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Purpose: The demographic and radiological risk factors of subchondral insufficiency fractures of the knee (SIFK) continue to be a subject of debate. The purpose of this study was to associate patient-specific factors with SIFK in a large cohort of patients., Methods: Inclusion criteria consisted of patients with SIFK as verified on magnetic resonance imaging (MRI). All radiographs and MRIs were reviewed to assess characteristics such as meniscus tear presence and type, subchondral oedema presence and location, location of SIFK, mechanical limb alignment, osteoarthritis as assessed by Kellgren-Lawrence grade and ligamentous injury. A total of 253 patients (253 knees) were included, with 171 being female. The average body mass index (BMI) was 32.1 ± 7.0 kg/m 2 ., Results: SIFK was more common in patients with medial meniscus tears (77.1%, 195/253) rather than tears of the lateral meniscus (14.6%, 37/253) (p < 0.001). Medial meniscus root and radial tears of the posterior horn were present in 71.1% (180/253) of patients. Ninety-one percent (164/180) of medial meniscus posterior root and radial tears had an extrusion ≥3.0 mm. Eighty-one percent (119/147) of patients with SIFK on the medial femoral condyle and 86.8% (105/121) of patients with SIFK on the medial tibial plateau had a medial meniscus tear. Varus knees had a significantly increased rate of SIFK on the medial femoral condyle in comparison to valgus knees (p = 0.016)., Conclusion: In this large cohort of patients with SIFK, there was a high association with medial meniscus root and radial tears of the posterior horn, meniscus extrusion ≥3.0 mm as well as higher age, female gender and higher BMI. Additionally, there was a particularly strong association of medial compartment SIFK with medial meniscus tears. As SIFK is frequently undiagnosed, identifying patient-specific demographic and radiological risk factors will help achieve a prompt diagnosis., Level of Evidence: Level IV., (© 2024 European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Abstract: This review provides a synopsis of current injury patterns, potential mechanisms, and off-ice exercise prevention considerations as the sport of figure skating evolves. The lifetime prevalence of injury for all skaters is estimated to be 79.5%, with the most common sites being spine and lower extremity. Singles skaters more often develop chronic injuries compared to acute (68.9% vs 31.1%), whereas non-singles skaters more often experience acute injuries. Lower limb stress fracture prevalence ranges from 10% to 21.4% across disciplines. Emerging contributors include training volume, technical difficulty and repetition of complex elements (multirotational jumps, lifts, holds), extreme ranges of movement about the spine and hip, age and experience level, and functional capacity (dynamic strength, flexibility, balance, and neuromotor control). Prevention programs in competitive figure skaters may include monitoring of training volumes, emphasis on technique, appropriate boot fit, and strength and conditioning content to prepare for increasing neuromotor, balance, and power demands of the sport., (Copyright © 2024 by the American College of Sports Medicine.)

Women, who comprise approximately 18% of the U.S. Armed Forces, suffer disproportionately higher rates of musculoskeletal injuries among active component service members. Using a retrospective study design, this study calculated incidence rates and rate ratios for acute hip fractures and hip stress fractures from January 1, 2018 through September 30, 2022 among female and male active component U.S. military members. Women who were younger than age 20 years, in recruit training, serving in the Army or Marine Corps, engaged in combat-related occupations, and with body mass indexes in the underweight or normal weight categories had the highest rates of both types of fractures. Women who had progressed beyond the recruit training phase had a higher female-to-male rate ratios of hip stress fractures than recruits. Despite an overall decline during the surveillance period, rates of acute hip fracture and hip stress fracture were higher among women than men. Changes in training and fitness policies may have contributed to the hip fracture rate declines among women. Continued efforts are needed to further reduce injuries among women.

Dancers are susceptible to relative energy deficiency in sport (RED-S), specifically low bone mineral density (BMD). Little is known about how dancers' BMD compares to other athletic populations. The objective of this study was to examine the association between participant characteristics and total body areal BMD (aBMD) among female pre-professional dancers compared to other female athletes. Two hundred sixty-nine females (132 pre-professional dancers (17.6 (3.2) years) and 137 sport participants (22.8 (2.6) years) were included in this study. aBMD (g/cm 2 ) was estimated using dual X-ray absorptiometry. Multivariable linear regression was used to examine the association between height-adjusted z -scores of total body aBMD (aBMD-Z) and age (years), body mass index (BMI) ( z -score), supplement intake, history of stress fracture, irregular menses, MRI/bone scan, 1-year injury history, oral contraceptives, and activity (dance/sport). Total body aBMD and aBMD-Z were lower in dancers than athletes (dancers: aBMD = 1.03 g/cm 2 (95% CI: 1.01, 1.05); aBMD-Z = -0.28 (-0.43, -0.12) ( p  < 0.001); athletes: aBMD = 1.14 g/cm 2 (95% CI: 1.12, 1.16); aBMD-Z = 0.41 (0.25, 0.57) ( p  < 0.001)). aBMD-Z increased with age (β = 0.054, 95% CI: 0.017, 0.092; p  = 0.004) and BMI (β = 0.221, 95% CI: 0.006, 0.415; p  = 0.043). Activity type modified the relationship between BMI and aBMD-Z (β = 0.323, 95% CI: 0.025, 0.621; p  < 0.033) with a stronger positive association in dancers, compared to other female athletes. Dancers had lower total body aBMD and aBMD-Z than other female athletes. aBMD-Z increases with age in female pre-professional dancers and other female athletes. A stronger association exists between aBMD-Z and BMI in dancers than athletes. Future studies should consider changes in aBMD-Z during adolescence and associations with increased risk of bone injury., Competing Interests: The authors declare there are no competing interests.

Objectives: To determine (1) the incidence rate of lower extremity (LE) bone stress injuries (BSIs) in United States Air Force Special Warfare (AFSPECWAR) trainees during the first 120 days of training, and (2) factors associated with sustaining a LE BSI., Design: Retrospective cohort study., Methods: AFSPECWAR Airmen (n = 2,290, mean age = 23.7 ± 3.6 years) entering an intensive 8-week preparatory course "SW-Prep" between October 2017 and May 2021. We compared anthropometric measurements, previous musculoskeletal injury (MSKI), fitness measures, and prior high-impact sports participation in those that did and did not suffer a BSI during the 120-day observation period using independent t-tests and chi-square tests. A multivariable binary logistic regression was used to determine factors associated with suffering a BSI., Results: A total of 124 AFSPECWAR trainees suffered a BSI during the surveillance period, yielding an incidence proportion of 5.41% and an incidence rate of 1.4 BSIs per 100 person-months. The multivariate logistic regression revealed that lower 2-minute sit-up scores, no prior history of participation in a high-impact high-school sport, and a history of prior LE MSKI were associated with suffering a BSI. A receiver operator characteristic curve analysis yielded an area under the curve (AUC) of 0.727., Conclusion: BSI incidence proportion for our sample was similar to those seen in other military settings. Military trainees without a history of high-impact sports participation who achieve lower scores on sit-ups tests and have a history of LE MSKI have a higher risk for developing a LE BSI during the first 120 days of AFSPECWAR training., (© The Association of Military Surgeons of the United States 2024. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Fragility fractures without significant trauma of the pelvic ring in older patients have an increasing incidence due to demographic change. Influencing factors other than osteoporotic bone quality that lead to an insufficiency fracture are not yet known. However, it is suspected that the pelvic tilt (PT) has an effect on the development of such an insufficiency fracture. This study explores the influence of the PTs in patients with insufficiency fractures of the posterior pelvic ring., Materials and Methods: A total of 49 geriatric patients with fragility fractures of the pelvic ring were treated at a university hospital level-1 trauma center during a period between February and December 2023, and their fractures were classified according to the FFP classification of Rommens and Hofmann. Complete sets of computer tomography (CT) and radiological images were available to determine the PT angle of the patients., Results: 34 FFP type 2 and 15 FFP type 3 classified patients were included in the study. Significant difference was seen in the pelvic tilt (PT) angle between the patient group with insufficiency fractures (n= 49; mean age: 78.02 ± 11.80) and the control group with lumbago patients (n= 53; mean age: 69.23 ± 11.23). The PT was significantly higher in the patients with insufficiency fractures (25.74° ± 4.76; p ⁎⁎⁎⁎ ≤ 0.0001)., Conclusions: The study demonstrates a significant extension of the PT angle of individuals with insufficiency fractures when compared to those with lumbago. The result suggests a potential association between pelvic tilt and fracture susceptibility., Trial Registration: A retrospective study about the influence of sagittal balance of the spine on insufficiency fractures of the posterior pelvic ring measured by the "pelvic tilt angle", DRKS00032120. Registered 20th June 2023 - Prospectively registered. Trial registration number DRKS00032120., Competing Interests: Declaration of competing interest The authors declare that they have no financial and non-financial conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Context: Bone-stress injury (BSI) is common in collegiate athletes. Injury rates and health care use in running athletes are not well documented., Objective: To describe the rate and classification of injury and associated health care use in collegiate cross-country runners with BSI., Design: Descriptive epidemiology study., Setting: Sports medicine facilities participating in the Pac-12 Health Analytics Program., Patients or Other Participants: Pac-12 Conference collegiate cross-country athletes., Main Outcome Measure(s): Counts of injury and health care resources used for each injury. Injury rates were calculated based on athlete-seasons., Results: A total of 168 BSIs were reported over 4 seasons from 80 team-seasons (34 men's and 46 women's team-seasons) and 1220 athlete-seasons, resulting in 1764 athletic training services and 117 physician encounters. Bone-stress injuries represented 20% of all injuries reported by cross-country athletes. The average BSI rate was 0.14 per athlete-season. Injury rates were higher in female (0.16) than male (0.10) athletes and higher in the 2019-2020 season (0.20) than the 2020-2021 (0.14), 2018-2019 (0.12), and 2021-2022 (0.10) seasons. Most BSIs occurred in the lower leg (23.8%) and the foot (23.8%). The majority of injuries were classified as overuse and time loss (72.6%) and accounted for most of the athletic training services (75.3%) and physician encounters (72.6%). We found a mean of 10.89 athletic training services per overuse and time-loss injury and 12.20 athletic training services per overuse and non-time-loss injury. Mean occurrence was lower for physician encounters (0.70), prescription medications (0.04), tests (0.75), procedures (0.01), and surgery (0.02) than for athletic training services (10.50)., Conclusions: Bone-stress injuries are common in collegiate cross-country runners and require considerable athletic training resources. Athletic trainers should be appropriately staffed for this population, and suspected BSIs should be confirmed with a medical diagnosis. Future investigators should track treatment codes associated with BSI to determine best-practice patterns., (© by the National Athletic Trainers' Association, Inc.)

Although a fifth metatarsal stress fracture is the most frequent stress fracture in soccer players, awareness of fifth metatarsal stress fractures among soccer coaches is unclear. Therefore, we performed an online survey of soccer coaches affiliated with the Japan Football Association to assess their awareness of fifth metatarsal stress fractures. A total of 150 soccer coaches were invited for an original online survey. Data on participants' age, sex, types of coaching licence, coaching category, types of training surface, awareness of fifth metatarsal stress fractures, and measures employed to prevent fifth metatarsal stress fractures were collected using the survey. Data from 117 coaches were analysed. Eighty-seven of the 117 coaches were aware of fifth metatarsal stress fractures; however, only 30% reported awareness of preventive and treatment measures for fifth metatarsal stress fractures. Licensed coaches (i.e., licensed higher than level C) were also more likely to be aware of fifth metatarsal stress fractures than unlicensed coaches were. Furthermore, although playing on artificial turf is an established risk factor for numerous sports injuries, soccer coaches who usually trained on artificial turf were more likely to be unaware of the risks associated with fifth metatarsal stress fractures than coaches who trained on other surfaces were (e.g., clay fields). Soccer coaches in the study population were generally aware of fifth metatarsal stress fractures; however, most were unaware of specific treatment or preventive training strategies for fifth metatarsal stress fractures. Additionally, coaches who practised on artificial turf were not well educated on fifth metatarsal stress fractures. Our findings suggest the need for increased awareness of fifth metatarsal stress fractures and improved education of soccer coaches regarding injury prevention strategies.　., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Miyamori et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Although stress fractures of the distal femur are rare, symptoms can overlap with other peri-articular knee pathology, delaying diagnosis. Untreated stress fractures have the potential to progress into completed fractures with a higher likelihood for requiring surgery and longer recovery times in otherwise healthy adolescents and young adults. This case series represents the largest cohort of adolescent athletes with distal femoral stress fractures who presented with activity-related knee pain., Methods: Patients treated nonoperatively and operatively for metaphyseal distal femur stress fractures at a tertiary referral center over a four-year period were retrospectively identified from the medical record., Results: Eight patients (mean age 16.8 y; range 14 to 22 y; 87.5% male; mean body mass index [BMI] 20.9) with a total of 10 distal femur stress fractures were identified. All patients were involved in competitive sports or military training. There was an average of 3.8 encounters with a medical provider between presentation with activity-related knee pain and diagnosis with distal femur stress fracture. All except 1 patient (87.5%) were initially incorrectly diagnosed with another type of peri-articular knee pathology. Six stress fractures (60%) were treated conservatively with protected weight bearing, activity modification, and gradual return to activity. Four completed stress fractures (40%) required operative fixation-3 healed uneventfully, while 1 had an asymptomatic delayed union. Vitamin D insufficiency (<30 ng/mL) was identified in 7 of 8 patients (87.5%) and 3 patients (37.5%) had an underweight BMI (<18.5). The mean clinical follow-up was 13.1 weeks (range, 2.8 to 32.0 wk)., Conclusions: High clinical suspicion for distal femoral stress fractures is needed to avoid misdiagnosis or delayed diagnosis in young, active individuals with activity-related knee pain refractory to conservative management. In this patient population, activity-related knee pain recalcitrant to activity modification, rest, and physical therapy warrants further workup with magnetic resonance imaging and orthopaedic evaluation. Though rare, misdiagnosis can result in catastrophic fractures with prolonged rehabilitation needs. An open line of communication and streamlined access for referral between primary care providers and orthopaedic surgeons is critical in preventing misdiagnosis and delayed treatment. Furthermore, the treatment of concomitant metabolic disorders and nutritional deficiency should not be neglected when treating distal femoral stress fractures., Level of Evidence: Level-IV (case series)., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Golf is a popular sport; however, there is a paucity of data in relation to golf-associated fractures, and the rate and timing of returning to golf. The aim of this review is to describe golf-associated fractures, including epidemiology, management, and timing of returning to golf following treatment. A literature search was performed using MEDLINE/PubMed, Embase, and Web of Science. Data were extracted and summarized in a narrative synthesis. A total of 436 articles were identified with an initial search of which 58 met the inclusion criteria. Twelve anatomical sites of golf swing-related fractures were identified, of which 10 sites were specific for stress fractures. The most common sites of golf swing-related stress fractures were the ribs followed by the hook of hamate. There was a common theme of delay to diagnosis, being initially assigned to a soft tissue injury. Most golfers with swing-related stress fractures were able to return to golf with the exception of osteoporotic associated vertebral stress fractures. Timing of returning to golf was between 4 and 12 months for most of the golfers with stress fractures following conservative management. Operative intervention was an option of hook of hamate nonunion, following a stress fracture, and tibial shaft stress fractures. Golf equipment-related fractures were not rare and were associated with major trauma and in some cases associated with significant persistent morbidity. Golf-related stress fractures commonly involve the ribs and hook of hamate; knowledge of this may aid in early diagnosis and appropriate treatment when symptomatic golfers are encountered. Although golf is a noncontact sport, fractures associated with golf equipment can be life changing, and safety training guidelines should be established., (Copyright © 2024 by the American College of Sports Medicine.)

Objective: To characterise the prevalence, incidence rate (IR) and burden of injuries in elite short-course triathletes over a 4-year training and competition period., Methods: Fifty elite Australian triathletes were prospectively monitored for injury during four consecutive seasons (2018-2021). Injuries requiring medical attention were prospectively recorded and further subcategorised according to time loss. The IR and burden (injury IR×mean injury severity) were calculated per 365 athlete days, with sex differences in IR compared using IR ratios (IRR) from negative binomial regression models., Results: Two hundred and sixty-six injuries were reported in 46 (92.0%) athletes, of which 67.3% resulted in time loss. The injury IR was 1.87 injuries per 365 athlete days (95% CI 1.70 to 2.80), and comparable between sexes (IRR 0.82, 95% CI 0.64 to 1.04, p=0.109). Most injuries (70.7%) were training related. The most frequently injured body sites were the ankle (15.8%), foot (12.4%) and lower leg (12.0%). Bone stress injuries (BSIs) were the most burdensome injury type with 31.38 days of time loss per 365 days (95% CI 24.42 to 38.34). Twenty athletes (40.0%) reported at least one bone stress injury (BSI) (range 0-3). The rate of BSIs in female athletes was three times greater compared with male athletes (IRR 2.99, 95% CI 1.26 to 7.07, p=0.013)., Conclusion: Two-thirds of injuries reported in elite short-course triathletes resulted in time loss, with the majority occurring during training activities. Foot, ankle and other lower leg injuries had the highest incidence, with BSIs carrying the highest injury burden. The considerably higher rate of BSI observed in female athletes warrants consideration for future prevention strategies in female triathletes., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Military recruits and athletes have high occurrence of stress fractures, with very high incidence among military recruits. Symptomatic stress fractures can be disabling in some people. This study aims at identifying pattern and distribution of such fractures in Nepal Police trainee and assess the risk factors and demographics that may help to develop the local guidelines., Methods: This study analysed 65 police trainees who presented to the orthopaedic Out Patient Department at Nepal Police and Province Police Hospital diagnosed as a case of stress fracture from 29 December, 2020 to 29 December, 2021. Ethical approval was obtained and different variables analysed were age, sex, Body Mass Index, location of fracture, duration of pain, method of treatment, time to heal the fracture and time to pain free mobilisation of patient., Results: There were 65 trainees with 86 sites of fracture at different bones with 50.8% (33) of male population. The majority of fracture was located at tibia (58.1%) followed by pubic rami (33.7%) with potentially debilitating fracture neck of femur seen in 4.6% subjects. Mean duration of pain was 20.7±14.2 days with mean time for pain free mobilisation 42.2±17.7 days after presentation. 96.5% of those recovered with conservative treatment (activity restriction or cast)., Conclusions: The location of stress fracture depends upon the type of training or activities. Modification of activities in early phase of training with early visit for medical care in case of trainees with increasing pain may decrease morbidities and complications requiring operative treatment.

Objectives: To describe bone injury patterns in elite track and field athletes. To investigate relationships between bone injury and athlete characteristics to inform future injury prevention strategies., Design: Descriptive epidemiology study., Setting: Elite athletics training centres across the United Kingdom and internationally, observed between 2012 and 2020., Participants: 207 Olympic programme senior track and field athletes., Main Outcome Measures: Injury number, Incidence, Severity, Burden, Time Loss., Results: There were 78 fractures during the study period. Gradual repetitive bone injuries were the most common type of injury mode. The foot, pelvis and the lumbar spine were the regions with the highest number of bone stress injuries. Stress fractures had a higher burden overall compared to stress reactions. Average return to full training was 67.4 days (±73.1) for stress reactions and 199 (±205.2) days for stress fractures. There was no relationship between bone injury type and age, sex, ethnicity, side dominance or event group., Conclusion: Bone stress injuries in athletics have a high severity and burden warranting continued efforts to prevent their occurrence and optimize management. Age, sex, ethnicity, side dominance and event region do not have any relationship with bone injury occurrence and are therefore unlikely to increase risk in this cohort., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Femoral neck stress fractures (FNSFs) are a unique injury pattern not commonly treated in the civilian trauma population; however, it is particularly high with military trainees engaged in basic combat training. To date, no study has surveyed a population of military orthopedic surgeons on treatment preferences for military service members (SMs) with FNSF., Questions: We aim to evaluate the extent of clinical equipoise that exists in the management of these injuries, hypothesizing that there would be consensus in the factors dictating surgical and non-surgical intervention for FNSF., Patients and Methods: A 27-question survey was created and sent to U.S. military orthopedic surgeon members of the Society of Military Orthopaedic Surgeons. The survey was designed in order to gather the experience among surgeons in treating FNSF and identifying variables that play a role in the treatment algorithm for these patients. In addition, seven detailed, clinical vignettes were presented to further inquire on surgeon treatment preferences. Binomial distribution analysis was used to evaluate for common trends within the surgeon's treatment preferences., Results: Seventy orthopedic surgeons completed the survey, the majority of whom were on active duty status in the U.S. Military (82.86%) and having under 5 years of experience (61.43%). Majority of surgeons elected for a multiple screw construct (92.86%), however the orientation of the multiple screws was dependent on whether the fracture was open or closed. Management for compression-sided FNSF involving ≥50% of the femoral neck width, tension-sided FNSF, and stress fractures demonstrating fracture line progression had consensus for operative management. Respondents agreed upon prophylactic fixation of the contralateral hip if the following factors were involved: Complete fracture (98.57%), compression-sided fracture line >75% (88.57%), compression-sided fracture line >50-75% with hip effusion (88.57%), contralateral tension-sided fracture (87.14%), and compression-sided fracture line >50-75% (84.29%). An FNSF < 50% on the contralateral femoral neck or a hip effusion was indeterminate in surgeons indicating need for prophylactic fixation. Majority of surgeons (77.1%) utilized restricted toe-touch weight-bearing for postoperative mobility restrictions., Conclusions: Consensus exists for surgical and non-surgical management of FNSF by U.S. military orthopedic surgeons, despite the preponderance of surgeons reporting a low annual volume of FNSF cases treated. However, there are certain aspects in the operative and non-operative management of FNSF that are unanimously adhered to. Specifically, our results demonstrate that there is no clear indication on the management of FNSF when an associated hip effusion is involved. Additionally, the indications for surgically treating contralateral FNSF are unclear., Level of Evidence: IV., (© The Association of Military Surgeons of the United States 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: An acromial stress fracture (ASF) is an uncommon complication after reverse total shoulder arthroplasty (RTSA) that can have severe clinical consequences on shoulder function. Although patient-specific factors have been identified to influence the risk of ASF, it is unclear whether modifying these factors can minimize risk. Moreover, there is limited information on the treatment outcomes of these fractures. Therefore, the purpose of this study was to determine modifiable risk factors for ASFs and the complication and revision rates of conservatively and operatively managed ASFs., Methods: The PearlDiver database was queried to identify a cohort of patients who underwent RTSA with minimum 2-year follow-up. Current Procedural Terminology and International Classification of Diseases codes were used to compare the demographic characteristics, comorbidities, and medication use of patients with and without ASFs. Surgical complication and revision rates were compared between operatively and conservatively treated fractures., Results: The overall incidence of ASFs was 1.4%. Patient-specific factors that were independently associated with the occurrence of an ASF included osteoporosis, rheumatologic disease, shoulder corticosteroid injection within 3 months before surgery, and chronic oral corticosteroid use. Among patients with osteoporosis, the initiation of physical therapy within 6 weeks after surgery also increased the risk of ASF. Patients who underwent surgical treatment of ASFs had a revision arthroplasty rate of 7.0% compared to a rate of 3.2% among those with conservatively managed fractures., Conclusion: ASFs are infrequent complications that can occur after RTSA. Preoperative factors that affect the quality of bone independently increase the fracture risk. Moreover, this risk can be minimized by avoiding shoulder corticosteroid injections 3 months before surgery and delaying physical therapy exercises among patients with osteoporosis. Surgical fixation of these fractures should be reserved for instances when conservative management has failed given high rates of infection, instability, and revision shoulder arthroplasty., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Previous research has shown a discrepancy in incidences of knee injuries, stress fractures, and concussions between cisgender men and women. Little is known regarding the incidence of musculoskeletal injuries among patients on gender-affirming hormone therapy (GAHT). This retrospective cohort study examines cumulative incidence of knee injuries, concussions, and stress fracture injuries among transgender patients on GAHT at one health system from 2011-2020. Using relevant ICD-9 and 10 codes, incidences of knee injury, concussion, and stress fracture were calculated. Cohorts included 1971 transgender and 3964 cisgender patients. Transgender patients had significantly higher incidence of all-cause knee injuries over the study period, 109 (5.5%) versus 175 (4.4%) ( p < 0.001; OR: 2.14, 95% CI [1.17-3.92]). Subgroup analysis showed significantly higher incidence of knee injuries among cisgender men (5.6%) versus cisgender women (4.1%) ( p = 0.042) and among transgender women (6.6%) versus cisgender women (4.1%) ( p = 0.005). There were no significant differences between incidences of concussion and stress fracture between groups. This sample showed that patients on GAHT had increased cumulative incidences of all-cause knee injury compared to controls but similar cumulative incidences of concussion and bone-stress injuries. Transgender women on exogenous estrogen had significantly higher cumulative incidences of all-cause knee injuries compared to cisgender women.

Introduction: Every year, approximately 35,000 recruits enter the United States Air Force Basic Military Training (BMT). Musculoskeletal problems are particularly vexing for BMT because a broad array of differentials render definitive diagnosis burdensome and while most sufferers will fully recover, healing often requires protracted training delays resulting in increased unrecoverable training costs to the program. The purpose of this study is to conduct a case-control study of basic military trainees entering service from 2012 to 2015 to assess detectable differences in demographics, retention, and health care utilization., Materials and Methods: This is a retrospective case-control study of existing data and records obtained from existing and active information record systems for individuals who attended BMT between the years 2012 and 2015. Cohort assignment was based on incidence of first stress fracture diagnosis (i.e., having a select diagnosis code in one's medical record) relative to arrival at BMT. Health care utilization is operationalized as medical encounter frequencies and associated international classification of disease (ICD) codes occurring for all patients from BMT recruit date of arrival to 6 months post-graduation (i.e., 180 days)., Results: The primary dataset includes 132,359 distinct individuals, of which 129,637 (98%) had no history of stress fracture diagnosis and 1,487 (1%) of which have a diagnosis of stress fracture more than 60 days after arrival at BMT; these are assigned to the CONTROL group. There are 1,235 (0.9%) assigned to the CASE group. CASE members presented with 30.1 unique ICD-10 codes post-graduation compared to 6.3 in the CONTROL group. Six of the top thirteen ICD-10 codes were musculoskeletal in nature and all presented significantly higher rates for the CASE group., Conclusions: Trainees who suffered a bone stress injury (BSI) during the United States Air Force BMT advanced in rank on par with trainees who did not, but BSI sufferers exhibited greater health care utilization than those who did not suffer BSI. The cost to replace a trainee unable to complete BMT is considerable; however, it is also important to consider the reduction in resiliency and readiness to the Department of Defense and the financial burdens from increased health care utilization. The 2-fold increase in BSI presentation in the graduated control group reflects that more needs to be done for all populations to identify better proactive efforts to foundationally support wellness and prevention rather than accept injury as the status quo., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Bone stress injury (BSI) risk in runners is multifactorial and not well understood. Unsupervised machine learning approaches can potentially elucidate risk factors for BSI by identifying groups of similar runners within a population which differ in BSI incidence. Here, a hierarchical clustering approach is used to identify groups of collegiate cross country runners based on 2-dimensional frontal plane pelvis and proximal femur geometry, which was extracted from dual-energy X-ray absorptiometry scans and dimensionally reduced by principal component analysis. Seven distinct groups were identified using the cluster tree, with the initial split being highly related to female-male differences. Visual inspection revealed clear differences between groups in pelvis and proximal femur geometry, and groups were found to differ in lower body BSI incidence during the subsequent academic year (Rand index = 0.53; adjusted Rand index = 0.07). Linear models showed between-cluster differences in visually identified geometric measures. Geometric measures were aggregated into a pelvis shape factor based on trends with BSI incidence, and the resulting shape factor was significantly different between clusters (p < 0.001). Lower shape factor values, corresponding with lower pelvis height and ischial span, and greater iliac span and trochanteric span, appeared to be related to increased BSI incidence. This trend was dominated by the effect observed across clusters of male runners, indicating that geometric effects may be more relevant to BSI risk in males, or that other factors masked the relationship in females. More broadly, this work outlines a methodological approach for distilling complex geometric differences into simple metrics that relate to injury risk., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to characterize the impact of detraining due to the COVID-19 pandemic on incidence of bony injuries and stress fractures in collegiate athletes., Methods: A comprehensive collegiate athletic conference injury database was queried for all in-season, sport-related bony injuries (defined as all stress reactions and fractures) that occurred across all sports from January 2016 to June 2021. The bony injury rate per 1000 athlete exposure hours (AEH) was calculated and compared between the immediate post-hiatus season and historic rates from pre-hiatus seasons (2016-2019). Injury characteristics were also compared between the pre- and post-hiatus time periods., Results: A total of 868 bony injuries across 23 sports were identified. The sports with highest overall baseline bony injury rates in historic seasons were women's cross country (0.57 injuries per 1000 AEH) and men's cross country (0.32). Compared to historic pre-hiatus rates, female cross-country runners demonstrated a significantly lower bony injury incidence rate in the post-hiatus season (0.24 vs. 0.57, p = 0.016) while male swimming athletes demonstrated a statistically significant increase in bony injury rate (0.09 vs. 0.01, p = 0.015). The proportion of bony injuries attributed to repetitive trauma increased; while, the proportion of injuries attributed to running decreased between the pre- and post-hiatus seasons., Conclusion: Across all sports, there was no consistent trend toward increased rates of bony injury in the immediate post-hiatus season. However, female cross-country runners demonstrated lower rates of bony injury in the post-hiatus season while male swimmers demonstrated higher rates. Furthermore, bony injuries in the post-hiatus season were more likely to be the result of repetitive trauma and less likely to be from running., Level of Evidence: Level III, retrospective, cross sectional study., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Pelvic insufficiency fractures (PIFs) are a late complication of radiotherapy for pelvic malignancies. We evaluated the incidence, radiologic findings, clinical course, and outcome of PIFs in patients treated with neoadjuvant (chemo)radiotherapy ((C)RT) for rectal cancer., Material and Methods: Data of patients diagnosed with rectal cancer from a large teaching hospital treated from 2002 to 2012 were extracted from the Dutch Cancer Registry. All hospital records were reviewed for the diagnosis of PIFs or pelvic bone metastases. An expert radiologist reassessed all imaging procedures of the lower back, abdomen, and pelvis., Results: A total of 513 rectal cancer patients were identified of whom 300 patients (58.5%) were treated with neoadjuvant (C)RT (long- vs. short-course radiotherapy: 91 patients [17.7%] vs. 209 [40.7%], respectively). Twelve PIFs were diagnosed initially according to hospital records and imaging reports of all 513 patients. These 12 patients were treated with neoadjuvant (C)RT. After reassessment of all pelvic imaging procedures done in this patient group (432 patients (84.2%)), 20 additional PIFs were detected in patients treated with neoadjuvant (C)RT, resulting in a 10.7% PIF rate in irradiated patients. One PIF was detected in the group of patients not treated with neoadjuvant (C)RT for rectal cancer. This patient had palliative radiotherapy for prostate cancer and is left out of the analysis. Median follow-up time of 32 PIF patients was 49 months. Median time between start of neoadjuvant (C)RT and diagnosis of PIF was 17 months (IQR 9-28). Overall median survival for patients with PIF was 63.5 months (IQR 44-120)., Conclusion: PIFs are a relatively common late complication of neoadjuvant (C)RT for rectal cancer but are often missed or misdiagnosed as pelvic bone metastases. The differentiation of PIFs from pelvic bone metastases is important because of a different treatment and disease outcome.

Objective: To assess the prevalence of foot insufficiency fractures (IF) in patients with rheumatic musculoskeletal disease (RMD) with foot pain., Methods: In a retrospective design, 1752 magnetic resonance imaging (MRI) scans of consecutive patients presenting with foot pain in 2 time periods between 2016 and 2018 were evaluated. The group with IF was matched with controls with foot pain without IF. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry. Multivariate analyses were performed., Results: A total of 1145 MRI scans of patients (median age 59 yrs, 82.9% female) with an inflammatory (65.4%) and of 607 with no inflammatory (34.6%) RMD (median age 58 yrs, 80.8% female) were available. Most patients had rheumatoid arthritis (RA; 42.2%), and others had psoriatic arthritis (22.4%), axial spondyloarthritis (11.1%), or connective tissue disease (CTD; 7.6%). Foot IF were found in 129 MRI scans of patients (7.5%). There was no difference between time periods. The prevalence of IF was highest in CTD (23%) and RA (11.4%). More patients with an inflammatory than a noninflammatory RMD had IF (9.1% vs 4.1%, respectively; P < 0.001). Using conventional radiography, IF were only detected in 25%. Low BMD and a history of fractures were more frequent in patients with IF than without (42.6% vs 16.2% and 34.9% vs 8.6%, respectively; P < 0.001)., Conclusion: A high prevalence of foot fractures was found in MRI scans of patients with RMD, many without osteoporosis. MRI was more sensitive than radiographs to detect IF., (Copyright © 2023 by the Journal of Rheumatology.)

Introduction: Military trainees are at an increased risk of stress fractures. Vitamin D availability is known to play an important role in both fracture prevention and healing. The purpose of this investigation was to assess 25-hydroxy vitamin D (25(OH)D) levels in soldiers with confirmed lower extremity stress fractures and assess the predictors of fracture location., Materials and Methods: Following Institutional Review Board approval, military trainees at a large training base presenting to the orthopedic clinic with a radiographically verified stress fracture were identified. Demographic data and 25(OH)D levels were collected. A descriptive analysis was performed in regard to patient age, body mass index (BMI), and 25(OH)D level. Interactions between variables were assessed using one-way analysis of variance for four fracture location groups (femoral neck, femoral shaft, tibial shaft, and foot and ankle). Bivariate correlations were examined between age, BMI, and vitamin D level., Results: A total of 155 lower extremity stress fractures were identified in 144 males and 11 females over 30 months. The mean age was 22.7 ± 4.85 years. The majority (60.7%) of fractures were located in the femoral neck. The average 25(OH)D level was 26.8 ± 8.37 ng/mL. Overall, 26% (N = 41) of enrolled patients had normal 25(OH)D levels, 48% (N = 74) had insufficient 25(OH)D levels, and 26% (N = 40) had deficient 25(OH)D levels. Patients with femoral neck fractures and tibial shaft fractures had significantly lower BMI than patients with foot and ankle fractures (23.3 vs. 27.7, P < .001 and 24.2 vs. 27.7, P = .003, respectively). Patients with foot and ankle fractures had significantly lower 25(OH)D levels than patients with femoral shaft fractures (21.1 vs. 30.1, P = .02). There were no significant findings regarding age and fracture location. Age correlated positively (but weakly) with BMI (0.338, P < .001). There was no correlation between age and vitamin D level or BMI and vitamin D level., Conclusion: Overall, 74% of patients in military training with lower extremity stress fractures had insufficient or deficient levels of 25(OH)D, highlighting a persistent area of concern in this population. Patients with femoral neck and tibial shaft stress fractures had significantly lower BMI than patients with foot and ankle stress fractures. This suggests that in stress fracture-prone patients, BMI may play a role in predicting fracture location., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Isolated first rib stress fractures in athletes are thought to be rare. In this case series, 3 National Collegiate Athletic Association Division I athletes developed isolated first rib stress fractures over the span of 1 year, indicating that these injuries may occur more often than previously understood. These fractures can be easily missed because of the low incidence, lack of clinical suspicion, and vague presentation. Further, radiographs can fail to reveal such fractures. To our knowledge, this is the largest case series of athletes with first rib stress fractures presenting with vague rhomboid interscapular pain. We also demonstrated that ultrasound successfully visualized these injuries; in the hands of an ultrasonographer or clinical provider trained in musculoskeletal ultrasound, this technique offers an advantageous point-of-care screening imaging modality., (© by the National Athletic Trainers’ Association, Inc.)

Introduction: Although metatarsal fractures are common, the significance of previous epidemiologic studies is limited to specific fracture entities, subpopulations, or heterogeneous fracture aetiologies. The aim of the study was to assess the epidemiology of isolated metatarsal fractures in an adult population at a level-1 trauma centre., Materials and Methods: Radiological and clinical databases were searched for a five-year period. Eligible were all patients with acute isolated metatarsal fractures over the age of 18 years with radiographs in two planes available. Stress fractures, injuries affecting Lisfranc joint stability, and concomitant injuries to other regions than the metatarsals were excluded. Data collection included general demographics, mechanism of injury, season of the trauma and fracture details., Results: Out of 3259 patients, 642 patients met the inclusion criteria and were included for the analysis. The patients' mean age was 44.5 ± 18.9 years, 50.6% were female. 83.3% suffered an isolated, 16.7% multiple metatarsal fractures. Single metatarsal fractures occurred predominantly at the fifth metatarsal bone (81.3%), their frequency decreased with increasing age, with a seasonal peak during the summer. Patients suffering multiple metatarsal fractures were significantly older (51.6 ± 21.2 vs. 43.0 ± 18.1 years; p < 0.001) and the injury resulted significantly more often from a high-energy trauma (6.7% vs. 23.4%; p < 0.001). Multiple metatarsal fractures occurred evenly throughout all metatarsals but revealed a focus on female population with no seasonal differences., Conclusion: Single metatarsal fractures predominantly occurred at the fifth metatarsal bone and showed a seasonal, gender and age dependency. Multiple metatarsal fractures were homogeneously distributed between the different metatarsals with distinct age-dependent gender differences., Level of Evidence: Level III., (© 2022. The Author(s).)

Introduction: Figure skating combines esthetic components with high impact, technically demanding elements requiring high volume repetitive training. The evidence base for the sport is limited, particularly regarding stress fracture injuries. This study aims to describe the prevalence and anatomical distribution of stress fracture injuries and assess for risk factors, as well as associations with acute fractures., Methods: An online anonymous retrospective survey of competitive figure skaters was distributed through social media networks and e-mail for completion by skaters from all three disciplines of figure skating., Results: In a sample of 164 skaters from novice to Olympic level, career prevalence of stress fractures was 24.4%, most commonly affecting tibia and ankle. There was statistically significant increased risk of stress fracture in those training ≥12 times/week (33.3% vs. 17.8%; P = 0.028) but no increased risk associated with level or gender of skater. There was a higher prevalence of acute fracture in those with a history of stress fracture (45.0% vs. 21.8%; P = 0.007)., Conclusions: Figure skaters are at a high risk of stress fractures, independent of the level performed at. There is a higher risk in those training more frequently and an association with additional acute fractures. Results advocate education on fracture features and bone health measures to skaters, coaches, and physicians, at all levels of the sport to facilitate early diagnosis and management.

Introduction: Stress fractures (SFx) represent a significant proportion of injuries in military recruits internationally. Stress fractures disproportionately affect female recruits, a disparity that has similarly been consistently demonstrated in female athletes. Stress fractures result in medical morbidity, financial burden, and medical discharge from military service. This review presents current literature regarding SFx risk factors to identify and/or mitigate in this high-risk population., Methods: A literature review was conducted using PubMed to find relevant articles. We utilized keywords stress fracture, military, recruits, female, risk factors, modifiable, non-modifiable, overuse, nutrition, and/or prevention. Articles older than 10 years (published before 2010) were not considered. Review articles were considered, but if a research article was cited by a review, the research was included directly. Articles with primary military data, members of the military as subjects, especially when female recruits were included, were strongly considered for inclusion in this review., Results: Modifiable risk factors for SFx include nutritional deficiency, especially of iron, vitamin D, and possibly calcium, poor physical fitness, suboptimal training programming for injury development and recovery, load carriage, and military footwear. Non-modifiable risk factors include female sex, greater height, lower weight and body mass index in females but lower or higher weight and body mass index in males, lower body fat percentage, and lower bone mineral density. In addition, menstrual dysfunction, low energy availability, later age at menarche, and iron deficiency pose unique risks to female recruits. Preventive measures include leadership education, programs with recovery considerations, and risk factor screening., Conclusion: This review, Part II of a two-part series, guides multidisciplinary management of military recruits, especially females, who are at risk for developing SFx. Unique nuances of the military recruit require specific knowledge to reduce high incidence rates of injury internationally., (© The Association of Military Surgeons of the United States 2022. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Stress fractures (SFx) represent a significant proportion of musculoskeletal injuries in military recruits internationally. Incidence rates as high as 40% have been reported, varying by country and branch of military cohorts. Tibial SFx are the most common, followed by other lower extremity sites, and are related to the emphasis on running during training. SFx disproportionately affect female recruits, similarly to a disparity demonstrated in female athletes., Methods: A literature review of articles relevant to our review was conducted using PubMed, utilizing keywords stress fracture, military, recruits, diagnosis, management, treatment, prevention, epidemiology, background, and/or female. Articles older than 10 years old (prior to 2010) were not considered. Review articles were considered, but if a research article was cited by a review, the research was included directly. Articles with primary military data, members of the military as subjects, especially when female recruits were included, were strongly considered for inclusion in this review., Results: SFx can cause medical morbidity and financial burden and can require discharge from military service. SFx management in the military has cost the United States approximately $100 million annually, which may be underestimated due to lost duty hours or medical discharge with resulting compensation. However, SFx incidence rates have been demonstrated to be reducible with concerted efforts in military cohorts., Conclusion: This review, Part I of a two-part series, provides updated information for multidisciplinary management of SFx in female military recruits. There are many similarities to management in athletes, but unique nuances of the military recruit require specific knowledge to reduce the high incidence rates of injury., (© The Association of Military Surgeons of the United States 2022. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Female soccer players are often diagnosed with medial shin pain, which includes tibial stress fracture, medial tibial stress syndrome, and chronic exertional compartment syndrome. As the possibility of varied sites of pain affecting sports activities has not been fully researched, an urgent discussion and evidence is required. This study investigates the prevalence and effect of sites of pain on the sports activities of female soccer players with medial shin pain., Methods: A questionnaire survey was conducted for 196 female soccer players with medial shin pain to assess symptom duration, the effect of practice and performance, and sites of pain. The players were classified into three conditions (tibial stress fracture, medial tibial stress syndrome, or medial shin pain with neurological symptoms) and compared based on sites of pain., Results: We observed that medial tibial stress syndrome had a lower impact on performance compared to that of tibial stress fracture and medial shin pain with neurological symptoms. While participants with tibial stress fracture had to suspend practice sessions more frequently, the difference in symptom duration between the classified groups was not statistically significant. The effect of sites of pain on sports activities was not significantly different in participants with medial tibial stress syndrome., Conclusions: Medial shin pain should be evaluated carefully to differentiate between medial tibial stress syndrome and medial shin pain with neurological symptoms. Restriction of sports activities may help improve the patient's condition early, regardless of the presentation.

Background: Stress fractures are caused by micro-trauma due to repetitive stress on bone, common in active individuals and athletes. Previous studies demonstrate that the weightbearing bones of the lower extremities incur stress fractures most often, especially in women and older adults., Hypothesis: Prior literature does not quantify the difference in frequency of stress fractures among different genders, age groups, or body mass indices (BMIs). We hypothesized that older female patients would have higher rates of lower extremity stress fractures than male patients., Study Design: Epidemiological research., Level of Evidence: Level 3., Methods: Records of female and male patients with lower extremity stress fractures from 2010 to 2018 were identified from the PearlDiver administrative claims database using the International Classification of Diseases (ICD)-9/ICD-10 codes. Stress fractures were classified by ICD-10 diagnosis codes to the tibial bone, proximal femur, phalanges, and other foot bones. Comorbidities were incorporated into a regression analysis., Results: Of 41,257 stress fractures identified, 30,555 (70.1%) were in women and 10,702 (25.9%) were in men. Our sample was older (>60 years old) (37.3%) and not obese (BMI <30 kg/m 2 , 37.1%). A greater proportion of female patients with stress fracture were older ( P < 0.001) and had foot stress fractures ( P < 0.001), while a greater proportion of male patients with stress fracture were younger than 19 years ( P < 0.001) and had metatarsal ( P < 0.001), hip ( P = 0.002), and tibia stress fractures ( P < 0.001)., Conclusion: Stress fractures commonly occur in women and older adults with low BMIs. Metatarsal and tibia stress fractures were the most common, and a greater proportion of women had foot stress fractures., Clinical Relevance: Our study examined the large-scale prevalence of different lower extremity stress fractures among a wide patient population sample of varying ages and BMIs. These findings can help clinicians identify active populations at greater risk for stress fracture injuries.

Introduction: Risk factors associated with subchondral insufficiency fracture (SIF) of the femoral head have not been established. The aim of the present study was to determine the incidence and risk factors for SIF of the femoral head following renal transplantation (RT)., Materials and Methods: We analyzed the cases of 681 RT patients (mean age at surgery: 49.5 ± 13.6 years, 249 women, 432 men) to determine the incidence of SIF. Hip magnetic resonance imaging (MRI) was performed 6 months post-RT. The following potential predictors of SIF were evaluated: (1) patient's condition at RT: bone mineral density (BMD), pre-RT laboratory values including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone; the patient and donor's blood relationship; and mismatching number of human leukocyte antigens (HLAs), and (2) post-RT dosage(s) of steroid(s), the immunosuppressive regimen, and the incidence of acute rejection., Results: SIF was observed in 15 hips (13 patients, 1.9%). We successfully matched 39 patients without SIF. A multivariate logistic regression analysis adjusted for cumulative dosages of steroids, revealed the following were risk factors for SIF: osteoporosis (OR: 11.4, p = 0.046), lumbar BMD (OR: 0.003, p = 0.038), pre-RT serum P (OR 2.68, p = 0.004), and pre-RT serum Ca × P (OR: 1.11, p = 0.005)., Conclusion: Since osteoporosis, the lumbar BMD, serum P, and serum Ca × P were identified as risk factors for a post-RT SIF, these factors should be evaluated before RT for the prediction of the SIF risk., (© 2022. The Japanese Society Bone and Mineral Research.)

Background: Lower extremity stress fractures result in lost time from work and sport and incur costs in the military when they occur in service members. Hypovitaminosis D has been identified as key risk factor in these injuries. An estimated 33% to 90% of collegiate and professional athletes have deficient vitamin D levels. Other branches of the United States military have evaluated the risk factors for stress fractures during basic training, including vitamin D deficiency. To the best of our knowledge, a study evaluating the correlation between these injuries and vitamin D deficiency in US Navy recruits and a cost analysis of these injuries has not been performed. Cutbacks in military medical staffing mean more active-duty personnel are being deferred for care to civilian providers. Consequently, data that previously were only pertinent to military medical providers have now expanded to the nonmilitary medical community., Questions/purposes: We therefore asked: (1) What proportion of US Navy recruits experience symptomatic lower extremity stress fractures, and what proportion of those recruits had hypovitaminosis vitamin D on laboratory testing? (2) What are the rehabilitation costs involved in the treatment of lower extremity stress fractures, including the associated costs of lost training time? (3) Is there a cost difference in the treatment of stress fractures between recruits with lower extremity stress fractures who have vitamin D deficiency and those without vitamin D deficiency?, Methods: We retrospectively evaluated the electronic medical record at Naval Recruit Training Command in Great Lakes, IL, USA, of all active-duty males and females trained from 2009 until 2015. We used ICD-9 and ICD-10 diagnosis codes to identify those diagnosed with symptomatic lower extremity stress fractures. Data collected included geographic region of birth, preexisting vitamin D deficiency, vitamin D level at the time of diagnosis, medical history, BMI, age, sex, self-reported race or ethnicity, hospitalization days, days lost from training, and the number of physical therapy, primary care, and specialty visits. To ascertain the proportion of recruits who developed symptomatic stress fractures, we divided the number of recruits who were diagnosed with a stress fracture by the total number who trained over that span of time, which was 204,774 individuals. During the span of this study, 45% (494 of 1098) of recruits diagnosed with a symptomatic stress fracture were female and 55% (604 of 1098) were male, with a mean ± SD age of 24 ± 4 years. We defined hypovitaminosis D as a vitamin D level lower than 40 ng/mL. Levels less than 40 ng/mL were defined as low normal and levels less than 30 ng/mL as deficient. Vitamin D levels were obtained at the discretion of the individual treating provider without standardization of protocol. Cost was defined as physical therapy visits, primary care visits, orthopaedic visits, diagnostic imaging costs, laboratory costs, hospitalizations, if applicable, and days lost from training. Diagnostic studies and laboratory tests were incorporated as indirect costs into initial and follow-up physical therapy visits. Evaluation and management code fee schedules for initial visits and follow-up visits were used as direct costs. We obtained these data from the Centers for Medicare & Medicaid Services website. Per capita cost was calculated by taking the total cost and dividing it by the study population. Days lost from training is based on a standardized government military salary of recruits to include room and board., Results: We found that 0.5% (1098 of 204,774) of recruits developed a symptomatic lower extremity stress fracture. Of the recruits who had vitamin D levels drawn at the time of stress fracture, 95% (416 of 437 [95% confidence interval (CI) 94% to 98%]; p > 0.99) had hypovitaminosis D (≤ 40 ng/mL) and 82% (360 of 437 [95% CI 79% to 86%]; p > 0.99) had deficient levels (≤ 30 ng/mL) on laboratory testing, when evaluated. The total treatment cost was USD 9506 per recruit. Days lost in training was a median of 56 days (4 to 108) for a per capita cost of USD 5447 per recruit. Recruits with deficient vitamin D levels (levels ≤ 30 ng/mL) incurred more physical therapy treatment costs than did those with low-normal vitamin D levels (levels 31 to 40 ng/mL) (mean difference USD 965 [95% CI 2 to 1928]; p = 0.049)., Conclusion: The cost of lost training and rehabilitation associated with symptomatic lower extremity stress fractures represents a major financial burden. Screening for and treatment of vitamin D deficiencies before recruit training could offer a cost-effective solution to decreasing the stress fracture risk. Recognition and treatment of these deficiencies has a role beyond the military, as hypovitaminosis and stress fractures are common in collegiate or professional athletes., Level of Evidence: Level III, prognostic study., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2022 by the Association of Bone and Joint Surgeons.)

Introduction: The Israel Defense Forces (IDF) has strict protocols for the diagnosis and treatment of stress fractures wherein diagnosis is clinical with imaging used for persistent symptoms only. The purpose of this study was to examine the incidence of clinical and radiological stress fractures during IDF combat training., Methods: Medical records of all soldiers enlisted to combat training between 2014 and 2017 were scanned for the diagnosis of stress fractures. We examined the imaging tests ordered (plain radiographs and bone scans) and their results and the time between the clinical diagnosis to imaging tests., Results: During 4 years, 62 371 soldiers (10.1% women) had started combat training, and 3672 of them (5.9%) were diagnosed with clinical stress fractures. Radiographs were ordered for 53.5% of those diagnosed, of whom 29.7% also had a bone scan. Some 42% of radiographs were taken within 21 days. Radiographs were positive for stress fractures in 11.1% of tests. Bone scans showed evidence of stress fractures in 49.7%, of which 49.2% diagnosed stress fractures in multiple bones., Conclusion: The high percentage of negative radiographs may indicate towards alternative causes for symptoms. Performing the radiograph before or after 21 days did not affect workup results diverting from current belief that later radiographs will be more sensitive. Multiple stress fractures are a common finding, indicating that the increased training load puts the whole musculoskeletal system at increased risk for injury. Research results may necessitate a revision of clinical guidelines for the diagnosis of stress fractures in military trainees., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Military initial training results in a high incidence of lower limb overuse injuries (stress fractures and medial tibial stress syndrome). This study aimed to determine whether the distance travelled by recruits, both on and off duty, was a risk factor for overuse injury., Methods: 14 male airborne infantry recruits from three training platoons carried global positioning system receivers throughout the first 19 weeks of basic military training. Total distance travelled each day was recorded. This was compared with time of clinical manifestation of 52 lower limb overuse injuries (stress fractures and medial tibial stress syndrome) collected from the 276 airborne infantry recruits in the period immediately preceding the study., Results: Recruits travelled significantly farther than the UK average male population in 17 of 18 measured weeks. Pearson correlation between distance travelled per week and injuries was not significant (p=0.4448); however, correlation between distance travelled per week and injuries two weeks later was significant (p=0.0263). A generalised linear model found distance travelled as a significant covariate (p=0.0144) to the expected number of injuries two weeks later., Conclusion: Recruits travel long distances during basic training, particularly in the first few weeks when they are not yet conditioned. This distance travelled is likely a contributing risk factor to the high incidence of overuse injuries seen during training, and strategies to reduce this distance should be explored., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Fragility fractures of the pelvis (FFP) encompass two fracture entities: fracture after low-energy trauma and insufficiency fracture without trauma. It is unclear whether the two subgroups differ in terms of diagnosis and therapy. The aim of this retrospective study was to evaluate insufficiency fractures with regard to defined parameters and to compare specific parameters with the fractures after low-energy trauma., Patients and Methods: In the period from 2008 to 2017, 203 patients with FFP were recorded at our clinic (Level 1 Trauma Centre DGU, SAV approval). Of these, 25 had an insufficiency fracture and 178 had a pelvic ring fracture after low-energy trauma. Epidemiological, diagnostic and therapeutic parameters were examined., Results: There was a relative increase in the insufficiency fracture within the FFP (2008 - 2009: 5.0% vs. 2015 - 2017: 17.8%). In these patients, osteoporosis tended to be more pronounced than in patients after low-energy trauma (t-value: - 3.66 vs. - 3.13). The diagnosis of insufficiency fractures showed increased use of MRI and DECT (60.9% vs. 26.0%) and a high proportion of type IV fractures after FFP (40.0% vs. 7.9%). In terms of therapy, surgical treatment of the insufficiency fracture was sought more often (68,2% vs. 52,1%), with a tendency towards increased use of combined osteosynthesis procedures (14.3% vs. 7.6%)., Conclusion: We were able to show that as the number of cases increases, the insufficiency fracture becomes more important within FFP. If these patients tend to have more pronounced osteoporosis, particular attention should be paid to the diagnosis and adequate therapy of the osteoporosis, especially in the case of an insufficiency fracture. In addition to the increased diagnostic testing using MRI and DECT to detect oedema and the increased surgical therapy for this type of fracture, it is also noteworthy that the insufficiency fracture can cause higher-grade fractures after FFP., Competing Interests: The authors declare that they have no conflict of interest./Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Aims: The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union., Methods: We retrospectively reviewed all periacetabular osteotomies (PAOs) performed for developmental dysplasia of the hip (DDH) at one institution over a six-year period between 2012 and 2017. Perioperative factors were recorded, and included demographic and surgical data. Postoperatively, patients were followed for a minimum of one year with anteroposterior and false profile radiographs of the pelvis to monitor for evidence of stress fracture and union of osteotomies. We characterized the incidence and locations of stress fractures, and used univariate and multivariable analysis to identify factors predictive of stress fracture and the association of stress fracture on osteotomy union., Results: A total of 331 patients underwent PAO during the study period with 56 (15.4%) stress fractures: 46 fractures of the retroacetabular posterior column, five cases of ischiopubic stress fracture, and five cases of concurrent ischiopubic and retroacetabular stress fractures. Overall, 86% (48/56) healed without intervention. Univariate analysis revealed that stress fractures occurred more frequently in females (p = 0.040), older patients (mean age 27.6 years (SD 8.4) vs 23.8 (SD 9.0); p = 0.003), and most often with the use of the broad Mast chisel (28.5%; p < 0.001). Multivariable analysis revealed that increasing age (odds ratio (OR) 1.04; 95% CI 1.01 to 1.07; p = 0.028) and use of the broad Mast chisel (OR 5.1 (95% CI 1.3 to 19.0) compared to narrow Ganz chisel; p = 0.038) and surgeon (p = 0.043) were associated with increased risk of stress fracture. Patients with stress fractures were less likely to have healed osteotomies after one-year follow-up (76% vs 96%; p < 0.001)., Conclusion: Stress fracture of the posterior column may be an under-recognized complication following PAO, and the rate may be influenced by surgical technique. Consideration should be given to using a narrow chisel during the ischial cut to reduce the risk of stress propagation through the posterior column.Cite this article: Bone Joint J  2022;104-B(9):1017-1024.

Objectives: The aim of the present study was to identify the habitual dietary intake and stress fractures history among sport types and to determine the factors related to the risk of stress fractures among Japanese female collegiate athletes., Methods: This study involved 589 Japanese female collegiate athletes. We investigated habitual dietary intake (food frequency questionnaire), eating attitude (EAT-26), demographics, training status, participation in sports events, history of injury in their career, and menstrual status using a self-reported questionnaire. A multivariate logistic regression analysis was conducted to determine the risk factors associated with stress fractures., Results: Thirty percent of the total participants had a history of stress fractures, although most participants had no risk of eating disorders. Most Japanese female collegiate athletes consumed less than the dietary reference intake levels for the general Japanese female population aged 18-29 years and the athletes' dietary guideline for key bone-health nutrients such as calcium and vitamin D. The multivariate logistic regression analysis revealed body mass index (BMI; OR, 0.91; 95% CI, 0.82-0.99) and energy intake (EI; OR, 0.99; 95% CI, 0.99-0.99) as significant and independent factors in the history of stress fractures among Japanese female collegiate athletes ( p  = 0.047 and p  = 0.039, respectively)., Conclusions: Japanese female collegiate athletes failed to meet energy and nutrient recommendations; BMI and EI were significantly associated with stress fractures, a diet that includes an appropriate amount of energy is essential.

Vitamin D is critically important to numerous physiologic functions, including bone health. Poor vitamin D status is a common but underrecognized problem that predisposes the military population to stress fracture and completed fracture. This has significant implications for force health protection, warfighter readiness, attrition, and cost. Despite this, vitamin D deficiency is still underdiagnosed and undertreated in the military. This is a major hindrance to military readiness and one that could easily be modified with awareness, prevention, and early treatment. In this commentary, we review the literature on vitamin D deficiency and critically examine the current status of policies and clinical practice related to vitamin D in the military health system. We offer several practical recommendations to increase awareness and readiness while decreasing musculoskeletal injury and the associated costs., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background and Purpose: Stress fractures of the femoral neck (sFNFs) are uncommon injuries. Studies on sFNFs are rare. We describe the demographics, classification, treatment, reoperation rates, and mortality in a cohort of sFNF patients from the Swedish Fracture Register (SFR)., Patients and Methods: We included 146 patients ≥ 18 years of age with an sFNF registered in the SFR between 2011 and 2020. The cohort was linked with the Swedish Arthroplasty Register and reviewed using medical records and radiographs. We assessed the presence of disorders of bone remodeling, duration of symptoms, fracture classification, treatment, reoperations, and mortality., Results: The mean age was 58 years (21-96), 75% were women and the median duration of symptoms was 23 days (1-266). 40% of patients had disorders of bone remodeling. 54% were undisplaced (uFNF), 30% displaced (dFNF), and 16% basicervical (bFNF). 14% of patients < 60 years were treated nonoperatively, by internal fixation (IF) in 77% and by arthroplasty in 10%. Patients ≥ 60 years were treated nonoperatively in 10%, IF in 40%, and arthroplasty in 49%. Nonoperative treatment was reserved for uFNFs or bFNFs, resulting in 35% receiving late surgery. The overall secondary or late surgery rate was 19%. Mortality was 2% at 90 days and increased to 3% at 1 year., Interpretation: sFNF has a biphasic age distribution. One-third of patients presented with a displaced FNF and those managed nonoperatively for an undisplaced sFNF were at risk of late surgery. The mortality rates for patients with these injuries was low.

Background: The objective of this study was to evaluate sex differences in the incidence and risk of ankle-foot complex (AFC) stress fractures among U.S. military personnel, which could assist in developing management strategies as females assume a greater role in U.S. military operations. Materials and Methods: The Defense Medical Epidemiology Database was used to identify all diagnosed AFC stress fractures in military personnel from 2006 to 2015. Cumulative incidence of AFC stress fractures was calculated and compared by year, service branch, and military rank. Sex differences in the risk of AFC stress fractures by occupation were examined, and integrated ( i.e. , male and female) occupations were compared with nonintegrated ( i.e. , male only) occupations. Results: A total of 43,990 AFC stress fractures were identified. The overall incidence rate was 2.76 per 1,000 person-years (p-y) for males and 5.78 per 1,000 p-y for females. Females consistently had higher incidence of AFC stress fractures across all subgroups, particularly among enlisted personnel. Female enlisted service members had the highest risk of AFC stress fractures in aviation (relative risk [RR] = 5.74; 95% confidence interval [CI]: 4.80-6.87) and artillery/gunnery (RR = 5.15; 95% CI: 4.62-5.75) occupations. Females in integrated occupations had significantly higher rates of AFC stress fractures than males in both integrated and nonintegrated occupations ( i.e. , special forces, infantry, and mechanized/armor). Conclusions: Females in the U.S. military have a higher risk of AFC stress fractures than males. As integration of females into previously sex-restricted occupations continues, focused prevention efforts may be needed to reduce injury burden and maximize medical readiness.

Objective: To identify predictive risk factors of lumbar stress (LS) fracture developing from an asymptomatic stress reaction of the pedicle among adolescent male soccer players., Design: Prospective cohort study., Setting: Amateur Japanese adolescent male soccer team., Participants: Japanese adolescent male soccer players (n = 195) aged 12 to 13 years., Assessment of Risk Factors Independent Variables: Height, body weight, body mass index, muscle tightness of both lower extremities (iliopsoas, hamstrings, and quadriceps), lumbar bone mineral content, developmental age, and lumbar lordosis angle were measured as baseline measurements., Main Outcome Measures Dependent Variable: Players who were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle at baseline were followed; extension-based lumbar pain was defined 1 year after the baseline. The players were assigned to the LS fracture or control (CON) group at follow-up., Results: At baseline, 40 boys were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle. The difference in muscle tightness between the kicking leg and supporting leg was significantly different (P = 0.012) between the LS (n = 16) and CON (n = 22) groups. Increase in iliopsoas muscle tightness in the kicking leg was a predictive risk factor of developing extension-based lumbar pain after adjusting for developmental age and body mass index (odds ratio, 1.54; 95% confidence interval, 1.05-2.27)., Conclusions: Development of extension-based lumbar pain from an asymptomatic stress reaction of the pedicle among adolescent male soccer players was associated with increased iliopsoas muscle tightness of the kicking leg relative to that of the supporting leg., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Describe the proportion of upper lumbar bone stress injuries (LBSI; T12-L3) relative to all LBSI, and the clinical presentation and diagnosis of upper LBSI in elite cricketers., Design: Case series., Setting: Professional domestic and international cricket teams over a 9-year period., Participants: Elite Australian cricketers., Independent Variables: Symptomatic upper LBSI diagnosed based on clinical findings and medical imaging., Main Outcome Measures: Prevalence, injury history, and clinical management., Results: Twenty-four pace bowlers (22 male and 2 female) sustained 39 cases of upper LBSI (T12:2, L1:3, L2:20, L3:14). Upper lumbar vertebrae were involved in 41% (95% CI 31-51) of all LBSI in this cohort. Twenty-seven (69%, 54-81) cases had an injury that occurred only on the side contralateral to the bowling arm. Ipsilateral injuries tended to occur secondary to a contralateral nonunited defect. In all 7 cases with known radiology follow-up that had a contralateral then ipsilateral LBSI, the contralateral injury did not achieve bony union before the onset of the ipsilateral LBSI. For stress fractures with imaging follow-up, those who achieved bony union took longer to return to bowling training [median 152 days (IQR 117-188)], compared to those who achieved partial or no union [median 68 days (IQR 46-115)]., Conclusions: Upper LBSI in elite cricketers occurs in approximately 2 out of 5 cases of LBSI. Clinicians should allow sufficient time for upper LBSI to resolve and unite (if a fracture) because cases that returned to bowling training earlier were less likely to achieve bony union, and those that failed to unite commonly went on to have a recurrent LBSI., Level of Evidence: Therapy/prognosis/diagnosis level 2b., Competing Interests: All authors are employed by Cricket Australia. The authors report no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Young paramilitary recruits, who undergo strenuous exercise during basic training, are often presented with stress fractures, which could be due to an inadequate vitamin D (25-hydroxyvitamin D) intake. This study aimed to find the prevalence of stress fracture among young paramilitary trainees visiting the orthopedic outpatient department of a paramilitary hospital., Methods: This was a descriptive cross-sectional study done among paramilitary trainees in a paramilitary Hospital of Nepal between April 2019 to April 2021. The study was approved by the Ethical Review Board (Reference number: 1003) of the Nepal Health Research Council. Convenience sampling was used. Anthropometric variables, serum 25-hydroxyvitamin D level, and bone mineral density of spine and hip were determined. Data analysis was performed using the Statistical Package for the Social Sciences software version 17.0. Point estimate at 95% Confidence Interval was calculated along with frequency, proportion for binary data and mean, standard deviation for continuous data., Results: Among 417 young paramilitary trainees, 24 (5.76%) (3.52-7.99 at 95% Confidence Interval) were found to have a stress fracture. The stress fracture patients had a serum 25-hydroxyvitamin D level of 21.47ng/mL±6.98. Similarly, the bone mineral density value of the spine and hip among the patients was -1.34g/cm2±1.37 and 0.36g/cm2±1.24, respectively., Conclusions: The prevalence of stress fracture among young paramilitary trainee was high compared to previous studies. Additionally, average Vitamin D and the bone mineral density value of the spine and the total hip among stressed fractured patients were also low.

Purpose: Fatigue stress fractures are a common overuse injury, frequently associated with high load-bearing endurance activities such as running, military training and aerobic exercise. While these fractures can arise at any site, sacral stress fractures are poorly studied with evidence consisting mainly of case reports and limited case series. This review aims to analyze and summarize all reports published to date describing cases of sacral stress fracture in athletes., Methods: PubMed, Embase, Web of Science and the Cochrane Database were systematically searched for studies reporting on Stress Fractures of the Sacrum. Insufficiency fractures of the elderly were excluded., Results: The literature review revealed 49 studies reporting on 124 cases of sacral stress fractures. Seventy-six patients (61%) were professional or collegiate level athletes, and 37 (30%) were military recruits or police officers in training. Seventeen female athletes were identified as suffering from low bone mineral density (25%), 9 of which reported menstrual irregularities. Thirteen female patients (19%) had a history of eating disorders., Conclusion: While most sacral stress fractures occur in normal bones exposed to abnormal repetitive loads, the high percentage of lower bone mineral density can blur the lines between fatigue fractures and insufficiency fractures. The causes of these fractures are multifactorial. High endurance sports and the features of the female athlete triad were found in high percentage of the cases. Conservative treatment is the mainstay of treatment, consisting of ceasing of training and a period of rehabilitation and gradual return to training and competition., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A fracture, being an acquired rupture or break of the bone, is a significant and debilitating injury commonly seen among athletes and military personnel. Stress fractures, which have a repetitive stress aetiology, are highly prevalent among military populations, especially those undergoing training. The primary aim of this review is to identify non-modifiable risk factors for stress fractures in military personnel undergoing training. A systematic search was conducted of three major databases to identify studies that explored risk factors for stress fractures in military trainees. Critical appraisal, data extraction, and a narrative synthesis were conducted. Sixteen articles met the eligibility criteria for the study. Key non-modifiable risk factors identified were prior stress fracture and menstrual dysfunction, while advancing age and race other than black race may be a risk factor. To reduce the incidence of stress fractures in military trainees, mitigating modifiable risk factors among individuals with non-modifiable risk factors (e.g., optimising conditioning for older trainees) or better accommodating non-modifiable factors (for example, extending training periods and reducing intensity to facilitate recovery and adaptation) are suggested, with focus on groups at increased risk identified in this review.

Background: Nutrient intake has an essential role in bone disorder prevention among long-distance runners. However, the influence of Vitamin A intake on the risk of stress fractures remains unknown. This prospective study aimed to investigate the association between Vitamin A intake, and stress fracture occurrence in male collegiate long-distance runners., Methods: Forty-one male long-distance runners were recruited from a top-class long-distance college running team whose complete survey data on bone mass, anthropometric measurements, blood and urine tests, food intake frequency, history of competing in long-distance races, and monthly running distance during 2009-2010 were available. The influence of factors related to stress fractures, including Vitamin A intake, at baseline and the occurrence of stress fractures during the 1-year period were investigated., Results: Four athletes experienced stress fractures during the study period (stress fracture group) and had significantly higher Vitamin A, calcium, and iron intake at baseline compared with that in the nonstress fracture group. In the stress fracture group, the mean daily Vitamin A intake was 2792 μg of retinol activity equivalents (RAE), which was higher than the upper intake limit for males aged 18-25 years in the Japanese Dietary Standard. Logistic regression analyses showed that only Vitamin A intake independently contributed to stress fracture occurrence. The odds ratio of developing stress fractures with a 100-μg RAE increase in Vitamin A intake was 1.22., Conclusions: A result of the present study suggested that Vitamin A intake was associated with stress fracture occurrence in male collegiate long-distance runners.

Purpose: Stress fractures are common overuse running injuries. Individuals with stress fractures exhibit running biomechanics characterized by elevated impact peak and loading rate. While elevated impact peak and loading rate are associated with stress fractures, there are few established metrics used to identify the presence of stress fractures in individuals. Here this study aims to exploit the linear relationship between the impact peak and loading rate to establish a metric to help identify individuals with stress fractures. We hypothesize that the ratio between the impact peak and loading rate will serve as a metric to delineate between healthy controls and those with stress fractures., Methods: Fifteen healthy controls and 11 individuals with stress fractures performed a running protocol. A linear regression model fit to the stress fracture impact peak and loading rate data produced a lower 95% confidence limit boundary that served as the demarcation line between the two groups., Results: Individuals with stress fractures tended to reside above the line with the line accurately classifying 82% of the individuals with stress fractures., Conclusion: The analysis supported the hypothesis and demonstrated how the relationship between impact peak and loading rate can help identify the presence of stress fractures in individuals.Clinical Relevance- The relationship between impact peak and loading rate has the potential to serve as clinically useful metric to identify stress fractures during running.

Purpose: This meta-analysis aims to provide updated evidence on the success rate, return to play (RTP) rate, time to RTP, and complications of operatively and conservatively managed navicular stress fractures (NSFs) as well as delays in diagnosis while avoiding limitations of previous similar studies., Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, two independent team members electronically searched MEDLINE (PubMed), EMBASE, Google Scholar, SCOPUS, and Cochrane databases throughout February 2021 using the following keywords with their synonyms: "Navicular stress fracture," "return to play," and "athletes." The primary outcomes were (1) management success rate, (2) RTP rate, and (3) time to RTP. The secondary outcomes were (1) non-union, (2) time to diagnosis, (3) refracture, and (4) other complications. Inclusion criteria were clinical studies on NSFs reporting at least one of the desirable outcomes. Studies not reporting any of the outcomes of interest or the full text was not available in English, German, French, or Arabic were excluded. Case reports, case series with less than ten cases, and studies reporting exclusively on navicular non-union management were also excluded. The Newcastle-Ottawa scale was used for quality assessment while Review Manager (RevMan) Version 5.4 was used for the risk of bias assessment. Data were presented by type of treatment (surgical or conservative). If enough studies were present that were clinically and statistically homogeneous and data on them adequately reported, a meta-analysis was performed using a fixed-effects model. In case of statistical heterogeneity, a random-effects model was used. If meta-analysis was not possible, results were reported in a descriptive fashion. The need to explore for statistical heterogeneity was determined by an I 2 greater than 40%., Results: Eleven studies met the inclusion criteria with a total of 315 NSF. Out of those, 307 (97.46%) NSFs were in athletes. One hundred eight (34.29%) NSFs were managed operatively, while 207 (65.71%) NSFs were managed conservatively. Successful outcomes were reported in 104/108 (96.30%) NSF treated operatively with a mean success rate of 97.9% (CI: 95.4-100%, I 2  = 0%). Successful outcomes were reported in 149/207 (71.98%) NSF treated conservatively, with a mean success rate of 78.1% (CI: 66.6-89.6%, I 2  = 84.93%). Successful outcome differences were found to be significant in favor of operative management (OR = 5.52, CI: 1.74-17.48, p = 0.004, I 2  = 4.6%). RTP was noted in 97/98 (98.98%) NSF treated operatively and in 152/207 (73.43%) NSF treated conservatively, with no significant difference between operative and conservative management (OR = 2.789, CI: 0.80-9.67, p = 0.142, I 2  = 0%). The pooled mean time to RTP in NSF treated operatively was 4.17 months (CI: 3.06-5.28, I 2  = 92.88%), while NSF treated conservatively returned to play at 4.67 months (CI: 0.97-8.37, I 2  = 99.46%) postoperatively, with no significant difference between operative and conservative management (SMD =  - 0.397, CI: - 1.869-1.075, p = 0.60, I 2  = 92.24). The pooled mean duration of symptoms before diagnosis was 9.862 (3.3-123.6) months (CI: 6.45-13.28, I 2  = 94.92%), reported in ten studies. Twenty (23.53%) refractures were reported after conservative management of 85 NSFs, while one (1.28%) refracture was reported after operative management of 78 NSFs, with a significant difference in favor of operative management (OR = 0.083, CI: 0.007-0.973, p = 0.047, I 2  = 38.78%)., Conclusion: Operative management of NSF provides a higher success rate, a lower refracture rate, and a lower non-union rate as compared to other non-operative management options. While not significant, there is a notable trend towards superior RTP rates and time to RTP following operative management. Therefore, we recommend operative fixation for all NSFs type I through III in athletes. Athletes continue to exhibit an alarmingly long duration of symptoms before diagnosis is made; a high index of suspicion must be maintained, therefore, and adjunct CT imaging is strongly recommended in the case of any work-up. Unfortunately, the published literature on NSFs remains of lower level of evidence and high-quality studies are needed., (© 2021. The Author(s).)

Background: Acromial (ASF) and scapular spine (SSF) stress fractures are well-recognized complications of reverse shoulder arthroplasty (RSA), but much of the current data are derived from single-center or single-implant studies with limited generalizability. This study from the American Shoulder and Elbow Surgeons (ASES) Complications of Reverse Shoulder Arthroplasty Multicenter Research Group determined the incidence of ASF/SSF after RSA and identified preoperative patient characteristics associated with their occurrence., Method: Fifteen institutions including 21 ASES members across the United States participated in this study. Patients undergoing either primary or revision RSA between January 2013 and June 2019 with a minimum 3-month follow-up were included. All definitions and inclusion criteria were determined using the Delphi method, an iterative survey process involving all primary investigators. Consensus was achieved when at least 75% of investigators agreed on each aspect of the study protocol. Only symptomatic ASF/SSF diagnosed by radiograph or computed tomography were considered. Multivariable logistic regression was performed to identify factors associated with ASF/SSF development., Results: We identified 6755 RSAs with an average follow-up of 19.8 months (range, 3-94). The total stress fracture incidence rate was 3.9% (n = 264), of which 3.0% (n = 200) were ASF and 0.9% (n = 64) were SSF. Fractures occurred at an average 8.2 months (0-64) following RSA with 21.2% (n = 56) following a trauma. Patient-related factors independently predictive of ASF were chronic dislocation (odds ratio [OR] 3.67, P = .04), massive rotator cuff tear without arthritis (OR 2.51, P < .01), rotator cuff arthropathy (OR 2.14, P < .01), self-reported osteoporosis (OR 2.21, P < .01), inflammatory arthritis (OR 2.18, P < .01), female sex (OR 1.51, P = .02), and older age (OR 1.02 per 1-year increase, P = .02). Factors independently associated with the development of SSF included osteoporosis (OR 2.63, P < .01), female sex (OR 2.34, P = .01), rotator cuff arthropathy (OR 2.12, P = .03), and inflammatory arthritis (OR 2.05, P = .03)., Conclusion: About 1 in 26 patients undergoing RSA will develop a symptomatic ASF or SSF, more frequently within the first year of surgery. Our results indicate that severe rotator cuff disease may play an important role in the occurrence of stress fractures following RSA. This information can be used to counsel patients about potential setbacks in recovery, especially among older women with suboptimal bone health. Strategies for prevention of ASF and SSF in these at-risk patients warrant further study. A follow-up study evaluating the impact of prosthetic factors on the incidence rates of ASF and SSF may prove highly valuable in the decision-making process., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine if running biomechanics and bone mineral density (BMD) were independently associated with bone stress injury (BSI) in a cohort of National Collegiate Athletic Association Division I cross country runners., Methods: This was a prospective, observational study of 54 healthy collegiate cross country runners over three consecutive seasons. Whole body kinematics, ground reaction forces (GRFs) and BMD measures were collected during the preseason over 3 years via motion capture on an instrumented treadmill and total body densitometer scans. All medically diagnosed BSIs up to 12 months following preseason data collection were recorded. Generalised estimating equations were used to identify independent risk factors of BSI., Results: Univariably, step rate, centre of mass vertical excursion, peak vertical GRF and vertical GRF impulse were associated with BSI incidence. After adjusting for history of BSI and sex in a multivariable model, a higher step rate was independently associated with a decreased risk of BSI. BSI risk decreased by 5% (relative risk (RR): 0.95; 95% CI 0.91 to 0.98) with each one step/min increase in step rate. BMD z-score was not a statistically significant risk predictor in the final multivariable model (RR: 0.93, 95% CI 0.85 to 1.03). No other biomechanical variables were found to be associated with BSI risk., Conclusion: Low step rate is an important risk factor for BSI among collegiate cross country runners and should be considered when developing comprehensive programmes to mitigate BSI risk in distance runners., Competing Interests: Competing interests: SAK is currently an associate editor for BJSM., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Only a few reports have described calcaneal insufficiency fractures (IFs) following total knee arthroplasty (TKA). Herein, we describe nine cases of calcaneal IFs following ipsilateral TKA. The purpose of this study was to investigate the incidence of calcaneal fractures following TKA and determine the characteristics of patients with IFs., Patients and Methods: We retrospectively investigated cases of calcaneal IF that occurred following TKA. We collected and analyzed radiographic and magnetic resonance imaging (MRI) findings as well as patient demographic data. We compared the demographic data, bone mineral density (BMD), and preoperative hip-knee-ankle angle (HKA) between cases with a calcaneal fracture following TKA and 100 cases without a fracture following TKA., Results: We performed a total of 1548 knee arthroplasties at our clinic from 2011 to 2020. Nine calcaneal IFs in eight patients were diagnosed following ipsilateral TKA. All patients were women with varus knee osteoarthritis (mean age, 71.8 years). The average change in the alignment angle was 14.7° ± 5.4°. In eight cases, dysfunction was observed in the opposite lower limb. The postoperative onset of hindfoot pain started at an average of 5.6 months. In seven patients, calcaneal fractures occurred idiopathically, but in one patient, two fractures occurred after long-distance walking. No abnormal findings on a calcaneus radiograph were seen for six fractures. MRI demonstrated a definite fracture line and bone marrow edema in all patients. All patients, except one with type 2 diabetes mellitus (T2DM), had osteoporosis. Fractures healed without complications in eight patients; however, the calcaneal anterior facet fracture became displaced and caused a flat foot in one case. The calcaneal IF rate was 0.58% among all cases. Besides one case with T2DM, significant differences were observed in preoperative HKA and BMD between cases with a calcaneal fracture following TKA and those without a fracture., Conclusions: A change in the load on the calcaneus due to changes in the alignment of the lower extremities after TKA may cause calcaneal IFs. Orthopedic surgeons should be aware of the possible occurrence of calcaneal IFs following TKA, especially in women with osteoporosis and severe varus knee., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)