Bilateral changes in somatosensory sensibility after unilateral below-knee amputation

Abstract

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

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

Setting: Canadian rehabilitation hospital research laboratory.

Participants: 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.

Interventions: Not applicable.

Main outcome measures: Threshold of movement detection and touch-pressure perception at the knee and foot levels.

Results: 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.

Conclusions: 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.