Abstract
Aim of the study
Aim of this study was to find out which factors influence the outcome after both column fractures of the acetabulum.
Methods
We performed a retrospective analyse of 115 patients with both column acetabular fractures. The period between the injury and follow-up ranges between 2 and 19 years, 5,7 years on average. The initial displacement, the presence of a dislocation of the hip and fractures of the femoral head were analyzed on the initial radiographs. Postoperative displacement was classified according the classification of Matta. The common classifications of Helfet (posttraumatic arthrosis), Ficat/Arlet (femur head necrosis) and Brooker (periarticular calcification) were used to radiologically classify the long term results. Statistics were performed by the Chi-square-test.
Results
We could find a clear tendency between the result of replacement and the radiological long-term result. 10 % of the patients with a postoperative displacement 1 mm had a joint failure compared to 28 % of the patients with 2–3 mm and 31,6 % with >3 mm displacement.
In cases with good radiological results the average of initial displacement was 11,4mm but it was 17,8 mm for patients with a bad result. This difference is high significant (p=0,008). If the primary displacement was < 10 mm the rate of joint failure was 10,85%, whereas the rate increased up to 27,5% in patients with primary displacement > 10mm. Patients with hip dislocations had no significant higher risk for a joint failure (21,5% without vs. 25,9% with dislocation). Also patients with injuries of the femoral head had no significant (p>0,05) worse outcome. 19,8% of the patients without femoral head injury suffers on joint failure in comparison to 15,4% (2) of the patients with impression or contusion of the femoral head. The presence of intraarticular fragments is accompanied by a worse result (p=0,041). In 50% of the cases with intraarticular fragments a joint failure appeared whereas only 18% of the patients without fragments developed joint failure.
Discussion
Matta could show in 1996 that anatomic replacement is a very important factor for a good outcome after acetabular fractures. These findings were supported by other publications. Our data show that there is a significant worse outcome after nonanatomical replacement. Several authors could show the presence of additional factors which predict the outcome independently of the replacement. In our data the primary displacement and the presence of intraarticular fragments showed a high influence. Dislocation of the hip, injuries of the femoral head and the presence of acetabular comminution had no significant influence but their number was maybe too small to detect it.
Conclusion
Anatomical replacement is the major goal to avoid joint failure in the treatment of both-column acetabular fractures. Additional factors including the primary displacement and intraarticular fragments have a worse influence independent of the replacement.
