ICJR Interviews: Influence of Cup Position on Dislocation after THA
Recent literature has shown no correlation between the so-called Lewinnek safe zone for acetabular cup position and instability of the hip after total hip arthroplasty (THA).
Which begs the question: Are there alternative anatomic landmarks in the hip that can be used to evaluate the impact of cup positioning on dislocation rates?
Carlos A. Higuera, MD, and his colleagues from Cleveland Clinic, believe there are.
In their recent retrospective study, they theorized that using the anterior and superior bony acetabular rims as a reference point for cup positioning would have a greater correlation with dislocation risk and patient-reported functional and general health outcomes than the safe zone.
Only 5 dislocations occurred among 114 hips included in their cohort. Because there were so few dislocations, they were not able to confirm a statistically significant correlation between cup positioning using the native acetabulum and dislocation.
They did note, however, a correlation between patient-reported outcomes and cup positioning based on the native acetabulum.
Additionally, using reconstructed CT scans of the hip to assess version and inclination, they confirmed there is no statistically significant correlation between dislocation and cup positioning outside the safe zone.
The same was true for a correlation between patient-reported outcomes and the safe zone.
Click the image above to hear Dr. Higuera’s comments on this study, “Relationship of Acetabular Cup Position to Dislocation Rate and Patient-Reported Outcomes in THA (Poster 093), which was presented at the 2016 Annual Meeting of the American Academy of Orthopaedic Surgeons in Orlando.
Producer: Henrik B. Pedersen, MD; Director: Michael Bugera; Post Production: Charles J. Maynard