Ultrasonography-assisted assessment of the influence of the volar prominence of the plate on the median nerve in distal radius fractures

Objective: The study aimed to explore the effect of differing volar locking plate (VLP) prominence on the median nerve (MN) in distal radius fracture (DRF) with ultrasound assistance to guide clinical treatment.Methods: Forty-four patients who received VLP for DRF at our department were admitted and followed-up be-tween January 2019 and May 2021. Different plate positions were graded using Soong classification; 13 were Grade 0, 18 were Grade 1, and 13 were Grade 2. The MN parameters at different wrist positions in patients with different Soong grades were measured with ultrasound assistance, including the median nerve cross-sectional area (MNCSA), diameter in the radial-ulnar direction (D1), and diameter in the dorsal-palmar direction (D2). The sensation in the affected finger and grip strength were collected at follow-up, scored using the Disabilities of the Arm, Shoulder, and Hand (DASH) scale to determine function, and statistically analysed.Results: The MNCSA differed significantly across Soong grades. The MNCSA at the flexed, neutral, and extended wrist positions was smallest at Grade 0 and largest at Grade 2 (P < 0.05), and that at the neutral position was not significantly different between Grades 1 and 2 (P > 0.05). There was no significant interaction between the wrist positions and Soong grade (P > 0.05). The differences in D1 and D2 among different Soong grades were not statistically significant (P > 0.05). There were no statistical differences in grip strength, DASH, and sensation among different Soong grades (P > 0.05).Conclusions: Differing plate protrusions in DRF treatment did not cause clinical symptoms during follow-up; however, excessive plate protrusion (Soong Grade 2) increased the cross-sectional area of the MN. We recom-mend placing the plate as proximal as possible during VLP treatment of DRFs to avoid excessive bulges affecting the MN.