1 Introduction

Acetabular fractures are complex injuries commonly resulting from high-energy trauma, such as vehicular accidents, and present significant challenges in surgical management.^1,2 Surgical treatment is indicated for fractures with displacement of >2 mm to restore joint congruity, ensure hip stability, and reduce the risk of post-traumatic arthritis.^3–5 Several factors influence clinical outcomes, including patient age,^3–5 fracture type, waiting time for surgery,^3,6,7 presence of associated hip dislocation,^3,6 and quality of fracture reduction.^3–5,7,8 Early surgical intervention and achieving high-quality reduction significantly improve outcomes, while the roles of age and fracture classification remain inconclusive.^3,4 This study aims to evaluate the clinical outcomes of surgical treatment for acetabular fractures and identify predictive factors associated with favorable results.

2 Patients and methods

Institutional Review Board approval was obtained for this study. This retrospective investigation included patients who underwent surgical treatment for acetabular fractures at Khon Kaen Hospital between October 2017 and September 2021 and had complete 12-month follow-up data. The initial cohort comprised 271 patients, including 76 treated non-surgically and 195 treated surgically. Of these, 156 had complete data at 12 months. Collected data included demographic variables such as age, sex, cause of injury, associated injuries, and fracture type according to the Judet and Letournel classification.

Predictive factors for prognosis were analyzed in five categories: age (<55 vs. ≥55 years, to represent the effect of osteoporosis), fracture classification (elementary vs. associated fractures), waiting time for surgery (<14 vs. ≥14 days), presence of associated hip dislocation, and quality of reduction based on the Matta scoring system,³ which classifies reductions as acceptable (anatomical and good reductions, 1–3 mm) or unacceptable (poor reduction). The quality of reduction was independently evaluated by two orthopedic surgeons, and in cases of disagreement, a third surgeon provided a final decision.

Clinical outcomes were obtained from medical records, specifically 12-month post-surgery assessments using the Merle d'Aubigné and Postel Hip score,⁹ which evaluates pain, hip range of motion, and walking ability. The primary outcome was the absolute hip function score, derived by combining the pain and mobility subscores. This total score was categorized as very good (11–12), good (10), medium (9), fair (8), or poor (≤7).

Statistical methods involved presenting descriptive data as mean ± standard deviation (SD) for quantitative variables and as percentages for categorical variables. The relationships between the Merle d'Aubigné and Postel Hip score and the predictive factors were examined using multiple logistic regression, with p-values <0.05 considered statistically significant (see Figs. 1-4).

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Fig. 1 Male (42 years old) (A) Complete two-column fracture of the right acetabulum. (B) Good reduction. (C) Very good outcome.

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Fig. 2 Male (32 years old) (A) Transverse fracture with posterior wall fracture and hip dislocation. (B) Inability to reduce the posterior wall. (C) Ankylosis of the hip and poor outcome.

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Fig. 3 Male (55 years old) (A) T-shaped fracture of the right acetabulum with hip dislocation. (B) Good reduction after surgery. (C) Avascular necrosis of the femoral head and poor outcome.

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Fig. 4 Male (59 years old) (A) Transverse fracture of the right acetabulum. (B) Good reduction; however, surgery was delayed because of associated injuries. (C) Poor outcome.

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THEORY/CALCULATION.

3 Results and discussion

A total of 156 patients who underwent surgical treatment for acetabular fractures were included in this study. The patients were mostly males (134 cases, 85.9 %), with females accounting for 22 cases (14.1 %). The mean age of the cohort was 42.71 years (SD = 14.82). Traffic accident was the most common cause of injury, reported in 123 cases (78.85 %), followed by falls from height in 33 cases (21.15 %).

The demographic data is presented in Table 1. Based on the Judet and Letournel classification, fractures were categorized as elementary in 74 patients (47.44 %) and associated in 82 patients (52.56 %). Associated hip dislocation was present in 64 patients (41.03 %) and absent in 92 (58.97 %). The quality of fracture reduction, assessed according to Matta's criteria, revealed an anatomical reduction in 73 patients (46.79 %), imperfect reduction in 41 (26.28 %), and poor reduction in 42 (26.92 %).

Regarding predictive factors (Table 2), most patients were aged <55 years (123 cases, 78.85 %), while 33 patients (21.15 %) were aged >55 years. Surgical intervention was performed within 14 days of injury in 111 cases (71.15 %), whereas 45 patients (28.85 %) underwent delayed surgery (i.e., after 14 days). The quality of reduction showed that 88 patients (73.08 %) had a displacement of ≤3 mm, while 68 (26.92 %) had a displacement of >3 mm.

Clinical outcomes (Table 3), evaluated using the Merle d'Aubigné and Postel Hip score at the 12-month follow-up, demonstrated that 88 patients (56.41 %) had very good, 17 (10.9 %) had good, 12 (7.69 %) had medium, 13 (8.33 %) had fair, and 26 (16.67 %) had poor. Additionally, nine patients (5.77 %) developed post-traumatic osteoarthritis, requiring total hip replacement surgery.

Univariate analysis (Table 4) revealed significant associations between clinical outcomes and several predictive factors. Early surgical intervention (≤14 days) was significantly associated with better outcomes (p = 0.024). The presence of associated hip dislocation negatively impacted clinical outcomes (p = 0.000), and the quality of reduction was a strong predictor of favorable outcomes, with anatomical or good reductions significantly linked to better results (p = 0.000). In contrast, patient age (p = 0.303) and fracture classification (p = 0.337) were not significantly associated with clinical outcomes.

Multivariate analysis (Table 5) adjusted for age, sex, and fracture type, confirmed that early surgical intervention (p = 0.045), absence of associated hip dislocation (p = 0.000), and high-quality reduction (p = 0.000) were independent predictors of very good clinical outcomes. Conversely, age and fracture classification remained non-significant predictors in the multivariate model.

These findings emphasize the critical role of timely surgical intervention, optimal reduction quality, and the absence of associated hip dislocation in achieving favorable clinical outcomes following surgical treatment for acetabular fractures.

Key Results: This study evaluated the clinical outcomes of surgical treatment for acetabular fractures and revealed key predictive factors influencing postoperative recovery. The findings revealed that early surgical intervention (within 14 days), high-quality reduction (displacement ≤3 mm), and the absence of associated hip dislocation significantly contributed to favorable clinical outcomes, as measured with the Modified Merle d'Aubigné and Postel Hip score. Specifically, 56.41 % of the patients achieved very good outcomes, and the presence of post-traumatic osteoarthritis requiring total hip replacement was relatively low (5.77 %). Factors such as patient age and fracture classification (elementary vs. associated) did not significantly affect outcomes, indicating that timely and precise surgical management plays a more critical role than do demographic or fracture pattern variables.

Limitations: This study had some limitations. First, the retrospective design inherently carries risks of selection and information biases. The reliance on medical records and radiographic data may have introduced inconsistencies in data collection, particularly regarding the subjective evaluation of reduction quality. Although assessments were conducted by two orthopedic surgeons, inter-observer variability cannot be completely excluded. Additionally, the study was conducted in a single center, potentially limiting the diversity of the patient population and surgical techniques, which could influence the external validity of the findings. Furthermore, the study had a relatively short follow-up period of 12 months. This duration allows for the assessment of early clinical outcomes; however, it may not fully capture long-term complications such as late-onset osteoarthritis, avascular necrosis, or implant-related issues. Moreover, factors such as rehabilitation protocols, patient compliance, and socioeconomic status, which could significantly impact recovery, were not systematically analyzed. The limited sample size, particularly in subgroup analyses (e.g., patients aged ≥55 years), may have reduced the statistical power to detect differences in certain variables.

Interpretation: The results of this study emphasize the critical significance of timely surgical intervention, meticulous reduction techniques, and managing associated hip dislocations to optimize outcomes in patients with acetabular fractures. The strong association between high-quality reduction and favorable functional outcomes aligns with the findings of previous studies, such as those of Matta et al. and Giannoudis et al., which highlighted the role of anatomical reduction in preventing post-traumatic arthritis and improving hip function.

The lack of significant association between age and clinical outcomes contrasts with some earlier reports suggesting that advanced age negatively impacts recovery. This discrepancy may be attributed to the exclusion of patients with severe comorbidities or the relatively healthy status of older patients included in our cohort. Similarly, the non-significant impact of fracture classification suggests that even complex fracture patterns can achieve good outcomes when managed with appropriate surgical techniques.

However, caution is warranted when interpreting these findings owing to the study's limitations. The potential for residual confounding, particularly from unmeasured variables, cannot be entirely ruled out. Additionally, while the multivariate analysis adjusted for several confounders, the possibility of Type II error exists in non-significant associations, particularly given the sample size constraints.

Generalizability: The generalizability of our findings is somewhat limited owing to the single-center design and the specific patient population treated at Khon Kaen Hospital. The surgical expertise, hospital resources, and rehabilitation protocols available in this setting may differ from those in other institutions, particularly in high-income countries with more advanced healthcare systems. However, the large sample size and inclusion of elementary and complex fracture types enhance the applicability of our results to diverse clinical scenarios. Moreover, the consistency of our findings with existing literature on the significance of surgical timing, reduction quality, and hip dislocation management supports their relevance in broader contexts. Future multicenter prospective studies with longer follow-up periods are required to validate these results and explore additional factors influencing long-term outcomes in patients with acetabular fractures.

Other considerations: This study contributes valuable insights into the surgical management of acetabular fractures, reinforcing the need for prompt and precise intervention regardless of patient age or fracture complexity. The findings may guide orthopedic surgeons in prioritizing early surgical scheduling and emphasizing reduction quality to optimize patient outcomes. Additionally, the results highlight areas for further research, such as the role of postoperative rehabilitation and the long-term impact of surgical techniques on hip joint preservation.

4 Conclusion

This study highlights the critical role of timely surgical intervention, high-quality fracture reduction, and the absence of associated hip dislocation in achieving favorable clinical outcomes following acetabular fracture surgery. Early surgical intervention within 14 days, achieving anatomical or good reduction (displacement of ≤3 mm), and managing cases without associated hip dislocation were identified as independent predictors of very good functional outcomes. Factors such as patient age and fracture classification did not significantly influence the clinical outcomes, underscoring the significance of surgical precision and timing over demographic or fracture-related variables. These findings emphasize the need for prompt and meticulous surgical management to optimize patient recovery and functional outcomes. Future multicenter studies with longer follow-up periods are recommended to validate these results and explore additional factors that may impact long-term outcomes in patients with acetabular fractures.

Ethical statement

This research has been reviewed by The Khon Kaen Hospital Institute Review Board in Human Research, based on the declaration of Helsinki and International Conference on Harmonization-Good Clinical Practice (ICH-GCP).

Guardian/patient's consent statement

This study does not involve human subjects requiring guardian or patient consent.

Funding statement

This research received no specific grant from any funding agency, commercial, or not-for-profit sectors.

CRediT authorship contribution statement

Udomsin Singjam: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Thananit Sangkomkamhang: Data curation, Formal analysis, Investigation, Methodology, Writing – original draft, Statistic Formal analysis. Wanjak Pongsmakthai: Resources, Data curation, Writing – original draft.