Compartment syndrome is a rare but serious complication of prolonged p
elvic surgery. Prompted by two recent cases the authors studied the ef
fect of limb angulation and elevation on Doppler ankle artery pressure
and compartment pressure in ten normal subjects. Mean ankle pressure
when supine was 130.5 (95 per cent confidence interval (c.i.) 124.5-13
6.5) mmHg and fell to 77.2 (95 per cent c.i. 64.6-89.8) mmHg in the Ll
oyd-Davies position with 10 degrees of head-down tilt. Reversing table
tilt to bring the ankle elevation to 0 degrees in Lloyd-Davies suppor
ts restored mean ankle pressure to 114.3 (95 per cent c.i. 105.5-122.9
) mmHg (P<0.001). Placing the lower limb in calf supports was found to
increase the mean intracompartmental pressure from 3.0 (95 per cent c
.i. 1.2-4.8) mmHg to 11.6 (95 per cent c.i. 9.1-14.1) mmHg. Reversing
table tilt significantly restores limb perfusion in patients undergoin
g prolonged pelvic surgery with the legs elevated and may protect agai
nst subsequent compartment syndrome.