EFFECTS OF FINGER POSTURE ON CARPAL-TUNNEL PRESSURE DURING WRIST MOTION

Persistent elevations in carpal tunnel pressure may aggravate carpal t unnel syndrome. This study examined the effects of finger posture on c arpal tunnel pressure during wrist motion. Carpal tunnel hydrostatic p ressure was measured using a saline-filled catheter inserted into the nondominant wrists of 14 healthy individuals. Range of motion tasks of wrist flexion-extension and radioulnar deviation were repeated with m etacarpophalangeal (MCP) joint angles of 0 degrees, 45 degrees, and 90 degrees flexion. Pressures were significantly greater with the finger s straight (MCP = 0 degrees) than when the MCP joints were flexed to 4 5 degrees for all radioulnar deviation angles and from 10 degrees of w rist flexion to all angles of wrist extension tested. Pressures were a lso significantly higher with MCP joints at 0 degrees than at 90 degre es for wrist extension angles from 10 degrees to 40 degrees. Pressures increased to over 30 mm Hg (4.0 kPa) in some wrist extension and ulna r and radially deviated postures. Finger and wrist postures should be considered when designing splints or evaluating tasks for patients wit h carpal tunnel syndrome. (J Hand Surg 1998;23A:1004-1009. Copyright ( C) 1998 by the American Society for Surgery of the Hand.).