Ultrasonic evaluation of the flexor pollicis longus tendon following volar plate fixation for distal radius fractures

Purpose To evaluate with ultrasound the thickness of the flexor pollicis longus (FPL) tendon and its relationship to the volar locking plate after the fixation of distal radius fractures. Methods We evaluated 27 type C2 and C3 distal radius fractures with ultrasound to evaluate damage to the FPL tendon after volar plate fixation. The thickness of the FPL tendon and its distance to the volar plate in the involved wrists and to the volar rim in the contralateral uninjured wrist were measured on sonograms taken 12 months postoperatively. Measurements of the involved wrists were compared with those of the intact wrists. Results The mean plate-tendon distance in the involved wrist was considerably shorter than the mean volar rim-tendon distance in the intact wrist, and the FPL tendon was considerably thicker in the involved wrist than in the intact wrist. Conclusions In distal radial fractures treated with volar locking plates, increases in the thickness of the FPL tendon and a consequent decrease in the distance between the tendon and the plate can be determined with ultrasonography. This finding is a warning that asymptomatic tenosynovitis may eventually cause tendon ruptures.