Clinical And Prosthetic Experiences With Porous Laminate Sockets

Newton C. McCollough, M.D. Jack L. Caldwell, CP. Ardis Traut, R.P.T.


The transition of socket materials from wood to aluminum, to polyester and epoxy resins has brought great benefits to the amputee population in the last twenty years. The strength, durability, decrease in weight, ease of fabrication and configuration, and cosmetic attributes of these plastics have given all interested parties a great sense of satisfaction. Plastics have, however, one major drawback. It seems to us that there is almost no material on the face of the earth, having the favorable characteristics stated above, which is more resistant to the transmission of air and water. Patients wearing impervious plastic sockets in hot, humid climates constantly complain of excessive retention of perspiration, sensations of extreme heat, unpleasant odor, the necessity of multiple sock changes, and skin reactions from irritations.

Until the present time we have used multiple socks and/or perforations, where applicable, to relieve these complaints to a degree; but there is no question in our minds that unfavorable patient reactions to the material frequently forms the basis for rejection of the prosthesis, especially in the cases of unilateral upper extremity amputees.

In the past, we have vociferously requested information about porous laminates and now,having acquired some clinical experience with it, our staff has prepared this preliminary report. Personally, we have been limited to twelve months' experience with the material, but have greatly benefited from the contributed (two years) experience of Dr. Richard E. King and J. E. Hanger, Incorporated, of Atlanta, Georgia.

Climatic Conditions

According to the United States Weather Bureau, the relative humidity varies from 55 to 100 percent during our long Florida summers. During the heat of the day the ability of the air to hold water increases as the temperature rises and the relative humidity may fall as low as 55 percent. However, the greater potential for water absorption is usually satisfied by the regular afternoon showers which may raise the relative humidity rapidly again to between 90-100 percent. A light covering helps cool the body faster because of the larger area of evaporation in the vicinity of the skin surface, but the skin loses its cooling function and body temperature may increase when an impenetrable covering holds the perspiration close to the body, preventing evaporation. We might conclude that a porous socket can induce cooling by evaporation from the skin, from the shirt above it, and to some degree from the socket itself.

The problem is accentuated in Florida in bilateral upper amelias, or in multiple amputees, where large areas of body surface are covered by plastic laminate. Moreover, congenital cardiac anomalies are not infrequent in bilateral upper amelias, and the weight and rigidity of the socket on the chest and the necessity of covering large areas of skin surface present serious embarrassment to these patients. Fortunately, in most bilateral upper amelias, great strength is not a prerequisite in shoulder and pectoral caps, and the porous laminates have sufficient stability for this purpose.

We have applied one below-elbow and five shoulder disarticulation sockets to four patients, including one bilateral amelia and one bilateral amelia-phocomelia. Four additional cases are being presented by the courtesy of Dr. Richard E. King, of Atlanta and J. E. Hanger, Inc., of Atlanta. The results of this series of eight cases will indicate our belief that we have found sufficient durability and acceptance Of this material to warrant continuation of its use in perhaps even wider areas as the efficiency of the material is improved. The prosthetists supplying our porous laminate sockets have had experience in approximately thirty such sockets. We will report on a few of those fabricated for use in Florida and Georgia.

Case Studies

Case 1 - A.M.-White female, Age 10, Right Phocomelia and left amelia (Fig. 1 ),

This patient was initially fitted with bilateral shoulder disarticulation prostheses at about the age of three. She has a congenital cardiac anomaly described as a patent ductus arteriosus and a septal defect, rather marked cardiac hypertrophy and complains of dyspnea and cyanosis on exertion, particularly during hot weather. She is a constant wearer and attends school daily. Until May 11, 1961, she had worn standard non-porous shoulder caps. She was proficient in the use of the limbs; however, she found them very tiring and was always happy to have them removed. The porous laminate sockets replaced those of polyester plastic on this date and she has less perspiration and less fatigue, and wears her limbs for longer periods with far more comfort.

The prosthetist experienced difficulty in keeping the humeral sections of the arm attached to the shoulder cap, due to the difference in the density of the porous and the non-porous plastics in the two sections. This difficulty was a technical one and has been overcome by inserting a filler of plastic resin and sawdust in the porous plastic at the area of attachment between the shoulder cap and the humeral section. There have been no

breakdowns since that time. The mother reports a definite decrease in shortness of breath and lip cyanosis. This may be attributed to the fact that the more flexible porous laminate pectoral portions of the socket allow a greater range of chest expansion. The greatest advantage has occurred during hot periods. The roughness of the sockets does not disturb the patient. These were made with the regulation nylon stockinette and are the most porous of any of the sockets we have applied. All the other sockets were made with nylon of lesser denier. No socket hygienic problems were encountered .

Case II - S.V.-White male, Age 7. (Fig. 2 ). Bilateral upper amelia, moderately obese, large for his age. There was no evidence of cardiac anomaly. He has an associated right paraxial hemi-melia, fibular, with marked shortening, which has been fitted with a non-standard socket and SACH foot. He is a very precocious child, physically and emotionally overactive, who perspires profusely and is resistive to suggestion. He was first fitted in 1960 with non-porous sockets. He did not like the arms, but wore them at school. Even in cool weather his shirts were damp with perspiration. Porous sockets were applied in February of 1962, and the results have been gratifying to the patient and to the parents. There is much less fatigue and perspiration reported, with increasing tolerance to the prostheses. The problem of the humeral section tearing loose from the shoulder cap was overcome by installing passive abduction hinges at the shoulder.

Case III - D. C.-White male, Age 7 (Fig. 3 ). Upper left phocomelia with associated congenital arthrodesis of the right elbow, including loss of pronation and supination. He has always been a regular arm wearer, is a very active, wiry patient, and highly intelligent. Perspiration has never been a problem with this boy, as it has in the two previously mentioned cases. However, he has had skin irritations at times while wearing the non-porous socket which was first applied on 3/23/59. On 6/15/61, the porous laminate socket was applied. His mother reports that he wears the arm longer hours without fatigue and that he has none of the skin irritations that were present with the old type socket. The patient and his mother both feel that it has been a definite advantage.

Case IV - R. P.-White male, Age 7. Right acheiria, first seen 6/25/59, a resident of south Florida, was fitted with his initial socket of conventional plastic on 7/23/59. He was re-fitted with a porous laminate socket on 2/22/62. The mother expressed concern about being able to cleanse the socket of surface dirt. The porous laminate socket, single wall wrist disarticulation type, was stable and allowed five pounds of pinch with the Dorrance terminal device.

The patient's mother believes this prosthesis is generally more comfortable, although the child complains of feeling hot when he goes to kindergarten. He perspires more than a normal child and it was noted that this prosthesis is cooler than the last one, and the perspiration evaporates more quickly. The child is wearing an extra sock while we await growth to compensate for some looseness of the socket. The mother feels that the socket will be more satisfactory from the standpoint of being cooler when the extra sock is discarded.

There have been no rashes or skin probl ems with the socket, and, from the internal aspect, there have been no complaints as far as hygiene or inability to keep the socket clean are concerned. The one definite complaint from the mother was the fact that the socket stains easily on the outside and is difficult to clean. The child gives the prosthesis hard usage, but so far it has withstood this and has had no cracks or breaks.

Case V - C.S.-White male, Age 18. This patient was originally fitted with a conventional above-elbow prosthesis on 2/4/60. Due to several factors he was unable to wear the prosthesis with any degree of comfort or success. On 4/4/60, a porous plastic above-elbow prosthesis was prescribed by Dr. King. This was their first porous plastic prescription. The patient accepted the porous socket with some degree of doubt, due mainly to the rough appearance of the socket. The problem of roughness has now been solved. Other than the rough socket, the patient accepted the prosthesis completely and as of this date has had no complications.

Case VI - J. B.-White male, Age 17. Elbow disarticulation. This patient has been fitted successfully with an Elbow Bearing prosthesis since the age of nine. A porous plastic prosthesis was prescribed for him and he was fitted on 2/7/62. The patient is active in sports and outdoor activities and the idea of the porous laminate was immediately accepted. He likes this prosthesis over all the previous ones, and has experienced no complications as of this date.

Case VII - A.B.-White female, Age 12. Above-elbow. This patient was fitted with a porous prosthesis on 11/29/61. Prior to the fitting of the present porous socket, she experienced difficulty with a rash on the distal end of the stump. After wearing the new porous socket for a few weeks, the rash cleared up. Whether this is a coincidence, or the air filtering through the walls helped to clear up the rash is questionable. The patient expressed 100% satisfaction with this type of prosthesis .

Case VIII - J. A.-Colored male, Age 16. He was initially fitted with a porous plastic prosthesis on 2/1/61, accepted the prosthesis, and after training was sent home. After two months of wear, it was found that the patient's prosthesis was extremely unsanitary, due to dirt and lint collecting in pores of the socket. He was sent home again, with instructions that the socket should be cleaned every night. The patient was checked again in three months, and it was found that the socket was in excellent condition and free from dirt and lint. He now accepts the prosthesis 100%.

Prosthetic Considerations

(The following section of our report, entitled "Prosthetic Considerations", was written by Mr. Caldwell, James W. Stanford, CP., and Marcus Phelps, CP., of J. E. Hanger, Incorporated.)

It is the unanimous opinion of the prostnetists participating in this project that the porous laminate socket has been accepted completely by the patients fitted with this type of appliance. There has been no reported incidence of reaction to the epoxy type resins from any of the patients.

Using only epoxy resins, which have greater strength than the polyesters, we have had no major breakdown of the socket construction due to failures of the lamination. However, since the oldest limb that we have fabricated of porous plastic is only a little over two years old, we cannot at this time make an unqualified statement regarding its durability.

Despite these positive characteristics, porous laminates present problems. Our earlier sockets were fabricated with regular nylon stockinette, which produced sockets with excellent porosity characteristics. However, the socket exteriors were rough, cosmesis was poor, and the edges were very difficult to smooth. The recent use of nylon of lesser denier and pigmentation has alleviated many of these defects, but has also reduced porosity. A degree of porosity, which will alleviate the undesirable characteristics referred to above and yet supply sufficient ventilation to the socket must be established clinically and prosthetically.

We have found also that the technique for making porous laminate plastic sockets is more time-consuming, expensive and difficult than the fabrication of standard plastic arms. According to one study in Atlanta, it takes approximately one and one-half times longer to make a porous plastic arm than is required for the non-porous product.

Summary

To date, our experience with porous laminates has been confined to upper extremity sockets and from a clinical point of view the new material has been most satisfactory. In our warm, humid climate the greatest benefits have been derived by patients with high amputations whose socket requirements involve covering large areas of the remaining body surface. However, expressions of acceptance and relief have been received even in cases of long below-elbow stumps. Thus, while it is our feeling that patients with shoulder disarticulations and short above-elbow stumps will be the prime benefactors, we will continue a wider application of the use of the material to search for the perimeters of its satisfactory function as a socket material.

The possible application of porous laminates to lower extremity sockets is of interest, but would appear to pose problems of strength, durability and, in the case of the above-knee amputee, the maintenance of suction as a means of suspension. We understand that these problems are under investigation at the Army Prosthetics Research Laboratory and elsewhere.

No disadvantages have been apparent from the clinical aspect. From the prosthetic standpoint, however, a number of special considerations (as compared to standard laminations) are involved:

  1. Achievement of a satisfactory porosity -cosmesis (roughness), balance.

  2. Provision of adequate strength ("fresh" resins, proper curing, reinforcement of retainer attachments and joint inserts).

  3. Observance of special precautions in handling the epoxy resin and hardener used in fabrication to avoid skin and eye irritation (proper curing of the laminate is also necessary to avoid the possibility of patient skin irritation, although we did not encounter any problems in this regard).

  4. Necessity of observing good socket hygiene.

We again express our appreciation to Dr. King, and also to Mr. Stanford and Mr. Phelps for their cooperation in permitting us to use their case studies, observations and conclusions in this report.

(Editor's Note: In view of Dr.McCollough's generally favorable experience with porous laminate sockets, a brief report on the status of this technique is presented in the following article.)

Florida Crippled Children's Commission Orlando, Florida