Interesting enough question. We know having a big cast on is a risk factor for VTE. I’ve seen one young guy die from a massive PE with a big cast on his leg.
It mightn’t be common, it mightn’t justify risk and expense but it’s definitely a valid question. But do we have an answer as yet?
I figured this paper might help me answer it.
Meek, Robert, and Roger Lien-Kien Tong. “Venous Thromboembolism in Emergency Department Patients with Rigid Immobilization for Lower Leg Injury: Incidence and Risk Factors..” Emergency Medicine Australasia : EMA 24, no. 3: 277–284. PMID 22672168
- Australia madated that all lower limb casts get LMWH. The guideline was for in patients (from what I can make out) but are ED patients really different.
- chart review using various search terms to pull out all the patients with lower limb casts
- tried to ascertain from records if they developed a VTE (obviously this can be a little problematic)
- they also tried to contact everyone in a 3 month period by post and phone to see if they ‘d had a VTE (also a little problematic)
- initial search yielded 10000, they narrowed this down to 6800 >18 and reviewing records left 1200 who actually got a splint
- found 33 VTEs (2.7%)
- in the small 3 month cohort (180 pts) who they actually contacted the rate was 1.7% (or 3 pts…)
- when they put together the VTE they found on chart review and those they found on postal survey they come up with a number between 3 and 7% incidence.
So after reading that, i’m not sure I really have my question answered. Is there anywhere else I can turn to?
Serendipitously there has just been a Best Bet published on this very topic. They come to the conclusion that the rate is about 11%.
As is only fitting StEmlyns have a whole post on it so go read that.