Bilateral changes in somatosensory sensibility after unilateral below-knee amputation

To evaluate possible alteration in proprioceptive and cutaneous sensibility in the nonamputated leg of unilateral transtibial amputees.

Cross-sectional study with between-subjects (amputees vs controls) and within-subjects (nonamputated vs amputated leg) comparisons.

Canadian rehabilitation hospital research laboratory.

Two groups of amputees (34 due to traumatic causes, 14 due to vascular causes), recruited more than 1 year after their prosthetic training; and 2 groups (n=34, n=14) of age-matched control subjects.

Not applicable.

Threshold of movement detection and touch-pressure perception at the knee and foot levels.

In the traumatic group, the sensory thresholds of the nonamputated leg were significantly higher than the control values in the 2 modalities tested. The movement detection was reduced at the knee and ankle levels, whereas a decrease in touch-pressure sensibility was observed only at the plantar site. As expected, a large proportion of the vascular amputees presented with severe sensory deficits in the nonamputated leg, particularly a loss in touch-pressure perception at the foot. The thresholds of movement detection were similar and correlated at both knees in the 2 groups of amputees. For the touch-pressure thresholds, no significant relationship was found between sides at the knee level.

Sensory changes observed in the nonamputated leg suggest that central sensory adaptations occur after amputation. For movement detection, they were marked by a matching of perception on both sides of the body. Functional significance of these changes remains to be determined.