Silent slipped capital femoral epiphysis in overweight and obese children and adolescents.

Abnormal loading of the hip in obese children may lead to anatomic alterations and an increased prevalence of slipped capital femoral epiphysis (SCFE). The aims of this study were to examine the hip motion in obese children and adolescents and to estimate the prevalence of SCFE in a subgroup of patients characterized by pathological clinical examination and/or pain in the knee or hip joint. A total of 411 individuals (196 males), mean age 14.5 ± 2.5 years (7.8-20.4), mean BMI of 32.9 ± 5.6 kg/m(2) (20.3-51.5, z score +2.65) who were consecutively admitted for an inpatient weight loss program were included in the study. Twenty-six percent of the patients had load-dependent and 11.7 % had load-independent pain in the knee joint. A total of 9.3 % had load-dependent and 4.7 % had load-independent pain in the hip joint. Two patients (0.5 %) underwent surgical treatment of SCFE prior to entry. A total of 18.2 % of the patients showed a reduced range of motion for hip flexion (<90°) and 18.5 % a pathological decreased internal rotation (<10°). Radiological evaluation of the hips in the clinically conspicuous subgroup (n = 54) revealed an abnormal head-neck ratio as a sign of prior silent slipped capital femoral epiphysis in 11 patients (20.4 % of the 54 patients, 2.7 % of total cohort). In conclusion, these data show a high prevalence of SCFE-like tilt deformities in a selected group of severely obese children. Mild deformation of the epiphysis at young age might be a major predisposing factor for the development of hip osteoarthritis in obese adults.

Herniation pits and cystic-appearing lesions at the anterior femoral neck: an anatomical study by MSCT and microCT.

OBJECTIVE: To determine distinguishing features between herniation pits (HPs) and other cystic-appearing lesions at the anterior femoral neck in multi-slice computed tomography (MSCT) and micro-computed tomography (microCT) examinations. MATERIALS AND METHODS: Institutional review board approval was obtained to examine 37 proximal femora of 23 cadaveric specimens (mean age available in 19 cadavers, 83 years; range 68-100 years; 9 female, 8 male, 6 unknown). All 37 femora were investigated by MSCT. 23 femora, which revealed cystic-appearing lesions at the anterior femoral neck in MSCT examinations, were additionally examined by microCT. Cystic-appearing lesions were categorized by their location, sclerotic margin, demarcation and shape in MSCT with assessment of inter-observer agreement. Detailed cortical and trabecular properties were evaluated in microCT examinations. RESULTS: There were seven HPs in three femora. There were a number of abnormalities potentially imitating HPs, including focal osteoporosis (13 in 13 femora), degenerative changes (5 in 4 femora) and trabecular restructuring (5 in 4 femora) at the anterior femoral neck. HPs were differentiated on the basis of their subchondral/subcortical location, completely surrounding sclerosis, clear demarcation and round-to-oval shape in MSCT. Because of their location and their microscopic appearance, HPs seem to resemble intra-osseous ganglia at the anterior femoral neck. CONCLUSION: HPs have to be differentiated from other cystic appearing lesions at the anterior femoral neck to avoid overestimation of their incidence in the context of diagnosis of femoroacetabular impingement.

CT assessment of herniation pits: prevalence, characteristics, and potential association with morphological predictors of femoroacetabular impingement.

The purpose of this study was to evaluate whether there is a correlation between the presence of herniation pits (HPs) and morphological indicators of cam and pincer femoroacetabular impingement (FAI) based on computed tomography (CT) examinations. CT studies of the pelvis obtained from 200 patients were retrospectively analysed for the presence of HPs and morphological abnormalities of the femoral head and acetabulum. As an indicator for cam FAI, we used the angle alpha, describing the anterior femoral head-neck junction. As an indicator for pincer FAI, we measured the acetabular coverage and the acetabular orientation. Student's t-test was used for statistical analysis. HPs were identified in 85 of the 200 patients. HPs were predominantly found in the superior portion of the proximal anterior femoral neck; some were located in the inferior portion. The angle alpha was significantly larger by 10% in the group with HPs. A correlation between the presence of HPs and morphological indicators of pincer FAI was not found. In conclusion HPs are not only located in the superior portion of the proximal anterior femoral neck, but also in the inferior portion. There is an association between the presence of HPs and a high value of angle alpha.