Extensor tendon dislocation in cerebral palsy.

An 18-year-old man with cerebral palsy presented with a flexion deformity of the middle finger particularly at the metacarpophalangeal joint and ulnar dislocation of the extensor tendon. Releasing the tight ulnar sagittal band and imbricating the attenuated radial sagittal band allowed centralization of the extensor tendon. For complete correction of other deformities intrinsic release and extrinsic flexor muscle lengthening were done. Extensor tendon instability in this case was due to the combined forces of the extrinsic and intrinsic muscles on the retinacular system of the extensor mechanism.