The results of a double-blind trial of pulsed electromagnetic frequency in the treatment of Perthes' disease.

A double-blind trial of the use of pulsed electro-magnetic frequency (PEMF) in the treatment of Perthes' disease was constructed by using this therapy to supplement a long-practised non-weight-bearing orthotic treatment, the Birmingham Containment Splint. Twenty-one boys with Perthes' disease were treated with this combined regimen; they were divided into two groups. All wore the orthosis but the treatment coil was inactive in one group; the state of coil activity was unknown to clinic staff or patients. The duration of non-weight-bearing orthotic treatment needed to achieve a stated degree of femoral head reconstitution was recorded; there was no discernible difference between the two groups, treatment time being 12 months in one group and 12.5 months in the other. It was concluded that PEMF cannot be offered for the therapy of Perthes' disease.