[Femoral revision using cemented stem and compacted bone graft: femoral migration analysis]

If the bone loss is significant, revision total hip arthroplasty can be most difficult. We present a series of 30 patients with major loss of bone stock treated with the X-change (Exeter) technique for revision total hip arthroplasty.

This prospective consecutive series included 30 reconstructions performed between 1996 and 2001. Compacted grafts with cryopreserved bone were used. Mean follow-up was 42 months (range 24-80). According to the SOFCOT classification, bone loss was stage II in one patient, stage III in 14 and stage IV in 15. The technique described by Gie, Linder and Ling was rigorously applied: smooth stem, no force on the Merckel, cement in the impacted allograft, filling of femoral bone defects. Reinforcement with plates, mesh, or wire was used as necessary to bridge cortical defects. The Postel-Merle-d'Aubigné (PMA) score was used to assess clinical outcome. Digital x-rays were obtained before and after surgery and at last follow-up to assess implant position (vertical migration and frontal deviation), changes in bone stock, and the Pierchon classification. Thirty patients were seen at two years follow-up. Two patients were lost to follow-up after two years. Material had to be removed in two patients because of mechanical intolerance. There was one postoperative fracture at six months. One patient died more than two years after implantation. The PMA score improved from 11 to 17 at last follow-up. Radiographic results showed mean 7.3 mm stem migration and mean 2 degrees frontal deviation which were not correlated with clinical presentation. The Pierchon classification revealed 20 situations of corticalization and eight of trabeculation. Factors affecting migration were modalities of graft preparation and time to first weight bearing. Migration was unchanged after twelve months.

The functional and radiographic results remained satisfactory in light of the initial bone loss. Implant migration did not affect outcome. We have modified the surgical technique in line with these results, particularly concerning preparation of the impacted bone graft. This technique has the advantage of filling bone defects and avoiding therapeutic escalation.