Knee Disarticulation In Childhood

William F. Donaldson, M.D.


The care of patients with two different types of problems necessitating knee disarticulation amputation stimulated my interest in amputations at this level. Two of these patients belong to that congenital group characterized by partial or almost complete absence of the tibia with a short, bowed fibula and a deformed but fairly normally segmented foot. When both patients were first seen, the amount of shortening already present ruled out the possibility of fibular transplant to the proximal portion of the tibia as an adequate salvage procedure.

The other two patients belong to an entirely different category in that they had sustained severe burns to the lower extremities with loss of blood supply to the extremity, in one patient bilaterally and in the other unilaterally. As a result of the loss of blood supply, guillotine amputations were performed below knee at the lowest possible level for soft tissue survival, as evidenced by the presence of any bleeding in the muscle. Full thickness skin loss was present in all three of these extremities, extending at least as high as the inguinal ligament.

In both patients, and in all three extremities, the approximate level of guillotine amputation was about three to four inches below the joint line. After they had worn a modified form of bent knee, knee-bearing prostheses, both of these patients were subsequently converted to conventional knee disarticulation amputations.

Adult Experience

Knee disarticulation, as an elective site of amputation, has become increasingly popular in the adult. In 1940, S. Perry Rogers reported on knee disarticulation, discussed its advantages and described his technique. In 1954, Colonel Joseph W. Batch, Colonel August W. Spittler, and Captain James D. McFaddin reported their experience with the procedure and described their technique.

It was the latter technique, essentially, that we followed in each of our cases. Our earlier experience was confined to the adult. We found it to be a very satisfactory type of amputation and enthusiastically performed the procedure when presented with the four juvenile cases to be described. We were richly rewarded with the functional results obtained. Consequently, it is our feeling that this technique has a real place in the management of certain problems in the juvenile requiring amputation at or about this level.

Advantages

The advantages of the knee disarticulation are:

  1. It provides an end weight-bearing stump of good quality.

  2. The juvenile patient does not "grow out" of the end of his stump, as occurs in certain instances of amputation through the continuity of bone in the juvenile.

  3. We have been able to obtain a good prosthesis which functions well, and which the child can use with great facility.

  4. Even more significantly, it has permitted us to ambulate two patients with split thickness skin graft coverage over the stump.

  5. It permits the patient to kneel and crawl and perform other similar chili hood activities with great ease.

  6. It has permitted the conservation of the maximum amount of usable stump length in each of our patients.

Technique of Surgery

The technique of surgery basically has been the same, except in the two burn patients, where the technique was modified because of the flexed knee position of the below-knee portion of the stump. In these particular instances, only the adherent portion of the skin about the distal tibia and fibula was excised. All other soft tissue was preserved. This gave us an eliptical incision which, on closure, placed the scar posterior and at about the level of the superior aspect of the femoral condyles. The residual portions of the tibia and fibula were excised extraperiosteally and the stump of the patellar tendon was sutured to the cruciate ligaments. The meniscii were excised.

We made no attempt in these cases to find the popliteal vessels or the ends of the peroneal or tibial nerves, which were encased in scar. The operative wound was then closed in a single layer and a compression dressing applied. All three of these extremities healed with no loss of flap. One required superficial secondary healing of an area about one centimeter in its maximum diameter.

In the two cases of congenital anomalies the technique was essentially that described by Batch, Spittler and McFaddin. A long anterior skin flap and a shorter posterior skin flap was used. The patellar tendon was sutured to the cruciate ligaments without ankylosing the patella to the femoral condyles.

In each instance, as soon as the wounds were healed sufficiently for fitting, the patients were fitted with knee disarticulation prostheses. These prostheses were conventional molded leather knee-bearing appliances with standard below-knee outside knee joints. The standard waist belt or hip joint was used with a fork strap suspension and a lift strap. A check lacer was used to prevent hyperextension of the knee and a SACH foot was used in each instance.

It is important that the leather for the molded socket be reasonably soft so that it molds well to the contours of the extremity. In one instance (Case I), when a second prosthesis was obtained, the leather used was much firmer and it did not mold well to the stump. This necessitated the making of a second molded socket.

Case Studies

Case I - G.E., a Negro female, was first seen at our hospital at the age of six years and ten months. Her right tibia was almost completely absent, measuring 3/4 inch in length. The fibula was bowed and the foot presented in a completely supina-ted position (Fig. 1 ). A disarticulation amputation was performed on March 4, 1954. She was fitted with her knee-bearing prosthesis on September 7, 1954. The patient required approximately four weeks of gait training. She was fitted with a second prosthesis on October 2, 1959 (Fig. 2a , Fig. 2b and Fig. 2c ). G.E. has been a successful prosthetic wearer to date, attending a regular school and performing essentially all normal activities for a girl of her age.

Case II - R.M., Negro female. This patient was seen for evaluation and treatment of her congenitally anomalous right lower extremity at the age of two years and one month. Her tibia measured 4 centimeter in length. She had a bowed fibula. The foot was in a position of 90 degrees of inversion and 110 degrees of dorsiflexion. A right knee-disarticulation was performed on October 31, 1960. She first wore her prosthesis on February 26, 1961. R.M. has been a successful wearer to date (Fig. 3 ).

Additional Case Studies

Case III - M.S., white male. He was admitted to Children's Hospital, Pittsburgh, on October 15, 1957, at the age of three years and ten months, having sustained extensive burns of both lower extremities, trunk, and second degree burns of the face and neck. It was estimated that 30 percent of body surface was involved in the burn.

Vascular supply to the lower extremities was obviously compromised when the patient was first seen, and on November 14, 1957, a left below-knee guillotine type of amputation was performed at the lowest possible level where viable muscle was found. A similar amputation was performed on the right leg on November 19, 1957 (Fig. 4a ).

Both of these extremities were treated in like manner. They were dressed with xero-form gauze compression dressings and, when a granulating surface had been obtained, split thickness skin grafts applied. M.S. was sufficiently healed for prosthetic wearing by December 8, 1958. Aside from minor superficial erosions, he bore entirely satisfactory weight on the prosthesis. These prostheses were modified to avoid any pressure on the distal portion of the flexed tibia and fibula (Fig. 4b and Fig. 4c ). Subsequently, on June 26, 1961, the left leg was converted to a knee disarticulation, with revision of the right leg following on September 11, 1961, as previously described. The patient has since been fitted with conventional knee-bearing prostheses.

Case IV - W.S., white male. He was admitted to the Children's Hospital, Pittsburgh, on May 23, 1954 at the age of four years and three months with burns of the right lower leg, right upper thigh, left upper leg and scattered areas of the back. It was estimated that 25 percent of body surface was involved in the burn. Because of complete vascular insufficiency in the lower right leg, guillotine below-knee amputation was performed on May 30, 1954. The patient was treated similarly to the previous case and was ready for prosthetic fitting by September 30, 1954. He was fitted with a prosthesis similar to Case III. On July 3, 1961 he was converted to a knee disarticulation as previously described, and was ready for prosthetic fitting on August 22, 1961.

Conclusions

The congenital amputees had normal weight bearing skin and one would anticipate a good result. However, we have been very pleased with the use of knee-bearing type of prosthesis in both of our burn cases. We feel that end weight bearing offers a much greater chance of success than an amputation at a higher level - for example, midthigh.

It is our belief that knee disarticulation is a good site of amputation in the juvenile, when indicated, and we urge its consideration by others when faced with similar problems.

Co-Clinic Chief Home for Crippled Children Pittsburgh, Pennsylvania

References:
Batch, Col. J. W., Spittler, Col. A. W., and McFaddin, Capt. J. G.: Advantages of the Knee Disarticulation Over Amputations Through the Thigh. J. Bone and Joint Surg., 36:921-928, Oct. 1954. 
Rodgers, S.P.: Amputation at the Knee Joint. J. Bone and Joint Surg., 22:973-979, Oct. 1940.