Some Preliminary Observations Concerning The Fitting Of Total Contact Sockets To Juvenile Amputees

Dr. McCollough Dr. Matthews Miss Traut Mr. Caldwell

Members of our staff attended schools on the Total Contact Below-Knee (Patellar Tendon Bearing Type) Socket as early as 1959. We were greatly impressed with the beneficial changes which occurred when this type of socket was applied to adult patients with chronic passive stump congestion. An improvement in gait and wide patient acceptance with the Total Contact Below-Knee Socket was also noted. In March 1959, we began to apply this fitting technique to juvenile amputees and have used it with increasing frequency to date.

In March 1959, the fitting of Total Contact Above-Knee sockets on an experimental basis* was initiated by Dr. Malcolm E. McPherson, Chief, Special Orthopedic Clinic, Veterans Administration Regional Office, St. Petersburg, Florida, and concurrently by our clinic. Patient response was overwhelmingly favorable and stump improvement was noted in many cases. As a result, by the Fall of 1960, we were fitting Total Contact Above-Knee Sockets on a routine basis. Three hundred and fifty to 400 sockets of this type have been applied in central Florida to date, primarily to adults, but 18 children have also been fitted in the last three years.

In this article, we are presenting our preliminary observations concerning the fitting of Below-Knee and Above-Knee Total Contact sockets to juvenile amputees.

Below-Knee Fittings

The active case load of our clinic includes 43 patients with below-knee amputations. Forty of these, including three bilaterale, are wearing Total Contact Patellar Tendon Bearing prostheses without sidebars and corsets. The remaining three patients have this supplementary support added to their prostheses.

Since there has been considerable clinical experience in the fitting of Total Contact (PTB) prostheses, this subject will not receive major treatment in our report. However, it should be pointed out that our method of fitting this type of prosthesis differs significantly from the standard or typical procedure in at least two respects. These differences are worthy of mention, together with our observations on the effect of fitting PTB prostheses to children.

In contrast to the usual practice of fabricating the socket with a soft insert liner, we are inclined to favor a hard socket with silastic injected dis-tally and worn with stump socks. With the distal silastic "filler", we are able to provide relief for bony overgrowth, and the need for new socket construction is thus reduced.

The accessory suspension provided for the Total Contact Below-Knee prosthesis is also atypical. It has been our experience that the supracondylar strap, commonly used elsewhere, is frequently inadequate to the needs of juveniles. The extremely hard usage that children give their prostheses and the varied and sometimes bizarre activities in which they engage, tend to create problems not encountered with the adult. Excessive piston action, contributing to bursa formation on the end of the stump, has been experienced, and even loss of the prosthesis is not uncommon, particularly with very short stumps. To obviate these difficulties, we have attempted to maintain a constant total contact relationship by the use of an interior strap and waist band. This method of suspension has worked out satisfactorily. Patient acceptance was good, even in cases with longer stumps, and we now apply it to the majority of our patients. In the following section of our report, Mr. Caldwell, the prosthetist member of our team, will describe the technique employed.

Mr. Caldwell's Remarks

When conventional suspension (such as leather cuffs or dacron straps) is used with the Total Contact Below-Knee Prosthesis, it is some times necessary to "cinch" up the straps tightly in order to achieve adequate retention and security. The Incidence and extent of this tightening is related to various factors, such as stump length, intimacy of socket fit, activity level, and the amputee's feeling of security. When the straps are tightened excessively, the amputee experiences a burning sensation across the quadriceps tendon above the superior pole of the patella. Circulatory embarrassment occurs at times, even in the juvenile patient. This embarrassment is more of a hazard to the adult, of course, and may present a real problem.

In an effort to eliminate these possible difficulties, we have applied a type of suspension designed to maintain the socket firmly against the stump, in all attitudes and under all conditions, without encircling the thigh.

This system consists essentially of two straps (lateral and medial)in the form of inverted V's, which run through a stainless steel ring of the Northwestern University type. This ring is attached to an anterior elastic strap which extends to a waist belt. Fig. 1 and Fig. 2 depict views of the strap with the amputee sitting and standing. Note the changes in the relative length of the anterior and posterior portions of the strap in the two positions. Observe also that the posterior portion of the strap provides a degree of extension-stop assistance. Fig. 3depicts the posterior attachments of the two straps. The posterior straps should be kept away from the hamstrings to prevent chafing and discomfort.

In following our below-knee patients, some for as long as three and four years, we have not observed any deleterious skeletal or soft tissue effects arising from the use of Total Contact Sockets. However, the achievement and maintenance of correct socket fit, and the need for more frequent changes of sockets, constitute a more time-consuming and expensive process than was the case with the old standard below-knee prostheses.

None of our patients has reported that the wearing of this type of suspension with a waist belt was a particular handicap. The suspension offers retention advantages in the juvenile, where vascularity is adequate; and its advantages are multiplied considerably with those patients whose limbs were lost as a result of vascular insufficiency.

Above-Knee Fittings

We began to fit juvenile amputees with Total Contact Above-Knee Sockets early in 1961. Although our juvenile case load in the state of Florida numbers between 500 and 600 patients, a majority of the children with above-knee amputations could not be fitted with Total Contact Sockets. A large percentage of these youngsters have congenital deficiencies and their "stumps" have irregularities and malformations which do not lend themselves to this type of socket.

Our experience in this respect, however, may not be typical of the country as a whole. In the "Normative Survey" of 1,018 cases recently conducted by New York University-Child Prosthetic Studies for the Subcommittee on Children's Prosthetics Problems, 399 children were reported as having 491 lower-extremity amputations or deficiencies. Of these 491 limbs, 165 were classified (for prosthetic purposes) as above-knee or knee-dis-articulation cases. One-hundred-and-fifty-two of these 165 limbs were described as amputation type or surgically converted deficiencies; or as acquired amputations. Precise confirming evidence is not available, but it seems likely that potential candidates for Total Contact Above-Knee Sockets are more numerous than we found in our experience.

In any case, the only patients to whom we have applied Total Contact Above-Knee Sockets nad amputations which were surgical in origin, as conversions of congenital deficiencies, or resulting from tumor, burn, trauma, etc. Eighteen children in these categories were fitted under the auspices of the Florida Crippled Children's Commission, which supports the treatment of juveniles to a maximum age of 21 years. Ten of the children were between the ages of 12 and 15 years, the youngest being seven years old and the oldest 19. Three of the 18 cases had knee-disarticulation amputations, while the other 15 were above-knee amputees.

Some of the sockets were suspended solely with suction. Others had suction plus a Silesian bandage, and one was suspended by a hip-joint and pelvic band, without suction. One of the knee-disarti-culation patients required a Silesian bandage initially, but has now reached the point where it can be safely discarded. This patient was nine years old and had gait difficulties which were through to be partially central in origin.

General Results

The general results obtained in fitting Total Contact Above-Knee Sockets to juvenile amputees were similar to those experienced with adults. Our patients responded enthusiastically and we were pleased to note less stump difficulties. Gait was significantly improved, with marked reduction of lurch, while the general management of the prosthesis on inclines and stairs was greatly improved. Marked stump shrinkage occurred (even in amputees who had previously used quadrilateral open-end sockets).

Subjective reactions of patients old enough to volunteer reliable information were similar to those of below-knee amputees fitted with Total Contact Sockets - they reported that the leg felt more a part of them and that they had better control of the foot, in that they knew more accurately where they were placing it. We attribute these reac-tions to increased proprioceptive feedback and to the fact that the intimate stump-socket contact provides the patient with improved (and more delicate) maneuverability of his prosthesis.

Pressure is exerted over the entire stump surface during stance phase with the Total Contact Socket and this pressure is released during swing phase. The alternating pressure and relaxation enhances the exchange of blood and body fluids between the stump and the central circulation. In a normal extremity, the exchange occurs as a result of muscle action, which is very much diminished in the amputation stump. This circulatory benefit of the Total Contact Socket is highly significant in adult patients with vascular problems, but is also a favorable consideration to the juvenile amputee.

It has been our experience that the average child fitted with a quadrilateral Total Contact Socket does not require a replacement any more frequently than the child wearing a quadrilateral non-total contact socket. The problem of circumferential growth is equivalent for both types of socket, and since the upper femoral epiphysis provides only one-third of the axial growth of the femur, longitudinal development is neither rapid nor extensive. It presents, in fact, less of a problem than is found with below-knee stumps, where the proximal plates of the tibia and fibula contribute 55 and 60 per cent of total growth. For the same reason, bony overgrowth of the femur is relatively rare, while this osseous phenomenon is common in the tibia and fibula.

Maintenance of Total Contact

The maintenance of total contact for proper stump physiology is as important for children as it is for adults. In several cases, we noted areas of redness and puffy edema in the distal two to three inches of the stump. In one case an actual bleb formation occurred. In the early stages we attributed these developments to excessive pressure and relieved the appropriate areas, only to find that prosthetic management of this type aggravated the condition. We then X-rayed one of the patients standing in the prosthesis and discovered a pocket of air directly over the area of the lesion, indicating lack of contact. We built up the area and found that the symptoms disappeared when total contact was re-established, Adults have demonstrated this phenomenon also, and here again, the condition should not be attributed to excessive pressure, but to loss of contact. An exception to this rule is when there is excessive pressure on the bony end of the stump where contact must be maintained. The provision of relief is necessary in cases of this type.

As mentioned earlier, our experience in the fitting of Total Contact Above-Knee Sockets extends down to the age of seven years. No problems related to age were encountered at this level. One of the youngest children in our group, a boy of nine years, was amputated because of osteogenic sarcoma of the distal femur and was fitted with a Total Contact Socket as a first prosthesis. He did not enjoy good health postoperatively, nor did he walk well with the prosthesis prior to his death about a year after fitting. However, he did not experience any stump trouble or prosthetic difficulty due to growth which would appear to contra-indicate use of total contact in a child of his age.

It should be emphasized that the use of Total Contact Sockets necessitates more frequent visits on the part of the patient because of decreased latitude in socket fit. However, the advantages deriving from Total Contact Socket application in juvenile amputees far outweigh the disadvantages presented by the fitting and alignment difficulties. These advantages are even more significant in above-knee cases than they are in below-knee amputees.

* The technique originally used to achieve total contact differed from the three methods now taught at the Prosthetic Schools. Initially, we simply fill in the bottoms of open-end sockets with polyester resin #410 and sawdust. Then we use wood socket brim templates with plaster of Paris wrapping of the distal stump to obtain a negative mold. Since that time we have used both UCB brims and the VAPC jig. It is our feeling that so long as total contact is obtained, the method by which it is achieved is of no great consequence.

Child Amputee Clinic Florida Crippled Children's Commission. Orlando, Florida