Assessment of lateral subluxation in Legg-Calvé-Perthes disease: a time-sequential study of magnetic resonance imaging and plain radiography.

Lateral subluxation of the femoral head is one of the poor prognostic factors of Legg-Calvé-Perthes disease. The aim of this study was to investigate the cause of lateral subluxation of the femoral head on the basis of the changes over time on MRI. Twenty-four patients with unilateral Legg-Calvé-Perthes disease were analyzed retrospectively. Lateral subluxation was measured as the tear drop distance on radiographs. We focused on joint fluid, medial articular cartilage thickening, and abnormal lesion on MRI. Lateral subluxation continued significantly in patients with poor results. Among the MRI findings, the presence of an abnormal lesion was associated significantly with the continuous lateral subluxation.

Detection of early changes after growth plate injury using MRI.

BACKGROUND: To elucidate the association between growth plate injury size and the beginning of physeal growth disturbance by MRI. METHODS: Thirty-two 5-week-old male Japanese white rabbits were used. Injuries were made to the right tibial proximal growth plate central region with a 3.0-mm and a 1.2-mm drill. The left tibia was used as a control. MRI (7.04 Tesla [T], gradient echo: repetition time [TR], 71.68 ms; echo time [TE], 3.60 ms; proton-density weighted imaging: TR, 2000 ms; TE, 12 ms) of the growth plates was performed at 1, 4, 8, 10, and 12 weeks postinjury. Tibia length, histology, radiography, and microcomputed tomography (µCT) were studied. RESULTS: MRI showed that at 10 and 12 weeks postinjury in the 3.0-mm group, the medial and lateral growth plates in the noninjured regions were significantly reduced compared with the controls (P < 0.05). At 12 weeks postinjury in the 1.2-mm group, medial and lateral growth plates in the noninjured regions were significantly reduced (P < 0.05). Tibia length and histological growth plate height of injured side in both groups were significantly shorter than controls at 12 weeks postinjury (P < 0.05). Comparison with the controls showed no significant difference at any of the time periods in either the 3.0- or 1.2-mm group according to the radiographic studies (P > 0.05). Bony bridges developed in all the subjects of the 3.0-mm group and in five of eight subjects of the 1.2-mm group, as shown by µCT images. CONCLUSION: This study suggested that growth plate injury size was associated with the timing of the beginning of physeal growth disturbance.

Use of a rugby helmet brace for postoperative treatment of muscular torticollis.

Prior to 1992, our postoperative management for congenital muscular torticollis consisted of either plaster cast immobilization or no immobilization, depending on the patient's age and the degree of contracture. However, some patients required further surgery and developed complications. In 1992, we produced rugby helmet braces for postoperative management. The purpose of this study was to compare the clinical results of the previous postoperative management with the results achieved using rugby helmet braces. Twenty-five children aged younger than 6 years underwent caudal partial resection of the sternocleidomastoid muscle. Twelve children aged 6 years and older underwent cranial tenotomy. These 37 patients were divided into 2 groups: no immobilization or plaster immobilization (group A; n=19) and rugby helmet braces (group B; n=18). Canale's method was used for evaluation of clinical results. In group A, the results were good in 12 patients, fair in 4, and poor in 3, whereas all 18 patients in group B had good results. Two patients in group A required further surgery, and complications were observed in 5 patients. In group B, alopecia areata was observed in 1 patient.The rugby helmet brace is easy to put on and remove, providing good retention and allowing for physiotherapy. It provides a useful method of postoperative management for congenital muscular torticollis.

Outcomes of new pogo-stick brace for Legg-Calvé-Perthes' disease.

In 1992, the authors developed a non-weightbearing unilateral ambulatory hip abduction brace, which was named the new pogo-stick brace for unilateral Legg-Calve -Perthes' disease. The hip abduction angle of the new pogo-stick brace was adjustable 45 degrees . The advantage of this brace was that even in the sitting position, the hip abduction angle was maintained. Twenty patients were treated with unilateral LCPD using the new pogo-stick brace. In the Catterall classification, one patient was classified as group 2, 17 as group 3, two as group 4. In Herring classification, one patient was classified as group A, 17 as group B, two as group C. Ultrasonography was performed to determine containment of the hip joints, and the abduction angle of the new pogo-stick brace was adjusted to get better containment, every 2 months. Mose's and acetabular head index methods were used for radiographic evaluation, and classified into good, fair and poor groups both at the primary healing and at the final follow-up. Total evaluation was defined as worse group between Mose's method and acetabular head index method. The average time from onset of disease to the primary healing was 25 months. The average bracing period was 21 months. The average follow-up period was 94 months. At the final follow-up appointment, patients who were classified into good and fair groups were 85% in Mose's method, 95% in acetabular head index method, 85% in total evaluation. In Stulberg classification, the total number of patients who were classified into classes I and II was 85%. The outcome of the new pogo-stick brace was not worse than that of any other treatment method, and was better than that of other unilateral ambulatory braces.

Usefulness of epiphyseal quotient measurement on magnetic resonance images for outcome prediction in patients with early-stage Legg-Calve-Perthes disease.

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.