Telemetric electromyographic analysis of muscle transferred to the os calcis.

Fifteen inphase muscle transfers to the os calcis from 11 patients with lower motor neuron paralysis were evaluated by means of telemetric electromyography during ambulation. In five of the limbs thus evaluated, electromyographic activity was found to resemble that of the normal triceps surae and had relatively normal proximal muscles. In ten limbs, contraction of the transferred muscle preceded heel strike. This was attributed primarily to proximal muscle weakness, which necessitated premature firing to ensure early knee extension during stance and hence to prevent the knee from buckling during weight-bearing.