March 10, 2019
1 min read

Acetabular fractures with posterior wall involvement, specific radiographic features may yield higher conversion rate to THA

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Published results showed patients with acetabular fractures involving the posterior wall that were managed with open reduction and internal fixation had poorer reduction and a higher rate of conversion to total hip arthroplasty if they had high-energy mechanisms and a combination of radiographic features.

At least 4 years out from surgery, Reza Firoozabadi, MD, MA, and colleagues reviewed preoperative and postoperative CT scans in 125 patients with acetabular fractures involving the posterior wall managed with open reduction and internal fixation for injury characteristics and reduction quality. Researchers contacted patients by telephone to document reoperations and functional outcomes, including SF-8 scores and modified Merle d’Aubigne Hip Scale. Conversion to THA was considered the main outcome measure.

Results showed an overall rate of conversion to THA of 5%, 14% and 17% at 2, 5 and 9 years, respectively. Researchers noted an association between the presence of specific radiographic features and the rate of conversion to THA, with a 50% conversion rate among patients with five specific radiographic features vs. an 11% conversion rate with the presence of four or fewer features. On postoperative CT scan, patients with less than 1 mm of diastasis/step-off had no conversions to THA compared with a 10% conversion rate for patients with 1 mm to 4 mm diastasis/step-off and a 54% conversion rate for patients with 4 mm or more of malreduction, according to results. Researchers found patients who did vs. those who did not undergo THA had no differences in SF-8 or modified Merle d’Aubigne scores.

“Patients should be counseled accordingly about the need for future arthroplasty, and surgeons can give consideration to primary THA in these severe cases,” the authors wrote. “When [open reduction and internal fixation] ORIF is undertaken, anatomic restoration of the acetabulum to within 1 mm of both step-off and diastasis, which cannot be accurately deterred with plain radiographs, is associated the lowest risk of posttraumatic arthritis.” – by Casey Tingle

Disclosures: The authors report no relevant financial disclosures.