New bone formation at amputation sites in electrically burn-injured patients.

Sixty-one amputation sites in 43 electrically injured men were examined for significant new bone formation. Twenty-eight amputations were classified as long bone (6 above knee, 4 below knee, 4 above elbow, 14 below elbow); 28 small bone (9 hand or finger and 19 foot or toe); and 5 disarticulations. Significant new bone formation occurred at the amputation site in 23 (82%) of the 28 long bone cases, but none occurred in the small bone or disarticulation cases. This difference was significant at the 0.0001 level (chi square = 40.53, 2 df). Fourteen (78%) of upper and nine (90%) of lower extremity sites had significant new bone formation. The average time from amputation to diagnosis of new bone was 38 weeks, range from 5 to 110 weeks. Eight of these 23 patients required surgical revision of the stump and/or revision or reconstruction of their prosthesis. Clearly, the ability to predict new bone formation in electrical burn amputees has important clinical and economic applications.