An important factor often ignored in operative treatment of fracture of acetabular posterior wall -- analysis of plate placement

Abstract

Objective To analyze the optimal position of reconstructive plate in the operative treatment of acetabular posterior wall fractures by comparing 2 plate placements. Methods From May 2004 to January 2014, 58 patients with acetabular posterior wall fracture according to Letournel-Judet classification were treated at our department. They were 46 men and 12 women, aged from 20 to 67 years. The fracture affected the left side in 27 cases and the right side in 31 ones. The time from injury to surgery ranged from 1 to 19 days. Their reduction and fixation were conducted with a 3.5 mm reconstructive plate and lag screws via the Kocher-Langenbeck approach. They were divided into 2 groups according to the positions of the plate and the screws. In group A of 25 cases, screws were placed behind the plate, far from the acetabular rim. In group B of 33 cases, screws were placed ahead of the plate, close to the acetabular rim. The 2 groups were compared in terms of reduction, fracture healing time, complications, and functional recovery. Results The 58 patients were followed up for an average of 2.3 years (range, from 1 to 5 years). According to the modified Matta criteria, anatomic reduction was achieved in all the patients. Fracture healing time averaged 14.8±3.5 weeks in group A and 14.6±3.4 weeks in group B, showing no statistically significant difference(t =0.073, P=0.788). According to the modified Merle d'Aubigne & Postel criteria, the hip function was excellent in 8 cases, good in 11, fair in 4, and poor in 2 in group A, giving an excellent to good rate of 76.0% ; the hip function was excellent in 11 cases, good in 17, fair in 4, and poor in one in group B, giving an excellent to good rate of 84.8%. There was a significant difference between the 2 groups (χ2 = 4.581, P=0.032). The incidence of complications in group A (32.0%, 8/25) was significantly higher than in group B (9.1%, 3/33) (χ2 = 5.926, P= 0.015). Conclusion In treatment of acetabular posterior wall fractures, the pelvic reconstructive plate should be placed as close as possible to the acetabular rim because the plate at this position can provide stronger and more stable fixation. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Bone plates; Treatment outcome