Redefining the Acetabular Component Safe Zone for Posterior Approach Total Hip Arthroplasty

Jonathan R Danoff; Jacob T Bobman; Gregory Cunn; Taylor Murtaugh; Prakash Gorroochurn; Jeffrey A Geller; William Macaulay

doi:10.1016/j.arth.2015.09.010

Redefining the Acetabular Component Safe Zone for Posterior Approach Total Hip Arthroplasty

J Arthroplasty. 2016 Feb;31(2):506-11. doi: 10.1016/j.arth.2015.09.010. Epub 2015 Sep 18.

Authors

Jonathan R Danoff¹, Jacob T Bobman¹, Gregory Cunn¹, Taylor Murtaugh¹, Prakash Gorroochurn¹, Jeffrey A Geller¹, William Macaulay¹

Affiliation

¹ Center for Hip & Knee Replacement, Department of Orthopaedic Surgery, New York Presbyterian Hospital/Columbia University Medical Center, New York, New York.

PMID: 26461487
DOI: 10.1016/j.arth.2015.09.010

Abstract

Background: Acetabular component orientation influences joint stability in total hip arthroplasty (THA). The purpose of this study was to evaluate the effect of cup orientation and other variables on hip dislocation risk and to define a posterior approach specific safe zone.

Methods: A cohort of 1289 posterior approach primary THA cases was prospectively followed and component position measured radiographically.

Results: Cup malposition, with respect to the Lewinnek safe zone, was an independent risk factor for dislocation (OR1.88). Modifying the anteversion safe zone limits to 10-25° strongly predicted increased dislocation risk (OR2.69). No dislocations occurred within a zone defined by a circle centered at 41.4° abduction and 17.1° anteversion, radius 4.3°.

Conclusion: Utilizing a posterior approach specific safe zone of 10-25° anteversion and 30-50° abduction may minimize THA dislocations.

Level of evidence: Level III.

Keywords: acetabulum; cup orientation; dislocation; safe zone; total hip arthroplasty.

MeSH terms

Acetabulum / surgery*
Aged
Arthroplasty, Replacement, Hip / methods*
Female
Hip Dislocation / etiology*
Hip Prosthesis / adverse effects*
Humans
Male
Middle Aged
Prospective Studies
Risk Factors