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Clinical Orthopaedics and Related Research®

, Volume 472, Issue 7, pp 2217-2230

First online:

Hip Resurfacing versus Total Hip Arthroplasty: A Systematic Review Comparing Standardized Outcomes

  • Deborah A. MarshallAffiliated withDepartment of Community Health Sciences, University of Calgary, Health Research Innovation Centre Email author 
  • , Karen PykermanAffiliated withDepartment of Community Health Sciences, University of Calgary, Health Research Innovation Centre
  • , Jason WerleAffiliated withDivision of Joint Reconstruction, Department of Surgery, University of Calgary
  • , Diane LorenzettiAffiliated withDepartment of Community Health Sciences, University of Calgary, Health Research Innovation Centre
  • , Tracy WasylakAffiliated withStrategic Clinical Networks & Clinical Care Pathways, Alberta Health Services
  • , Tom NoseworthyAffiliated withUniversity of CalgaryAlberta Health Services
  • , Donald A. DickAffiliated withBone & Joint Strategic Clinical Network, Alberta Health Services
  • , Greg O’ConnorAffiliated withUniversity of Alberta
  • , Aish SundaramAffiliated withUniversity of Alberta
    • , Sanne HeintzbergenAffiliated withHealth Technology & Service Research, University of Twente
    • , Cy FrankAffiliated withAlberta Innovates Health SolutionsAlberta Bone and Joint Health Institute

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Abstract

Background

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

Questions/purposes

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

Methods

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

Results

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95–3.1) versus 7.8 for THA (95% CI, 7.2–8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1–11.3) versus 7.1 (95% CI, 6.7–7.6; p = 0.068), and 7.9 (95% CI, 5.4–11.3) versus 1.8 (95% CI, 1.3–2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2–4.6) versus 0.9 (95% CI, 0.6–1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

Conclusions

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.