Carpal tunnel pressures and wrist position in patients with colles' fractures.

Intracarpal canal interstitial fluid pressures were determined in the wrists of 22 patients with 23 Colles' fractures. Mean values were 18 mm Hg in neutral wrist position, 27 mm Hg in 20 degrees flexion, 47 mm Hg in 40 degrees flexion, and 35 mm Hg in 20 degrees extension. Ten of 23 wrists (45%) had pressures greater than 40 mm Hg in 40 degrees of flexion. Because of the high incidence of median neuropathy associated with immobilization of wrist fractures in a position of marked flexion, an awareness of the magnitude of increased interstitial fluid pressure should lead to alternative methods of treatment in many cases.