Muscle imbalance at the shoulder may lead to internal rotation contracture
of the shoulder and to posterior dislocation of the head of the humerus
(Figure 261.1). Posterior dislocation of the head of the humerus requires
articuloplasty and release of the muscle contracture that led to it. Lengthening
of the subscapularis muscle tendon usually achieves shoulder muscle balance
without causing an unstable shoulder. Flexion contracture of the elbow,
and supination or pronation deformities of the forearm may also occur
and require surgical management.
The possibility of surgical reconstruction of the plexus or neurolysis of the neuroma should be considered in patients who do not recover. The neuroma results from scarring and aberrant axonal growth at the site of injury (Figure 261.2).
Figure 261.2.— Neuroma of the brachial plexus.