Neutral pelvic positioning during recording of anteroposterior pelvic radiographs has been recommended for precise interpretation of acetabular deformities. Because the effect of pelvic positioning is controversial in the literature, we asked whether the weightbearing position would alter radiographic interpretations. We obtained sets of supine and weightbearing anteroposterior pelvic radiographs of 31 patients with developmental dysplasia of the hip and measured pelvic tilt, acetabular version, center edge angle, acetabular index, joint space width and femoral head translation. For both genders the pelvis extended when patients were repositioned from supine to weightbearing but extension was more pronounced in women compared with men. The number of patients with apparent acetabular retroversion was reduced from 11 supine to four when weightbearing. The center edge angle, acetabular index, joint space width and femoral head translation were similar in both views. We recommend weightbearing anteroposterior pelvic radiographs be obtained to assess DDH given the differences in pelvic flexion-extension and interpretations of acetabular version.

Background We used a stereologic method based on 3D CT scanning to estimate the projected load-bearing surface in the hip joint.Patients and methods 6 normal hip joints and 6 dysplastic hips were examined. The latter were CT-scanned before and after periacetabular osteotomy.Results We found that the average area of the projected load-bearing surface of the femoral head preoperatively was 7.4 (6.5-8.4) cm 2 and postoperatively 11 (9.8-14) cm 2 , which was similar to the load-bearing surface in the normal control group. We performed double measurements and the coefficient of error of the mean was estimated at 1.6%. Due to overprojection, an overestimation of about 3.8% on the projected loadbearing surface occurred. Consequently, the stereologic method proved to be precise and unbiased. Interpretation Our findings indicate that this method is of value for monitoring the load-bearing area in the hip joint of patients undergoing periacetabular osteotomy.

Diagnostic study, Level II (development of diagnostic criteria on consecutive patients [with universally applied reference "gold" standard]). See the Guidelines for Authors for a complete description of levels of evidence.

The ability of US examination in diagnosing acetabular labral tears is not yet good enough. The technique is still to be developed, and more experience, especially with the interpretation of US examinations, is needed.

Background:Anterior cruciate ligament reconstruction (ACLR) in skeletally immature patients can result in growth plate injury, which can cause growth disturbances.Purpose:To evaluate radiological tibial and femoral length and axis growth disturbances as well as clinical outcomes in skeletally immature ACLR patients treated with a transphyseal drilling technique.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 39 pediatric patients with ACL injury and open physes at time of surgery, as diagnosed clinically and with magnetic resonance imaging (MRI), were treated using transphyseal ACLR using hamstring graft. Mean patient age was 11.7 years (range, 9.0-14.0 years). Patients were evaluated with full extremity radiographs measuring leg length discrepancy and malalignment, as well as clinical evaluation with KT-1000 arthrometer measurements and Tegner activity scale and Knee injury and Osteoarthritis Outcome Score (KOOS) outcomes after follow-up of 68 months (range, 29-148 months).Results:Of the 39 initial patients, 33 were evaluated both clinically and radiographically. We found a mean femoral length shortening of 3.5 mm (P = .01) on the operated leg. Eight patients (24%) had a more than 10-mm shortening of the operated leg, whereas only 1 patient (3%) had a 10-mm shortening of the nonoperated leg. In 27 of 33 patients (82%; P < .001), the anatomic femoral axes of the operated leg were found to be more than 2° of valgus compared with the nonoperated leg. The tibial anatomic axes changed into a less pronounced varus angulation (P = .02). The femoral-tibial anatomic axes were not significantly different when comparing the 2 legs. We did not find any statistical difference in growth arrest comparing patients treated surgically at the ages of 13 to 14 years to patients younger than 13 years. Tegner and KOOS scores were significantly lower among girls compared with boys. Side-to-side KT-1000 arthrometer difference improved from 5.2 mm preoperatively to 1.6 mm at follow-up.Conclusion:This study shows that transphyseal ACLR in children results in minor length growth disturbances in 24% of patients. The surgically induced distal femoral valgus angulation is counterbalanced by a proximal tibial varus angulation. Growth disturbance after surgery is not associated with a certain pediatric age group. Otherwise, transphyseal ACLR has satisfactory clinical outcomes, with good subjective outcomes, function level, and knee stability.