Keeping the blood flowing

A waterfall with beautiful softness illustrating the delicacy of flow
Keeping the venous blood flowing after knee arthroplasty is vital. The image is CC by Dominik Starosz

As always it is interesting with a randomized controlled trial (RCT). I recently stumbled upon Westrich et al’s RCT on prophylaxis after knee arthroplasties. They randomized between aspirin and enoxaparin (LMWH) where both groups received mechanical pumps immediately after surgery. The difference in DVT:s was really small, 14% vs 18% in favor for enoxaparin. This was not significant in 275 patients.

The study uses ultrasound to detect of DVT:s instead of a venography/phlebography, the gold standard, but I doubt that this has any clinical relevance. Ultrasound diagnostic is today standard practice for detecting DVT:s. There is also frequently a striking difference in the reported DVT:s in these kind of studies, and one’s experience when meeting the patients at a three month follow-up.

What I find fascinating is that this study came out in 2006 and yet very few use mechanical compression in Sweden. In a meta-analysis on mechanical compression vs LMWH after trauma Eppsteiner et al found:

pooled relative risk for mechanical compression compared with subcutaneous heparin was 1.07

Seeing this minimal effect of LMWH I can’t help but wonder: Is it time not to implement mechanical compression on a wider scale?

G. H. Westrich, F. Bottner, R. E. Windsor, R. S. Laskin, S. B. Haas, and T. P. Sculco, “VenaFlow plus Lovenox vs VenaFlow plus aspirin for thromboembolic disease prophylaxis in total knee arthroplasty,” J Arthroplasty, vol. 21, no. 6 Suppl 2, pp. 139–143, Sep. 2006.

R. Eppsteiner, J. Shin, J. Johnson, and R. van Dam, “Mechanical Compression Versus Subcutaneous Heparin Therapy in Postoperative and Posttrauma Patients: A Systematic Review and Meta-Analysis,” World Journal of Surgery, vol. 34, no. 1, pp. 10–19, 2010.

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