The pelvic support osteotomy: indications and preoperative planning.

The pelvic support osteotomy is a double level femoral osteotomy with the objective of eliminating a Trendelenburg and short limb gait in young patients with severe hip joint destruction as a consequence of neonatal septic arthritis. The osteotomy has seen several changes and a brief historical overview is provided to set the evolution of the modifications of the procedure in context. We present an analysis of the preoperative assessment that will assist the surgeon to plan out the procedure. Specifically, we set out to answer the following questions: (a) Where should the first osteotomy be performed and what is the magnitude of valgus and extension correction desired at this level? (b) Where should the second osteotomy be performed and what is the magnitude of varus and derotation desired at this level?