Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.

Validation of the Longitudinal Reproducibility of Medial Joint Space Width Quantification in Knee Osteoarthritis.

Goker1,  Berna, Akalin1,  Tayfun, Block2,  Joel A.

Gazi University Medical School, Ankara, Turkey
Rush University Medical Center, Chicago, IL.


Quantification of the radiographic tibio-femoral joint space width (JSW) is a widely used method to evaluate progression of osteoarthritis (OA) and remains the only structural outcome accepted by the US FDA to demonstrate OA disease modification. The aim of this study was to validate the short and long term reproducibility of measurements using Image J (US NIH, Bethesda, MD, in medial knee OA. In addition to being a freely available public access software, it provides a flexible platform for optimizing measurement views for JSW quantification that can be readily learned in only a few minutes.


42 patients with symptomatic medial knee OA (Kellgren-Lawrence grade 2–3, pain on ambulation >30 mm on a 100 mm visual analog scale) were assessed. Semi-flexed fluoroscopy-guided PA knee radiographs (Schuss view) were obtained. Medial knee JSWs, defined as the narrowest interbone distance, were measured independently by two observers, one of which was an experienced observer and the other was a first time Image J user. Inter-observer variability (before and after one hour training) and intra-observer variability, at short term (3 weeks) and long term (4 years) were calculated by using coefficient of variation (CV), as well as intraclass correlation coefficient (ICC).


The index knees (most painful) of 37 patients were analyzed. Patients with lateral compartment OA and medial JSW less than 1 mm were excluded (5 patients). Intra-observer variability at 3 weeks was similar to that at 4 years (Table). One hour training resulted in significant improvement in inter-observer variability.

 CV (%)ICC
Inter-observer variability  
  Before training6.60.89
  After training4.40.98
Intra-observer variability  
  Experienced observer  
   Short term (3 weeks)3.50.98
   Long term (4 years)3.80.97
  First-time user after training  
   Short term (3 weeks)3.80.98


Quantification of the medial JSW of the knee in patients with OA using Image J is reproducible. This method is convenient to apply and requires only brief training to obtain high reproducibility. Moreover, these data confrim that quantitative JSW measurements provide meaningful information, as the method yields results that are stable over a several year period.

To cite this abstract, please use the following information:
Goker, Berna, Akalin, Tayfun, Block, Joel A.; Validation of the Longitudinal Reproducibility of Medial Joint Space Width Quantification in Knee Osteoarthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :2004

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