High Rate of Early Intraprosthetic Dislocations of Dual Mobility Implants: A Single Surgeon Series of Primary and Revision Total Hip Replacements

Dual mobility (DM) articulations have become an increasingly popular bearing choice in efforts to reduce dislocation rates in high risk primary and revision total hip arthroplasties (THA). However, DM dislocations can still occur. Intraprosthetic dislocation (IPD) is a unique failure mode for DM compared to standard femoral heads. Currently, the incidence of this phenomenon during attempted hip reduction is unknown.

A retrospective analysis of a consecutive series of all primary, revision, and conversion THA procedures performed by a single surgeon was collected. For all dislocations, patient demographics, location where reduction was performed, type of anesthetic used was recorded. For DM dislocations, the rate of successful closed reduction, reoperation due to failure of closed reduction, and incidence of IPD at time of reduction was recorded. Descriptive statistics were conducted on the data.

In total, 527 cases were included for analysis. The overall rate of dislocation (with and without DM) was 2.85%. Among DMs, the dislocation rate was 4.55%. The rate of IPD after closed reduction was 5/7 (71%) with all five requiring revision surgery to either another DM bearing or constrained liner.

We report a high rate of early IPD after DM dislocation. This study supports alternative treatment protocols for these patients including regional or general anesthesia to be administered in the operating room and for the reduction to be performed under fluoroscopy. Dislocated DM components handled in this manner could reduce the high incidence of IPD reported.