Surgical treatment of acetabulum posterior wall fractures: Comparison between undercountering and marginal impaction...

Modern treatment principles for posterior wall fractures have become widespread in the last decade in many countries by means of international or local courses. The purpose of this study was to compare the clinical and radiologic outcomes of acetabulum posterior wall fractures using unconventional methods of fixation, including plates placed in unusual directions, or, in the case of reoperation, only interfragmentary screws. In addition, we examined acetabulum posterior wall fractures treated by open reduction and internal fixation with standard undercountered plates from ischion to iliac bone in latter cases.

Twenty-one patients who had open reduction and internal fixation of an unstable unilateral fracture of the posterior wall of the acetabulum between 2009 and 2013 were included. Group 1 was composed of 10 former patients who were treated with unconventional methods that included a compression technique with a direct plate or solely screw fixation. Group 2 was composed of latter 11 patients who were treated with standard surgery that included undercountered plates oriented from the ischial tuberosity to the iliac bone proximally and reconstruction of marginal impaction if necessary. The functional outcome was evaluated with the use of the clinical grading system adopted by Merle d'Aubigné and Postel. The Kellgren-Lawrence radiologic criteria were used for the radiologic assessments. The reduction of the fracture, posterior dislocation, marginal impaction, mean fracture particle amount, trochanteric osteotomy and avascular necrosis were compared between the two groups and examined with the Mann-Whitney U test.

In Groups 1 and 2, the median score of the modified Merle d'Aubigné and Postel clinical scoring system was 16 (8-18) and 18 (14-18), respectively. The clinical scores between the two groups were statistically significant (p < 0.01). When two groups were compared using the Kellgren-Lawrence radiographic criteria for the development of osteoarthritis, the median value in Groups 1 and 2 was 3 (0-4) and 1 (0-3), respectively (p < 0.01).

This study displays the evolution of the surgical treatment of acetabular fractures of the posterior wall in our clinic. The older methods failed in terms of exposure, diagnosis of fracture anatomy and fixation techniques. Patients treated after the surgeons took courses in this field showed evidence of superior clinical and radiological scores. We attribute these benefits to exposure, definition and treatment of marginal impaction and fixation principles.