| On Stump Socket Lamination |
The Tanzania Training Centre for Orthopaedic Technologists (TATCOT) at the Kilimanjaro Christian Medical Centre (K.C.M.C.) in Moshi, Tanzania offered an advanced professional seminar in August 1980. One of the participants, an American Mennonite missionary nurse, Miss Mary Harnish, working at the Shirati Hospital, Lake Victoria, presented some of the prostheses and orthoses manufactured by herself and her assistants in the most simply equipped rural workshop at their hospital. No professional would have thought that these devices would give proper service to their users.
Fortunately Mr. S. Heim, orthopaedic-engineer and project manager of TATCOT, which is assisted by the German Agency for Technical Cooperation (GTZ), and I, an orthopaedic surgeon specialized in orthopaedic technology, had been invited to visit Shirati Hospital after the seminar. We were greatly surprised at the simplicity of manufacture, especially of a PTB below-knee prosthesis with cuff suspension which was exclusively hand-made due to a lack of machinery commonly available.
We followed the prosthetic manufacture step by step, with the amputee sitting and his thigh resting on a small stool. Prominent bony and pressure sensitive areas of the below-knee stump were padded with some cotton material, then two handknitted woolen stockings were pulled on to the stump and the knee. Afterwards the entire assembly was covered with a thin sheet of plastic foil, followed by four layers of stockinette. Resin was prepared and brushed on the stockinette. After setting the socket was taken off and cut along trimlines to PTB shape. A hand-carved, roughly preshaped lower shank-foot-"component" made from a locally grown, extremely light wood was cut to proper length and glued to the provisional socket by a mixture of resin and sawdust. After another check of length and fit the entire prosthesis was painted with resin again, reinforced all over (including the rockerlike foot) by fibre glass patches this process being repeated two or three times. Finally, a cotton stockinette was pulled over the prosthesis and painted with a brown coloured resin. A sole of lyre-rubber was attached to the rocker foot, a piece of inner tube was prepared for supracondylar suspension and a sheet of plastazote was glued on the interior of the socket, and the prosthesis was then ready for use.
On the occasion of our first visit we met two or three patients who had just been or were just being fitted; one of them, a completely blind bilateral below-knee leprosy amputee convinced us that this kind of simple manufacture could be more helpful than we ever would have thought possible. However, evaluation after long term use under the severe conditions due to climate and in a farming environment had not been made yet. Additional difficulties in the patients returning to the workshop for review restricted repairs even if necessary.
For these reasons we had the distinct interest to follow-up those patients who had been fitted in Shirati throughout the last 10 years and more recently at Sikonge Hospital. The GTZ became interested in our proposals; with additional financial assistance from the
German Leprosy Relief Association (DAHW) Mr. J. Fischer, certified prosthetist and orthotist from Denmark, and I returned to Tanzania in November/December 1982 for evaluation of a total of 47 amputees.
Some 38 of them had a below-knee amputation due to leprosy and were most likely to develop serious stump problems. They were living in rural areas, mainly as subsistence farmers; only a few of them were occupied in small trade, some others were unemployed due to their severe disability. Prosthetic treatment of these patients showed on average unexpectedly good results with an overall positive effect on daily life and general rehabilitation.
Despite this satisfying outcome there were some prostheses that were no longer usable due to improper fit of the socket, causing pressure sores and ulcerations of the stump. The plastazote soft liner, which was compressed and non functional after a short period of use, turned out to be by far the weakest link in this kind of prosthesis, and no other part had been repaired or replaced so often. However these leprosy patients used their appliances regardless of pressure sores because the decrease or total loss of sensitivity and the protheses were absolutely necessary for ambulation as most of them could not walk with crutches alone.
Besides other minor criticisms from a professional technical point of view, the principles as well as the long term results indicated that this simply manufactured prosthesis had proved valuable under the local conditions. Its method of manufacture, however, had to be improved prior to its introduction to other developing countries with similar local conditions.
The necessity for less problematic sockets, especially for a long-lasting soft liner that would help prevent pressure sores and ulcerations, were the reasons for initiating a research programme. The results are laid down in this manual as the first part of a complete guide for the manufacture of this type of prosthesis. It describes how to fabricate an improved socket and soft liner according to proper professional prosthetics and biomechanical principles. The handling of plastics for this purpose, avoiding the use of heavy and sophisticated machinery, is well explained and incorporates modern materials such as fibre glass, resin and PE foam. The first trials are promising and future follow-up of a reasonable number of patients fitted with the new-socket should be an important step forward to further progress.
I should like to thank Mr. J. Fischer for his fine cooperation during our basic evaluation as well as Mr. S. Heim and Mr. W. Kaphingst, who developed the techniques drafted in this manual, for their excellent work. I hope and wish it will become an additional "brick" for building up professional orthopaedic technology in developing countries.
Priv. Doz. Dr. med. Georg Neff