A novel patient-specific 3D printed guide for accurate femoral derotation osteotomies: a case report

BACKGROUND: Femoral malrotation errors are prevalent after intramedullary (IM) nailing for femur fractures. Supposing fracture consolidation has occurred, only a derotation osteotomy can offer a solution to this complication, despite in situ nail interference. The authors present a novel case-based surgical technique using 3D technology to obtain an accurate derotation correction and desired clinical outcome while facilitating surgery technics. CASE DESCRIPTION: A 32-year-old woman was referred to our clinic with ongoing right anterior groin pain. Three months earlier, she sustained a high energy fall resulting in a subtrochanteric femur fracture. This was treated with a long IM femoral nail (PFNA™, Synthes, Solothurn, Switzerland) elsewhere. Postoperatively, she developed a limping gait pattern with ‘toeing-in’ and persistent hip pain during walking. In supine position, a notable axial malalignment towards endo-rotation was visible as compared to the contralateral side. CT-scan showed a side to side difference of 36° anteversion. It was decided to perform a subtrochanteric femoral derotation osteotomy. Outcomes concerning restoration of painless gait and bony healing were successfully obtained at 4 months. CONCLUSIONS: The application of a 3D guide with uni-cortical K-wire placement for derotation osteotomies provides additional correction control during surgery and accurate outcome, while facilitating the flow of this technically demanding procedure.