Studies on Discrepancy in Length of the Lower Extremities in Poliomyelitis. II. Time Course Change of Discrepancy in Length of the Lower Extremities

To study the time course change of discrepancy in length of the lower extremities after the onset of poliomyelitis, 11 patients were observed for at least 8 years (rapidly progressive type and slowly progressive type) and 5 patients were observed for at least 5 years (non progressive type). Three patterns of change in the discrepancy were observed. a. In the rapidly progressive type, a final discrepancy more than 6.3cm was seen about 12 years after the onset of the disease. The aggravation of the discrepancy appeared as an oblique weak S-shaped curve as it gradually approached the final discrepancy. b. In the slowly progressive type, 3.3 to 5.8cm in the final discrepancy was seen about 12 years after the onset of the disease. The aggravation of the discrepacny showed a slightly upward convex curve, as it gradually approached the final discrepancy. c. In the non progressive type, a discrepancy not exceeding 3.0cm was seen 6 to 8 years after the onset of the disease, after which it remained constant. The rapidly progressive type apperaed to follow the logistic curve, set forth by Verhulst. To test the fitting of this curve, diagrams of finite differences were used. The plotted points were distributed almost along the straight line of finite differences. The slowly progressive type also appeared to follow the logistic curve. To test the fitting of this curve, diagrams of finite differences were used. The plotted points were distributed almost along the straight line of finite differences . The prediction of discrepancy in adult life can be obtained by making a straight line on the diagrams of finite differences based on plotted 3 or 4 points measured at 4 or 5 years after the onset of the disease. A point of intersection of the straight line against the diagonal line between the vertical axis and the horizontal axis indicates the final discrepancy. The predicted values were close to the actual values, and this method of prediction may be useful for the planning of limb equalization