EXTENDED REPORT

Comparison of quantitative and semiquantitative indicators of joint space narrowing in subjects with knee osteoarthritis

S A Mazzuca¹, K D Brandt², B P Katz¹, K A Lane¹, K A Buckwalter³

¹ Department of Medicine, Indiana University School of Medicine, Indianapolis, IN USA
² Department of Medicine and Department of Orthopaedic Surgery, Indiana University School of Medicine
³ Department of Radiology, Indiana University School of Medicine

Correspondence to:
Dr Steven A Mazzuca
Indiana University School of Medicine, Rheumatology Division, 1110 W. Michigan St, Room LO 545, Indianapolis, IN 46202-5100, USA; smazzuca{at}iupui.edu

Objective: To compare quantitative estimates of change in joint space width (JSW) with semiquantitative ratings of the progression of joint space narrowing (JSN) with respect to sensitivity to change over time.

Methods: 431 obese women 45 to 64 years old with unilateral radiographic knee osteoarthritis were randomised to 30 months’ treatment with doxycycline 100 mg twice daily or placebo. Quantitative estimates of change in JSW in the medial tibiofemoral compartment from fluoroscopically assisted semiflexed AP radiographs were obtained at baseline and 16 and 30 months after randomisation. Radiographic JSN was rated (0–3 scale) in the same images by two readers using a standard atlas. Changes in overall severity of knee osteoarthritis were derived from gradings of conventional standing AP radiographs at baseline and 30 months, with blinding to treatment group and chronological order of examination.

Results: Follow up radiographs were obtained from 381 subjects (88%) at 16 months and from 367 (85%) at 30 months. The treatment groups did not differ in the frequency of significant loss of JSW by dichotomous criteria (0.5 mm, 1.0 mm, 20%, or 50% of baseline JSW). Progressors and non-progressors, as defined by each of the dichotomous outcomes, differed significantly in mean value for quantitative measurement of change in JSW at 30 months (p0.001).

Conclusions: Quantitative and semiquantitative indicators of progression of osteoarthritis in fluoroscopically standardised radiographs of osteoarthritic knees are highly related, but the effect of doxycycline on articular cartilage thickness was more easily detected with quantitative measurements of change in JSW than with semiquantitative ratings of JSN.

Abbreviations: DMOAD, disease modifying osteoarthritis drug; ECHODIAH, evaluation of the chondromodulating effect of diacerein in osteoarthritis of the hip; JSN, joint space narrowing; JSW, joint space width; K&L, Kellgren and Lawrence (radiographic criteria); WOMAC, Western Ontario and McMaster Arthritis Index

Keywords: knee osteoarthritis; osteoarthritis progression; joint space narrowing

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Houssiau, F (2007). Thirty years of cyclophosphamide: assessing the evidence. Lupus 16: 212-216 [Abstract]