R. C. Stedman2, A. Husain1, D. Lim1, C. `. Nelson1 1University Of Pennsylvania Health System,Philadelphia, PA, USA 2Howard University College Of Medicine,Washington, DC, USA
Introduction: Dislocation occurs in more than 3% of revision total hip arthroplasty (THA) surgeries. The most frequent complication of revision THA is dislocation. It is also the leading risk factor for patients that receive subsequent revision procedures. Risk factors for dislocation, are multivariate and not well understood. Patient variables as well as surgical variables all contribute to the overall risk of dislocation following a THA procedure. Patient variables include BMI, ASA score at time of surgery, age, and gender. Surgical variables include component exchange and components used during the revision procedure.
Methods: A retrospective analysis of 203 consecutive revision THA procedures performed by a single surgeon with a minimum two year follow up between June 2012 and May 2003 was performed through reviewing medical records and a phone survey. Five (2.4%) died and 76 (37.4%) were lost to follow-up leaving 122 revision procedures in 43 men (55 procedures) and 53 women (67 procedures).
Results:About 5.8% of all patients reviewed experienced a dislocation episode. Of those, 43% had a history of recurrent dislocation that was the primary reason for having a subsequent revision THA. In our experience, 85% of the patients who dislocated after their revision THA had single component exchanges performed. About 20% of the traditional components failed and about 13% of those with a constrained liner failed.
Conclusion:Patient variables for dislocation are identified as well as surgical techniques that might be susceptible to instability and failure. Multiple risk factors contribute to the overall risk for dislocation and THA failure. Other factors such as impingement, limited ROM, and faster wear on the components are considered in patients that may chronically dislocate. While all of these factor into the risk of dislocation, we found that single component exchanges present a significant risk for dislocation if a suboptimal component is accepted in hopes that it functions appropriately with its complement component. We propose a rational algorithm to determine whether or not a constrained liner is indicated in the setting of revision THA for patients with a history of dislocation.