Presentation: Progression of Joint Space Narrowing in Knee Osteoarthritis (OA): An Analytic Literature Synthesis (2007)

1693 Progression of Joint Space Narrowing in Knee Osteoarthritis (OA): An Analytic Literature Synthesis

Purpose: Knee OA is highly prevalent and disabling. While it is recognized that the disease progresses insidiously over time, published results with respect to joint space narrowing rates differ across studies. We aim to estimate annual joint space narrowing rates with data from randomized controlled trials (RCT) and cohort studies, and to describe the influence of technical factors and study design on progression rates.
Methods: We used PubMed to search literature published between 1985 and 2006 for studies that analyzed knee OA progression. We included studies that assessed radiographic progression in cohorts with prevalent knee OA and with sample sizes greater than 10. We focus here on studies that report estimates of quantitative change in plain radiographic joint space width (JSW). We excluded literature reviews and studies not published in English. We noted whether studies included or cited inter- and intra-reader reliability analyses. We extracted specific study features, including participant demographic characteristics, study design, and radiographic view and analyzed their associations with annual progression estimates. We performed a meta-regression to identify factors explaining variability of JSW.
Results: Of 411 studies identified by the search, 23 met the inclusion criteria, presenting 27 distinct JSW progression estimates. 87% (20/23) of studies included measures of reader reliability. The mean annual change in JSW across all estimates was 0.14mm/yr ± 0.14 (see Figure). Progression estimates ranged from -0.10mm/yr (an increase in JSW) to 0.70mm/yr. Follow-up times ranged from 8-72 months. The extent of progression was associated with study design and radiographic view (see Figure). The effect of radiographic view differed across cohort and RCT designs (p for interaction=0.019). Full extension view was associated with the least progression in cohort studies and the most in RCTs, while flexion view, with or without fluoroscopy, was associated with the most progression in cohort studies and the least in RCTs. Progression rates were not associated with mean age, % female, and whether reader reliability was examined.
Conclusions: Progression rates derived from RCTs are significantly lower than progression rates derived from cohort studies. Radiographic view modified this relationship. There is a pressing need for consensus on a standardized method to evaluate change in JSW to estimate a clinically important measure of progression.

 P.S. Emrani, None; J.N. Katz, None; C.L. Kessler, None; W.M. Reichmann, None; E.A. Wright, None; T.E. McAlindon, None; E. Losina, None.