He Surgical Management And Prosthetic Fitting Of A Child With Bilateral, Intercalary, Paraxial Hemimelia-Fibular

Edward F. Wenzlaff, M.D.

This child was born on May 29, 1965, with congenital absence of the fibulae bilateral, bowing and shortening of the tibiae, unstable knee ligaments, and bilateral dislocations of the ankles (Fig. 1 and 2 ). Sensory and motor modalities were relatively normal.

The baby was the product of a nine-month gestation, complicated by a fall experienced by the mother in the fifth month, which resulted in a fractured skull, fever, and rash. Delivery was vaginal and uncomplicated, the child's birth weight being 6 pounds 9 ounces. Congenital anomalies at and below the knees were noted at birth. The neonatal course was uncomplicated, but at seven weeks the child weighed only 6 pounds 10 ounces, despite a history of adequate caloric intake. Changes in the feeding formula resulted in improved nutrition and weight gain.

When the boy was 18 months of age, it became apparent, following repeated amputee clinic visits, that the prominent medial malleoli were embarrassing the circulation to the skin overlying these bony prominences on the medial aspects of the dislocated ankles. Therefore, resection of the bony prominences was accomplished on December 9, 1966. The child's recovery was uneventful.

The clinic members and orthopedic staff then grappled with the problems posed by further management of the lower extremities, and by prosthetic fitting. It was believed that the feet were useless for walking, and that the possibility of making them suitable for ambulation by surgical or other means was quite remote. Instability of the knee joints further complicated matters. Marked laxity of all ligamentous components existed bilaterally. The child could actively subluxate the tibiae posteriorly. Despite this laxity, the strength of the quadriceps and hamstring muscles of both extremities was good. Hence, the decision to be made was whether to simply ablate the feet, and attempt to fit the child with Syme's (or below-knee) prostheses, or to perform knee disarticulation amputations and fit to that level.

After interclinic consultation and much deliberation, it was decided to perform bilateral Syme's-type amputations. It was felt that functional muscular activity of the knee joints, combined with protected weight-bearing afforded by prostheses and eventual ambulation, would improve the general joint integrity. These procedures were delayed on two occasions because of microcytic hypochronic anemia and pharyngitis. The amputations were finally effected on July 13, 1967. However, because of premature weight-bearing, in spite of attempts to restrain the child, debridement and revision was necessary 11 days later. Ultimately, complete healing was obtained.

By September 18, 1967, the be-low-knee Syme's-type stumps were well healed. Essentially, the child had the equivalent of two 6-inch below-knee stumps, measured from the center of the knee axis, with excellent weight-bearing potential (Fig. 3 ). The child continued to pull himself to a stump-standing-erect position in his crib, and it became apparent that he was most anxious to begin bipedal activity. The ligamentous laxity persisted (Fig 4 ), and it was feared that further deterioration of these structures would occur with continued unprotected standing on the stumps. Accordingly, a prescription for bilateral below-knee prostheses with side hinges and thigh lacers was formulated. The sockets were end-bearing, with soft inner liners. Over-the-shoulder-strap suspension was included (Fig. 5 ).

The patient began formal gait training. His response to the prostheses was positive. He readily attained balance control, maintaining a wide base of support. When step-taking was instigated, the child was unable to maintain the knees in the extended position during stance phase on each individual limb. It therefore became necessary to apply manually controlled drop locks to the outside hinge joint of each prosthesis. With the knee joints locked, the child began taking steps in a satisfactory reciprocal progression.

The patient is now two and a half years old. His training has progressed satisfactorily, and with assistance he can ambulate using quadri-pod canes. He wears his limbs daily, with no complaint. His gait pattern still leaves much to be desired, in that he has not perfected foot placement and continues to employ a wide base of support. Nevertheless, the clinic is optimistic that this youngster will eventually achieve independent ambulation. His future progress will be closely watched to determine the effect of prosthetic wear, particularly with respect to the knee joints. Hopefully, active control of the knees will eventually be attained, thus eliminating the need for joint locks on the prostheses.

Edward F. Wenzlaff, M.D. is associated with the Amputation Clinic Chief Kernan Hospital Baltimore, Maryland