Prosthesis, also called artificial limb, is the replacement of the part of the body a patient would have lost due to disease, illness, injury, etc.
Each amputee has a unique shape of the amputated limb and this means that each prosthetic limb must be designed and built according to the patient’s body. For a prosthesis to be used in a most effective manner, there are several factors to be considered while building a prosthesis.
The prosthetist takes precise measurements of the patient’s body. Whenever possible, the prosthetist may take measurements before the amputation is done so that the prosthesis can almost meet the measurements of the natural limb.
The prosthetist and the surgeon team up to decide upon the dressing of the surgical wound. Usually the dressing is done with a compressive garment to remove the fluid from the residual limb. Removal of fluid gives shape to the amputed stump and also promotes healing. A post-operative prosthesis may be fitted temporarily to help in early mobility and weight-bearing activities.
Once the wound has healed and the excess swelling of the residual limb has reduced, the prosthetist takes a plaster mold or fiberglass cast of the residual limb. This cast is used to build the positive model of the patient’s limb using plaster, water and vermiculite. This positive mold is modified meticulously to design the actual wearable interface. A plastic replica of the anatomical residual limb is developed from this modified mold. The replica is used to test the fitting of the prosthesis during the initial building stages.
Once the fitting is finalized the plastic socket is transformed into a more durable carbon fiber or acrylic laminated socket and assembled for the final shaping of the limb. Factors considered while designing the artificial limb include:
Materials used for making prostheses vary according to the requirement, personal choices, comfort, mobility and budget. Materials like thermoplastics, resin, carbon,, silicone, aluminium, titanium, etc are used to create the prosthesis. Some patients prefer life-like appearance and a foam cover and a flexible skin cover on the top of it solves the problem.
Even after the limb has been created and fitted, various adjustments are done over time to provide maximum benefit and effective use of the limb.
Physical therapy is sought by the patient to learn to use the new limb and how to distribute body weight on the new lower limb. Physical therapy also focuses on ADL (Activities of Daily Living).
With advances in technology and designing of the artificial limbs, prosthetics can be custom-made for many special types of uses. Certain types of sports like running, skiing, etc can be done by modifying the prosthesis to suit the needs. Prosthetic arms can be designed for activities like shooting a crossbow, eating with a fork, playing basketball, etc.