Percutaneous screwing of the pubic ramus presents several limitations, such as the infeasibility within a bone corridor that is too narrow or too curved, or the lack of proximal locking, which may result in the mobilization of implants. This technical note presents an original method for percutaneous fixation of pubic ramus fractures using retrograde locked nailing. The implant used is the fibula rod system (Acumed), a proximally locking fibula nail. Four patients underwent surgery for pelvic ring fractures with anterior fixation using this technique, allowing immediate weight-bearing. All the patients had no corridor for a 6.5 mm canulated screw according to our pre-operative planning. No intra- or postoperative complications were observed. Further studies on fracture consolidation are required in larger series with longer radio-clinical follow-up. Retrograde locked nailing of pubic ramus fractures offers a new solution for anterior pelvic ring fixation, addressing the various limitations associated with retrograde screwing.Level of evidence: IV Retrospective study.

In our practice, the treatment of pelvic bone tumors should begin with a multidisciplinary sarcoma-board evaluation that integrates biopsy-proven histology, high-resolution CT/MRI/PET imaging, neurovascular and visceral involvement, Enneking zone, expected survival, and patient-specific functional goals. For potentially curable primary pelvic sarcomas, we consider negative-margin resection the non-negotiable oncologic priority. Limb-salvage internal hemipelvectomy is preferred when an R0 resection can be achieved while preserving limb viability and a meaningful postoperative function; external hemipelvectomy should be reserved for tumors with unreconstructable femoral or iliac vessel involvement, extensive sciatic or lumbosacral plexus invasion, uncontrolled infection, or recurrent disease in which safe margins cannot otherwise be obtained. Histology should drive sequencing: osteosarcoma and Ewing sarcoma generally require effective neoadjuvant systemic therapy before definitive local treatment, whereas conventional chondrosarcoma requires meticulous wide en bloc surgery because chemotherapy and conventional radiotherapy have limited curative value. Reconstruction should not be selected by technology alone. For non-weight-bearing or palliative defects, no reconstruction, flail hip, hip transposition, or standard metastatic acetabular procedures may offer the best time-adjusted quality of life. For long-term survivors with periacetabular, sacroiliac, or spinopelvic instability, we favor anatomy-restoring reconstruction using navigation-assisted resection and carefully planned biological, modular, or patient-specific 3D-printed implants, provided soft-tissue coverage and infection risk are acceptable. Emerging tools such as computer-assisted navigation, robotics, artificial intelligence-based segmentation, liquid biopsy, digital twins, and smart biomaterials should be used to reinforce classic oncologic principles rather than replace them. Their adoption should depend on validated margin benefit, durable functional gain, complication reduction, cost-effectiveness, and equitable access.

Multifocal skeletal tuberculosis is an uncommon manifestation of osteoarticular tuberculosis characterized by noncontiguous involvement of multiple skeletal sites. When associated with a mass-like pulmonary lesion, it may closely simulate disseminated malignancy. We report a 26-year-old immunocompetent male presenting with progressive neck stiffness, fever, cough, weight loss, and dysphagia. Imaging demonstrated a large right upper lobe mass with internal air bronchograms and associated centrilobular tree-in-bud nodules, along with multifocal destructive lesions involving the cervical, thoracic, and lumbar spine, sternum, sacroiliac joint, and pelvic bones. Extensive posterior-element involvement was present, with associated prevertebral, paraspinal, and epidural soft-tissue collections resulting in early spinal cord compression. Laboratory evaluation revealed elevated inflammatory markers, a strongly positive Mantoux test, and negative HIV serology. Bronchoalveolar lavage was negative for malignancy and acid-fast bacilli. Histopathological examination of a CT-guided biopsy demonstrated granulomatous inflammation with Langhans-type giant cells, while GeneXpert MTB detected Mycobacterium tuberculosis, confirming the diagnosis. The constellation of a pulmonary mass and multifocal destructive skeletal lesions initially raised strong suspicion for disseminated metastatic disease. This case highlights an uncommon radiologic phenotype of tuberculosis that closely mimics malignancy and underscores the importance of maintaining a high index of suspicion and obtaining early tissue diagnosis to facilitate appropriate management.

In this study, we provide a detailed description of the eggs, larvae, and juveniles of Hoplias intermedius, focusing on their morphological, meristic, and morphometric characteristics. Specimens were obtained through induced spawning using the hypophysation technique. The eggs (n = 82) were large and spherical, with a yellowish yolk, transparent chorion, and a small perivitelline space. During development, 135 larvae and 16 juveniles were examined, with standard lengths ranging from 5.48 to 39.00 mm. Larvae exhibited a terminal mouth, simple nostrils, spherical eyes, a large yolk sac, occupying approximately one-third of the body, and an intestine extending beyond the mid-body region. Pigmentation was initially sparse but became more intense during the preflexion stage. Juveniles already exhibited body morphology similar to that of adults. Fin rays counts varied as follows: pectoral (9-10), pelvic (7-9), dorsal (12-14), anal (10-13), and caudal (18-20). The total number of myomeres ranged from 36 to 44, with a modal distribution of 28 preanal and 16 postanal myomeres. Morphometric analysis revealed variation in body height (from elongated to moderate), head length (from small to large), and eye diameter (from moderate to large). Throughout development, increases were observed in snout length, head height, and distances from the snout to the pectoral, pelvic, dorsal, and anal fins. Growth analyzes indicated that most morphometric variables changed progressively during ontogeny, although some exhibited shifts in growth trajectories (breakpoints), likely associated with major developmental transitions such as yolk absorption and fin differentiation. These findings expand knowledge on Neotropical fish development. Specifically, the convergence of the lower margins of the dentary bones toward the mandibular symphysis provides a reliable diagnostic character to distinguish Hoplias intermedius from its congeners. This study offers essential morphological and meristic criteria for taxonomic identification, with direct implications for aquaculture and biodiversity conservation.

Retinoblastoma is the most common pediatric intraocular malignancy and rarely presents with distant metastases. We present the case of a 6-y-old boy with unilateral retinoblastoma who developed extensive skeletal and bone marrow metastases 3.5 y after initial successful treatment. Imaging demonstrated multifocal involvement of the skull, long bones, and pelvic bones. Bone marrow biopsy confirmed metastatic round blue cell tumor compatible with retinoblastoma, with no cerebrospinal fluid involvement. This case highlights the risk of late osseous metastasis in relapsed retinoblastoma and emphasizes the role of multimodality imaging and pathologic confirmation for accurate diagnosis and management.

Human childbirth is mechanically difficult because a large-headed, broad-shouldered fetus must pass through a comparatively narrow, twisted bony birth canal. Traditional explanations of this "obstetrical dilemma" emphasize the role of bipedal locomotion in inhibiting the evolution of a wider, more spacious pelvis. Yet recent evidence suggests that additional selective pressures shaped human pelvic anatomy. The pelvic floor hypothesis proposes that expansion of the bony birth canal would compromise the pelvic floor's stability by increasing the distance over which it must span to support the lower abdominal organs. Here, we summarize comparative, clinical, and population-based empirical evidence, as well as findings from biomechanical modeling studies, in order to evaluate the pelvic floor hypothesis. Across mammals, pelvic canal shape and size covary with posture and gravitational loading. In humans, wider and more mediolaterally expanded pelves are consistently associated with an increased risk of pelvic floor disorders, while biomechanical models show disproportionate increases in pelvic floor deformation and tissue stress with increasing canal width. Evidence that pelvic floor disorders can reduce biological fitness supports their evolutionary relevance. Together, these findings identify pelvic floor stability as an important and previously underappreciated factor constraining the evolution of the human pelvis.

Extra-articular bony impingement may contribute to posture-specific groin pain after total hip arthroplasty (THA), but the relative roles of bony morphology and functional pelvic tilt remain unclear. CT reconstructions from 100 cadavers (200 hips) were used to build three-dimensional bone-on-bone collision detection models to quantify impingement-free range of motion (RoM). Femora were rotated in internal/external rotation and abduction/adduction from 30° hyperextension to 120° flexion in 5° flexion increments. Simulations were repeated with pelvic tilt ranging ±30° from neutral as extreme boundaries. The contribution of bony anatomy to early impingement was evaluated using Pearson correlations and two-stage regression, with nested cross-validation used for supplementary internal validation. Mean external rotation to extra-articular bony impingement in extension was 46.6° ± 14.8°, and mean internal rotation to impingement at 90° flexion was 34.4° ± 14.1°. In standing, 30° posterior pelvic tilt reduced external rotation clearance by 13.2° ± 10.2° (p < 0.001); while sitting, 30° anterior pelvic tilt reduced internal rotation clearance by 33.0° ± 12.1° (p < 0.001). Standing impingement was most frequently between the ischial tuberosity and posterior intertrochanteric crest or lesser trochanter, whereas seated impingement predominantly involved the anterior inferior iliac spine (AIIS) and intertrochanteric crest. Multivariable models showed strong in-sample fit and retained good held-out performance on nested cross-validation. High-risk morphologies combined with adverse pelvic tilt produced markedly earlier impingement, with the greatest reduction observed in the seated high-risk subgroup under extreme anterior tilt. These findings quantify posture-dependent extra-articular bony constraints and identify morphology-based phenotypes associated with reduced clearance, providing a biomechanical framework for future patient-specific and implant-based studies after THA.