[A functional and anatomical study of finger deformities in Duchenne muscular dystrophy]

Functional and anatomical studies were performed on 145 patients with Duchenne muscular dystrophy. In the early stage, finger deformities were characterized by hyperextension of the PIP joint together with an extended MP joint, while the DIP joint was extended or flexed. At the advanced stage, the MP joint tended to flex while the position of the PIP and DIP joint remained unchanged. In addition, various modified deformities were observed in a small number of fingers. At the terminal stage, the MP joint, including the PIP and DIP joints, exhibited contracture. The following pathomechanic factors in finger deformities were considered to be important in the development of muscle atrophy and degeneration: Muscle imbalance between weakened extrinsic muscles and not severely weakened intrinsic muscles, retraction of muscles and tendons, and deviation of finger tendons.