The Journal of Bone and Joint Surgery, Vol 69, Issue 8 1155-1160, Copyright © 1987 by Journal of Bone and Joint Surgery, Inc
Disarticulation of the knee in children. A functional assessment
RT Loder and JA Herring
Texas Scottish Rite Hospital for Crippled Children, Dallas 75219.
We assessed the functional abilities of six patients who had had
disarticulation of nine knees during childhood by analyzing their gait
using electrocardiographic telemetry. Those who were more than five years
old were further studied by timing them as they ran the fifty-yard
(45.7-meter) dash and by testing the strength of the musculature of the hip
girdle using a Cybex dynamometer. The physiological cost-index of Butler et
al. was used to assess energy consumption. Three patients had had
unilateral disarticulation and three had had bilateral disarticulation.
Kinematic studies showed persistent bilateral abduction of the hip
throughout the gait cycle in all six patients. The flexion-extension arc of
the hip was decreased in the three who had had bilateral disarticulation.
Increased flexion of the hip was noted on the normal side and decreased
flexion, on the affected side in those who had had unilateral
disarticulation. Phase reversal of pelvic obliquity was noted in the
amputees who had had bilateral disarticulation. The prosthetic knee showed
good flexion during the swing phase. All patients showed a mild decrease in
the velocity of gait and in the length of step and stride. The patients who
had had unilateral disarticulation showed decreased duration of the
bilateral stance and single stance phases and increased duration of the
swing phase. Those who had had bilateral disarticulation of the knee had a
normal distribution of the components of the gait cycle: bilateral stance,
single stance, and swing. The physiological cost-index for all six was
within the normal range, indicating minimum energy handicap.(ABSTRACT
TRUNCATED AT 250 WORDS)