows, the ability to store large amounts of electrical energy is of increasing importance. Solid-electrode batteries maintain discharge at peak power for far too short a time to fully regulate wind or solar power output. In contrast, flow batteries can independently scale the power (electrode area) and energy (arbitrarily large storage volume) components of the system by maintaining all of the electro-active species in fluid form. Wide-scale utilization of flow batteries is, however, limited by the abundance and cost of these materials, particularly those using redox-active metals and precious-metal electrocatalysts. Here we describe a class of energy storage materials that exploits the favourable chemical and electrochemical properties of a family of molecules known as quinones. The example we demonstrate is a metal-free flow battery based on the redox chemistry of 9,10-anthraquinone-2,7-disulphonic acid (AQDS). AQDS undergoes extremely rapid and reversible two-electron two-proton reduction on a glassy carbon electrode in sulphuric acid. An aqueous flow battery with inexpensive carbon electrodes, combining the quinone/hydroquinone couple with the Br2/Br(-) redox couple, yields a peak galvanic power density exceeding 0.6 W cm(-2) at 1.3 A cm(-2). Cycling of this quinone-bromide flow battery showed >99 per cent storage capacity retention per cycle. The organic anthraquinone species can be synthesized from inexpensive commodity chemicals. This organic approach permits tuning of important properties such as the reduction potential and solubility by adding functional groups: for example, we demonstrate that the addition of two hydroxy groups to AQDS increases the open circuit potential of the cell by 11% and we describe a pathway for further increases in cell voltage. The use of π-aromatic redox-active organic molecules instead of redox-active metals represents a new and promising direction for realizing massive electrical energy storage at greatly reduced cost.