Proximal femoral reconstruction with impaction bone grafting and circumferential metal mesh.

INTRODUCTION

Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in revision hip arthroplasty. Here we examine the clinical and radiographic outcome of this procedure using a cemented stem, including experimental analysis of the initial stability of mesh-grafted bone-cemented stem complexes.

METHODS

We retrospectively reviewed six hips (six patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 3.9 years (range 2.4-4.8 years). Hip joint function was evaluated using the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of mesh-grafted bone-cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur.

RESULTS

The hip score improved from 50 (range 10-84) preoperatively to a mean of 74 (range 67-88) at the final follow-up. The overall implant survival rate was 100 % at five years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within one year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no relationship between IBG reconstruction rates under axial compression and stem subsidence or failure load. In contrast, under rotational load, the rotation angles of the stem to the stainless steel mesh were strongly affected by the IBG reconstruction rate.

CONCLUSIONS

The short-term results show good outcomes for reconstruction of proximal bone loss with IBG and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half the length of the implanted stem.