Evaluation of the Three-Dimensional Translational and Angular Deformity in Slipped Capital Femoral Epiphysis.

The purpose of this study was to quantify three-dimensional translational and angular deformity (defined as theta) present at the proximal femoral physis in slipped capital femoral epiphysis (SCFE), and to use theta to differentiate between SCFE hips, contralateral unaffected hips, and normal hips by comparing to the current gold standard measure of the Southwick slip angle (SSA). 3DCT reconstructions of the pelvis and femur in SCFE patients and normal adolescents were obtained and pelvic position was standardized. The center point and direction vector of the femoral epiphysis was determined. The femoral neck axis was defined. The angle between the femoral neck axis and epiphysis vector defined the 3D angle of deformity (theta). The 3D translation of the femoral epiphysis, measured as a percentage of femoral neck diameter, was measured in three planes. The average theta angle was significantly greater in SCFE hips (46.5 ± 24.3°) compared with control (13.7 ± 6.4°) or normal (11.7 ± 3.7°) hips (p < 0.001). There was no significant difference in theta angle between control and normal hips (p = 0.468). Theta angle correlated strongly with SSA (rs = 0.737, p < 0.001). Statement of clinical significance: The proximal femoral deformity in patients with slipped capital femoral epiphysis can be defined by measuring displacement of the epiphysis in all three dimensions in relation to the femoral neck axis. This information can be used in epiphyseal reorientation surgery to ensure anatomic reduction. The similarity between control and normal hips may argue against the thought that there is pre-existing deformity in a pre-slip condition of unaffected contralateral hips in SCFE patients. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1081-1088, 2020.

Obesity Is Associated With Increased Thoracic Kyphosis in Adolescent Idiopathic Scoliosis Patients and Nonscoliotic Adolescents.

STUDY DESIGN: Retrospective comparative cohort study. OBJECTIVE: To compare radiographic parameters between adolescents with a greater body mass index (BMI) percentile to underweight individuals. SUMMARY OF BACKGROUND DATA: Increased BMI percentile has been associated with increased complications after surgical correction of adolescent idiopathic scoliosis (AIS). However, association between BMI percentile and preoperative sagittal plane alignment has not been evaluated. The purpose of this study was to evaluate the effect of BMI percentile on sagittal alignment in AIS patients compared with nonscoliotic adolescents. METHODS: Posterior-anterior and lateral spinal radiographs of 1,551 AIS patients with a thoracic major curve (Lenke 1-4) and 70 nonscoliotic adolescent patients were compared. BMI percentile was determined based on age and sex, and patients were divided into four categories: underweight (<5th percentile), normal-weight (5th-85th percentile), overweight (85th-95th percentile), and obese (≥95th percentile). RESULTS: Coronal plane deformity magnitude was not significantly different between the 4 categories of AIS patients (p = .51). Increased BMI percentile was associated with increased thoracic kyphosis globally (T2-T12: p < .005) as well as segmentally (T2-T5: p < .001; T5-T12: p < .001) in patients with AIS. This was also true in obese adolescents without spinal deformity (p < .04). Lumbar lordosis, pelvic incidence, and pelvic tilt were not significantly different between AIS patients in the four BMI percentile categories (p > .07). Pelvic incidence was significantly greater in AIS patients compared with nonscoliotic adolescents (54 ± 13 vs. 46 ± 11; p = .01). CONCLUSION: Increased BMI percentile is associated with increased thoracic kyphosis in AIS patients and nonscoliotic adolescents. Excess weight may reduce anterior vertebral growth. AIS patients have an increased pelvic incidence compared with nonscoliotic adolescents; however, this variable is not influenced by body mass. These relationships should be taken into account when planning sagittal plane deformity correction or considering neuro axis disorders (also associated with increased kyphosis) in patients with scoliosis. LEVEL OF EVIDENCE: Level II.