Limb Prostheses

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Limb Prostheses
Limb Prostheses

• Definition
• A prosthesis is an artificial replacement for any
  or all parts of the lower or upper extremities,
  it is a device that is designed to replace, as
  much as possible, the function or appearance of a
  missing limb or body part.

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Purpose

• A prosthesis is used to provide an individual who
  has an amputated limb with the opportunity to
  perform functional tasks, particularly ambulation
  (walking), which may not be possible without the
  limb.
• The prosthesis may also be made for use during
  activities or sports, such as dancing, swimming,
  cycling, golfing, and climbing.
• The type of prosthesis (artificial limb) used is
  determined largely by the extent of an amputation
  or loss and location of the missing extremity.

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Characteristics of a successful prosthesis

• Be comfortable to wear,
• Easy to put on and remove,
• Lightweight,
• Durable, and cosmetically pleasing.
• Function well mechanically and require only
  reasonable maintenance.
• Depends on the motivation of the individual, as
  none of the above characteristics matter if the
  patient will not wear the prosthesis

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Considerations when choosing a prosthesis

• Amputation level.
• Contour of the residual limb.
• Expected function of the prosthesis.
• Cognitive function of the patient.
• Vocation of the patient (eg, desk job vs manual
  labor).
• A vocational interests of the patient (ie,
  hobbies).
• Cosmetic importance of the prosthesis .
• Financial resources of the patient.

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Problems may occur when using prosthesis are

• The poor fitting of the prostheses, causes
  unequal weight load to lower limbs. This may
  cause extra stress or pressure on the other
  (unaffected) leg, or on the stump. The increased
  pressure may lead to pain and skin problems. Skin
  breaks that are not treated can become infected.
  Over time, this may also make another amputation
  necessary.
• Walking with prosthesis on takes extra energy.
• The stump should be checked every day for
  redness, blisters, soreness, or swelling.
• Prosthesis need to be adjusted several times
  before it fits well.

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Prostheses (Artificial limbs) are typically
manufactured using the following steps

• Measurement of the stump.
• Measurement of the body to determine the size
  required for the artificial limb.
• Creation of a model of the stump.
• Formation of thermo-plastic sheet around the
  model of the stump This is then used to test
  the fit of the prosthetic.
• Formation of permanent socket.
• Formation of plastic parts of the artificial limb
  
• Different methods are used, including vacuum
  forming and injection molding.
• Creation of metal parts of the artificial limb
  using die casting.
• Assembly of entire limb.

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Prostheses are either preparatory (temporary) or
definitive (permanent).

• temporary prosthesis is fitted while the residual
  limb is still maturing. A preparatory prosthesis
  allows the patient to train with the prosthesis
  several months earlier in the process. Use of a
  preparatory prosthesis often results in a better
  fit for the final prosthesis, since the
  preparatory socket can be used to mold the
  residual limb into the desired shape. During this
  period, the patient test drives the prosthesis
  and learns what it can and cannot do.

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The advantage to using a temporary prosthesis

• It shrinks the residual limb more effectively
  than the elastic wrap.
• It allows early bipedal ambulation.
• Certain individuals can return to work.
• It is a positively motivating.
• It reduces the need for complex exercise program.
• It can be used by individuals who may have
  difficulty obtaining payment for permanent
  prostheses.

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Lower Limb Prostheses

• There are several levels of lower limb
  amputation, including
• 1) Partial foot,
  2) Ankle disarticulation,
• 3) Transtibial (below the knee),
• 4) Knee disarticulation,
• 5) Transfemoral (above the knee),
• 6) Hip disarticulation.
• The most common are transtibial (mid-calf) and
  transfemoral (mid-thigh).

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Lower Limb Prostheses
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Upper Limb Prostheses