Evaluating fixation and bone graft integration at two years post-surgery in uncemented acetabular revisions with...

Impaction bone grafting of the acetabulum to treat segmental and cavitary defects has been shown to be successful for uncemented acetabular revisions. Concerns remain about graft integration and implant stability when severe bone defects require large amounts of bone graft. This study evaluates bone graft density and implant migration in patients undergoing uncemented acetabular revision with screw fixation and impaction bone grafting using large bone graft volumes.

In this exploratory study, nine patients undergoing acetabular revision surgery were evaluated to assess bone graft volume, bone mineral density (BMD), and implant migration using dual-energy CT and CT-based micromotion analysis, performed directly postoperatively and at 6, 12, and 24 months of follow-up.

The mean volume of bone graft used was 64.0 cm³ (SD 36.9) and the BMD in the graft increased from a mean of 317 mg/cm³ (SD 96.4) postoperatively to 466 mg/cm³ (SD 104.2) at 24 months (p = 0.002), while iliac BMD changed from 96 mg/cm³ to 111 mg/cm³ (p = 0.258). The median total translation at 24 months was 1.6 mm (IQR 0.82 to 2.7). Cups with graft volumes ≥ 50 cm³ exhibited slightly larger proximal translation than those with < 50 cm³, with median 1.5 mm (IQR 1.4 to 1.6) compared with 0.6 mm (IQR 0.30 to 1.2).

Uncemented acetabular revisions using large allograft volumes exhibit a migration pattern that is consistent with other revision techniques. Despite the large amount of bone graft used, bone density increases over time.