The anterior center edge angle has limited ability to predict three-dimensional coverage of the femoral head in patients with developmental dysplasia of the hip undergoing curved periacetabular osteotomy.

INTRODUCTION: Femoral head coverage in patients with hip dysplasia (DDH) is typically quantified using 2D measurements of the lateral center edge angle (LCEA) and anterior center edge angle (ACEA). However, as the morphology of DDH is complex and varies between patients, 2D measurements may not predict the true 3D femoral head coverage. Herein, 2D and 3D coverage were quantified before and after curved periacetabular osteotomy (CPO) and their relationships were assessed. MATERIALS AND METHODS: Forty-three hips that underwent CPO for DDH were analyzed. For 2D evaluation, LCEA was quantified from X-rays and CT images. The ACEA was measured from CT images (CT-ACEA) and digitally reconstructed radiographs generated from CT images (DRR-ACEA). Three-dimensional coverage was quantified from CT reconstructions of the hip and evaluated in the anterior, superior, posterior, and inferior regions of the femoral head. Two-dimensional measurements were correlated to 3D coverage to assess their relationships. RESULTS: The median preoperative 3D percent coverage was 17.7, 36.1, 56.1, and 14.6% for the anterior, superior, posterior, and inferior region, respectively. After CPO, all LCEAs and ACEAs increased significantly (all p < 0.001). For the 3D coverage, anterior and superior coverage significantly increased while the posterior and inferior coverage decreased (all p < 0.001). Moderate to strong correlations were detected between the two LCEAs and the 3D superior coverage in both the preoperative and postoperative period. For the correlation between 3D anterior coverage, no significant correlation was found between the CT-ACEA while a moderate correlation was found between the DRR-ACEA (rs = 0.41, p = 0.023). CONCLUSIONS: Our results indicate that the LCEA can be used to predict 3D coverage in the superior region of the femoral head. However, as the CT-ACEA or DRR-ACEA had no or only moderate correlation between the 3D anterior coverage, these measurements are not recommended for evaluating/estimating the 3D anterior coverage in patients with DDH.

Primary cauda equina lymphoma diagnosed by nerve biopsy: A case report and literature review.

Primary cauda equina lymphoma (CEL) is a rare malignant tumor among various neoplasms that affects the cauda equina nerve roots. The present case report described the case of a 65-year-old man who presented with cauda equina syndrome with progressive motor palsy in the legs and gait disturbance over the last 5 months. Magnetic resonance (MR) images showed enlargement of the cauda equina occupying the dural sac from the L1-S1 level with isointensity to the spinal cord signal on both T1- and T2-weighted imaging. Enhancement of the cauda equina was seen on contrast MR images. On F-18 2-fluoro-2-deoxy-glucose positron emission tomography examination, diffuse accumulation of 2-fluoro-2-deoxy-glucose was observed in the cauda equina with a maximum standardized uptake value of 4.9. Based on elevation of soluble interleukin 2 receptor in cerebrospinal fluid and a biopsy of the enlarging cauda equina, a diagnosis of CEL of the diffuse large B-cell type was made. The present case report provided a detailed case discussion and a review of the available literature on this rare entity, focusing on clinical characteristics and imaging of primary CEL.