Background: Periarticular bony erosions are common in chronic cases. This study was designed to evaluate the accuracy of Ultrasound in diagnosing periarticular bony erosions compared to plain X-Ray films.
Material and Methods: The study was designed as a clinical trail descriptive study.15 patients with chronic AR that were clinically suspicious for having periarticular bony erosions were examined by PA X-ray of hand and subsequently had Ultrasound. The US machine used was Volosun GE and 13 MhZ linear probe was used. The study was double blinded and the radiologist performing the Ultrasound was not aware of X-Ray findings and the Rheumatologist was unaware of US findings.
Results: From 15 patents 420 small joints were examined from which 42 joints were excluded as the films were not available due to error in filing .132 metacarpophalyngeal, 120 proximal interphalyngeal and 126 distal phalyngeal joints were examined. In metacarpophalengeal joints 67 erosion was diagnosed by ultrasound and 72 by x-Ray. Bony erosion was diagnosed in 44 proximal interphalengeal joints by ultrasound and 36 on X-ray. No erosion was seen in distal interphalengeal joints by either method. The sensitivity and specificity of ultrasound for metacarpophalengeal joints was 73% and 80%, for proximal interphalengeal 75% and 82% respectively.
Conclusion: The sensitivity and specificity of Ultrasound in diagnosing erosion of small joints was 74% and 88% respectively. With accuracy of 75 % for metacarpophalyngeal joints and 80% for interphalyngeal joints’ erosion ultrasound proved to be accurate and simple method for diagnosing periarticular bony erosions of Ruomatoid Arthritis.