Cubital tunnel syndrome is a common peripheral nerve entrapment disorder, which may lead to significant functional impairment in severe cases due to intrinsic hand muscle atrophy. As the disease progresses, clinical prognosis of cubital tunnel syndrome tends to decline, particularly in functional recovery. Traditional treatment strategies have been proven ineffective in restoring intrinsic hand muscle function postoperatively in severe cases. Transposition of motor branch of pronator quadratus surgery has emerged as a solution, offering a better therapeutic option for the patients. This procedure involves end-to-side anastomosis of the pronator quadratus muscle branch with the deep branch of ulnar nerve, introducing additional axons to promote nerve regeneration and providing a novel strategy for functional recovery. Transposition of motor branch of pronator quadratus surgery significantly improves strengths in gripping and pinching as well as fine motor function in patients with severe cubital tunnel syndrome, with notable enhancements in postoperative electrophysiological indicators and improvement of quality of life. The mechanism of it is based on the principles of nerve regenerative biology, utilizing collateral sprouting of axons from the pronator quadratus muscle branch and the supportive microenvironment of distal Schwann cells to achieve reinnervation of target muscles. This article reviews the definition, mechanism, anatomical basis, classification of cubital tunnel syndrome, surgical indications and clinical efficacy of transposition of motor branch of pronator quadratus surgery, intended to provide reference opinions for clinical doctors to gain a deeper understanding and rational application of transposition of motor branch of pronator quadratus.

Cubital tunnel syndrome is a common peripheral nerve entrapment disorder, which may lead to significant functional impairment in severe cases due to intrinsic hand muscle atrophy. As the disease progresses, clinical prognosis of cubital tunnel syndrome tends to decline, particularly in functional recovery. Traditional treatment strategies have been proven ineffective in restoring intrinsic hand muscle function postoperatively in severe cases. Transposition of motor branch of pronator quadratus surgery has emerged as a solution, offering a better therapeutic option for the patients. This procedure involves end-to-side anastomosis of the pronator quadratus muscle branch with the deep branch of ulnar nerve, introducing additional axons to promote nerve regeneration and providing a novel strategy for functional recovery. Transposition of motor branch of pronator quadratus surgery significantly improves strengths in gripping and pinching as well as fine motor function in patients with severe cubital tunnel syndrome, with notable enhancements in postoperative electrophysiological indicators and improvement of quality of life. The mechanism of it is based on the principles of nerve regenerative biology, utilizing collateral sprouting of axons from the pronator quadratus muscle branch and the supportive microenvironment of distal Schwann cells to achieve reinnervation of target muscles. This article reviews the definition, mechanism, anatomical basis, classification of cubital tunnel syndrome, surgical indications and clinical efficacy of transposition of motor branch of pronator quadratus surgery, intended to provide reference opinions for clinical doctors to gain a deeper understanding and rational application of transposition of motor branch of pronator quadratus.