Reduced femoral component subsidence with improved impaction grafting at revision hip arthroplasty

Despite stem subsidence being a major complication of femoral impaction bone grafting in cemented revision hip arthroplasty, few studies have distinguished subsidence at the prosthesis-cement interface from that at the cement-bone interface. It is unknown how technique developments intended to improve the procedure influence stability of the stem.

We used a sensitive technique to measure subsidence of a cemented polished collarless double-taper stem at each interface after femoral impaction grafting and compared subsidence, radiographic loosening, complications, and reoperations over three series of hips defined by technique developments.

Three series were defined: Series 1 (n = 23, irradiated allograft), Series 2 (n = 12, double-washed, size-profiled graft, nonirradiated bone, long stems as required), and Series 3 (n = 21, modular tamps). Stem subsidence was analyzed with Ein Bild Röntgen Analyse software. Radiographic loosening, complications, and reoperations were also determined.

The median subsidence at 12 months for Series 1, 2, and 3 were 2.1, 0.5, and 0.7 mm at the prosthesis-cement interface and 1.3, 0.1, and 0.1 mm at the cement-bone interface. There were two postoperative Vancouver B periprosthetic fractures in Series 1, four hips were revised for loosening in Series 1, and there were no fractures or loosening in Series 2 and 3 at minimum 2 years' followup. There were no surviving hips radiographically classified as possibly or probably loose.

Evolution in techniques of femoral impaction grafting in this study were associated with reduced subsidence of the stem at both the prosthesis-cement interface and cement-bone interface when compared to the original series. Concurrent with reduced stem subsidence was the absence of periprosthetic fracture, radiographic loosening, and complications requiring rerevision.