Introduction Management of acetabular fractures is challenging, especially when a medial acetabular fracture is complicated by central hip dislocation. We retrospectively investigated the clinical outcome and risk factors of secondary hip osteoarthritis requiring total hip arthroplasty after the surgical treatment of acetabular fractures with central hip dislocation. Materials and Methods The medical records of all patients who had acetabular medial wall fractures with central hip dislocation treated with open reduction and internal fixation by a single surgeon between January 2015 and June 2017 were reviewed. Surgical reduction was performed with the modified Stoppa with/without the Kocher-Langenbeck (KL) approach. Patients were followed for a minimum of three years, and the Majeed scoring system was used for functional evaluation. Multivariate logistic regression analysis was used to assess the association of patients' characteristics with the likelihood of advanced posttraumatic arthritis developing with conversion to total hip arthroplasty. Results Fifty patients were included in this study, with disease classified as AO/OTA 2018 62B/62C. Thirty-five patients (70%) had good or excellent Majeed pelvic scores. Eleven patients (22%) eventually received total hip arthroplasty because of end-stage posttraumatic arthritis. Three risk factors identified for total hip arthroplasty were male sex, initial marginal impaction, and sciatic nerve injury. Kaplan-Meier survivorship analysis estimated that the cumulative probability of free-from-end-stage arthritis was 78% (95% confidence interval, 73%–90%) at the 5-year follow-up. Conclusion Surgical fixation with the modified Stoppa and the KL approach for acetabular medial wall fractures with central hip dislocation is an effective approach with a satisfactory functional outcome. A prodromal factor was marginal impaction concomitant with articular damage. The trauma of high axial loading and the occupational distribution (males performing heavy manual labor and heavy lifting) with preoperative sciatic nerve injury increased the odds of developing end-stage arthritis.