Legg-Calve-Perthes disease. Part II: Prospective multicenter study of the effect of treatment on outcome.

BACKGROUND

The treatment of Legg-Calve-Perthes disease has been based on uncontrolled retrospective studies with relatively small numbers of patients. This large, controlled, prospective, multicenter study was designed to determine the effect of treatment and other risk factors on the outcome in patients with this disorder.

METHODS

We enrolled 438 patients with 451 affected hips in a prospective multicenter study in which each investigator applied the same treatment method to each of his or her patients. The five treatment groups consisted of no treatment, brace treatment, range-of-motion exercises, femoral osteotomy, and innominate osteotomy. All patients were between 6.0 and 12.0 years of age at the onset of the disease, and none had had prior treatment. Three hundred and forty-five hips in 337 patients were available for follow-up at skeletal maturity. All hips were classified with the modified lateral pillar classification and the system of Stulberg et al.

RESULTS

There were no differences in outcome among the hips with no treatment, those treated with bracing, and those treated with range-of-motion therapy. There were also no differences between the hips treated with a femoral varus osteotomy and those treated with an innominate osteotomy. Treatment did not have a significant effect on children who had a chronologic age of 8.0 years or less or a skeletal age of 6.0 years or less at the onset of the disease. In the lateral pillar B group and B/C border group, the outcomes of surgical treatment were significantly better than those of nonoperative treatment in children over the age of 8.0 years at the onset of the disease (p < or = 0.05). Patients who were 8.0 years old or less at the onset of the disease in lateral pillar group B did equally well with nonoperative and operative treatment. Hips in lateral pillar group C had the least favorable outcomes, with no differences between the operative and nonoperative groups. The lateral pillar classification (p < 0.0001) and the age at the onset of the disease (p = 0.0001) were both strong prognostic factors. Female patients did significantly worse than male patients if they were over the age of 8.0 years at the onset of the disease (p = 0.004).

CONCLUSIONS

The lateral pillar classification and age at the time of onset of the disease strongly correlate with outcome in patients with Legg-Calve-Perthes disease. Patients who are over the age of 8.0 years at the time of onset and have a hip in the lateral pillar B group or B/C border group have a better outcome with surgical treatment than they do with nonoperative treatment. Group-B hips in children who are less than 8.0 years of age at the time of onset have very favorable outcomes unrelated to treatment, whereas group-C hips in children of all ages frequently have poor outcomes, which also appear to be unrelated to treatment.