The use of both conventional and dual-mobility components in primary total hip arthroplasty is safe in a university hospital practice.

AIMS: Dislocation after total hip arthroplasty (THA) is a frequent cause of revision. Patients with intrinsic risk factors have been identified. The use of a dual-mobility (DM) acetabular component has shown great effectiveness in preventing dislocation, with questions regarding selective or absolute use. The aim of this study was to compare the outcome of conventional THA (C-THA) and DM-THA, when used for selected patients.

METHODS

This retrospective continuous cohort study evaluated 531 patients, of whom 313 received C-THA and 218 DM-THA. There were 354 primary osteoarthritis (67%), 121 femoral neck fractures (FNFs) (23%), and 56 other indications (10%). The surgical approach was anterior (AA) in 75% cases (398) and posterior (PA) in 25% of cases (133). In the DM-THA group, 189 patients (87%) presented at least one dislocation risk factor compared to 151 patients (48%) in the C-THA group (p < 0.001). The primary outcome was major surgical complications within two years (including deep infection requiring surgery, dislocation requiring closed or open reduction, or revision surgery). Secondary outcomes included length of hospital stay and component positioning.

RESULTS

There were no differences in major complications at two years' follow-up, with six patients (2.7%) in the DM-THA group and eight in the C-THA group (2.6%) (p = 0.301). There were four dislocations in the DM-THA group (three PA and one AA) and three in the C-THA group (three AA) (p = 0.402). The length of stay was significantly longer in the DM-THA group, with seven days (2 to 12) compared to four days (1 to 7) in the C-THA group (p = 0.001).

CONCLUSION

C-THA and DM-THA are complementary devices in the management of patients requiring primary THA. C-THA associated with AA is a safe option for patients with or without dislocation risk factors, excluding FNF. The selective implantation of the DM component was associated with a low rate of dislocation when THA was undertaken for FNF. The identification of dislocation risk factors is important to select patients requiring DM-THA and provide reproducible outcomes in a university hospital practice with various levels of surgeon experience.