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This study aimed to evaluate femoral perfusion using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for two weeks after the simultaneous initiation of electrical stimulation (ES) and steroid treatment in a steroid-induced osteonecrosis (ON) model. A single dose of methylprednisolone was injected into 14 rabbits. Seven rabbits underwent ES (ES group), and seven rabbits did not (control group). DCE-MRI was performed before steroid administration and 1, 5, 10, and 14 days after steroid administration. Regions of interest were set in the bilateral proximal femora. The enhancement ratio, initial slope, and area under the curve were analyzed. These parameters were evaluated after steroid administration in each group and between the two groups, and the ratios of ON in both groups were compared. In the control group, the minimum values of all parameters decreased significantly after steroid administration (P < 0.05), but in the ES group, the parameters did not decrease. In the ES group, all parameter values were significantly increased on the 10th and 14th days (P < 0.05). All parameter values in the ES group were significantly higher than those in the control group on the 14th day (P < 0.05). In the control group, ON was detected in three of five rabbits (in three of ten femora). In the ES group, ON was not detected. These results suggest that increased femoral blood flow elicited by ES may be related to ON prevention after steroid administration.

Objective: The aim of this study was to investigate the relationship between abnormal acetabular labrum depicted by radial magnetic resonance and progressive joint space narrowing (JSN) of hip dysplasia., Methods: Subjects were 23 joints [21 patients; mean age: 35.1 years (16-53 years)] that had acetabular dysplasia with lateral center-edge angle of Wiberg (CE angle) greater than 5 degrees and smaller than 25 degrees (mean, 16.4 degrees ), which did not show any arthrotic changes on plain radiograms and were followed up for 3 years or longer. Radial images of acetabular labrum were classified into three stages., Results: Progression of JSN was not significantly related to CE angle but to progression of MRI stage (P=.006). In multivariate analysis, one rank progression of MRI stage was significantly associated with progression of JSN (adjusted OR=11.41, 95% CI: 1.51-86.24, P=.018)., Conclusion: Our findings showed that in patients whose acetabular dysplasia has 5-25 degrees CE angle, MRI staging based on radial MRI is a better factor for prediction of progression of JSN than CE angle.

To investigate the usefulness of epiphyseal quotient (EQ) measurement for outcome prediction in patients with Legg-Calve-Perthes disease (LCPD), magnetic resonance (MR) imaging was performed in 26 patients with unilateral LCPD within 6 months of the disease onset and subsequently once every 3 months. All the patients were treated conservatively in our institute between 1990 and 1999. The mean follow-up period was 80 months. Clinical outcome was evaluated based on the plain radiograms of the femoral head at the final examination according to Stulberg's classification: the patients whose outcome was class I were regarded as 'excellent' (excellent group), class II as 'good' (good group), and classes III, IV and V as 'poor' (poor group). The excellent group consisted of 10 patients, the good group of 12, and the poor group of four. The EQ measured on MR images (MR-EQ) decreased remarkably in the poor group chronologically, whereas there was no decrease in the excellent group and a slow decrease in the good group. The mean MR-EQ at or before the sixth month (range, 2-6 months; mean, 4.9 months) was 86.2 (range, 76.8-94.8) in the excellent group, 78.3 (57.0-93.4) in the good group, and 67.4 (57.8-74.5) in the poor group (P<0.05 among the three groups). According to our results, because all patients having an MR-EQ at or before the sixth month of 75 or higher were classified in the excellent or good groups, it is thought that the ongoing method of treatment can be continued. On the other hand, since half of the patients having an MR-EQ at or before the sixth month of lower than 75 were classified in the poor group and had a high potential for a poor outcome, it is thought that these patients require strict containment therapy, and altering the surgical procedure could be considered depending on the particular patient. It was thought that the MR-EQ is a useful predictive factor of LCPD prognosis.

Background and purpose - It has been suggested that avascular osteonecrosis (AVN) of the femoral head occurs early after systemic steroid administration. The purpose of this study was to investigate the risks regarding development of AVN at a very early stage after renal transplantation. Methods - The presence or absence of AVN was determined by MRI at 4 weeks, at 6-12 weeks, at 24 weeks, and at 12 months after renal transplantation in 286 patients (183 males) with a mean age of 39 (16-65) years. The relationship between AVN and age, sex, absence or presence of acute rejection (AR), type of transplanted kidney (living or cadaveric), type of immune suppressor, and total dose of orally administered steroids given in the 2-week period after transplantation was investigated. Results - There were no statistically significant correlations between the development of AVN and age, sex, absence or presence of AR, type of transplanted kidney, or type of immune suppressor. A significant dose-response relationship was found between development of AVN and the total dose of steroid administered in the first 2 weeks after surgery. Interpretation - We found a relationship between AVN development and steroid dose in the early postoperative period, and we also showed a dose-response relationship. [ABSTRACT FROM AUTHOR]

We report the case of a 29-year-old Japanese man with transient osteoporosis of the left hip (TOH) following contralateral TOH, paying special attention to the initial changes on MRI. MR images showed no abnormal findings 6 weeks before the clinical manifestation, but the images just after the onset depicted a linear abnormality equivalent to a subchondral insufficiency fracture. Both radiological findings and clinical symptoms disappeared completely without any surgical intervention within 10 months. [ABSTRACT FROM AUTHOR]