Use Of Triple Wall Sockets For Juvenile Amputees

William E. Gazeley, M.D. Mildred C. Ey, O.T.R. William Sampson, CP.

Our clinic, serving nineteen counties in the Northeastern section of New York State, has attempted to find a solution to the heavy financial burden placed on families or other paying agencies because of the frequent socket changes necessitated by growth in the juvenile amputee. To this end, a triple wall laminated socket, rather than the usual double wall, has been used with a number of children. The results have been gratifying both prosthetically and economically. It is anticipated that by this means total long range prosthetic expense for these children will be considerably reduced.

The Third Wall

The third wall, or inner socket, is made in such a way that it can be easily removed when it becomes too tight for the stump. This provision accommodates an increase in the girth of the stump but does not allow for longitudinal growth. It is therefore recommended that a socket of the maximum allowable length be fabricated initially so that the limbs will tend to equalize during the growth process. Before the child outgrows the socket, the prosthesis may have become slightly short but the disparity is not sufficient to be a problem.

Fabrication Procedures

The following fabrication procedure has been found to be satisfactory:

  1. Start with a prepared cast of the stump, well smoothed, and covered with two coats of clear lacquer (HiGlo).

  2. Lubricate cast with petrolatum and pull FVA bag firmly and smoothly over the cast. Cap distal end of bag.

  3. Lay up inner socket (Fig. 1 -Laminate A). Use two layers of nylon stockinet. Apply another PVA sleeve and proceed with lamination in the usual manner, e.g., using a 75-25 (approximately) mixture of polyster 4110 and 4134. After the laminate is cured leave the outer PVA sleeve in place, again capping the distal end of the bag.

  4. Lay up outer socket (Fig. 1 -Laminate B), using an appropriate number of layers of nylon stockinet for the desired strength. Cover the PVA sleeve, laminate, and cure.

  5. Remove outer layer of PVA from socket B.

  6. Make a form for the forearm extension and prepare a build-up of wax or poly-urethane foam.

  7. Proceed with lamination of outer wall (Fig. 1 - Laminate C) by covering the extension form with an appropriate number of layers of nylon stockinet (usually four), pulling on the outer PVA sleeve, and introducing plastic.

  8. After curing, cut approximate trim line through laminates B and C following the proximal rim of the cast. Be sure not to cut through socket A.

  9. Using heat gun, separate socket A from B and C.

  10. Remove socket A from cast.

  11. Remove outer PVA sleeve from socket A.

  12. Roughen the proximal outer edge on socket A and the inner proximal edge of socket B, along the final trim line to facilitate bonding. A roughened surface of 1/8 inch on each socket should be sufficient.

  13. Fuse socket A and socket B together by applying a thin gunk consisting of a mixture of S0LKA - FL0C and 4110 polyester resin to roughened edges and inserting socket A into socket B.

  14. When the child outgrows socket A, delaminate the area of fusion with a heat gun, and remove the inner socket.

The illustration shows a below-elbow socket. The principle of the triple wall socket could also be applied to the above-elbow prosthesis and we will do this when the opportunity arises. To date, we have applied one triple wall above-knee prosthesis (see Case V), made from a wrap cast shaped by hand, since the available jigs were too big for our purpose. The initial fitting presented no particular difficulty. The below-knee application may present more of a problem because of bony prominences on the stump. However, we plan to attempt this fitting at the first opportunity, utilizing an all-plastic PTB type prosthesis without a soft liner.

The children for whom this technique has been used include six with congenital skeletal limb deficiencies (four upper extremity; one lower extremity; one upper and lower - but with the triple wall procedure used on the upper extremity only) and one traumatic bilateral upper extremity amputee.

Case Histories

Case I

This female child was first seen by our clinic in August 1963 at the age of two and one-half years. She was found to have a left terminal transverse partial hemime-lia with a functional amputation level of short below-elbow. In September 1963, she received her first prosthesis including a triple wall laminated socket. Seven months later, in April of 1964 the inner socket was removed. A clinic appointment was not kept for September 1964, but the mother reported that there were no problems. This child is an excellent user and wears the prosthesis during all waking hours.

Case II

This male child was first seen by our clinic in October 1963 at the age of twenty-three months. He has a congenital deficiency described as a right terminal transverse partial hemimelia, with a functional amputation level of wrist disarticulation. In January 1964 he received his first prosthesis which included a triple wall laminated socket. When last seen in July 1964, the socket was still satisfactory. On his next clinic visit, removal of the inner socket will probably be necessary. He wears his prosthesis all day and is a skillful user.

Case III

This female child was first seen by our clinic in March 1962 at the age of eight months. Her deficiency was a left terminal transverse partial hemimelia, with a short below-elbow functional amputation level. She was fitted with a prosthesis, including a conventional double-wall socket and baby mitt, in May 1962. Eleven months later, April 1963, she was fitted with her second prosthesis, which included a triple-wall socket and an active terminal device. Eleven months later, in March 1964, the inner socket was removed. The child was last seen in July 1964, at which time the socket was still satisfactory. This child wears the prosthesis well and uses it for gross activities.

Case IV

This female teen-ager was eleven and one-half years of age when she was referred to the clinic in September 1962, for prosthetic fitting of a right terminal transverse partial hemimelia, with a functional amputation level of very short below-elbow. In February 1963 she received her first prosthesis, which included a triple-wall socket. Nine months later, in November 1963, the inner socket was removed. In July 1964, fifteen months after the initial fitting, a new prosthesis was prescribed. This young lady wears her prosthesis all her waking hours, and uses it well in bilateral activities.

Case V

This male child was first seen in our clinic in May 1962 at the age of thirteen months. He was found to have a right terminal transverse hemimelia, knee disarticulation, the functional amputation level also being knee disarticulation. He had been fitted with a pylon and pelvic band.

His left club foot had been corrected by casts and was being held in place by a brace. The pylon prosthesis was worn continuously, with adjustments, until August 1964, when he was fitted with a triple-wall plastic laminated above-knee prosthesis.

This was the first above-knee juvenile amputee we fitted with a triple-wall socket prosthesis. The device incorporates a quadrilateral plastic socket with a pelvic joint band and belt, a single axis knee and a SACH foot. Since the leg has been worn for only three months it is still too early to draw definite conclusions on the efficacy of the triple-wall socket for this type of amputation.

Case VI

This male child, first seen in our clinic in November 1962 at the age of nine and one-half months, was found to have terminal transverse partial hemimelias of the left upper extremity and both lower extremities. Functional amputation levels were as follows: left upper extremity - very short below-elbow; left lower extremity -short below-knee; right lower extremity -medium below-knee. He received his prosthesis in May 1963. These consisted of bilateral PTB prostheses with knee joints and thigh lacers for the lower extremities, and a passive prosthesis for the left upper extremity. Because of the multiplicity of his involvements, the child was not fitted with an active upper extremity prosthesis until July 1963, when he was two and one-half years old. He had been making good use of the passive prosthesis in gross bilateral activities, and his mother reported that he tried to hold things in his baby mitt. He has now been fitted with an elbow disarticulation prosthesis (the below-elbow portion of stump was too small to be utilized at this time) with a triple-wall laminated socket. This child wears prosthesis during all waking hours, uses it well for gross activities, and is learning to use the active terminal device in fine bilateral activities.

Case VII

This female child was first seen by our clinic in June 1961. She was then seven years old and had worn prostheses since she was two and one-half years old, at which age she had sustained traumatic bi lateral short below-elbow amputations. She received two new arms in August 1961 and these were worn until April 1963, when they were replaced with a pair of triple-wall socket prostheses. The inner sockets were removed in October 1963. The child was last seen in May 1964, at which time the prostheses were still satisfactory. This child is an excellent prosthetic user, and is even able to perform fine bilateral activities.


Through the use of triple-wall laminated sockets, we have been able to prolong the life span of prostheses for children by six to twelve months, since under ordinary circumstances a new prosthesis would have been necessary at the time the inner socket was removed. Thus, the families and/or paying agencies have been and will be saved several hundred dollars per child during his growing years. Furthermore, because of the time saved by removing an inner socket, as opposed to making a new prosthesis, the prosthetist's efficiency has been increased and he can render faster service to all amputees. We have now adopted the use of triple-wall sockets as standard procedure for all juvenile amputees to whom they are applicable.

William Gazeley and Mildred Ey are associated with the Child Amputee Clinic Sunnyview Rehabilitation Center in Schenectady, New York

William Sampson is associated with the LaTorre Orthopedic Laboratory in Schenectady, New York