Amputation or limb-lengthening for partial or total absence of the fibula. Thirty-two patients who had ablation of the foot by the Syme or Boyd technique for partial or total absence of the fibula, with subsequent fitting of a prosthesis, were compared with eleven patients who had lengthening of the lower limb by the Wagner method, to assess the long-term results of each procedure. The final results were evaluated on the basis of pain, limp, limb-length discrepancy, level of physical activity, and satisfaction of the patient. Of the thirty-two patients who had an amputation, twenty-eight (88 per cent) had a satisfactory result, compared with only six (55 per cent) of the eleven patients who had limb-lengthening. The amount of inequality between the lower limbs was classified as follows: Group I--the foot of the shorter extremity was at the distal third of the contralateral, normal limb, and the percentage of shortening was 15 per cent or less; Group II--the foot of the shorter extremity was at the level of the middle third of the contralateral, normal limb, and the percentage of shortening was between 16 and 25 per cent; and Group III--the foot of the shorter extremity was at the level of the proximal third of the contralateral, normal limb, and the percentage of shortening was greater than 26 per cent. Lengthening was best suited for patients in Group I who had stable hips, knees, and ankles and a plantigrade foot. Patients in Groups II and III were best served by ablation of the foot and fitting of a prosthesis. 