Use of a Multiply Adjustable Hip-Control Orthosis in Cerebral Palsy *
BY R. S. RIGGINS, M.D., R. G. TAYLOR, M.D., AND Y. SETOGUCHI, M.D. Child Amputee Clinic, University of California Davis Medical Center, Sacramento, California
One technique for the management of children with proximal focal femoral deficiency (PFFD) involves converting the limb to a single lever arm by knee fusion and disarticulation of the ankle, and then fitting the child with an above-knee prosthesis. Frequently, continued growth from the distal femoral growth plate and proximal tibial growth plate causes the stump to become too long, so that the prosthetic knee is far below the child's normal knee. We have attempted to obviate this problem by excising the knee through the distal femoral and proximal tibial growth plates at the time of fusion. Following the ankle disarticulation, the only significant growing element is the distal tibial epiphysis, and this epiphysis can also be removed at the time of ankle disarticulation if necessary. A slightly better end-bearing stump results, however, if this epiphysis does not have to be excised. The following case illustrates the principles of this method.
J.M. was born with a Type II PFFD and, when seen in our Child Amputee Clinic at 1 year of age, he was 6 cm short on the involved right side, with a total limb length of 25 cm and a tibial length of 14cm (Figure 1) . At the age of 1 and 1/4years, a knee fusion was carried out by removing the knee through the distal femoral and proximal tibial growth plates. At the same time, the fibular head was also excised through its proximal growth plate. A posterior approach was used so that the neurovascular structures could be adequately protected. A compression clamp and transfixion pin were used to stabilize the fusion (Figure 2) . Two months later the pins and clamps were removed, and an ankle disarticulation was done. The fusion has progressed satisfactorily (Figure 3) , and the child is presently fitted with an end-bearing, above-knee, pylon-type prosthesis with a SACH foot and no knee joint. An ischial seat is used to reduce the pistoning of his unstable hip. In the near future we plan to add a knee joint which initially will have outside hinges until his normal extremity has grown sufficiently long to allow the use of a conventional knee. We estimate that the final length of the child's stump will be between 35 and 40cm1. Since the average length of a male's femur is 47cm at the termination of growth, the child's stump should be short enough to allow the use of a conventional prosthetic knee, aligned at the same level as his normal knee.
1. Anderson, M., M. B. Messner, and W. T. Green, Distribution of length on the normal femur and tibia in children from one to eighteen years of age. J Bone Joint Surg, 46-A:1198, 1964.