Abstract
BACKGROUND: We report two cases of biceps brachii and brachialis paralysis due to musculocutaneous nerve injury in which elbow joint flexion was reconstructed using rotational transfer of the latissimus dorsi muscle with sutures to the radial and ulnar tuberosities, thereby enabling flexion by simultaneous activation of the humeroradial and humeroulnar joints. In cases of associated brachialis paralysis, weaker flexion strength can be expected when the forearm is in a pronated position than when it is in a supinated state. To the best of our knowledge, no previous study has reported the rotational position of the forearm during elbow joint flexion reconstruction. CASE PRESENTATION: Case 1 involved a 30-year-old Asian male who presented with a rupture of the musculocutaneous, median, radial, and ulnar nerves. Reconstruction was performed by rotational transfer of the latissimus dorsi muscle. In this case, the supination and pronation flexion forces were equal. Case 2 involved a 50-year-old Asian man who presented with partial loss of the musculocutaneous nerve, biceps brachii, and pectoralis major due to debridement. Reconstruction was performed by rotational transfer of the latissimus dorsi muscle. In this case, supination and pronation flexion strengths were demonstrated to be equal. Our reconstruction method used the rotational transfer of the latissimus dorsi muscle; the distal muscle flap was divided into radial and ulnar sides to allow elbow joint flexion by simultaneously activating the humeroradial and humeroulnar joints. These sides were then fixed to the anchors at the radial and ulnar tuberosities. Finally, they were wrapped around the myotendinous junction of the biceps brachii or brachialis and secured using sutures. CONCLUSIONS: Although larger studies are required to verify these methods, this case study successfully demonstrates the following: (1) the flexion strength in the supinated position was equal to that in the pronated position; (2) the stability of the humeroradial and humeroulnar joints was unaffected by the forearm's rotational position; and (3) a satisfactory range of motion of the elbow joint was obtained, with no complications.