Acetabular fractures, typically attributable to high-energy trauma associated with upper or lower extremity fractures, as well as brain, chest, or abdominal injuries, are difficult to treat surgically and more prone to postoperative complications123456). Since Letournel7) proposed that surgical treatment was associated with a better prognosis than conservative management in patients with acetabular fractures and dislocations, open reduction with internal fixation and early ambulation have been recommended as basic management. Patient's age, delay to injury-related surgery (in days), the presence of hip dislocations, fracture types, the preoperative degree of displacement, the degree of postoperative reduction, and femoral head and associated injuries have been identified as factors that may influence the outcomes of surgical management for acetabular fractures7891011121314). However, a limited number of domestic studies have been conducted in order to explore factors affecting the treatment outcomes of acetabular fractures. Therefore, this study aimed to identify the factors that may influence postoperative clinical and radiological outcomes in acetabular fractures treated surgically.

Of the 106 patients with acetabular fractures treated surgically, 76.4% achieved anatomical reductions, 78.3% had excellent or good clinical outcomes, and 82.1% had excellent or good radiological outcomes. Statistical analyses revealed that the postoperative degree of reduction and the initial displacement were critical factors for predicting patient clinical and radiological outcomes, and the postoperative degree of reduction was found to be a predictive factor for the occurrence of arthritis.

Matta11) reported that preoperative displacements had a insignificant effect on prognosis in 262 acetabular fracture patients with a mean initial displacement of 20 mm. Conversely, Meena et al.18) demonstrated significantly poorer results in patients with an initial displacement of >20 mm. The results from the current study were comparable with those of the latter study, showing significantly (P=0.001) poorer radiological and clinical outcomes in the group with an initial displacement of >20 mm.

A large number of studies have addressed the importance of anatomical reductions in the management of acetabular fractures111219). Bhandari et al.20) evaluated the clinical outcomes of 109 patients with acetabular fractures according to the modified Merle d'Aubigne and Postel score. Of these, 84% had excellent or good outcomes, and the study authors suggested that the postoperative degree of reduction was the most important factor for prognosis. In the current study, near-anatomical reductions were associated with satisfactory clinical and radiological outcomes (P<0.001).

In order to achieve precise reductions, it is important to choose a surgical approach appropriate for each fracture type according to the AO fracture and dislocation classification21). In both-column acetabular fractures in particular, an extensile approach is considered as a better option for more precise reductions; however, the results of a previous study found satisfactory outcomes from indirect reductions of the posterior column using an ilioinguinal approach22). Isaacson et al.23) obtained satisfactory outcomes in anterior-column and both-column acetabular fractures using the Stoppa approach. However, that study was not designed to verify the effects of surgical approaches on treatment outcomes.

The results of a few studies have suggested that fracture types according to the Letournel classification showed significant effects on prognosis1624). Furthermore, the results from previous studies revealed an unfavorable prognosis for patients with posterior column, posterior column + posterior wall, and T-shaped fractures12131419). Since the Letournel system classifies fracture types according to fractures of the column or wall of the acetabulum, Meena et al.18) proposed that fracture types were helpful in guiding decisions regarding surgical approaches, but were not predictive of prognosis. Similarly, fracture type was not found to be a significant factor for predicting clinical and radiological outcomes or arthritis incidence in the current study.

In a study conducted by Moed et al.25), a poor prognosis was observed in 100 patients with posterior wall fractures and an age >55 years. In contrast, Matta.11) suggested that postoperative reductions were significant factors affecting treatment outcomes, as compared to age, which had an insignificant effect. Although age was associated with clinical and radiological outcomes in the current study, age was not found to be a prognostic factor for treatment outcomes or arthritis occurrence.

Osteoarthritis occurred in nine patients (8.4%). Of these, the outcomes of postoperative reductions were anatomical in three cases, incomplete in one case, and poor in five cases. In a study conducted by Chiu et al.1), osteoarthritis occurred in 13.2% of all satisfactory reductions and in 43.5% of unsatisfactory reductions. The likelihood of reduction achievement tended to reduce the risk of post-traumatic osteoarthritis. In the current study, postoperative reductions were found to be predictive of the risk of developing osteoarthritis after the surgical management of acetabular fractures, and the likelihood of reduction achievement significantly decreased the incidence of osteoarthritis.

The current study analyzed acetabular fractures by dividing them into simple and associated fractures due to the relatively small sample size. Therefore, further large-scale studies are warranted in order to analyze detailed fracture types according to the Letournel classification.

The results of the current study revealed that the initial degree of displacement and the quality of reductions were important factors affecting the prognosis of patients with acetabular fractures, and that the achievement of anatomical reductions was more likely to reduce the risk of osteoarthritis.