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Prosthesis Fitting

By

Jan J. Stokosa

, CP, American Prosthetics Institute, Ltd

Last full review/revision Jan 2021| Content last modified Jan 2021
Click here for the Professional Version

A prosthesis has 7 basic parts:

  • Residual-limb gel cushion interface: A silicone gel or viscoelastic material that protects the skin and adjusts pressure

  • Suspension system: Connects the prosthesis to the body

  • Socket: Rigid plastic receptacle into which the residual limb with gel interface is inserted (there may be an inner primary flexible socket that helps adjust pressure)

  • Joints (ankle, knee, wrist, elbow) and terminal appendage (hand, foot)

  • Modular endoskeletal system connection couplings: Connect prosthetic joints and terminal appendages and provide adjustability

  • Anatomic shape: Soft foam material that simulates muscle contours and protects endoskeletal components

  • Synthetic skin: Thin, tone-matching layer applied over the anatomic shape

During the fitting process, the prosthetist makes a mold of the residual limb (stump) using plaster or fiberglass bandages or by digital imaging. The mold or digital image is used to create a positive model of the limb, which is then modified to better match the individual characteristics of the person's residual limb.

A socket is formed around the model. This socket is integrated into a diagnostic prosthesis to test various component combinations and determine which option provides the most comfort, stability, function, and efficiency. Because the fit of the prosthetic socket is so important, prosthetists may require several tries to achieve optimal socket comfort and stability.

Once the socket fit is finalized and the components and design have been determined, the definitive socket is fabricated, usually of carbon fiber and other durable materials, and the definitive prosthesis is aligned and optimized. The external appearance is created, either an anatomically realistic one or one that leaves the components exposed. The fitting process takes 7 to 18 visits, depending on complexity, and about 16 laboratory fabrication procedures.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
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