Abstract: Arthrograms are commonly carried out in conjunction with an examination under anaesthesia before surgical intervention in Perthes disease. It is routinely undertaken as an independent day case procedure in the radiology department. Our protocol dictates that a containment procedure is considered in patients who lose their ability to abduct the affected hip during the fragmentation stage of the disease. The main role of the arthrogram and EUA is to confirm that the affected hip has adequate abduction under anaesthesia to meet the prerequisites of a varus osteotomy and to confirm that the head is containable with no hinge abduction. This study was carried out to investigate whether arthrogram findings ever altered the pre operative clinical decision. Our findings question the role of arthrography as a routine before surgical intervention and the cost benefit ratio is evaluated.

Material and methods: The study was carried out at Alder Hey Hospital, UK. 107 cases were reviewed retrospectively. This included the treatment decision before arthrogram on the last clinic letter, any major findings on arthrogram and change in treatment decision after the procedure. The acetabular head index, central edge angle and the lateral pillar height were measured on routine antero-posterior radiographs and arthrogram on affected side.

Results: 22 patients were excluded from the study due to inadequate records. Out of the remaining 85 there was no change in decision in 69 patients after the procedure. Only 5 patients required different management after arthrogram than what was planned earlier based on clinical findings. We found a good correlation between AHI measured on pre-operative x-ray and the arthrogram. The study revealed that the surgical decision based on clinical findings, was not altered by arthrography in most cases. The EUA findings were more valuable. It helps the surgeon to decide the angle of varus osteotomy, required to contain the femoral head in acetabulum and confirms an adequate abduction to undertake the procedure. This quick assessment can be carried out at the time of the proposed osteotomy under the same anaesthesia without the need for arthrography. In conclusion we recommend that arthrography should be reserved for questionable cases where clinical findings are inconclusive and therefore the appropriateness of treatment is uncertain