Finger surgery

The application of polymeric materials in medicine is a fairly specialized area with a wide range of specific applications and requirements. Although the total volume of polymers used in this application may be small compared to the annual production of polyethylene, for example, the total amount of money spent annually on prosthetic and biomedical devices exceeds 16 billion in the United States alone. These applications include over a million dentures, nearly a half billion dental fillings, about six million contact lenses, over a million replacement joints (hip, knee, finger, etc.), about a half million plastic surgery operations (breast prosthesis, facial reconstruction, etc.), over 25,000 heart valves, and 60,000 pacemaker implantations. In addition, over AO,000 patients are on hemodialysis units (artificial kidney) on a regular basis, and over 90,000 coronary bypass operations (often using synthetic polymers) are performed each year (]J. 

In the area of surgery, Beasley (1983) described a surgical procedure to provide a functional four-DOF hand for persons with C5-C6 quadriplegia. This procedure makes possible precision prehension with careM positioning of the stabili d thumb to oppose the actively flexed index and middle fingers. The result is a functional hand that retains some of its sense of touch. 

Naidu, S. H. (2007) Oxidation of silicone elastomer finger joints. Journal of Hand Surgery-American Volume, 32, 190-193. 

Swanson, A. B. (1972) Hexible implant arthroplasty for arthritic finger joints - rationale, technique, and results of treatment. Journal of Bone and Joint Surgery-American Volume, A54, 435-544. 

Several workers have proposed new combinations of materials in an attempt to overcome wear. Studies involving polyimides, polyamide-imides, and poly-tetrafluoroethylene-filled polyoxymethylene demonstrated that although wear characteristics were good in dry conditions, the presence of lubricants (blood plasma, water) decreased the wear resistance. Results obtained with reinforcing materials such as carbon fibre and with an aluminium oxide ceramic ball used in conjunction with a polyethylene socket have been presented, Examples of other types of reconstructive surgery involving hard tissue replacement are the use of poly(methyl methacrylate) in chest wall reconstruction and repair of depressed skull fractures, the repair of major crano-orbital defects with the aid of a polyurethane-coated poly(ethylene terephthalate) mesh, and the use of silicone rubber in total finger joint and carpal bone replacement. 

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