The One-Bone Leg

Charles I. Hancock, M.D. Richard E. King, M.D.


Since the prime function of the lower extremities is locomotion, adequate length and stability of the limbs are essential. When severe defects are present in the lower extremities, surgical procedures to maintain adequate length and to provide stability are sometimes necessary. In certain defects, creation of a one-bone leg satisfies these two requirements.

In 1905 Huntingtonl first described in detail an operation for replacing a large amount of lost tibia by transfer of the fibula. His patient was a seven-year-old boy who had a diaphysectomy of the tibia for osteomyelitis. The tibia partially regenerated, but the end result was that a 5-inch segment of tibia was missing. The fibula was cut at a point opposite the lower end of the upper tibial fragment. The divided end of the fibula was then firmly planted into a cup-shaped depression in the tibia. Six months later Huntington transferred the lower end of the fibula into the distal tibial fragment. "The wound healed kindly and the boy progressed admirably," he reported. A 3/4-inch shortening of the limb resulted.

Putti2 in 1922 described other methods of substituting the fibula for the absent tibia, as follows: The proximal fibula end is transferred into the inner condylar notch of the femur and may be made to fuse there. Its distal end is implanted into the superior surface of the talus.

When part of the tibia is absent (as in our cases), the fibula is shifted and fused to the shaft of the tibia proximally. If the femur is short, as it often is, the proximal tibia (when present) or the proximal fibula is fused with the distal femur to construct a stump of sufficient length to fit a prosthesis.

In the present paper differing methods of treatment used in two cases of congenital partial absence of the tibia are described.

Case 1 (B.C.)

This patient was born with a congenital partial absence of the left tibia (Fig. 1 and 2 , Fig. 3 ). He was observed until the age of two and one-half years, when a disarticulation of the foot was done. He was then fitted with a patellar-tendon-bearing Syme's-type prosthesis. He used this type of prosthesis until approximately one year ago, when fitting became a problem because the proximal fibula was riding high on the lateral side of the leg. The lower fibula was unstable.

It was decided that a one-bone leg should be made, preserving the proximal tibia and the distal fibula. At surgery with pneumatic tourniquet hemostasis, a skin incision was made from the head of the fibula distally and anteriorly over the tibia. The proximal fibula was exposed subperiosteally and resected (Fig. 4 ). The peroneal nerve was identified and preserved. The tibial fragment was exposed and an osteotomy made through the tibia approximately 3/4 inch distal to the level at which the fibula had been osteotomized. The distal fragment of the tibia was removed. The distal fibula was then telescoped into the medullary canal of the proximal tibia (Fig. 5 ). After satisfactory alignment, the periosteum was closed over the tibiofibular junction and X-rays were taken (Fig. 6 and 7 ). A plaster cast extending to the groin was applied with the knee extended.

When the child returned in one month for follow-up and to be measured for a prosthesis, his cast was broken but the wound had healed. His prosthesis was ordered and applied one month later. When he was last seen 11 months after surgery, new bone formation had occurred and socket pressure was being experienced in the region of the anterior tibia (Fig. 8 ). The anterodistal socket was relieved, and his discomfort was alleviated.

Case 2 (P.P.)

This child was first seen at six weeks of age (Fig. 9 and 10 ) when X-rays showed congenital partial absence of the tibia (Fig. 11 and 12 ). He was observed until the age of four years, when a below-knee amputation was done at the level of the distal tibial segment. He was then fitted with a plug-type below-knee prosthesis. Two years later he had developed overgrowth of the tibia and fibula (Fig. 13 and 14 ), requiring reamputation. When last seen in March 1967 he was doing well.

Discussion

When amputations are performed through the long bones of children, overgrowth is often a problem. If overgrowth can be avoided, additional surgery, hospitalization, and related expenses (a new or a revised prosthesis) can be eliminated. Various techniques have been proposed to decrease the incidence of overgrowth, but the results are not predictable. However, if the epiphysis at the distal end of a growing bone can be preserved, overgrowth will not occur. Case 1 illustrates this important point. Case 2 illustrates the overgrowth problem when long bones are sectioned. In all probability Case 1 will require no further surgery, whereas Case 2 has already been subjected to reamputation once and may require additional reamputation and stump shortening before growth ceases.

Conclusions

  1. Creation of a one-bone leg provides a stable skeletal lever of adequate strength for prosthetic fitting.

  2. Preservation of the distal fibular epiphysis retains growth potential.

  3. Overgrowth requiring reamputation and further stump shortening does not occur if epiphyses are preserved.

Charles I. Hancock, M.D. and Richard E. King, M.D. are associated with the Amputee Clinic Scottish Rite Hospital for Crippled Children Decatur, Georgia

References:
1. Huntington, Thomas W., "Case of Bone Transference," Ann. Surg. 41:249, 1905. 
2. Putti, V., Chiv. d. org, di Movimento, 13:513, 1929.