UNASSIGNED: The significance of taking femoral neck stress fractures into account as a possible consequence in sickle cell anemia patients is underscored by this case report. In this high-risk group, early identification, timely diagnosis, and suitable care are crucial for averting major problems and improving results. When sickle cell anemia patients complain with hip or groin discomfort, healthcare practitioners should keep a high index of suspicion for femoral neck stress fractures to assure prompt management and prevent long-term impairment.
UNASSIGNED: Sickle cell disease (SCD) is a prevalent genetic hemoglobinopathy with significant global implications, affecting a substantial portion of the population. Avascular necrosis of the femoral head is a common complication in SCD, leading to severe joint damage and immobility. This case report is of a 20-year-old male who presented with severe hip pain due to a femoral neck stress fracture, which progressed to a complete fracture. This patient had a past medical history of sickle cell anemia and a malunited subtrochanteric fracture that resulted in shortening, external rotation, and a limping gait. Surgical treatment via subtrochanteric osteotomy with fixation using a dynamic hip screw with or without iliac crest bone graft was planned, with a satisfactory reduction and closure of the fracture gap, postoperatively. In cases of sickle cell anemia patients, bone complications such as both osteonecrosis and stress fractures are common. As a healthcare provider, it is important to manage and address these not only through medical interventions, but also through counseling and patient education. Patients must be reminded about the importance of compliance with medical advice to avoid progression or recurrence of complications.

Military training increases tibial density and size. Female sex hormones may influence the adaption of bone to loading, but it is unknown if women using different hormonal contraceptives adapt similarly to military training. One hundred and sixteen women (57 women not using hormonal contraceptives [non-users], 38 combined oral contraceptive pill [COCP] users, 21 depot medroxyprogesterone acetate [DMPA] users) completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4 %, 14 %, 38 %, and 66 % sites) at the start (week 1) and end (week 14) of British Army basic training. Circulating markers of bone and calcium metabolism were measured at weeks 1, 2, 4, 6, 10, and 14. Training increased trabecular vBMD at the 4 % site, periosteal perimeter at the 14 % and 66 % sites, and total area, cortical area, cortical thickness, and bone strength at all sites (0.1 to 1.6 %, p ≤ 0.009), with no differences between hormonal contraceptive groups (p ≥ 0.127). Trabecular vBMD increased at the 14 % site in non-users (0.8 %, p = 0.005), but not in COCP or DMPA users (p ≥ 0.205). Periosteal perimeter increased at the 38 % site in COCP (0.4 %, p < 0.001) and DMPA (0.5 %, p < 0.001) users, but not in non-users (p = 0.058). Training had no effect on periosteal perimeter at the 4 % site or cortical vBMD or endosteal perimeter at any site (p ≥ 0.168). βCTX decreased and PINP increased during training with no difference between hormonal contraceptive groups. Training increased iPTH in non-users, but not COCP or DMPA users. Hormonal contraceptives may exert site-specific effects on the mechanobiology of bone, with higher endogenous oestradiol promoting trabecularisation and inhibiting periosteal expansion in non-users compared with hormonal contraceptive users.

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.

To compare the clinical, radiologic, and functional outcomes between shockwave and operative treatments for proximal fifth metatarsal stress fractures in soccer players in a pilot study.
Between 2017 and 2019, 18 soccer players with fifth metatarsal stress fractures attended at Mutualidad de Futbolistas Españoles-Delegación Catalana were included. Patients were randomly assigned into 2 groups receiving either surgery with an intramedullary screw (group 1) or high-energy focused extracorporeal shockwave treatment (group 2 performed once a week for 3 weeks using 2000 impulses at an energy flux density of 0.21 mJ/mm2 and 4 Hz frequency). Clinical (pain), radiologic (bone healing), and functional (Tegner Activity Scale and American Orthopaedic Foot & Ankle Society [AOFAS] ankle-hindfoot scales) outcomes before and after receiving the treatment were compared between both groups. In addition, ability and time to return to play was also compared between groups.
No patients were lost to follow-up. There were no statistically significant differences at last follow-up between surgery and extracorporeal shockwave treatment for bone healing, pain relief, AOFAS ankle-hindfoot score, Tegner score, and time return to play. No complications were reported in either of the 2 groups.
In this pilot study, extracorporeal shockwave treatment and operative treatment were found to be equally effective at reducing pain, achieving bone healing, and allowing the soccer players to return to play after proximal fifth metatarsal stress fractures. This study suggests that ESWT may be a good option for the management of proximal fifth metatarsal stress fractures in soccer players. If this approach proves successful in larger trials, the shockwave approach might help avoid known complications of the surgical treatment like wound problems, nerve injury, and hardware intolerance. Further investigations with larger sample size should be conducted in order to confirm the present conclusions.
Level II, therapeutic, pilot randomized controlled trial.

BACKGROUND: Although the diagnostic criteria for atypical femoral fracture (AFF) exclude periprosthetic fractures, reports of periprosthetic femoral fractures with characteristics of AFF are rapidly increasing. In this study, we investigated the frequency and pathogenesis of periprosthetic AFF associated with total knee arthroplasty (TKA) based on a theory of AFF subtypes that divides AFFs into two main types: fragility stress fractures of the bowed femoral shaft in the mid-shaft and \"typical\" subtrochanteric AFFs due to suppression of bone turnover (e.g., by bisphosphonates).
METHODS: This multicenter prospective study of AFFs was conducted from 2015 through 2022. Clinical, pathological, and morphological characteristics were investigated in patients with periprosthetic AFFs associated only with non-stem TKA. Then, biomechanical investigation of the periprosthetic AFF was performed by computer tomography-based finite element analysis (CT/FEA) using two models with different load axes to examine how the correction of lower limb alignment by TKA influences the tensile stress distribution of the femur and the location of the AFF.
RESULTS: Four of 61 AFFs (6.6%) were identified to be periprosthetic AFF (1 mid-shaft; 3 subtrochanteric). Periprosthetic AFFs had characteristics including mechanical stress due to bowing deformity and potentially suppressed bone turnover due to long-term exposure to specific drugs (e.g., bisphosphonates and glucocorticoids). Although 2 periprosthetic AFFs appeared to involve a bowed femur, one with both of the aforementioned characteristics occurred in the subtrochanteric region, which would be an unusual site for a bowed AFF, and it was demonstrated histologically to have biological activity at the fracture site, suggesting a stress fracture. Furthermore, CT/FEA revealed that tensile stress distribution changed proximally as load axis was shifted laterally according to correction of lower limb alignment by TKA.
CONCLUSIONS: Orthopedic surgeons should recognize the presence of TKA-associated periprosthetic AFF caused by various factors including specific drugs, bowing deformity, and lower limb alignment. X-rays of the full-length femurs should be checked regularly after TKA, especially in patients with bowed femurs or long-term exposure to specific drugs.

BACKGROUND: Ultrasound is extensively used for soft tissue pathology. Scanning bone superficial structures may reveal clear pathologic features to aid diagnosis.
METHODS: We present the case of a stress fracture in the second metatarsal, with the clinical aspect of a gouty attack. Ultrasound examination showed cortical thickening and disruption, hypoechoic periosteal swelling, hyperemia, soft tissue edema, and displacement of the extensor tendon. The diagnosis was confirmed by X-ray and MRI. The value of different diagnostic tools is discussed, and the importance of gray-scale and color Doppler ultrasound as a first-hand modality is underlined.
CONCLUSIONS: Sonography clearly identifies cortical and periosteal abnormalities, differentiates surrounding soft tissue pathologies, and offers dynamic evaluation, and follow-up possibility with low cost, high accessibility, and no risks. Periosteal and cortical irregularities are important diagnostic issues when performing ultrasound examinations for soft tissue pathology.

Females are up to four times more likely to sustain a stress fracture than males. Our previous work, using statistical appearance modeling in combination with the finite element method, suggested that sex-related differences in tibial geometry may increase bone strain in females. The purpose of this study was to cross-validate these findings, by quantifying sex-related differences in tibia-fibula bone geometry, density, and finite element-predicted bone strain in a new cohort of young physically active adults. CT scans of the lower leg were collected for fifteen males (23.3 ± 4.3 years, 1.77 ± 0.09 m, 75.6 ± 10.0 kg) and fifteen females (22.9 ± 3.0 years, 1.67 ± 0.07 m, 60.9 ± 6.7 kg). A statistical appearance model was fit to each participant\'s tibia and fibula. The average female and male tibia-fibula complex, controlled for isotropic scaling, were then calculated. Bone geometry, density, and finite element-predicted bone strains in running were compared between the average female and male. The new cohort illustrated the same patterns as the cohort from the previous study: the tibial diaphysis of the average female was narrower and had greater cortical bone density. Peak strain and the volume of bone experiencing ≥4000 με were 10 % and 80 % greater, respectively, in the average female when compared to the average male, which was driven by a narrower diaphysis. The sex-related disparities in tibial geometry, density, and bone strain described by our previous model were also observed in this entirely new cohort. Disparities in tibial diaphysis geometry likely contribute to the elevated stress fracture risk observed in females.

OBJECTIVE: This study aimed to clarify the relationship between vitamin D status and complications after periacetabular osteotomy.
METHODS: A total of 46 hips of 39 patients (3 men and 36 women; mean age at surgery, 41.0 years; mean postoperative follow-up duration, 63 months) were reviewed to obtain the following information: patients\' serum 25-hydroxyvitamin D [25(OH)D] status, prevalence of postoperative delayed union of osteotomy sites in the greater trochanter (DUGT) and ischiopubic stress fractures (IPSFs), and risk factors.
RESULTS: The mean serum 25(OH)D level was 11.9 ng/ml. DUGT and IPSF were found in four (10.3%) and three (7.7%) patients, respectively. Serum 25(OH)D levels ≤ 11 ng/ml were significantly associated with DUGT in female patients (p = .02). Serum 25(OH)D levels ≤ 9 ng/ml and smoking were significantly associated with IPSF (p = 0.01 and 0.02, respectively). Overall, 21.7% of patients with serum 25(OH)D levels ≤ 11 ng/ml developed at least one complication; no complications occurred when serum 25(OH)D levels were >11 ng/ml.
CONCLUSIONS: Severe vitamin D deficiency was highly prevalent in relatively young patients. Vitamin D deficiency and smoking were independent risk factors for postoperative complications. Proactive supplementation is advisable to reduce postoperative complications, especially in patients with serum 25(OH)D levels ≤ 11 ng/ml.

The tibia is a common site for bone stress injuries, which are believed to develop from microdamage accumulation to repetitive sub-yield strains. There is a need to understand how the tibia is loaded in vivo to understand how bone stress injuries develop and design exercises to build a more robust bone. Here, we use subject-specific, muscle-driven, finite element simulations of 11 basketball players to calculate strain and strain rate distributions at the midshaft and distal tibia during six activities: walking, sprinting, lateral cut, jumping after landing, changing direction from forward-to-backward sprinting, and changing direction while side shuffling. Maximum compressive strains were at least double maximum tensile strains during the stance phase of all activities. Sprinting and lateral cut had the highest compressive (-2,862 ± 662 με and -2,697 ± 495 με, respectively) and tensile (973 ± 208 με and 942 ± 223 με, respectively) strains. These activities also had the highest strains rates (peak compressive strain rate = 64,602 ± 19,068 με/s and 37,961 ± 14,210 με/s, respectively). Compressive strains principally occurred in the posterior tibia for all activities; however, tensile strain location varied. Activities involving a change in direction increased tensile loads in the anterior tibia. These observations may guide preventative and management strategies for tibial bone stress injuries. In terms of prevention, the strain distributions suggest individuals should perform activities involving changes in direction during growth to adapt different parts of the tibia and develop a more fatigue resistant bone. In terms of management, the greater strain and strain rates during sprinting than jumping suggests jumping activities may be commenced earlier than full pace running. The greater anterior tensile strains during changes in direction suggest introduction of these types of activities should be delayed during recovery from an anterior tibial bone stress injury, which have a high-risk of healing complications.

BACKGROUND: Stress fractures are a common and potentially debilitating overuse injury to bone and occur frequently among military recruits and athletes. Recovery from a lower body stress fracture typically requires several weeks of physical rehabilitation. Teriparatide, a recombinant form of the bioactive portion of parathyroid hormone (1-34 amino acids), is used to treat osteoporosis, prevent osteoporotic fractures, and enhance fracture healing due to its net anabolic effect on bone. The study aim is to investigate the effect of teriparatide on stress fracture healing in young, otherwise healthy adults undergoing military training.
METHODS: In a two-arm, parallel, prospective, randomised controlled, intention-to-treat trial, Army recruits (n = 136 men and women, 18-40 years) with a magnetic resonance imaging (MRI) diagnosed lower body stress fracture (pelvic girdle, sacrum, coccyx, or lower limb) will be randomised to receive either usual Army standard care, or teriparatide and usual Army standard care. Teriparatide will be self-administered by subcutaneous injections (20 μg/day) for 16 weeks, continuing to 24 weeks where a fracture remains unhealed at week 16. The primary outcome will be the improvement in radiological healing by two grades or more, or reduction to grade zero, 8 weeks after randomisation, assessed using Fredericson grading of MRI by radiologists blind to the randomisation. Secondary outcomes will be time to radiological healing, assessed by MRI at 8, 10, 12, 14, 16, 20 and 24 weeks, until healed; time to clinical healing, assessed using a clinical severity score of injury signs and symptoms; time to discharge from Army physical rehabilitation; pain, assessed by visual analogue scale; health-related quality of life, using the Short Form (36) Health Survey; and adverse events. Exploratory outcomes will include blood and urine biochemistry; bone density and morphology assessed using dual-energy X-ray absorptiometry, peripheral quantitative computed tomography (pQCT), and high-resolution pQCT; physical activity measured using accelerometers; and long-term future fracture rate.
CONCLUSIONS: This study will evaluate whether teriparatide, in addition to standard care, is more effective for stress fracture healing than standard care alone in Army recruits who have sustained a lower body stress fracture.
BACKGROUND: ClinicalTrials.gov NCT04196855 . Registered on 12 December 2019.