Background Increased attention is being placed on hip preservation surgery in the early adolescent. An understanding of three-dimensional (3-D) acetabular development as children approach maturity is essential. Changes in acetabular orientation and cartilage topography have not previously been quantified as the adolescent acetabulum completes development. Questions/purposes We used a novel 3-D CT analysis of acetabular development in children and adolescents to determine (1) if there were sex-specific differences in the growth rate or surface area of the acetabular articular cartilage; (2) if there were sex-specific differences in acetabular version or tilt; and (3) whether the amount of version and tilt present correlated with acetabular coverage. Methods We assessed acetabular morphology in 157 patients (314 hips); 71 patients were male and 86 were female. Patient ages ranged from 8 years to 17 years. A 3-D surface reconstruction of each pelvis was created from CT data using MIMICs software. Custom MATLAB software was used to obtain data from the 3-D reconstructions. We calculated articular surface area, acetabular version, and acetabular tilt as well as novel measurements of acetabular morphology, which we termed ''coverage angles.'' These were measured in a radial fashion in all regions of the acetabulum. Data were organized into three age groups: 8 to 10 years old, 10 to 13 years old, and 13 to 17 years old. Results Male patients had less acetabular anteversion in all three age groups, including at maturity (7°versus 13°, p \ 0.001; 10°versus 17°, p \ 0.001; 14°versus 20°, p \ 0.001). Males had less acetabular tilt in all three age groups (32°versus 34°, p = 0.03; 34°versus 38°, p \ 0.001; 39°versus 41°, p = 0.023). Increases in anteversion correlated with increased posterior coverage angles (r = 0.805; p \ 0.001). Increases in tilt were correlated with increases in superior coverage angles (r = 0.797; p \ 0.001). The posterosuperior regions of the acetabulum were the last to develop and this process occurred earlier in females compared with males.

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Introduction: The effect of the treating surgeon's subspecialty training on the outcomes of managing displaced supracondylar humerus fractures in the pediatric cohort remains under debate. The objective of this study was to examine patient outcomes and treatment variables for these injuries based on the surgeon subspecialty training. Methods: A retrospective study of children who had undergone primary closed reduction and percutaneous fixation for displaced supracondylar humerus fractures was done from January 2012 through May 2019. The following four groups with differing orthopaedic subspecialty training were evaluated: (1) pediatric fellowship trained (2) trauma fellowship trained, (3) sports medicine fellowship trained, and (4) all others. Outcomes examined included time to surgery, surgical time, fluoroscopy usage, postoperative follow-up protocols, radiographic measurements of alignment, and complications between surgeon groups. Results: Two hundred thirty-one cases were included (mean age 6 ± 2 years). Pediatric fellowship-trained surgeons took patients to surgery in a more delayed fashion (>12 hours, P = 0.02). Surgical time and fluoroscopy usage were significantly shorter for pediatric fellowship-trained surgeons (P < 0.001). No statistical difference was noted in pin configuration constructs between the groups. Pediatric fellowship-trained surgeons, on average, saw patients two times postoperatively within a year with most patients being within 30 days. Complications were not statistically different between the groups. Conclusions: Pediatric fellowship-trained orthopaedic surgeons provide more efficient care on a more delayed basis for displaced supracondylar humerus fractures than other subspecialty-trained orthopaedic surgeons. However, if barriers exist that limit the practicality or availability of these specialists, nonpediatric fellowship-trained surgeons achieve similar and satisfactory outcomes. Level of Evidence: Level III retrospective cohort study

Aerosol mixing resulting from turbulent flows is thought to be a major mechanism of deposition in the upper respiratory tract (URT). Because turbulence levels are a function of gas density, the use of a low-density carrier gas should reduce deposition in the URT allowing the aerosol to reach more peripheral airways of the lung. We performed aerosol bolus tests on 11 healthy subjects to investigate the effect of reduced gas density on regional aerosol deposition in the human lung. Using both air and heliox (80% helium, 20% oxygen) as carrier gas, boluses of 1 and 2 microm-diameter particles were inhaled to five volumetric lung depths (V(p)) between 150 and 1200 mL during an inspiration from residual volume (RV) to 1 liter above functional residual capacity at a constant flow rate of approximately 0.50 L/sec, which was immediately followed by an expiration to RV at the same flow rate. Aerosol deposition and axial dispersion were calculated from aerosol concentration and flow rate measured at the mouth. For 1 microm-diameter particles, deposition was significantly reduced by 29 +/- 28% (mean +/- SD, p < 0.05) when breathing heliox instead of air at shallow V(p) (150 mL) and significantly increased by 11 +/- 9% at deep V(p) (1200 mL). For 2 microm-diameter particles, deposition was significantly higher at V(p) = 500 mL by 6 +/- 7% and the predicted V(p) to achieve 100% deposition was significantly lower with heliox (834 +/- 146 mL) compared to air (912 +/- 128 mL) (p < 0.05). Despite a decrease in deposition at shallow V(p), there was no change in axial dispersion, suggesting that other factors such as radial turbulent mixing result in decreased aerosol deposition. Our results suggested that heliox reduces upper airway deposition of 1 and 2 microm-diameter particles allowing more particles to penetrate and subsequently deposit in the peripheral lung.

The purpose of this study was to correlate measures of sagittal spinopelvic alignment [lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI)] and measures of acetabular coverage [lateral center edge angle (LCEA) and Tonnis angle] in asymptomatic adolescents on standing biplanar radiographs. We hypothesized that subjects with increased pelvic incidence and LL would have increased anterior PT and increased measures of acetabular coverage. Upright anteroposterior and lateral spinopelvic radiographs were obtained using EOS imaging technique. LCEA and Tonnis angle were calculated on the anteroposterior images and the lateral images were analyzed for LL, PI, PT and SS. LL was found to have a strong correlation with SS (rs = 0.786, P  <  0.001), moderate correlation with PI (rs  =  0.529, P  <  0.001), and a poor inverse correlation with PT (rs  = −0.167, P  =  0.018). However, LCEA was not found to be significantly correlated with PT (rs  =  0.084, P  =  0.238) and Tonnis angle was not found to be correlated with any of the sagittal spinopelvic measures. Healthy, asymptomatic adolescents with increased pelvic incidence and lumbar lordosis did not have increased anterior PT or increased measures of acetabular coverage. The correlations identified in previous cadaveric studies or clinical studies evaluating changes between supine and standing radiographs are not supported in this healthy adolescent population. Our findings may suggest that an individual’s acetabulum develops as a dynamic adaptation to one's particular sagittal spinopelvic alignment to optimize femoral head coverage. Level III. Diagnostic – Investigating a diagnostic test.

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