Abstract
Introduction: It is recommended that at least 50% of the uncemented component porous surface should come into contact with living, stable host bone in acetabular reconstruction. This study evaluated primary and secondary stability where virtually 100% of the uncemented acetabular component contacted with the impaction morsalized cancellous allograft.
Methods: This study evaluated 16 cases which had received revision THA using impaction morsalized cancellous allografts for reconstruction of acetabular defects. In 8 cases there was full contact between the uncemented component and the allograft and the other cases also had full contact except for at the superior rim. Primary fixation of the acetabular component was made via 2–3 screws. Acetabular defects were evaluated according to the Paprosky classification. Allograft incorporation was assessed radiologically. The Mann- Whitney U test and Pearson correlation co-efficient were used for statistical assessment.
Results: The average age was 52.4 years (37–74) and average post-operative follow-up period 4.9 years (2–7). Of the cases, 68.7% were Paprosky Type 3A and 12.5% Type 3B An average of 134.7 cc. (60–270 cc) morsalized cancellous allograft was used in the reconstruction of the defects. In the 8 cases where there was no rim contact in the superior weight-bearing area, the superior migration was found to be statistically significantly high. At the final observation the modified Harris hip score was average 84 (53–100). No case required re-revision due to acetabular loosening.
Discussion: We conclude that in acetabular reconstruction when primary stability of the acetabular component has been achieved by impaction allografts and screws, the proportion of contact between the component and allograft does not affect the progress of biological fixation.
Correspondence should be addressed to Mr John Hodgkinson, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
