MRI abnormalities of the acetabular labrum and articular cartilage are common in healed Legg-Calvé-Perthes disease with residual deformities of the hip.

BACKGROUND: Varying degrees of femoral deformity may result as Legg-Calvé-Perthes disease heals. Our aims were to investigate the prevalence of abnormalities of the acetabular labrum and cartilage, using noncontrast magnetic resonance imaging, and to correlate the findings with radiographic deformities that may exist after the healing of Legg-Calvé-Perthes disease. METHODS: In a sample of ninety-nine patients with healed Legg-Calvé-Perthes disease, anteroposterior and lateral radiographs were used to assess the Stulberg classification, femoral head size and sphericity, femoral neck morphology, and acetabular version. A subgroup of fifty-four patients (fifty-nine hips) underwent noncontrast magnetic resonance imaging of the hip an average of eight years after disease onset. The acetabular labrum was evaluated according to a modified classification system, and the acetabular cartilage was evaluated for the presence of delamination and defects. The association among abnormalities of the acetabular labrum, articular cartilage, and radiographic deformities was assessed. RESULTS: Abnormalities of the acetabular labrum and cartilage were found on magnetic resonance imaging scans in 75% and 47% of the hips, respectively. An alpha angle of ≥55° was the deformity most significantly associated with labral and cartilage abnormalities, followed by coxa brevis. Coxa magna and a higher greater trochanter showed a significant association with labral abnormalities only. Acetabular retroversion showed an increased risk for labral abnormalities when the alpha angle was normal. When deformities coexisted, the alpha angle showed the greatest relative risk for abnormality. CONCLUSIONS: On the basis of magnetic resonance imaging evaluation of the hip, labral and cartilage abnormalities were a common finding in patients with healed Legg-Calvé-Perthes disease. Our results suggest that hip deformities are significantly associated with labral and cartilage abnormalities on magnetic resonance imaging, and the main predisposing factor was the asphericity of the femoral head with a reduced femoral head-neck offset.

[Alternative method for measuring the mechanical axis of the knee]. / Método alterno para medición del eje mecánico de rodillas.

OBJECTIVE: To identify the existence of significant differences in the degrees of mal-alignment of the mechanical axis of the knee between a traditional measuring method and an alternative method. MATERIALS AND METHODS. One hundred mechanical axes of the knee were determined in patients of both sexes. The degree of axis mal-alignment was obtained first using the traditional measuring method and subsequently using the alternative method. The results obtained from the two methods were then compared. The measurement variable control was standardised by positioning the patients in the same place during radiography when beginning mechanical axis determination. A wooden ruler on which each centimetre was indicated by a metal strip and numbered at every 10-centimeter interval was used to evaluate the degree of pelvic mal-alignment. The ruler was then used as a mechanical axis correction reference in accordance with the characteristics of each patient. RESULTS: The following results were obtained from 100 mechanical axes evaluated by the traditional method and by the alternative method, respectively: varus deformity of the right pelvic segment was 21 degrees +/- 16 degreesuv. 7 ++/-6. degrees varus deformity of the left pelvic segment was 22 _+/-170 degreesvs. 8 ++/-50 degrees valgus deformity of the right pelvic segment was 21 - /-150 degreess. 8 + +/-; and valgus deformity of the left pelvic segment was 16 +/- 11 vs. 6 +/- 5 degrees. CONCLUSIONS: Our results suggest that the proposed method provides more accurate mechanical axis measurement and that the correction is exponential: the greater the angle measured traditionally, the greater the correction with our proposed method.

Knee flexion deformity from poliomyelitis treated by supracondylar femoral extension osteotomy.

Between April 1979 and August 1993, we treated 39 patients (49 knees) with knee flexion deformity after Poliomyelitis. All were subjected to fractional hamstring lengthening and supracondylar femoral extension osteotomy in the same surgical procedure. The goal was to correct the deformity and fit the lower extremities in long braces to improve or promote gait. Patients' mean age was 19.5 (6.5-39) years and the mean knee flexion deformity was 65 degrees (24-158 degrees). The mean follow-up was 15.5 (11.5-25) years. Postoperatively, 22 knees had full extension, in 26 there was an extension lag between -1 and -10 degrees and in one a lag greater than 10 degrees. There were no neurovascular complications and all patients were fitted with long leg braces. Surgical planning is important, especially in severe deformities, where shortening of the femur is necessary to facilitate the osteotomy and relax the neurovascular structures.