Certain Congenital Limb Deficiencies Occurring In Twins And Half-Siblings

Chestley L. Yelton, M. D.


Paraxial fibular hemimelia, often called congenital absence of the fibula, and paraxial tibial hemimelia, often called congenital absence of the tibia, have been reported and described by many authors. Of all the long bones, it is generally agreed that the fibula is the one most commonly absent in congenitally affected patients. O'Rahilly observed that, after the fibula, congenital absence of the radius, femur, tibia, ulna, and humerus follow in order of frequency. The absence of these bones is usually associated with other malformations and deficiencies in the extremity, such as talipes valgus or varus, syndactylism and suppression, or absence of one or more rays.

Of the reported cases of absence of the tibia, and of the reported cases of absence of the fibula, it seems that total absence is more frequent than partial. Unilateral absence is more frequent than bilateral, and, in the unilateral cases, the deficiency is more frequently on the right. The deficiency is nearly always at the distal focus when the defect is partial. In the bilateral cases, there may be total absence on both sides (Fig. 1 ), or total on one side and partial on the other (Fig. 2 ).

Originally, I intended to describe our cases of limb deficiencies involving the tibia and fibula. In reviewing our cases, however, I found that our experience with these conditions parallels that of authors of the racently published reports. Therefore, this article will be limited to a few remarks concerning these deficiencies and to a discussion of certain limb deficiencies in five of our patients, consisting of one set of twins and three half-siblings.

Etiology

The etiology of limb deficiencies is not known. The consensus of opinion is that there are insufficient findings to suggest a hereditary factor in most of the recorded cases. Embryologic studies indicate that the defect in the germ plasm or developmental accident to the embryo occurs at or before the fifth or sixth week of intrauterine life.

Limb deficiencies have been produced experimentally by various means. Multiple skeletal abnormalities appeared in the offspring of rats when the mothers were reared on a diet deficient in riboflavin. The tibiae were affected in a high percentage of instances. It is interesting that the tibiae were also affected in a high proportion of the cases of insulin induced skeletal deformities in chickens. Multiple skeletal deformities have appeared in the descendants of irradiated mice. The theory of constriction by the umbilical cord, amniotic bands, et cetera, as a causative factor is no longer held. Mechanical interference is not involved in any way with long bone deficiencies .

Treatment

No one type of treatment can be outlined for all of these cases. Each is a separate individual problem and treatment varies with the age of the patient, associated anomalies, previous treatment, or neglect of the condition. Conservative measures hold little hope of obtaining a good functional result unless a considerable portion of the proximal tibia, a good stable knee,and a foot whose heel and sole can be made to touch the floor are present. The end result of many of these cases is predictable. Many will end up with leg length inequality and, sooner or later, request amputation.

The modern artificial limb is more useful, makes the child appear more normal, and is less cumbersome than any appliance which can be fitted to one of the cases, whether conservative operative procedures have or have not been performed.

Case Reports

Case 1. J.J. (Fig. 3a , Fig. 3b , Fig. 3c , Fig. 3d , Fig. 3e ), a colored female, is one of twins who were born prematurely with congenital limb deficiencies of the legs and forearms on August 28, 1956. The twins' family is composed of their parents, J. and M., 39 and 30 years old respectively, and three full siblings -two sisters, age 6 and 2 years, and one brother, age 4 years. The twins also have half-siblings - two girls, age 18 and 14, and a boy, age 17 years. These half-siblings are the children of the father's first marriage. All of the siblings and half-siblings are apparently entirely normal. The parents exhibit no abnormality.

J. J. was first seen in the Birmingham Amputee Clinic on November 29, 1961. Her history indicated that she had been fitted with lower extremity prostheses in the past and could not wear them. She walked into the clinic on her knees. Both knees exhibited marked instability, requiring only mild stress to demonstrate the laxity of the ligaments (Fig. 3a and Fig. 3b ).

Examination of both upper extremities shows extensive and multiple deformities from the elbows downward (Fig. 3c ). On the right, the ulna is short and the radius is seen only as several fragments for a distal focal segment. Carpals and metacarpals are fused. Most of the phalanges appear as whorls, with the exception of a single reasonably formed digit. The changes are similar on the left, except that the rudimentary radius and ulna are fused and there is more extensive fusion of the small bones of the hands and no satisfactorily formed digit is present.

Examination of the lower extremities shows changes similar to those in the upper extremities, the right and left side being about equally deformed (Fig. 3d and Fig. 3e ). On the right and left, the tibia and fibula are present only at their proximal ends, with no evidence of a distal focus for either bone. Surgical revision of these abnormalities will be delayed until such time as conservative measures fail.

Case 2. H. J. (Fig. 4a , Fig. 4b , Fig. 4c , Fig. 4d , and Fig. 4e ), a colored male, is a twin of Case 1.

Examination of both upper extremities shows extensive and multiple deformities from the elbows downward (Fig. 4b ). There is marked shortening of the radius and ulna, bilaterally. The carpal and metacarpal abnormalities are not as marked as those of his twin. The phalanges are indeterminate.

Examination of the lower extremities reveals that the tibia and fibula are present in their entirety, bilaterally (Fig. 4c and Fig. 4d ). The right tibia and fibula appear to be identical to the left tibia and fibula; however, each fibula is proportionally longer. The proximal fibular epiphyseal line is at joint level and the distal fibular epi-shyseal line is at the same level of that of the lower tibial epiphyseal line, bilaterally. Examination of the feet shows striking abnormalities (Fig. 4d and Fig. 4e ). Several of the phalanges actually are in a transverse position. He walks well on these extremities and treatment will be conservative.

Additional Case Reports

Case 3. J. P. (Fig. 5a and Fig. 5b ), a colored male, was born on May 15, 1954, and was first seen in the Birmingham Amputee Clinic on January 7, 1959, with congenital abnormalities of both lower extremities.

X-ray examination of the right lower extremity revealed absence of the distal one-half of the tibia. There was evidence of complete inversion of the foot with only two of the tarsal bones showing and the fifth metatarsal and phalanges were missing (Fig. 5a ).

Examination of the left lower extremity revealed the shafts of the tibia and fibula to be normal. There was evidence of complete inversion of the foot with only two of the tarsal bones showing, with three metatarsals and phalanges (Fig. 5a ). The patient walked into the clinic on the ends of his legs. Both a feet were located posteriorly, appearing " like cavus feet that had been plantar flexed 180 degrees with their soles pointing cephalad. He was hospitalized on January 11, 1959, and on January 13, 1959, the left foot was removed, converting this extremity to a modified Syme stump. This was essentially an ankle disarticulation; the lower tibial and fibular epiphyses being undisturbed. On February 9, 1959, a small portion of the distal tibia was removed and the distal one-half of the fibula was moved over under the tibial stump and the two were fixed in end-to-end position with a Rush nail.

On April 2, 1959, the right foot was disarticulated at the ankle, leaving the lower fibular epiphysis undisturbed, and prosthetic-wise, converting this extremity to a Symes. He was fitted with Canadian type Syme prostheses bilaterally on July 1, 1959. The end results, prior to removal of the Rush nail, are shown in Fig. 5b . He soon attained a good gait and wore the original prostheses until June 1, 1960, when, because of longitudinal bone growth, it became necessary to fit him with new prostheses. As expected, he grew out of the left prosthesis sooner than the right. The Rush nail was removed on June 6, 1961, and on July 19, 1961, he was fitted with his third pair of prosthesis, having grown out of those fitted on June 1, 1960. He continues to walk with a good gait.

Case 4. J. W. (Fig. 6 ), a colored male, was born on September 3, 1947, and was first seen in the Birmingham Amputee clinic on January 7, 1959. He was found to have a knee disarticulation on the right and a lobster-type foot on the left. This patient was seen at the Crippled Children's Clinic in 1948, and his records state that X-rays revealed a congenital absence of the right tibia. Unfortunately, the films cannot be located. The knee disarticulation was carried out in November, 1950. He walks with an excellent gait.

Case 5. B. P., a colored female, was born on November 17, 1948, and was first seen in the Birmingham Amputee Clinic on January 7, 1959, with a knee disarticulation on the left and an eight-inch below-knee stump on the right She was seen at the Crippled Children's Clinic in 1949, and her record notes that X-rays show marked congenital deformities of the lower extremities, especially of the legs and feet". Unfortunately, these X-rays cannot be located. According to the record, it seems that there was a congenital ab-sence of the tibia on the left and that the deformity of the right lower extremity is similar to that of the left lower extremity of Case 3. Her surgery had been carried out in 1953.

The family histories of Cases 3, 4, and 5 briefly are as follows: The three mothers are unrelated, each have numerous other children, and all appear normal. However, Cases 3, 4, and 5 are half-siblings, all having the same father, who is married to the mother of Case 3. The parents exhibit no abnormalities.

Summary

Ten instances of Lower limb deficiencies occurring in five patients are reported. Of these five patients, two are twins, and, in addition to their lower limb deficiencies, each twin presents deficiencies in both upper extremities. The remaining three patients are half-siblings.

In 1925, Ollerenshaw reported absence of the tibia in identical twins. These few cases intrigue me, suggesting as they do the possibility of determining the etiolog-ic factors of these abnormalities through genetic research.

Chestley Yelton is Clinic Chief, Amputee Clinic Birmingham, Alabama