Aim: During periods of rapid growth hip diseases can deteriorate unexpectedly. This retrospective evaluation should determine standard values that might allow earlier determination of such growth disturbances and a better classification of almost normal findings.

Methods: 520 standardized made and normal pelvis x-rays of children aged 4–16 years were examined under respect to the development of the hip and pelvis itself (20 x-ray pictures per age-group and gender). Among others these parameters were assessed: acetabular index (AC) and ACM-angle, acetabular width, depth and length, width and altitude of the epiphysis, transverse pelvic diameter and pelvic altitude.

Results: At the age 6–14 years boys have a higher ace-tabular index and ACM-angle than girls. The acetabular index decreases up to the age of 15 to 10 in average, the ACM-angle up to the age of 9 years to 47 in boys and 45 in girls to be subsequently constant. The bony acetabulum grows concentrically and spherically in form and slower than the femoral head. The acetabulum of girls is deeper, smaller and stops growing at the age of 14. The pelvic growth proceeds with the exception of iliac width in girls up to the age of 16.

Conclusion: Due to an age depending mechanical load of the femoral head on the acetabulum a mild DDH can develop to severe pathology in times of rapid growth. With the found normal values and its variations it is easier to assess the development of hip joints especially in such cases.

Purpose: To evaluate the vascularisation of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after surgery with use of contrast-enhanced MRI

Methods and Materials: 20 consecutive children, 13 boys and 7 girls, aged 9–15 years, with slipped capital femoral epiphysis, were included into the study. The classification of SCFE was performed traditionally due to the patient’s history, physical examination and findings of the radiographs. There were no pre-slips, 9 children had acute, 5 children had acute-on-chronic and 6 children had chronic SCFE. The MRI-examinations were performed in a 1.5 Tesla MR-scanner with use of the body coil and all postoperative MR-examinations were carried out within 4 weeks after surgery. The examination protocol included a coronal fat-suppressed STIR-sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence and a sagittal 3D-gradient-echo (FFE) sequence. Morphology, signal intensities and contrast-enhancement of the femoral head were assessed retrospectively by two experienced radiologists in consensus.

Results: Morphologic distortion of the physis, bone marrow edema in the metaphysis and epiphysis and joint effusion were the preoperative MRI-findings of slipped capital femoral epiphysis in each child. In 17 children, who underwent in situ-fixation with a single screw, and in one child, who underwent open reduction of the epiphysis, the vascularisation of the femoral head before and after surgery was normal. An avascular zone in the posterior-lateral aspect of the epiphysis was visible preoperatively in one child, which completely revascularized after open reduction and internal fixation of the epiphysis with two screws. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction and corrective osteotomy through the physis.

Conclusion: MRI allows for accurate evaluation of the femoral head vascularisation before and after surgery in children with slipped capital femoral epiphysis.