The complications related to revision for acetabular component protrusion with material migrating into the intrapelvic region remain rare but potentially serious. Today, the literature reports no epidemiological data on the subperitoneal approach (SPA) in revision total hip arthroplasty (RTHA) for protrusion. Therefore we conducted a retrospective study on a large revision arthroplasty database to answer the following questions: (1) What is the frequency of this approach in this population? (2) What are the factors related to this procedure? (3) Is morbidity and mortality of the SPA higher than for an isolated conventional approach?

Major protrusions with material in the superomedial quadrant (SMQ) have a higher probability of being operated using a SPA.

This multicenter retrospective study included 260 cases of THA with endopelvic protrusion of material at least 15mm inside the Kohler line. The degree of protrusion was assessed on the AP pelvic X-ray with the construction of the SMQ. The reason for the subperitoneal approach, the duration of surgery, and the preoperative exams were also collected.

Nineteen procedures out of the 260 RTHAs included (7.8%) had a SPA in addition to the approach for the revision THA. The frequency of the SPA varied among centers (range: 1.7-50%). In four cases, the SPA was indicted to care for a vascular complication identified preoperatively. For one patient, the SPA was indicated intraoperatively. The other indications were either to extract the implant (n=7) or prevent a potential intraoperative assault of neurovascular structures (n=9). The cases presenting major protrusion on the AP X-ray with material in the SMQ were more often operated through the SPA (12/19; 63.2%) than cases with no SMQ involvement (4/241; 1.7%) (P< 0.001). Vascular structures were explored with imaging in 15 out of 19 (88.9%) of the SPA cases versus 26 out of 177 (14.7%) of the revisions without the SPA (41 with no information in the non-SPA group) (P< 0.001). Early mortality (before 45 days) of patients who had undergone the SPA (1/19; 5.3%) was not significantly different than for the patients who had not undergone the SPA (3/241; 1.2%) (P=0.26). Although the duration of surgery was longer in the SPA group (210±88 [range: 70-360] versus 169±52 [range: 60-300]; P=0.04), bleeding was not greater in the SPA group (1488±1770mL [range: 500-5000mL]) than in the non-SPA group (1343±987mL [range: 75-3500mL]; p>0.05).

Despite the limitations related to the retrospective and multicenter design of this study, to our knowledge it is the only one that examines SPA procedures within the context of severe material protrusion with THA. Based on these results, it seems preferable to plan for SPA every time there is an acetabular protrusion in the SMQ, after exploration with CT angiography. The SPA does not result in greater mortality or morbidity.

IV, retrospective study.