Surgical fixation of pediatric pelvic ring injuries is gaining popularity to avoid the poor long-term outcomes of pelvic asymmetry. The surgical techniques and fixation choices depend on the individual injuries affecting the anterior and posterior pelvic ring areas. The immature bony pelvis of young children has anatomic differences including soft bones, elastic ligaments, and the presence of growth centers. Understanding the unique pediatric lesions with unstable pelvic fractures is essential for treatment decisions. Anterior lesions include pubic symphysis disruption through the pubic apophysis, single ramus fractures, pubic rami fractures through the triradiate cartilage, and/or the ischiopubic synchondrosis; ischiopubic ramus infolding injury; or the unstable superior and inferior quadrant lesions. Posterior pelvic lesions include iliac wing infolding and sacroiliac joint dislocation or transiliac (crescent) fracture/dislocations through the iliac apophysis growth plate. Pubic symphysis and sacroiliac disruptions are physeal injuries in children, and they have excellent healing potential. External fixation is an ideal choice for anterior ring fixation including bony and pubic symphysis injuries. Posterior lesions are mostly sacroiliac joint disruptions with iliac apophysis separation that can serve as a landmark for vertical displacement correction. Posterior lesions can be treated by percutaneous iliosacral screw fixation or open reduction techniques.

The articulation of the femoral head with the acetabulum forms the hip joint. This articulation connects the axial skeleton with the lower extremity and functions to transmit forces encountered during daily activities from the axial skeleton through the lower extremities. The hip joint’s ability to balance forces through its full range of motion provides providing the stability required to execute everyday tasks such as standing upright, maintaining a smooth and balanced gait, rising from a chair, and lifting weight from a squatting position.  [1] The hip joint is a spheroidal, or ball-and-socket-type, synovial joint stabilized by bony and ligamentous restraints. The osseous anatomy of the femoroacetabular articulation contributes to the hip’s inherent stability. The pelvis is made up of three parts: the ilium, ischium, and pubis. These innominate bones come together at the triradiate cartilage to form the cup-shaped socket known as the acetabulum. At 15 to 17 years of age, the triradiate cartilage begins to ossify, and it completely fuses by 20 to 25 years of age. Acetabular development is a complex process that involves both endochondral growth from the triradiate cartilage and intramembranous growth from primary and secondary ossification centers of the innominate bones.[2] The acetabulum covers approximately 40% of the femoral head at any position of hip motion. Additional stability is conferred by the labrum, a rim composed of circumferential collagen fibers that surrounds the acetabulum and acts to deepen the hip socket and limit the extreme range of motion. The acetabular labrum contributes approximately 22% of the articulating surface of the hip and increases the volume of the acetabulum by 33%. [1] The hip joint capsule is formed by three major ligaments: the iliofemoral, pubofemoral, and ischiofemoral ligaments. The capsular ligaments run in a spiral fashion preventing hip extension and are surrounded by thick longitudinal fibers that provide additional stability in the lateral plane. The capsule is thicker anterosuperiorly, where the predominant stresses of weight bearing occur, and thinner posteroinferiorly.[1] The ligamentum teres fans out from the fovea of the femoral head and attaches to nearly the full length of the acetabular ligament.

Previous studies evaluating sexual dimorphism in subadult pelvic features present variable, and at times conflicting, conclusions. As a result, there is yet to be a consensus on whether the subadult pelvis can be used in sex estimation methods. This study aims to assess the forensic utility of ilium shape and greater sciatic notch morphology in sexing subadult pelves prior to acetabular fusion. A sample of 397 modern U.S. individuals with unfused acetabula (i.e., tri-radiate cartilages) aged birth to 14 years was queried from a larger sample of postmortem computed tomography scans. Elliptical Fourier analyses were performed on ilium and greater sciatic notch outlines and resultant PCs were evaluated for significant effects of sex and age. Greater sciatic notch metrics were also collected. Stepwise linear discriminant function analyses with leave-one-out cross-validation were performed on the PCs and metric variables. Analyses were performed on pooled samples, on age-specific cohort samples, and on samples that iteratively removed the youngest one-year cohort. Cross-validated correct classification rates ranged from 57% to 65% and no patterns were observed to support an appearance and/or consistent expression of sexually diagnostic traits. Based on the results, sex estimation using these features is not recommended in pelvic remains prior to acetabular fusion, although the sample sizes of individuals over 5 years of age were limited in this study. Future studies should focus on the sexually diagnostic ability of pelvic traits in subadult samples post-fusion of the acetabulum.