[RECONSTRUCTION MODE SELECTION OF ACETABULAR BONE DEFECT AND EFFECT ON ACETABULAR CUP POSITION IN CEMENTLESS TOTAL...

To investigate the reconstruction mode selection of acetabular bone defect and the effect on the acetabular cup position in cementless total hip arthroplasty (THA).

A retrospective analysis was made on the clinical data of 78 patients (78 hips) with acetabular bone defect according to the selection criteria who underwent THA between February 2008 and February 2014. In 39 cases having acetabular posterosuperior bone defect with defect area less than 30%, impaction bone grafting was performed (group A); in 24 cases having acetabular posterosuperior bone defect with defect area of 30%-50%, structural bone or tantalum block grafting was performed (group B); in 10 cases having acetabular medial wall bone defect with defect area less than 30%, impaction bone grafting was performed (group C); and in 5 cases having acetabular medial wall bone defect with defect area of 30%-50%, titanium mesh combined with impaction bone grafting was performed (group D). There was no significant difference in gender, age, and side between groups A and B, and between groups C and D (P > 0.05). The acetabular abduction angle, anteversion, the horizontal and vertical distances of actual and true rotation center after operation were compared.

The patients were followed up 7-25 months. Prosthesis loosening occurred in 2 cases of group A, sciatic nerve injury and hip joint dislocation in 1 case of group B, respectively. At immediate after operation and last follow-up, there was no significant differences in the horizontal or vertical distance of actual and the true rotation center between groups A and B (P > 0.05); significant difference was found in the horizontal distance between groups C and D (P < 0.05), but no significant difference in the vertical distance (P > 0.05). Difference was statistically significant in the acetabular abduction angle and anteversion between groups A and B (P < 0.05), but difference was not significant between groups C and D (P > 0.05).

In patients with acetabular posterosuperior bone defect, reconstruction methods will have effect on acetabular abduction and anteversion; early acetabulum prosthesis loosening may be associated with too large acetabular abduction angle and inappropriatejeconstruction methods. In patients with acetabular medial wall bone defect, the vertical distances of rotation center will shift upward in varying degrees, and reconstruction methods have effect on the horizontal distances of rotation center.