Graded compression stockings in elective orthopaedic surgery. An assessment of the in vivo performance of commercially available stockings in patients having hip and knee arthroplasty.

We recruited 89 patients who had hip or knee replacements to assess the performance of below-knee graded compression stockings. The pressure gradients generated by the stockings were measured and all patients had venography of the ipsilateral leg. We found that 98% of stockings failed to produce the 'ideal' pressure gradient (+/- 20%) of 18, 14 and 8 mmHg from the ankle to the knee, while 54% produced a 'reversed gradient' on at least one occasion during the course of the study. The overall rate of deep-venous thrombosis was 16.7%. Stockings which produced reversed gradients were associated with a significantly higher incidence of deep-venous thrombosis (p = 0.026) than those with the correct gradient (25.6% v 6.1%). This suggests that the performance of graded compression stockings can be improved if reversed pressure gradients are detected and prevented.