Evaluation of flexor pollicis longus tendon attrition using color Doppler imaging after volar plate fixation for distal radius fracture.

Abstract

Early diagnosis of attritional wear of the flexor pollicis longus (FPL) tendon is essential in preventing subsequent tendon rupture. There are currently few objective methods of assessing FPL attrition. We hypothesized that color Doppler imaging could visibly detect FPL tendon attrition, and analyzed our results. We evaluated ultrasound imaging of the contact between the FPL tendon and a volar locking plate using the real-time B-mode and Doppler waveforms of the FPL tendon using the continuous Doppler wave mode in 40 patients who underwent fixation of the distal volar locking plate for distal radius fracture. Twenty out of 40 patients underwent plate removal surgery after ultrasound evaluation. We also assessed the relationship between the Doppler waveforms and attrition of the FPL tendon in these 20 patients. Based on the ultrasound findings (n=40), we divided Doppler waveforms of the FPL tendon into three categories: type 1, spindle wave; type 2, spindle wave with spike; and type 3, spike wave. There were 23, 11, and six patients with type 1, 2, and 3 waveforms in the affected hand, respectively. There were 37 patients with type 1, three with type 2, and no patient with type 3 waveforms in the contralateral wrist. Of the 20 patients who underwent plate removal, five had type 3 waveforms. We found tendon fraying or partial tears in three of these five patients. In addition, all five patients showed changes to type 1 or 2 waveforms after plate removal. None of the other 15 patients with type 1 or 2 waveforms had any tendon injuries during plate removal. Spike Doppler waveform can indicate abnormal findings, and may be a useful method to predict tendon attrition, because of its visibility. Level III evidence.