Clinical Orthopaedics and Related Research®

, Volume 471, Issue 2, pp 422–429

Should We Worry About Periacetabular Interference Gaps in Hip Resurfacing?

  • Bruno Gomes
  • Michael Olsen
  • Michael Donnelly
  • Ashesh Kumar
  • Emil H. Schemitsch
Symposium: Papers Presented at the Annual Meetings of The Hip Society



Press-fit acetabular component seating in hip resurfacing can be challenging as a strong interference fit is required. It has not been established whether reducing the acetabular underream minimizes incomplete component seating or leads to increased acetabular loosening.


We examined (1) the incidence and natural history of postoperative interference gaps in hip resurfacing and (2) whether reduction of the acetabular underream from 2 mm to 1 mm reduces the incidence of periacetabular interference gaps.


Of 327 Birmingham Hip™ Resurfacings (Smith & Nephew Inc, Memphis, TN, USA) performed by a single surgeon from 2005 to 2010, we evaluated 306 hips with a minimum 1-year radiographic followup. Postoperative periacetabular interference gaps were monitored for radiographic gap resolution at latest followup. The frequency of incomplete component seating was compared between acetabula prepared with 1- and 2-mm underream techniques. Minimum followup was 1 year (mean, 2.7 years; range, 1–6 years).


Fifty-one percent of the postoperative radiographs demonstrated the presence of a periacetabular interference gap. At latest followup, 96% of these gaps were no longer visible. We observed a reduction in the number of interference gaps identified when acetabular preparation changed from a 2-mm underream (63%) to a 1-mm underream (39%). There were no revisions due to acetabular failure.


Periacetabular interference gaps were common in this series but not associated with acetabular component failure. The use of a 1-mm underream is sufficient for adequate short-term press-fit fixation of the acetabular component in Birmingham Hip™ Resurfacing arthroplasty.

Level of Evidence

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.


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Copyright information

© The Association of Bone and Joint Surgeons® 2012

Authors and Affiliations

  • Bruno Gomes
    • 1
  • Michael Olsen
    • 2
  • Michael Donnelly
    • 1
  • Ashesh Kumar
    • 1
  • Emil H. Schemitsch
    • 1
  1. 1.Division of Orthopaedic Surgery, Department of SurgerySt Michael’s HospitalTorontoCanada
  2. 2.Martin Orthopaedic Biomechanics LaboratorySt Michael’s Hospital, University of Toronto, Li Ka Shing Knowledge InstituteTorontoCanada

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