Extra-articular hip resection with maintenance of pelvic continuity in malignant tumours of the proximal femur with articular invasion.

Introduction: Extra-articular hip resection may be necessary in cases of malignant tumour of the pelvic bone or of the proximal femur invading the hip joint. When the tumour is in the proximal femur, it is possible to resect the acetabulum en bloc by performing a periacetabular osteotomy, but this creates a discontinuity in the pelvic ring with difficult reconstruction and diminished function. Several techniques described recently seek to be as sparing as possible on the pelvic bone by preserving the posterior column or both columns in order to facilitate reconstruction and improve function. However, these still require complex reconstructions and can necessitate intra-pelvic dissection.

Technique: We describe here an extra-articular hip resection technique for tumours of the proximal femur invading the joint, with maintenance of pelvic continuity by preserving both columns and the quadrilateral plate of the acetabulum, without intra-pelvic dissection, that can be performed on patients in whom the medial wall of the acetabulum is thick enough. Our preliminary assessments have included studies on dry bone and imaging analyses. The technique was first tested on a single cadaver pelvis (encompassing 2 hips) and subsequently performed on a patient with a pathological fracture of the femoral neck due to osteosarcoma secondary to Paget's disease.

Conclusions: Further clinical applications are essential to evaluate the overall effectiveness, safety and impact on patient functionality of this experimental technique.