Role of preoperative arthrography in early Perthes disease as a decision-making tool. Is it really necessary?

Arthrograms are commonly done in conjunction with an examination under anaesthesia (EUA), before any surgical intervention in Perthes disease. This usually is done as an independent day case procedure in the radiology department. The aim of this study is to confirm that the affected hip meets the prerequisites of a containment procedure. This study was carried out to investigate whether arthrogram findings ever altered the preoperative clinical decision of proposed osteotomy. One hundred and seven cases were reviewed retrospectively. Forty patients were excluded. Decision was not changed in 62 out of 67 hips, after the procedure. Five patients required different management following arthrogram and this was based mainly on EUA findings. EUA under image intensification helps the surgeon to decide the angle of varus osteotomy, required to contain the femoral head in the acetabulum and confirms an adequate range of abduction to undertake the procedure. This quick assessment can be done at the time of surgery under the same anaesthesia without the need for arthrography. Our findings question the role of arthrography as a routine before surgical intervention in Perthes disease and suggest that it may represent an unnecessary cost. We now reserve arthrography for cases of late Perthes disease where valgus osteotomy may be appropriate or for those unusual or questionable cases where clinical findings are inconclusive and therefore the type or appropriateness of treatment is uncertain.