Acta Stereologica



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Leszek Wojnar, Edward Czerwiński & Janusz E. Badurski

Measurement of knee joint space depth using image analysis methods

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Precise measurement of the joint space is very important in diagnosis of osteoarthritis and for the evaluation of treatment results. Classical analysis of radiographs, due to brightness and contrast variation, unsharp object boundaries as well as "human factor", enables getting results with precision not more than 0.5-0.7 mm. This is not nearly sufficient for evaluating progress in the rate of disease or its treatment. In order to improve accuracy of knee joint depth measurements, a new procedure based on image analysis methods, has been developed and tested. Control tests on a series of 60 real radiographs have shown that the image analysis based procedure gives highly repeatable results that agree well with other independent examinations. The precision of measurements has been estimated at a minimum 0.2 mm. Thus, application of image analysis enables getting results with precision approx. 3 times higher than in classical measurements. The analysis does not require very costly equipment - it is enough to use a PC computer and image analysis software. Measurements are relatively quick - one image requires approx. 5 mins to be analysed, including grabbing the image by a CCD camera.

Keywords : image analysis, joint space depth, knee joint, radiographs

To cite this article

Leszek Wojnar, Edward Czerwiński & Janusz E. Badurski, «Measurement of knee joint space depth using image analysis methods», Acta Stereologica [En ligne], Volume 15 (1996), Number 2 - Applications of stereology in life sciences - July 1996, 193-200 URL :

About: Leszek Wojnar

Institute of Materials Science, Cracow Technical University of Technology, Al. Jana Pawła II 37, 31-864 Cracow, Poland

About: Edward Czerwiński

Department of Orthopaedics, Med. Coll. Jagiellonian University, ul. M. Kopernika 19a, 31-501 Cracow, Poland

About: Janusz E. Badurski

Department of Medicine and Rheumatology, Śniadecki Hospital, ul. M. Skłodowskiej 26, 15-950 Białystok, Poland