Thirty established fixed flexion deformities of the knee in 18 rheumatoid arthritis patients were studied prospectively to assess the results of 8 weeks of out-patient treatment using the Flowtron intermittent compression stocking. A 44% mean correction of the fixed flexion deformity was obtained from an initial mean of 29 +/- 1 degrees to 16 +/- 1 degrees (P less than 0.001). More than 85% of this correction was obtained in the first 4 weeks of treatment. There was a significant correlation between the correction obtained and the inflation pressure (P less than 0.05), but the time of daily use (minimum 60 min) was not a significant factor. The modified Stanford Health Assessment Disability Index fell from an initial mean of 2.17 to 2.03 (P less than 0.01).