Abstract
Introduction: The authors systematically reviewed the available literature in order to define the outcomes for avascular necrosis (AVN) and spontaneous osteonecrosis of the knee (SPONK) after unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA).
Materials and Methods: A literature review yielded seven reports with Hospital for Special Surgery (HSS) or Knee Society Score (KSS) outcomes for arthroplasty secondary to either AVN or SPONK. The mean pre-operative, post-operative, and difference in KSS or HSS scores plus the mean revision rates for the arthroplasties for each underlying disease (AVN and. SPONK) were tabulated and reported in this order. The reported means were weighted by the number of knees in each study.
Results: A total of 63 TKAs were performed for AVN and 85 TKAs were performed for SPONK. Additionally, 74 UKAs were performed for SPONK. TKAs performed secondary to AVN had mean KSS scores of 50.6, 90.2, and 39.4 points. The revision rate was 12.5% (SD=10.45). TKAs performed for SPONK had mean HSS scores of 55.6, 82.5, and 27 points. The revision rate was 5.9% (SD=2.79). UKAs performed for SPONK had mean HSS scores of 54, 83.1, and 29.1 points with a revision rate was 9.7% (SD=5.9).
Discussion: Although the KSS for TKAs performed for AVN match the KSS performed in osteoarthritic patient populations receiving TKAs, the revision rate is higher in the AVN group. The HSS scores for patients with SPONK receiving TKAs or UKAs are similar although the revision rate is higher for UKAs.
Editorial Secretaries: Lynne C. Jones, Ph.D.* and Michael A. Mont, M.D. Address for Correspondence: *Lynne C. Jones, Ph.D., Suite 201 GSH POB, 5601 Loch Raven Blvd., Baltimore, MD 21239, USA. Email: ljones3@jhmi.edu
