Abstract
Background
Cup migration and bone graft resorption are some of the limitations after acetabular impaction bone grafting (IBG) technique in revision hip surgery when used for large segmental defects. We asked whether the use of a metallic mesh may decrease the appearance of this complication. We compared the appearance of loosening in patients with a bone defect 3A or 3B according to Paprosky.
Materials and Methods
We assessed 204 hips operated with IBG and a cemented cup according to Slooff et al between 1997 and 2004. There were 100 hips with a preoperative bone defect of 3A and 104 with a 3B. We used 142 medial and/or rim metallic meshes for uncontained defects. The mean follow-up for unrevised cups was 10.4 years. We detemined postoperative radiological cup position and acetabular reconstruction of the hip center according to Ranawat in both groups. We assessed the appearance of radiological loosening and resorption of the graft.
Results
Postoperative cup position improved in both groups (p<0.001 for all parametres). Distance to the approximate center of the hip decreased from 23.5 to 8.5 mm. 8 hips showed radiological loosening in group with a bone defect 3A and 16 in group 3B. The survival rate for loosening at 15 years was for 83.2 +12% for group 3A and 72.5 + 12% for group 3B (Mantel-Cox, p=0.04). The survival rate when using mesh or not at 15 years for loosening was: No Mesh 89.1 + 14%, Medial mesh 84.9 + 12%, Rim 79.6 + 12%, Medial and Rim 53.9 + 22 % (Mantel Cox, p=0.008). Patients with a bone defect 3B and a rim metallic mesh had a higher risk for loosening (p=0.047; Hazard Ratio: 2.36, Confidence Interval 95% (CI) 1.01–5.5, and, p=0.026; HR: 3.7, CI 95%: 1.13–12.4, respectively).
Conclusions
IBG provides an improvement of the reconstruction of the rotation of the hip centre in acetabular revision surgery. Although results are good for contained or medial large defects, hips with a rim large segmental defect may need other options for reconstruction of these challenged surgeries.
