The Brown Procedure in Congenital Absence of the Tibia A Report of Two Cases

Alfred B. Swanson, M.D. Van N. Polglase, Jr., M.D. William Applegate, M.D.


Failure of the tibia to develop longitudinally6,7, or complete paraxial tibial hemimelia3, is a relatively rare congenital abnormality manifested by complete absence of the tibia and usually by absence of the medial rays of the foot. The limb is shortened and the fibula is displaced proximally and posteriorly toward the popliteal fossa. The foot is inverted with marked heel varus. There may be associated partial aphalangia or adactylia of the upper extremities. In 1961 Frantz and O'Rahilly3 reported three cases that had been seen at the Area Child Amputee Center in Grand Rapids, Mich. The present report describes two additional cases in which construction of a knee joint by centralization of the remaining fibular head under the femoral condyles as described by Brown2 was undertaken.

Prior to the development of the Brown technique, the accepted treatment for this disorder was knee disarticulation and fitting with a prosthesis1,4,5. The two cases reported here provide further clinical evaluation of this operative procedure.

Case Reports

Case 1.-A Negro girl, born Feb. 15, 1960, (Fig. 1 ), was first seen at the Area Child Amputee Center at the age of two-and-one-half years. She was the product of a normal pregnancy and delivery, with no family history of limb malformations. No known teratogenic drugs were taken by the mother during the pregnancy. Examination of the child revealed bilateral involvement of the lower extremities with complete absence of the tibiae, flexion contractures of the knees, and subluxation of the fibular heads laterally, posteriorly, and somewhat proximally. The feet were held in marked inversion with the distal fibulae palpable along the lateral aspect of the ankle. Each foot had a single ray. A firm mass was palpable on the distal medial aspect of the right limb with a healed surgical incision overlaying this area. In addition, the child had aphalangia of the little finger of each hand.

X-ray examination (Fig. 2 and Fig. 3 ) revealed bilateral absence of the tibiae and displacement of the fibulae. The knees were in flexion. A large exostosis was evident on the medial aspect of the right distal femur. The monodigital feet were in marked inversion.

Prior to her examination in our clinic, the girl had been treated elsewhere by serial plaster casting in an attempt to correct the knee-flexion contractures. In 1962 an attempt had been made to remove the exostosis from the distal femur.

In October 1962 Dr. Frederic Brown attended our clinic and demonstrated his procedure by operating on this child's left leg. Difficulty was encountered in correcting the flexion deformity, and notching of the distal femur to receive the fibular head was necessary. Postoperatively the position of the left lower limb was maintained with Kirschner wire fixation and a long-leg cast at 25 deg. of knee flexion, further extension being impossible. The right knee was treated by serial wedging casts.

Six weeks later a Syme's-type ankle disarticulation was performed on the left leg. A resection osteotomy of the right distal femur, removing three-fourths of an inch of distal femur including the exostosis, was also done. It was hoped that this shortening would allow greater extension of the right knee when relocation of the fibular head was attempted at a later date. Fixation of the osteotomy was by a four-hole plate. The child was then placed in a bilateral spica cast which held the knees in extension.

In January 1963 a Syme's-type disarticulation of the right foot was performed. One month following this, the spica cast was removed. The left knee lacked 20 deg. of full extension and was fixed in this position. The osteotomy of the right femur had healed. The right fibular head was then relocated into the femoral intercondylar notch and fixed with two crossed Kirschner wires. Again it was impossible to obtain full extension, and 30 deg. of flexion at the knee had to be accepted. A single, right, spica cast was applied. The left knee remained quite stiff, almost ankylosed, at 25 deg. of flexion, and wedging casts were applied.

The fixation wires were removed from the right knee six weeks after surgery. Despite night splints, the right knee gradually developed a flexion contracture requiring wedging casts. In June 1963 the child was fitted with end-bearing Syme's-type prostheses with lacer thigh corsets and single-action rigid knee joints. By August the girl was able to ambulate using axillary crutches and a four-point gait. At this time range of motion of the right knee was from 20 to 50 deg. passively, with 20 deg. of varus and valgus instability. The left knee was essentially ankylosed at 25 deg. of flexion and was stable on varus and valgus pressure.

Over the next 18 months the patient required one additional hospitalization for wedging casts, prosthetic replacement, and construction of extension braces for night use.

In May 1965 she was again seen and the right knee was found to have a flexion contracture of 80 deg., with 20 deg. of varus and valgus instability. The left knee was essentially ankylosed at 70 deg. of flexion with only a trace of motion (Fig. 4 ). The girl was unable to ambulate at this time. She was again treated with wedging casts which produced a range of motion on the right knee of 5 to 40 deg. On the left, improvement was obtained to a fixed flexion contracture of 15 deg.

In July 1965 bilateral biceps femoris tendon transfers were performed in an attempt to alleviate the problem of the progressive and recurrent flexion contractures of the knees. Despite this surgery, the girl again gradually developed flexion deformities. On the right, 15 deg. of extension was lacking with flexion to 60 deg. The left side became fixed at 40 deg. of flexion with no passive motion. In July 1967, in an attempt to straighten her legs, a high fibular osteotomy was performed on the right limb, and an arthroplasty of the left knee, utilizing a Silastic-button implant, was done. The button was placed in the proximal end of the fibula and made to articulate in the intercondylar notch of the femur. With these two procedures, full extension was finally achieved. The child was immobilized in a bilateral spica cast. Mobilization of the left knee was begun two weeks postoperatively, but the right limb was kept immobilized for seven weeks. Little motion was achieved by the arthroplasty. Ambulation was reinstituted in October 1967.

In July 1968 the range of motion of the right knee was from 10 to 45 deg. of flexion, with 20 deg. of varus and valgus instability. The left knee was fixed at approximately 15 deg. of flexion. She was ambulatory and had no discomfort (Fig. 5 ). X-rays (Fig. 6 ) show the healed osteotomy of the right fibula with satisfactory widening of the fibular metaphysis. Both epiphyses remained open and the head was well seated under the femur. On the left limb (Fig. 7 ) the Silastic button remained in place. However, considerable adaptive changes about the head had occurred with marked narrowing of the joint space. Satisfactory widening of the metaphysis had occurred.

When last evaluated in March 1970, the patient was ten years of age. She was ambulatory in bilateral Syme's-type prostheses with knee hinges and thigh corsets. She did not require any external support, but her gait was not good. The knees were stiff and flexed. The right knee showed a passive range of motion from 35 deg. to 85 deg. There was no active extension. Twenty deg. of varus instability and 50 deg. of valgus instability were present. The left knee was ankylosed in 30 deg. of flexion and 25 deg. of valgus.

Case 2.-This Caucasian boy, born Apr. 5, 1967, was first seen at the Area Child Amputee Center at three months of age (Fig. 8 and Fig. 9 ). The pregnancy and delivery had been normal; the mother had taken no unusual medication, and there had been no illness during her pregnancy. On examination the child's knees flexed to 90 deg. and passively extended to 50 deg. The fibular heads were subluxated posteriorly and slightly laterally. There were small dimples over the knees. There was marked laxity on varus and valgus stressing. The feet showed internal rotation of 90 deg. The right foot had three toes and the left foot had two toes, the medial rays being absent in each foot. The remainder of the examination yielded normal findings.

When the child was still three months of age, the left proximal fibula was surgically placed beneath the femur and into the intercondylar notch. Fixation was achieved with a single Steinmann pin inserted through the medullary canal of the fibula, and proximally into the femur. As in Case 1, full extension was impossible due to contractures of the soft tissues posterior to the knee. All possible soft tissues were released and the medial hamstrings were transferred anteriorly. A one-and-one-half spica cast was used for immobilization. Three weeks later a similar procedure was performed on the right limb. On this side both medial and lateral hamstrings were transferred to the anterior fibula and a Silastic membrane was placed between the fibular head and the distal femur. Again, it was impossible to achieve full extension. A bilateral spica cast was applied. This surgery was complicated by a wound infection which cultured Pseudomonas. This required removal of the Steinmann pin and the Silastic material. The wound then healed uneventfully. The spica cast was removed in September 1967 and the Steinmann pin was removed from the left fibula. The boy was then placed in a brace hinged at the knee to provide gradual extension. Knee pads fitted on the proximal fibular areas provided gentle pressures to hold the fibulae centered within the intercondylar notches. Passive range-of-motion exercises were started. On discharge from the hospital in January 1968 the ranges of motion of the knees were from ten to 90 deg. of flexion bilaterally with 20 deg. of varus and valgus instability.

This exercise program was continued at home. The boy was readmitted to the hospital in July 1968. The range of motion at that time was from 15 to 95 deg. of flexion in the right knee, and from 15 to 75 deg. of flexion in the left. A Syme's-type disarticulation of the left foot was performed. In September 1968 a Syme's-type disarticulation of the right foot was carried out. His bracing program was continued (Fig. 10 and Fig. 11 ).

X-rays (Fig. 12 and Fig. 13 ) showed flaring of the fibular metaphyses with maintenance of good joint space and good positioning beneath the femurs.

In November 1968 nonstandard, end-bearing, Syme's-type prostheses were fitted, with rigid knee hinges and a toddler harness (Fig. 14 ). The knee on the right lacked five deg. of full extension and flexed to 60 deg., with 20 deg. of varus and valgus instability. On the left, five deg. of extension was lacking, with flexion to 45 deg., and 15 deg. of varus and valgus instability.

This child was last seen in November 1970. He was three years and seven months of age and was ambulatory in prostheses with locked knee hinges. He walks without external support but was unable to walk with the knee hinges unlocked. Both knees showed a passive range of motion from 35 to 70 deg. of flexion. The right knee had 20 deg. of varus and 20 deg. of valgus instability. The left had ten deg. of varus and ten deg. of valgus instability. Marked flaring of the proximal fibula beneath the femoral condyles was noted on x-ray. Active extension of the knee was fair on the right. None was present on the left.

Discussion

From these two cases and those reported by Brown, two major problems can be seen to arise following transfer of the fibular head beneath the femoral condyles. These are 1) a tendency to develop flexion contractures, and 2) instability of the knee joint in the mediolateral plane. In our first case, followed eight years after initial surgery, the child was two-and-one-half years of age when the procedure was performed. This girl required repeated applications of wedging casts and, eventually, hamstring transfers followed by arthroplasty and fibular osteotomy before satisfactory extension was achieved. In the second case the hamstrings were transferred anteriorly as part of the centralization procedure. The knees were also held in extension for a prolonged period by utilizing braces; but he, too, shows a tendency toward development of a progressive flexion deformity.

It would appear from our experience that better results could possibly be obtained with this operative procedure if the patient were operated on earlier in life. As in the treatment of any other orthopaedic disability, the possibilities are better for obtaining a stable knee joint with motion when the surgical procedures are done in infancy.

Concerning the mediolateral instability, this appears impossible to control except by using a thigh corset and rigid knee hinges for support. This requirement is to be expected from the nature of the abnormality and the findings at surgery of poor or absent ligamentous support to give stability to the knee.

In both cases, no attempt was made to salvage the feet. We agree with Brown that Syme's-type disarticulations will allow improved function through fitting of end-bearing prostheses. Although the epiphyses remain open at the fibular ends, a deficiency of fibular growth is to be expected. Compensation for this deficiency can be readily provided in the prostheses.

Summary

Two cases of bilateral, complete tibial hemimelia are presented. Both had knee construction by centralization of the fibulae beneath the femoral condyles and Syme's-type disarticulations as described by Brown. The problem of recurrent knee-flexion deformities is discussed and early hamstring-tendon transfer is suggested. We feel that the procedure described is superior to knee disarticulation in children with this type of deformity.

Area Child Amputee Center, Michigan Department of Public Health Grand Rapids, Michigan

References:
1. Aitken, George T., Amputation as a treatment for certain lower-extremity congenital abnormalities, J. Bone and Joint Surg., 41-A:7:1267-1285, Oct. 1959. 
2. Brown, F. W., Construction of a knee joint in congenital total absence of the tibia (paraxial hemimelia tibia), J. Bone and Joint Surg.,47-A:4:695-704, June 1965. 
3. Frantz, Charles H., and Ronan O'Rahilly, Congenital skeletal limb deficiencies, J. Bone and Joint Surg., 43-A:8:1202-1224, Dec. 1961. 
4. Frantz, C. H., Clinical aspects of phocomelia and related malformations, Soc. Inter, de Clin. Ortho, et Trauma, Symp. IV, 409-431, Sept. 1963. 
5. Sulamaa, M., and S. Ryöppy, Congenital absence of the tibia, Acta Orthop. Scand., 34:337-348, 1964. 
6. Swanson, Alfred B., Classification of limb malformations on the basis of embryological failures, Inter-Clin. Information Bull., 6:3:1-15, Dec. 1966. 
7. Swanson, A. B., A. Barsky, and M. Entin, Classification of limb malformations on the basis of embryological failures, Surg. Clin, of N.A., 48:5:1169-79, Oct. 1968.