The outcome of conversion total hip arthroplasty following acetabular fractures: a systematic review and meta-analysis of comparative studies

Background Conversion total hip arthroplasty (THA) is considered the main treatment plan for patients with first-line treatment failure of acetabulum fracture. This meta-analysis aims to assess the effect of the type of initial treatment and timing of surgery on the outcomes of conversion THA. Methods Using PRISMA guidelines, MEDLINE/PubMed, Scopus, Web of Science, and CENTRAL Cochrane were searched for articles published before October 14, 2022. Comparative studies investigating the outcome of THA following treatment failure of acetabular fracture were included. These articles were categorized into three groups, and the outcomes of treatment plans in each group were compared: (A) primary THA vs. conversion THA, (B) THA following conservative treatment vs. THA following ORIF, and (C) acute THA vs. delayed THA following prior treatment failure. Review Manager (RevMan, version 5.3) software was utilized to perform the statistical analysis. Results Twenty-four comparative studies met the inclusion criteria (reported the data of 13,373 patients). Concerning group (A), the following complications were significantly higher in conversion THA: Infection (OR [95% CI] 3.19 [2.12, 4.79]; p value < 0.00001), dislocation (OR [95% CI] 4.58 [1.56, 13.45]; p value = 0.006), heterotopic ossification (OR [95% CI] 5.68 [3.46, 9.32]; p value < 0.00001), and Revision (OR [95% CI] 2.57 [1.65, 4.01]; p value < 0.00001). Postoperative HHS (SMD [95% CI] − 0.66 [− 1.24, − 0.08]; p value = 0.03) was significantly lower and operation time (SMD [95% CI] 0.88 [0.61, 1.15]; p value < 0.00001), blood loss (SMD [95% CI] 0.83 [0.56, 1.11]; p value < 0.00001), and bone graft need (OR [95% CI] 27.84 [11.80, 65.65]; p value < 0.00001) were significantly higher in conversion THA. Regarding group (B), bone graft need (OR [95% CI] 0.48 [0.27, 0.86]; p value = 0.01) was considerably higher in patients with prior acetabular fracture conservative treatment, while other outcomes were comparable. Respecting group (C), there were no significant differences in analyzed outcomes. However, systematically reviewing existing literature suggested a higher incidence rate of DVT following acute THA. Conclusion There were significantly higher postoperative complications and lower functional outcomes in conversion THA compared to primary THA. While complications and functional outcomes were comparable between ORIF and the conservative groups, the bone graft need was significantly higher in the conservative group. There were no significant differences between aTHA and dTHA. These results can assist surgeons in designing treatment plans based on each patient’s clinical situation. Prospero registration code : CRD42022385508. Level of evidence : III/IV.