Session VII Pelvis and Acetabulum

Total Hip Arthroplasty after Fracture of the Acetabulum

Mark C. Reilly, MD, Joel M. Matta, MD

Good Samaritan Hospital, Los Angeles, CA

Purpose: Patients who have had fractures of the acetabulum and subsequently developed post-traumatic arthritis may have difficult problems to be addressed at the time of hip arthroplasty. The early results of total hip arthroplasty were reviewed to determine if prior acetabulum fracture has a significant adverse effect on the outcome of subsequent arthroplasty.

Materials and Methods: 57 total hip arthroplasties in 56 patients with previous acetabulum fractures were performed by the senior author over a 10 year period. The average age at fracture was 51.9 years and the average time from fracture to arthroplasty was 1.9 years. 71% of the patients had associated fracture patterns. 45 (80%) of the fractures were initially treated operatively. 51% of the patients were operated through an isolated Kocher-Langenbeck or ilioinguinal approach while 29% were operated through an extended approach. All patients developed post-traumatic arthritis but this was complicated by non-union or malunion in 20% and failure of initial fixation in 14%. 6 patients were excluded for inadequate follow-up and 2 patients were deceased prior to 2 years. 49 patients were followed for a minimum of 2 years following arthroplasty (mean 3.9 years).

Results: Nine patients underwent revision surgery. Only 3 (6.2%) revisions were for aseptic loosening of the acetabular component. Two of these cases were complicated by an associated non-union (one transverse and one posterior column) which did not heal and likely contributed to loosening of the acetabular component. The third patient had symptomatic incomplete ingrowth. One uncemented femoral component was revised for persistent thigh pain. 4 patients had revision due to recurrent dislocations. In all cases the acetabular component was found to be well fixed at revision. Additionally, one patient required change of a polyethylene liner following a traumatic dislocation. Radiographic loosening was present in 4 femoral components and was symptomatic in 2. Acetabular loosening was present in 2 cases and was symptomatic in 1. Femoral head/neck autografts were utilized with rigid internal fixation in 23 (41%) of the cases. Healing and early incorporation of the autograft was demonstrated in all cases except the two arthroplasties which failed due to persistent innominate non-union. No evidence of graft collapse or resorption was found at this follow-up.

Conclusion: The overall early revision rate of 18.8% is significantly less than that reported previously [1]. Only 6.2% of the arthroplasties required revision for aseptic acetabular component loosening. Transverse or anterior/posterior column non-union may contribute to poor component stability and survival. Consideration should be given to a 2 stage reconstruction in which the non-union may be addressed prior to definitive arthroplasty. Total hip arthroplasty may be successfully performed with reasonable early revision rates for post-traumatic arthritis following acetabulum fracture. Bulk autograft from the femoral head/neck is a promising technique for the reconstruction of bony defects encountered at arthroplasty.

[1] Total Hip Arthroplasty for Post-Traumatic Arthritis Following Acetabular Fractures. Karpik, K., MD, Mears, D., MD and Hardy, S., MD. Presented OTA October 1,1995. Tampa, FL.