Pressure and tendon strain in the sixth extensor compartment of the wrist during simulated provocative maneuvers for diagnosing extensor carpi ulnaris tendinitis.

Abstract

Various provocative maneuvers for diagnosing extensor carpi ulnaris (ECU) tendinitis have been reported; however, it remains unclear which maneuver is the most sensitive to detect ECU tendinitis. To clarify this, we investigated and compared the extratendinous pressure and ECU tendon strain in the sixth extensor compartment of the wrist during various provocative maneuvers for diagnosing ECU tendinitis. Nine upper extremities from nine fresh-frozen cadavers were examined. We investigated extratendinous pressure in the ECU fibro-osseous tunnel of the distal ulna and ECU tendon strain during eight forearm positions-neutral rotation, pronation, supination, pronation with wrist flexion, supination with wrist flexion, supination with wrist extension, both hand and forearm supination, and supination with ECU full loading-to simulate provocative maneuvers reported to detect ECU tendinitis. Pressure was significantly higher during both hand and forearm supination (carpal supination test) and during supination with wrist extension (prayer's hand supination test) than during neutral rotation. The pressure during the carpal supination test was 3 times higher than that during the prayer's hand supination test and 27 times higher than that during the neutral position. Strain was significantly higher during the carpal supination test and during supination with ECU full loading (the ECU synergy test) than during other maneuvers. Both pressure and tendon strain increased most notably during the carpal supination test compared to the other maneuvers, which suggests that the carpal supination test is the most sensitive for the detection of ECU tendinitis.