Shear Wave Elastography (SWE) Evaluation of Asymptomatic Flexor Pollicis Longus Tendon Condition After Volar Plate Fixation for Distal Radius Fracture

OBJECTIVE: This study aimed to evaluate asymptomatic flexor pollicis longus (FPL) tendon condition after volar plate fixation for distal radius fracture using shear wave elastography (SWE). METHODS: We evaluated 36 distal radius fractures with shear wave elastography to evaluate the FPL tendon after volar plate fixation. Ultrasonography was used to measure the FPL distance to the volar plate in the involved wrists, and the thickness of the FPL tendon in the involved wrists was measured on SWE sonograms taken 12 months postoperatively. Measurements of the involved wrists were compared with those of the intact wrists. The radiographic parameters and Soong grade were collected to analyze the correlation between these indicators and the value of the Young’s modulus and asymptomatic tendon injury. RESULTS: The mean values of the Young’s modulus for involved wrist were lower than for intact wrist tendons. The values of the Young’s modulus were correlated with the FPL distance, radial inclination, and Soong grade. FPL tendons of involved wrists exhibited in the majority a yellow (intermediate) SWE signal, compared to intact wrist tendons, which exhibited a red (hard) signal in the vast majority, and there were significant differences between the involved and intact wrist. CONCLUSION: FPL tendon may develop asymptomatically changes after volar locking plate fixation of distal radius fractures, which can be detected by SWE effectively. FPL distance, radial accretion, and Soong grade may be the main causes of asymptomatic FPL tendon erosion.