In 2000, Reinhold Ganz developed a surgical technique for treating slipped capital femoral epiphysis using his surgical hip dislocation approach to facilitate anatomical reconstruction of the slipped epiphysis—reportedly, without risk of avascular necrosis. This technique is now being adopted cautiously in paediatric orthopaedic centres internationally.

The technique will be described and early results presented. Complications and their treatments will also be discussed.

Early experience suggests morbidity following the procedure is not insignificant and until more corroborating safety data is available, the author suggests this technically demanding surgery should only be offered to children whose significant deformity would otherwise result in childhood disability.

The childhood hip conditions of Developmental Dysplasia, Legg-Calve-Perthes Disease and Slipped Capital Femoral Epiphysis have a wide spectrum of anatomical outcomes following childhood treatment; ranging from morphologies, which result in normal hip function throughout life, to severely deranged morphologies, which result in pain and disability during childhood and adolescence. Some of these outcomes are as a result of well-intentioned interventions that result in catastrophic complications.

In 2003, after years of working with impingement complicating periacetabular osteotomies and building on the work of William Harris, Reinhold Ganz published his concepts of ‘cam’ and ‘pincer’ hip impingement, and how these anatomical morphologies resulted in hip arthritis in adulthood. These concepts of impingement were added to his previous published work on hip instability to provide a comprehensive theory describing how hip arthritis develops on the basis of anatomical abnormalities. Surgical techniques have been developed to address each of these morphological pathologies.

Ganz's concepts of hip impingement and instability may be applied to severe paediatric hip deformities to direct reconstructive joint preserving surgery to both the femur and the acetabulum. Ganz's surgical approaches have also been refined for use in paediatric hip surgery to allow radical reshaping salvage osteotomies to be performed on the developing femoral head with minimal risk of the devastating consequence of vascular Necrosis.

Aim: To compare acetabular development and hip stability over time in patients treated for developmental dysplasia of the hip (DDH) by open reduction combined with either varusderotation (VDRO) or innominate (IO) osteotomies.

Method: Patients who underwent open reduction for DDH, combined with either VDRO (38 patients) or IO (33 patients), between 15 months and 4 years of age were reviewed. Both groups comprised a single surgeon consecutive series, differing only in the type of osteotomy performed. A total of 490 postoperative radiographs over a maximum follow-up period of 13.6 years were analyzed. We used repeated measures analysis of variance to compare the change in acetabular index (AI) as well as several other radiographic indices of acetabular development and hip stability over time.

Results: After osteotomy, the AI decreased in both groups but the magnitude of the decrease was significantly different between groups over time (p< 0.0001). The AI of patients undergoing VDRO never decreased as much as that of patients undergoing IO, with a mean difference of 10.4 degrees after 4 years (p< 0.0001). Similarly the IO group demonstrated more favourable acetabular architecture and hip stability over time compared to the VDRO group, as quantified by change in the acetabular floor thickness (p< 0.03), lateral centring ratio (p< 0.0001) and superior centring ratio (p < 0.0001).

Conclusions: Acetabular remodelling after IO was more effective at reversing acetabular dysplasia and maintaining hip stability than VDRO. Long-term follow-up of VDRO will be necessary to determine if late improvement occurs. IO may be preferable over VDRO in the treatment of hip dislocation after walking age.