Occult periprosthetic fractures of the acetabulum in THA using an elliptic cup design have no adverse impact on outcome

Occult periprosthetic fractures have been defined as a fracture only visible on postoperative CT scans but not on postoperative plain radiography after an uneventful surgery without intraoperative fracture. The fracture rate for hemispherical and peripheral self-locking cups has been described as 8.4%. We retrospectively analyzed postoperative CT scans after primary THA to clear the question whether such occult periprosthetic fractures of the acetabulum require particular treatment strategy. Between 2014 and 2018 we identified 115 CT scans of 114 patients after primary cementless THA with elliptical cups using a direct anterior approach. The CT scans were obtained as part of other investigations. Localization of the fracture, patients demographics, clinical (WOMAC, Harris Hip Score) and radiological outcome were analyzed. Fracture and non-Fracture group were compared with regard to demographics and short-term outcome after 1 year. Four occult fractures (3.5%) were identified. Three fractures involved the posterior wall. All patients had an uneventful routine postoperative rehabilitation. Patients with occult fractures showed similar post- operative HHS and WOMAC scores at 3 (HHS p = 0.576, WOMAC p = 0.128) and 12 (HHS p = 0.479, WOMAC p = 0.588) months. There were no cup loosening nor radiolucent lines at latest follow-up (mean FU 22 months, range 12-34 months). Clinical and radiological short-term outcome was not impaired by the occurrence of an occult periprosthetic fracture of the acetabulum. The incidental detection of an occult periprosthetic fracture of the acetabulum does not seem to oblige the surgeon to adapt the postoperative regime.

Treatment of anterior column posterior hemitransverse fracture with supra-ilioinguinal approach

Objective To report the feasibility and effect of the supra-ilioinguinal approach for treatment of anterior posterior hemitransverse fracture of the acetabulum. Methods Nineteen consecutive patients who underwent treatment for an anterior column posterior hemitransverse fracture of the acetabulum from January 2013 to June 2018 were retrospectively analyzed. All patients underwent treatment by the single supra-ilioinguinal approach with at least 1 year of follow-up. Results The mean time to surgery, operative time, incision length, and blood loss were 10.2 ± 3.8 days, 157 ± 125 minutes, 10.2 ± 0.6 cm, and 876 ± 234 mL, respectively. According to the Matta scoring system, the reduction quality was excellent in 13 patients, good in 6, and poor in 0. According to the Merle d'Aubigné scoring system, the outcome at the last follow-up was excellent in 12 patients, good in 5, fair in 1, and poor in 1. Postoperative complications occurred in three patients (deep vein thrombosis in one, lateral femoral cutaneous nerve injury in one, and both complications in one). Conclusions Use of the supra-ilioinguinal approach for treatment of anterior column posterior hemitransverse fracture of the acetabulum produced excellent clinical results because of the direct visualization of the anterior column and quadrilateral plate.