49. TOTAL HIP ARTHROPLASTY AFTER OSTEOSYNTHESIS OF AN ACETABULAR FRACTURE

Abstract

Purpose of the study: Correct implant position is one of the factors of long-term success of total hip arthroplasty (THA). Acetabular architectural defects caused by trauma can create difficult situations leading to potential complications and poor outcome. The purpose of this study was to examine retrospectively the results of THA implanted after fracture of the acetabulum treated surgically. The objective was to analyse the specific features and search for factors favouring poor outcome.

Material and method: The series included 43 patients who had a THA implanted after treatment of an acetabular fracture. Mean age at trauma was 44.5 years (range 16–87). Five patients had a THA immediately, mean age 75 years (63–87). Thirty eight patients had osteosynthesis. According to the Letournel classification, the fracture was elementary in 12 cases and complex in 26. In ten patients, there was residual joint incongruence measuring more than 2 mm after osteosynthesis. The hips evolved to degenerated joint (n=34) and or necrosis (n=10).

Results: Mean time from acetabular osteosynthesis to THA was 94.6 months (range 3–444), excluding those patients whose THA was implanted at the time of the osteosynthesis. Arthroplasty required removal of the osteosynthesis material (n=11), insertion of a supportive ring (n=14) associated with a bone graft (n=13). The acetabular implant was considered to be well positioned according to the Pierchon criteria in 16 hips and was lateralised (n=21) and/or ascended (n=17) in the other hips. Inclination was 42.8 on average, range 10–18. The five-year survival was 80%.

Discussion: Arthroplasty after surgical treatment of an acetabular fracture is a difficult procedure. Complementary procedures are often necessary complicating the surgery and increasing the risk of perioperative complications, particularly infection. It is difficult to position the acetabular implant, increasing the risk of postoperative instability and early loosening. This study demonstrated the difficulties of implanting a THA in this context where the revision rate is significantly higher than in first-intention THA.