Pinch Strength and Electromyography in Cubital Tunnel Syndrome: Nerve Stability Pre- and Postsurgery

초록

Background: Cubital tunnel syndrome (CuTS) is a prevalent compressive neuropathy with various surgical treatments but no established consensus on the optimal technique. This study compared outcomes and electromyography (EMG) findings between in situ decompression (ISD) and anterior ulnar nerve transposition (AT) and assessed correlations between preoperative EMG parameters and muscle strength. Materials and Methods: We retrospectively analyzed 81 patients with unilateral idiopathic CuTS. Thirtythree underwent ISD and 48 underwent AT, determined by intraoperative ulnar nerve stability. Outcomes included pinch strength, 2-point discrimination, and functional scores (disabilities of the arm, shoulder and hand [DASH], visual analog scale, Bishop). Preoperative EMG measures were compound muscle action potential (CMAP) amplitude and conduction velocity. Correlations were analyzed with adjustment for age. Results: Both ISD and AT improved DASH scores, pinch strength, and 2-point discrimination (P<.05), with no significant differences in postoperative outcomes. Preoperative CMAP amplitude correlated moderately with pinch strength in ISD (P<.05) but weakly or not at all in AT. Postoperatively, no strong correlations between EMG and pinch strength were observed. Conclusion: Both ISD and AT yield comparable improvements in CuTS. Preoperative EMG, particularly CMAP amplitude, may predict muscle strength in ISD but is less predictive in AT, emphasizing the role of pathophysiology in interpreting results. Larger prospective studies are needed to refine surgical decision-making. [Orthopedics. 2025;48(3):159-165.]

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