Our experience of the modified Dunn procedure in children with slipped capital femoral epiphysis (preliminary results)

Backgrоund. The spatial correlations of the epiphysis and acetabulum during slipped capital femoral epiphysis (SCFE) with acute (at the stage of partial synostosis) and chronic displacement of the epiphysis to a severe degree were restored using different extra-articular corrective hip osteotomy techniques and the standard Dunn procedure. A large number of postoperative ischemic complications and/or the remaining residual displacement of the epiphysis, which is the cause of FAI, was the rationale for improving traditional surgical methods. In 2007, a modified technique of the classic Dunn procedure was proposed using a low traumatic surgical hip dislocation.

Aim. The aim of the study was to evaluate the effectiveness of the modified Dunn procedure in the treatment of children with SCFE.

Materials and methods. The data of preoperative and postoperative clinical and radiological studies of 10 patients (six males and four females) aged 11–15 years who were suffering from SCFE with severe epiphyseal displacement were analyzed. In five cases, the displacement of the epiphysis was chronic, in four cases it was acute associated with chronic, and in one case it was primarily acute. In the joints with acute displacement at the time of surgery, there were signs of partial synostosis at the level of the epiphyseal growth plate. All children underwent a modified Dunn procedure with strict adherence to the author’s technique. The maximum follow-up period was 1.5 years.

Results. Evaluation of the most short-term anatomical and functional treatment results confirmed a satisfactory result in half (5/10) of the observations with the possibility of an additional three. In two cases, a poor treatment result was obtained due to the development of an early complication in the form of aseptic necrosis of the femoral head. The number of early complications of surgical treatment that were recorded is consistent with the literature.

Conclusions. To date, the modified Dunn procedure is the only intervention with a relatively small number of complications that provides a complete and accurate reposition of the epiphysis, thereby eliminating FAI in the above anatomical situations. The modified Dunn procedure can be characterized as an effective intervention for SCFE with severe, acute (at the stage of partial synostosis), and chronic displacements of the epiphysis. The authors intend to continue using the procedure in practice.