[MRI as decisive diagnostic procedure in Perthes disease. Early diagnosis of femoral head necrosis in childhood].

PROBLEM: In order to achieve better final results in Perthes disease, the diagnosis should be established as early and as accurately as possible. This is rarely achieved with conventional X-ray procedures.

OWN EXPERIENCE: Since 1986, a total of 50 children with Perthes disease were submitted to MRI follow-up examinations employing T1 and T2-weighted coronary an sagittal sections and the results compared with the findings of conventional X-ray examinations.

RESULTS

The authors developed their own MRI staging and typing scheme on the basis of the MRI extent of the necrosis. Catterall's group classification could not be translated to the MRI since the latter usually showed more extensive necrosis. Agreement was found only in group I. With the aid of MR imaging, it proved possible to diagnose a case of Perthes disease earlier, the total extent of the necrosis was established earlier, and also the final form of the epiphysis after completion of re-modelling was already predictable in stage II. The indication for treatment and intra-trochanteric osteotomy was established on the basis of the MR image. Further invasive investigations were not needed.

CONCLUSIONS

In the case of Perthes disease, MRI should be given preference over other diagnostic procedures and, despite the greater expenditure of time and greater cost, should be routinely employed in this disease.