The Fabrication of the last wooden prosthesis
A page was turned over for PROTEOR last June, when our industrial production site in France manufactured its last wooden prosthesis. It was ordered by our Centrale Fabrication unit to be exhibited on site and to remind these fabrications which has earned PROTEOR the nickname of “The Wooden Leg” in the region.
This wooden prosthesis is the result of the work of a Centrale Fab’s team including Jean-Noël PETITCLAIRE, the operator who made most of the prosthesis, Bernard TERRIER, foreman of the prosthesis workshop in which the prosthesis has been made, Marc LANTERNIER, configurator who translated the CPO’s data into manufacturing data, and lastly Alain BOIVIN who took care of all the lining of the prosthesis, in other words the finishing.
From left to right: Alain BOIVIN, Bernard TERRIER, Marc LANTERNIER and Jean-Noël PETITCLAIRE
The socket (the upper part) is hand-made by the operator from a raw wooden block, whereas the lower part is the assembly of components manufactured and delivered by the Components Factory and so assembled to obtain a custom-made prosthesis matching the patient’s morphology.
The wooden block is rectangular, but its inner shape is square. The operator has quadrangular templates and carves the block in order to obtain a specific circumference tested every five centimeter. Finally, the inside shape corresponds to the residual limb, and the outside shape to the volume of patient’s thigh. The data inputs are essential. “If the data are not correct, the entire socket has to be re-carved” explains Marc LANTERNIER. Cutting the wood requires good visual assessment and great vigilance because of the machines used. Jean-Noël PETITCLAIRE says that he never “felt apprehensive about it”, but Bernard TERRIER explains that colleagues have not been so confident in the past.
Before finishing, the prosthesis is first sent to an Orthopedic Center where the CPO proceeds to fitting trial with the patient. Modifications can be made if needed. Otherwise, the finishing work starts. The operator begins to take off the extra wood, which decreases the prosthesis weight. The next step consists of circling the socket with string in order to reinforce it. Then a linen cloth is glued onto the socket to avoid the wood to crack or to explode while it is drying. The cloth acts as an armor. The following step is a parchment finish for aesthetic purpose. The parchment is made from a sheepskin dived in water for softening and elasticity. Fixed with wood glue, it has the particularity to tighten the entire wood part while drying. Finally the prosthesis is varnished or painted.
The sense of innovation
The fabrication of this prosthesis requires more than 16 hours of work and noble materials only : wood, leather, sheepskin… In 2016, Jean-Noël PETITCLAIRE still carved fifty wooden blocks. His retirement happens at the same time as the end of the fabrication of these prosthesis which have fitted veterans for a long time. But they progressively disappear and today almost all the prosthesis are made with new materials in fiberglass or carbon.
This evolution is in line with the sense of innovation. “The first cars were in wood, they were carriages. Today, some are in carbon fiber. We could continue to make them in wood, but we make them with other materials, remind Francis NAWROCKI, the director of the Central Fab. This is the same for the prosthesis, we are in line with the evolution. Today’s materials are more easily implemented, with reinforced security conditions and with shorter training times. In a close future, sockets will certainly be made by 3D printing.