Is the morphology of the posterior superior iliac spine in Chinese population related to gender, age and bilateral symmetry? Insights from morphometric analysis based on CT 3D reconstruction and its clinical implications.

The sacrotuberous ligament has an oblique course, from a broad fan-like origin in the posterior superior iliac spine, transverse tubercles of the sacrum and the upper part of the coccyx, descending laterally to attach to the medial surface of the ischial tuberosity. It provides stability to the pelvic girdle, including the sacroiliac joint, counterbalancing its rotation and limiting its movement. Magnetic resonance imaging (MRI) can identify this ligament, depicting its origin, course and continuity with the conjoined biceps femoris and semitendinosus tendon. However, there is no previous report of injuries to the midportion of this ligament, with normal hamstring tendons. In this article, we report three cases of sports-related sacrotuberous ligament injury, with normal hamstring tendons and associated with gluteus maximus muscle strain. MRI demonstrated thickening and irregularities of the sacrotuberous ligament, as well as edema along its fibers and in the adjacent gluteus maximus muscle, with no bone edema and normal tendons. All patients improved with rest and nonsteroidal anti-inflammatory medications.

Avulsion fractures of the pelvis and hip primarily affect active adolescents. Although most cases are successfully treated with nonoperative management, surgical intervention may be indicated as displacement and risk for nonunion increase. The literature remains heterogeneous and limited by small comparative cohorts. This study summarizes available evidence comparing outcomes after nonoperative and operative treatment, with particular attention to displacement. A literature search of Ovid Medline, Embase, Scopus, the Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov was completed in July 2024. Patient characteristics, type of activity at the time of injury, displacement distance, treatment modality, complications, and patient outcomes were recorded for specific fracture types, as available. Twenty-four eligible studies were identified and contributed a total of 852 fractures in 849 patients (mean age 14.4±1.7y, 79% male) for analysis. The most common fracture sites were the anterior superior iliac spine (ASIS, 33.1%) and anterior inferior iliac spine (AIIS, 30.4%), followed by the ischial tuberosity (ISCH, 15.5%), lesser trochanter (LT, 13.5%), and iliac crest (IC, 7.5%). Overall, 86.6% of fractures were managed nonoperatively, and 13.4% were managed surgically. In displacement-stratified cohorts, ISCH fractures with displacement >15mm achieved high functional scores with both operative and nonoperative treatment, although pseudoarthrosis occurred in some nonoperatively treated cases with minimal functional limitation. ASIS fractures with displacement >15mm showed similar transient complications before resolution to excellent outcomes in both treatment groups, but faster RTS with the operative management alone. Rates of persistent pain were highest in ISCH fractures (27.3% surgically, 10.9% nonoperatively) and AIIS fractures treated nonoperatively (13.8%). Return to sport was achieved in nearly all cases, with surgically treated ISCH fractures requiring the longest recovery periods (6mo). Both nonoperative and operative management result in favorable outcomes for most adolescent pelvic avulsion fractures. Although displacement frequently influences surgical decision-making, current evidence does not establish a validated threshold at which outcomes reliably diverge. Before displacement can be considered a reliable surgical indication, higher-quality evidence demonstrating superior outcomes at clear displacement thresholds is needed. Level III.

The subpubic angle and palpable pelvic parameters in sex estimation using machine learning algorithms in a Turkish population.

Accurate bone age assessment is crucial in forensic medicine and pediatrics. This study aimed to systematically characterize the MRI developmental patterns of the iliac crest and ischial tuberosity and to develop machine learning models for age estimation and age threshold classification. A retrospective analysis was conducted on pelvic MRI scans from 680 individuals aged 6-30 years. A four-stage method was used to assess ossification stages of the iliac crest and ischial tuberosity, followed by a descriptive analysis. We trained and test multiple machine learning models for: (1) regression models for continuous age prediction, and (2) classification models for determining legal age thresholds (12, 14, 16, 18 years). Models were validated on both internal and external test sets. Inter- and intra-observer agreements were good (k > 0.9). the minimum ages for complete fusion of iliac crest and ischial tuberosity were 15.00 years and 15.75 years in males, while both 14.00 years in females. Chronological age and ossification stage showed strong positive correlations (r > 0.8). No significant differences were found regarding sex, sequence, or side (p > 0.05), except the side difference in female ischial tuberosity (p = 0.008). For age regression, the optimal model achieved a mean absolute error of 2.957 years on the internal set and 2.252 years on the external set. For classifying legal age thresholds (12, 14, 16, 18 years), models demonstrated outstanding performance, with the highest AUCs of 0.977, 0.992, 0.969, and 0.931 on the internal set, and 0.955, 0.984, 0.997, and 0.997 on the external set. This study provided foundational MRI reference data for pelvic apophyseal development and showed the exciting potential of integrating pelvic MRI with machine learning for age estimation.

Leg length discrepancy is a common and clinically important complication following total hip arthroplasty. It may lead to patient dissatisfaction, altered gait, and functional impairment. Although radiographic assessment is widely used, existing measurement methods can be affected by pelvic rotation and anatomical variations. This study aimed to evaluate the reliability and validity of a novel radiographic method based on the distance between the greater trochanter and the ischial tuberosity for assessing leg length discrepancy after hip arthroplasty. This retrospective cohort study included 56 patients who underwent hip arthroplasty between 2020 and 2023 and had appropriate postoperative standing pelvic radiographs. Leg length was measured clinically using the anterior superior iliac spine-medial malleolus distance, and radiographically using 3 different methods: teardrop to lesser trochanter, greater trochanter to ischial tuberosity, and anterior superior iliac spine to ankle. All radiographic measurements were performed twice, 2 weeks apart, by 2 orthopedic surgeons. Intraobserver and interobserver reliability were assessed using the intraclass correlation coefficient (ICC). Pearson correlation analysis was used to evaluate the relationship between the measurement methods. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of each method in identifying leg length discrepancy of ≥ 10 mm. The mean age of the patients was 66.8 ± 9.1 years. The greater trochanter-ischial tuberosity method showed excellent intraobserver and interobserver reliability (ICC > 0.84). A strong positive correlation was found between this method and the anterior superior iliac spine-ankle measurement (P < .001). The novel method also demonstrated the highest diagnostic accuracy in detecting leg length discrepancies ≥ 10 mm (AUC: 0.96). The greater trochanter-ischial tuberosity distance is a reliable, reproducible, and practical radiographic measurement method for assessing leg length discrepancy after hip arthroplasty. Its reduced sensitivity to pelvic rotation and anatomical variation makes it a promising alternative to traditional methods, especially in clinical settings where full-limb imaging is not available.

Polymyalgia rheumatica (PMR)-like manifestations are among the most common rheumatological immune checkpoint inhibitor (ICI)-related adverse events. 18F-fluorodeoxyglucose (FDG) PET/CT is useful for the follow-up of various solid organ cancers and for PMR assessment. The aim of this study was to describe PET/CT aspects of ICI-related PMR (ICI-PMR) in comparison with idiopathic PMR. This was an observational, comparative, retrospective, single-centre study. Inclusion criteria were a diagnosis of ICI-PMR or idiopathic PMR and availability of an 18F-FDG PET/CT within 3 months before diagnosis. 18F-FDG uptake in 20 musculoskeletal regions of interest (ROIs) on PET/CT was assessed by two independent readers. PET/CT features of ICI-PMR and idiopathic PMR were compared. Twenty patients with ICI-PMR were compared with 23 patients with idiopathic PMR. Patients with ICI-PMR were mostly treated for metastatic melanoma. Compared with patients with idiopathic PMR, patients with ICI-PMR had similar C-reactive protein levels but a higher frequency of peripheral arthritis. On PET/CT, patients with ICI-PMR had significantly lower 18F-FDG uptake at ischial tuberosities, greater trochanters, anterior pubic symphysis, iliopectineal bursae, sternoclavicular joints and interspinous bursae than patients with idiopathic PMR. These differences remained significant for five of the six ROIs after stratification according to peripheral arthritis. Leuven and Besançon scores were significantly lower in ICI-PMR, regardless of the presence of peripheral arthritis. The distribution of musculoskeletal inflammation on 18F-FDG PET/CT differed between ICI-PMR and idiopathic PMR. ICI-PMR was associated with less intense musculoskeletal uptake, especially in extra-articular regions, even after stratification based on peripheral arthritis.

The hamstring muscle complex comprises several biarticular posterior thigh muscles. These muscles originate from the ischial tuberosity and attach distally to the knee. Hamstring muscle injuries are among the most common in the lower extremities of active individuals. Hamstring injuries follow a consistent pattern and medical history, including a sudden, explosive movement (sprinting, kicking, jumping, or lunging). The onset of pain is usually acute in the proximal posterior aspect of the upper thigh. Injured individuals may describe a “pop” or “snap” or a sensation as if someone kicked them in the back of the thigh. An accurate diagnosis of proximal hamstring overuse, partial tears, or ruptures is essential for appropriate treatment planning and optimizing patient outcomes. Diagnostic musculoskeletal ultrasound (MSKUS) offers a portable, real-time, and cost-effective alternative, gaining traction in rehabilitation and sports medicine settings. MSKUS has emerged as a valuable, non-invasive imaging modality for evaluating proximal hamstring injuries, including tendinopathy, muscle strains (partial tears), and ruptures. MSKUS is excellent at detecting changes in tendon and muscle composition and continuity. This manuscript will review the utility of MSKUS in evaluating proximal hamstring tendon and muscle injury, including anatomy, common injury patterns, sonographic techniques, and clinical implications for rehabilitation professionals. By integrating MSKUS into clinical practice, providers can improve diagnostic accuracy, enhance diagnostic confidence, monitor healing progression, and guide rehabilitation strategies to achieve optimal patient outcomes for those with hamstring injuries.

Avulsion fracture of the ischial tuberosity (AFIT) is a clinically rare injury that primarily occurs in adolescents participating in competitive sports. AFIT can be challenging to diagnose and manage due to its subtle presentation and the potential for misdiagnosis. Selecting an appropriate treatment method remains challenging due to the lack of universally accepted, evidence-based treatment guidelines for optimal management. A review of the relevant literature indicated that AFIT exhibits more complex healing patterns than other pelvic avulsion fractures with conservative management, and also that the outcomes of AFIT following the surgical treatment of chronic cases are often not as favorable as those of acute cases. Therefore, clinicians should increase their awareness of this type of fracture and consider aggressive surgical intervention in patients with displaced AFIT to ensure optimal outcomes and expedite their return to pre-injury athletic performance levels.

Cross-sectional observational study. Deep-tissue injury (DTI) originates in subcutaneous soft tissue and progresses outward without early skin changes, making diagnosis difficult in people with spinal-cord injury (SCI). We evaluated the incidence of DTI with magnetic resonance imaging (MRI) and sought associated risk factors. Kibikogen Rehabilitation Center for Employment Injuries, Japan. Fifty-six wheelchair-dependent adults with SCI of at least 1 month's duration underwent pelvic sagittal STIR MRI screening. DTI-positive sites were defined by signal changes in subcutaneous fat or muscle. Ultrasonography, body composition, seating-related variables, and laboratory data were collected concurrently. Univariate and multivariate logistic-regression analyses identified independent risk factors. MRI detected subclinical DTI in 33 of 112 ischial regions (29.5%). Ultrasonography was concordant in only 15 sites (45.5%). Multivariable analysis showed that longer daily wheelchair use (p = 0.018), greater subcutaneous-tissue thickness at the ischial tuberosities (p = 0.028), and less-frequent pressure-relief manoeuvres (p = 0.031; protective) were independently associated with DTI. BMI, peak interface pressure, and routine haematologic or nutritional markers were not significant. MRI screening revealed subclinical DTI in nearly one-third of wheelchair-dependent patients with SCI and outperformed ultrasonography for early detection. Extended sitting time, thicker subcutaneous fat at the ischial tuberosity, and infrequent pressure relief emerged as modifiable risk factors. A risk-based MRI surveillance strategy may enable timely preventive interventions and reduce progression to overt pressure ulcers.

Background: Ischiofemoral impingement (IFI) syndrome is the narrowing of the space between the lateral aspect of the ischium and the medial aspect of the lesser trochanter. IFI is a frequently unrecognized generator of vague or posterior hip pain that is commonly preceded by trauma or previous hip surgery. IFI can also be a result of atypical pelvic/proximal femur anatomy, adductor/abductor imbalances, or ischial tuberosity enthesopathies. Management typically consists of conservative treatments, including activity modification, anti-inflammatories, physical therapy, and corticosteroid injections. Endoscopic decompression of the ischiofemoral space has been shown to be an effective surgical intervention in treating IFI. Indications: Indications for endoscopic ischioplasty and secondary repair of the proximal hamstring origin include symptomatic IFI that has failed extensive conservative treatment measures. Technique Description: The width of the ischium is measured. The sciatic nerve is identified and protected. The proximal hamstring origin is exposed, and an arthroscopic burr is used to perform an osteoplasty of the lateral ischium. An endoscopic repair of the proximal hamstring is performed on the decorticated ischial tuberosity. Results: Limited clinical studies exist that report outcomes after ischioplasty for IFI. Many studies reporting outcomes after endoscopic treatment of IFI focus on iliopsoas release and lesser trochanter osteoplasty. The endoscopic treatment of IFI has been demonstrated to provide effective results after 2 years of follow-up in appropriately selected patients. Specifically, lesser trochanter osteoplasty has also shown satisfactory outcomes with symptom relief and good functional results in patients with IFI. Discussion/Conclusion: Endoscopic ischioplasty in the setting of IFI, while concomitantly performing a secondary repair of the proximal hamstring origin, allows for the enlargement of the ischiofemoral space. This approach spares the need to perform a lesser trochanter osteoplasty, which disrupts the insertion of the iliopsoas. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

The reconstruction of bilateral ischial pressure sores presents a formidable challenge in reconstructive plastic surgery. Adequate padding over the ischial tuberosity and proper resurfacing of the defect are critical in preventing recurrence after reconstruction. We present a case of bilateral ischial sores reconstructed using two different approaches. A 62-year-old paraplegic man with bilateral ischial sores and osteomyelitis of both ischial tuberosities presented to the plastic surgery department. After serial debridement, the 6×4 cm ischial sore on the left side was reconstructed using dual-plane flaps—two independent flaps consisting of a biceps femoris muscle flap and a perforator-based fasciocutaneous island flap. The 7×4 cm ischial sore on the right side was reconstructed using a single hamstring flap, a composite flap consisting of a semitendinosus muscle flap with a distally linked skin flap. Both defects were successfully reconstructed, and the patient regained wheelchair ambulation. Both approaches—the dual-plane flaps and the single hamstring flap—are effective options for ischial sore reconstruction, as they provide sufficient volume and adequate resurfacing. Given the hamstring flap’s capacity to significantly reduce operative duration, it may be considered the primary surgical option. However, in the absence of a reliable perforator between the hamstring muscle and the overlying skin, dual-plane flaps should be selected.

Background: Accurate evaluation of pressure distribution at the socket–limb interface is essential for improving prosthetic fit and comfort in transfemoral amputees. This study aimed to develop a proof-of-concept framework that integrates machine learning–based segmentation with the finite element method (FEM) to explore the feasibility of an initial workflow for residual-limb analysis during socket application. Methods: MRI data from a transfemoral amputee were processed using a custom image segmentation algorithm to extract adipose tissue, femur, and ischium, achieving high F-measure scores. The segmented tissues were reconstructed into 3D models, refined through outlier removal and surface smoothing, and used for FEM simulations in LS-DYNA. Pressure values were extracted at nine sensor locations and compared with experimental measurements to provide a preliminary qualitative assessment of model behaviour. Results: The results showed consistent polarity between measured and simulated values across all points. Moderate correspondence was observed at eight low-pressure locations, whereas a substantial discrepancy occurred at the ischial tuberosity (IS), the primary load-bearing site. This discrepancy likely reflects the combined influence of geometric deviation in the reconstructed ischium and the non-physiological medial boundary condition required to prevent unrealistic tissue displacement. This limitation indicates that the current formulation does not support reliable quantitative interpretation at clinically critical locations. Conclusions: Overall, the proposed framework provides an initial demonstration of the methodological feasibility of combining automated anatomical modeling with FEM for exploratory pressure evaluation, indicating that such an integrated pipeline may serve as a useful foundation for future development. While extensive refinement and validation are required before any quantitative or clinically meaningful application is possible, this work represents an early step toward more advanced computational investigations of transfemoral socket–limb interaction.

Introduction The cushion microclimate is an important risk factor for pressure injury. To date, the microclimate responses to wheelchair cushions have not been assessed in warm environments where they are potentially most problematic. A cooling wheelchair cushion has been developed to minimise temperature and moisture accumulation; however, no independent research has been conducted on this cushion. This study aimed to evaluate the effect of wheelchair cushions and a novel cooling wheelchair cushion on temperature, moisture and perception during passive sitting in a warm environment. Methods A randomised crossover study was conducted to determine microclimate responses to three wheelchair cushions of differing properties. Eighteen able-bodied participants sat passively on each cushion for two hours in 28-30 °C. Tympanic temperature, skin and groin temperature, relative humidity and thermal perception were measured. Results The cooling cushion produced significantly lower temperatures at the ischial tuberosities and the groin. The air cushion produced significantly lower temperatures at the posterior thigh. Conclusion The novel cooling cushion was effective in reducing temperatures in the areas closest to the cooling element, while the air cushion effectively reduced the temperature at the posterior thigh where the comparator cushions had foam properties.

Abstract This cadaveric radiographic study aimed to define the proximal hamstring footprint using reproducible ischial landmarks and to compare pelvis and hip posterior–anterior (PA) radiographs in depicting its borders. The goal was to provide practical reference values to guide anatomical anchor placement during endoscopic repair. A total of 10 hips (from five formaldehyde-fixed cadavers) were examined. Marking pins were placed at the proximal hamstring tendon footprint to identify anatomical boundaries. Pelvis PA and hip PA radiographs were obtained to determine the radiological borders and their relationship with the ischial tuberosity. The distances from the superior, medial, lateral, and inferior borders of the tendon to the line connecting the ischial tuberosities and the ischial apex were measured. The pelvis and hip radiographs were compared using the Mann–Whitney U test. Four cadavers were male, with a mean age of 67 years. Distances from the tendon’s borders to the ischium and ischial apex were consistent across the pelvis and hip radiographs, with no statistically significant differences (P &amp;gt; 0.05). Median distances of tendon footprint borders ranged from 15.5 (IQR: 8.6) to 35.5 (IQR:5.4) mm for the ischial tuberosity line and 30.05 (IQR: 9.07) to 47.1 (IQR: 9.6) mm for the ischial apex. Similar results were observed in hip radiographs. Radiographic localisation of the proximal hamstring footprint is feasible and yields consistent measurements on both pelvic and hip PA views. These values offer practical anatomical guidance that may support more accurate anchor placement during endoscopic proximal hamstring repair.

This study aims to systematically review the current literature on treatment strategies for ischiofemoral impingement (IFI), focusing on the outcomes of nonoperative, arthroscopic, and open surgical interventions. IFI is an uncommon but increasingly recognized cause of posterior hip and deep gluteal pain, resulting from narrowing of the space between the ischial tuberosity and the lesser trochanter. Seven studies (level IV evidence) encompassing 101 patients (107 hips) were identified. Majority of patients were female (91%) with mean ages 26-47 years and follow-up ranging 18-48 months. Image-guided quadratus femoris injections provided short-term pain relief but limited long-term benefit. Arthroscopic lesser trochanter (LT) resection demonstrated consistent improvement in hip function and return to activity, with minimal complications and revision rates. One study on open derotation osteotomy reported significant improvements in range of motion, reduced impingement symptoms, and high patient satisfaction. Both conservative and surgical treatments improve symptoms of IFI, though surgical decompression reports sustained benefit. Arthroscopic LT resection shows promise as a safe and effective intervention. However, current evidence is limited to small, retrospective series without direct comparisons. Future prospective, comparative studies using standardized outcome measures are needed to define optimal management strategies for IFI.

Abstract Ischiofemoral impingement is an extra-articular form of hip pain caused by narrowing of the space between the ischial tuberosity and lesser trochanter. The ischiofemoral space (IFS) can vary with hip morphology, as well as dynamically change throughout hip range of motion. The objectives of this study were to evaluate the impact of movement (gait, standing pivot, and neutral standing) and sex on IFS, as well as determine what morphological characteristics correlate with IFS. Synchronized biplane radiographs were collected from 24 participants during treadmill walking, standing pivot, and neutral standing. Subject-specific bone models, created from CT images, were used to create digitally reconstructed radiographs that were registered to the biplane radiographs using a validated matching technique. The ischial tuberosity and lesser trochanter were digitally marked to dynamically measure the IFS. Morphologic measurements were correlated with the IFS, and the effects of sex and movement on IFS were calculated. During the gait cycle, IFS was narrowest at contralateral heel strike (47%–53% of the gait cycle) and greatest during mid-swing (~85% of the gait cycle). Across all movements, IFS was greatest during standing (P &amp;lt; .001). There was a moderate negative correlation between acetabular version (AV) and IFS during gait (P = .002) and standing pivot (P = .007). McKibbin index was moderately negatively correlated with IFS during standing pivot (P = .001). The IFS varies with hip position, with motion involving hip extension, such as walking and pivot activities, resulting in a smaller IFS. Greater central AV and McKibbin index are associated with a smaller IFS.

Revisiting the Sciatic Nerve: A Landmark-based Classification of Division Patterns in Relation to the Ischial Tuberosity

This study explores the scope of sexual and age‐related discrimination in the hemipelvises of Lama guanicoe guanicoe (Müller 1776), a species that lacks postcranial secondary sexual characteristics. Using two‐dimensional geometric morphometric techniques, changes in shape and size of the coxae bones from 50 individuals of both sexes and varying ontogenetic development from the Patagonian locality of Cinco Chañares (Río Negro, Argentina) were analyzed. The results indicate differences in the shape and size of the guanaco hemipelvis according to sex and age. The study provides novel morphological information on the variation in sections of the coxal bone, such as the ilium body, the ischial tuberosity, and the acetabulum. Additionally, the changes recorded along the dorsal border of the hemipelvis, mainly in the ischial notch and crest, reinforce the diagnostic nature of qualitative traits and metric variables previously described by other researchers as being associated with sexual dimorphism. The indirect evaluation of the biological parameters of sex and age, through the morphology and size of the coxae bones, represents a reliable skeletal indicator that can significantly contribute to biological studies and management plans for the species.

Proximal hamstring tendons are commonly injured among athletes, and when tendon tears are indicated for surgery, the gold standard has been open repair with suture anchors. However, endoscopic repair techniques like the technique described in this study for hamstring undersurface concealed crescentic injuries (HUCCIs) have been shown to have high patient satisfaction and limit perioperative complications. General indications for surgery for hamstring tears are 2-tendon, partial tears with >2 cm of retraction or 3-tendon complete tears that have been recalcitrant to nonoperative treatment. This technique focuses specifically on the repair of partial undersurface tears of hamstring tendons that are often concealed by partially intact superficial tendon tissue. This technique guide describes a minimally invasive endoscopic technique for repairing proximal HUCCIs using 4 interlinked knotless suture anchors to create an X-formation repair construct. Patients are positioned prone with the operative leg resting on a Mayo stand to help extend and abduct the leg during the procedure. Two portals are used primarily, one in the distal gluteal crease and another proximal lateral portal used primarily for anchor placement. Sciatic nerve identification, neurolysis, and mobilization are performed under direct visualization. The undersurface injury is identified, bursectomy is performed, and a split is made in the interval between the conjoint tendon and semimembranosus. Through the interval, the ischial tuberosity is decorticated, and 4 interlocked, knotless anchors are used to create the HUCCI-X repair. Patients treated with endoscopic proximal hamstring repairs generally have significant improvement in patient-reported outcome metrics equivalent to open repair techniques. In the literature, return to sport after endoscopic proximal hamstring repairs has ranged from 77% to 95%. The HUCCI-X repair technique offers a novel, safe, and effective way to repair undersurface proximal hamstring tears endoscopically. This technique combines the benefits of a minimally invasive endoscopic hamstring repair, including lower perioperative complications, with the compressive force of "suture staples" created by interlinked knotless suture anchors. Future studies may focus on patient postoperative outcomes after treatment with this technique. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.