Can CT-based gap and step-off displacement predict outcome after nonoperative treatment of acetabular fractures?

Aims: The aim of this study was to investigate the association between fracture displacement and survivorship of the native hip joint without conversion to a total hip arthroplasty (THA), and to determine predictors for conversion to THA in patients treated nonoperatively for acetabular fractures. Methods: A multicentre cross-sectional study was performed in 170 patients who were treated nonoperatively for an acetabular fracture in three level 1 trauma centres. Using the post-injury diagnostic CT scan, the maximum gap and step-off values in the weightbearing dome were digitally measured by two trauma surgeons. Native hip survival was reported using Kaplan-Meier curves. Predictors for conversion to THA were determined using Cox regression analysis. Results: Of 170 patients, 22 (13%) subsequently received a THA. Native hip survival in patients with a step-off ≤ 2 mm, > 2 to 4 mm, or > 4 mm differed at five-year follow-up (respectively: 94% vs 70% vs 74%). Native hip survival in patients with a gap ≤ 2 mm, > 2 to 4 mm, or > 4 mm differed at five-year follow-up (respectively: 100% vs 84% vs 78%). Step-off displacement > 2 mm (> 2 to 4 mm hazard ratio (HR) 4.9, > 4 mm HR 5.6) and age > 60 years (HR 2.9) were independent predictors for conversion to THA at follow-up. Conclusion: Patients with minimally displaced acetabular fractures who opt for nonoperative fracture treatment may be informed that fracture displacement (e.g. gap and step-off) up to 2 mm, as measured on CT images, results in limited risk on conversion to THA. Step-off ≥ 2 mm and age > 60 years are predictors for conversion to THA and can be helpful in the shared decision-making process.

Quantitative Three-Dimensional Measurements of Acetabular Fracture Displacement Could Be Predictive for Native Hip Survivorship.

This study aims to develop a three-dimensional (3D) measurement for acetabular fracture displacement, determine the inter- and intra-observer variability, and correlate the measurement with clinical outcome. Three-dimensional models were created for 100 patients surgically treated for acetabular fractures. The '3D gap area', the 3D surface between all the fracture fragments, was developed. The association between the 3D gap area and the risk of conversion to a total hip arthroplasty (THA) was determined by an ROC curve and a Cox regression analysis. The 3D gap area had an excellent inter-observer and intra-observer reliability. The preoperative median 3D gap area for patients without and with a THA was 1731 mm2 versus 2237 mm2. The median postoperative 3D gap area was 640 mm2 versus 845 mm2. The area under the curve was 0.63. The Cox regression analysis showed that a preoperative 3D gap area > 2103 mm2 and a postoperative 3D gap area > 1058 mm2 were independently associated with a 3.0 versus 2.4 times higher risk of conversion to a THA. A 3D assessment of acetabular fractures is feasible, reproducible, and correlates with clinical outcome. Three-dimensional measurements could be added to the current classification systems to quantify the level of fracture displacement and to assess operative results.

Does 3D-Assisted Acetabular Fracture Surgery Improve Surgical Outcome and Physical Functioning?-A Systematic Review.

Three-dimensional technology is increasingly being used in acetabular fracture treatment. No systematic reviews are available about the added clinical value of 3D-assisted acetabular fracture surgery compared to conventional surgery. Therefore, this study aimed to investigate whether 3D-assisted acetabular fracture surgery compared to conventional surgery improves surgical outcomes in terms of operation time, intraoperative blood loss, intraoperative fluoroscopy usage, complications, and postoperative fracture reduction, and whether it improves physical functioning. Pubmed and Embase databases were searched for articles on 3D technologies in acetabular fracture surgery, published between 2010 and February 2021. The McMaster critical review form was used to assess the methodological quality. Differences between 3D-assisted and conventional surgery were evaluated using the weighted mean and odds ratios. Nineteen studies were included. Three-dimensional-assisted surgery resulted in significantly shorter operation times (162.5 ± 79.0 versus 296.4 ± 56.0 min), less blood loss (697.9 ± 235.7 mL versus 1097.2 ± 415.5 mL), and less fluoroscopy usage (9.3 ± 5.9 versus 22.5 ± 20.4 times). The odds ratios of complications and fracture reduction were 0.5 and 0.4 for functional outcome in favour of 3D-assisted surgery, respectively. Three-dimensional-assisted surgery reduces operation time, intraoperative blood loss, fluoroscopy usage, and complications. Evidence for the improvement of fracture reduction and functional outcomes is limited.