Abstract
Introduction
Impaction bone grafting (IBG) is a reliable technique for acetabular revision surgery with large segmental defects. However, bone graft resorption and cup migration are some of the limitations of this tecnique. We assess frequency and outcome of these complications in a large acetabular IBG series.
Patients and Methods
We analysed 330 consecutive hips that received acetabular IBG and a cemented cup in revision surgery with large bone defects (Paprosky types 3A and 3B). Fresh-frozen femoral head allograft was morselized manually. The mean follow-up was 17 years (3–26). All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. Changes in different paremeters regarding cup position were assessed pre- and postoperatively and at the follow- up controls. Only variations greater than 5º and 3 mm were considered.
Results
The mean Harris Hip Score improved from 48.3+8.5 to 84.6+12.8 at final follow-up. The radiological analysis showed cup migration in 42 hips. The mean appearance time was 4.3 years (range, 1–25). Migration was progressive and painful in 27 hips (67.5%) requiring cup revision. Lateral mesh was more frequently associated with migrated cups (p=0.034). Cup tilt was found in 37 out 42 migrated cups, however cranial migration was more frequent in progressive migrated cups (p=0.02). There were 34 re-revisions, 27 due to aseptic cup loosening, 6 due to dislocation and one due to infection. The survival rate for any cause at 16 years was 81.2% (95% Confidence Interval (CI): 74.0 to 88.4) and for aseptic cup loosening was 83.4% (95% CI: 76.2–90.6). In all surviving hips trabecular incorporation was observed without radiolucent lines.
Conclusions
IBG continues to be a reliable technique for large defects in acetabular revision surgery. Bone graft resorption and cup migration was not frequent in this large series and one-third of cases were not progressive. Cup migration was more frequent in cases with a segmental roof defect in which a lateral mesh was used.
