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Lower Extremity Amputation and Prosthetics
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Lower Extremity Amputation and Prosthetics
Lower Extremity Amputation and Prosthetics
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1
Question
What is the major cause of lower extremity amputation today?
Answer
The major cause of lower extremity amputation today continues to be peripheral vascular disease (PVD), particularly with associated diabetes.
2
Question
What percentage of all lower extremity amputations in the United States are due to complications of diabetes?
Answer
Two-thirds of all lower extremity amputations in the United States today are due to complications of diabetes.
3
Question
What are the levels of amputation for lower extremities?
Answer
1. Partial toe: Excision of any part of one or more toes. 2. Toe disarticulation: Disarticulation at the metatarsal phalangeal joint. 3. Partial foot ray resection: Resection of the 3rd, 4th, 5th metatarsals and digits. 4. Transmetatarsal: Amputation through the midsection of all metatarsals. 5. Ankle disarticulation (Symes): Ankle disarticulation with attachment of heel pad to distal end of tibia may include removal of malleoli and distal tibial-fibular flares. 6. Long transtibial (below knee): More than 50% of tibial length. 7. Transtibial (below knee): Between 20% and 50% of tibial length. 8. Short transtibial (below knee): Less than 20% of tibial length. 9. Knee disarticulation: Amputation through the knee joint, femur intact. 10. Long transfemoral (above knee): More than 60% of femoral length. 11. Transfemoral (above knee): Between 35% and 60% of femoral length. 12. Short transfemoral (above knee): Less than 35% of femoral length. 13. Hip disarticulation: Amputation through hip joint, pelvis intact. 14. Hemipelvectomy: Resection of lower half of the pelvis. 15. Hemicorporectomy: Amputation of both lower limbs and pelvis below L4-L5 level.
4
Question
What are the principal lower extremity prostheses?
Answer
The principal lower extremity prostheses are partial foot, Symes, transtibial, and transfemoral, as well as knee and hip disarticulation.
5
Question
What is the purpose of partial foot prostheses?
Answer
The purposes of partial foot prostheses are to restore, as much as possible, foot function, particularly in walking, and to simulate the shape of the missing foot segment.
6
Question
What is a transtibial prosthesis?
Answer
A transtibial prosthesis, formerly known as below knee, refers to an amputation in which the tibia and fibula are transected while the patient retains the anatomical knee with its motor and sensory functions.
7
Question
What components are included in a transtibial prosthesis?
Answer
The components of a transtibial prosthesis include the foot-ankle assembly, shank (lower leg), socket, and suspension component.
8
Question
What is the function of the foot-ankle assembly in a prosthesis?
Answer
A foot-ankle assembly restores the general contour of the patient's foot, absorbs shock at heel contact, plantarflexes in early stance, and simulates metatarsophalangeal (MTP) hyperextension toe-break action in the latter part of the stance phase.
9
Question
What are non-articulated feet?
Answer
Non-articulated feet include designs like the Solid Ankle Cushion Heel (SACH), which has a wooden or metal keel covered with rubber for shock absorption and plantarflexion, and the SAFE foot which allows for moderate lateral motion.
10
Question
What differentiates flexible foot and springlite foot?
Answer
Flexible foot and springlite foot are described as energy storing, energy releasing, or dynamic, with a long band of carbon fiber extending from the toe to the proximal shank that acts as a leaf spring.
11
Question
What is a single-axis foot?
Answer
A single-axis foot is an example of an articulated foot that absorbs shock and controls plantarflexion but does not allow for medial-lateral or transverse motion.
12
Question
What are multiple-axis feet designed to do?
Answer
Multiple-axis feet move slightly in all planes to aid the wearer in maintaining maximum contact with walking surfaces, and some include electronic sensors for greater ankle excursion.
13
Question
What is the function of a shank in a prosthesis?
Answer
The shank is the substitute for the human leg, restoring leg length and transmitting body weight from the socket to the prosthetic foot.
14
Question
What are two types of shank in prosthetics?
Answer
The two types of shank are exoskeletal and endoskeletal.
15
Question
What is an exoskeletal shank?
Answer
An exoskeletal shank, also called crustacean, is typically made of rigid plastic and shaped to simulate the contour of the anatomical leg, usually finished with plastic tinted to match the wearer's skin color.
16
Question
What is an endoskeletal shank?
Answer
An endoskeletal shank is a modular shank consisting of a central aluminum or rigid plastic tube, usually covered with foam rubber, allowing for slight adjustments to alignment.
17
Question
What is the purpose of a socket in a prosthesis?
Answer
The socket is designed to contact all portions of the amputated limb for maximum load distribution, assist venous blood circulation, and provide maximum tactile feedback.
18
Question
What is a lined socket?
Answer
A lined socket generally includes a resilient liner made of materials like polyethylene foam, polyurethane, or silicone, providing cushioning and facilitating alterations in socket size.
19
Question
What is the function of socks, sheaths, and liners in lower extremity prostheses?
Answer
Socks, sheaths, and liners are used to ensure a snug fit in the prosthesis, with varying thicknesses and materials to accommodate the volume changes in the amputation limb.
20
Question
What are cuff variants in prosthetic suspension?
Answer
Cuff variants include supracondylar cuffs made from leather or flexible plastics that encircle the thigh above the femoral condyles, allowing for adjustable snugness of suspension.
21
Question
What is vacuum-assisted suspension in prosthetics?
Answer
Vacuum-assisted suspension combines a pump, liner, and sleeve to achieve elevated vacuum in an airtight environment, promoting fluid exchange and increasing proprioceptive awareness.
22
Question
What is osseointegration in relation to prosthetics?
Answer
Osseointegration is a surgical approach where a metal post is implanted in the distal bone, allowing direct attachment of the prosthesis, eliminating the need for traditional suspension systems.
23
Question
What is supracondylar (SC) suspension?
Answer
Supracondylar suspension involves extending the medial and lateral walls of the socket above the femoral condyles, which increases stability and eliminates the need for a cuff.
24
Question
What are the advantages of supracondylar suprapatellar (SCSP) suspension?
Answer
Supracondylar suprapatellar (SCSP) suspension provides increased medial-lateral stability, a pleasing contour at the knee, and eliminates the need for buckles or closures.
25
Question
What is the function of SCSP suspension in amputated limbs?
Answer
SCSP suspension accommodates the short amputated limb.
26
Question
What potential issues might arise from the high anterior wall of a prosthesis?
Answer
The high anterior wall may interfere with kneeling and presents a conspicuous contour when the wearer sits.
27
Question
What is a thigh corset suspension and how does it benefit individuals with sensitive skin?
Answer
Thigh corset suspension is a type of prosthetic suspension that may benefit individuals with sensitive skin by providing support through metal hinges attached to a flexible plastic corset.
28
Question
What are some benefits of a thigh corset in prosthetic use?
Answer
The corset increases frontal plane stability and provides increased area for weight-bearing load distribution.
29
Question
What are the drawbacks of using a thigh corset suspension?
Answer
The resulting prosthesis is heavier, can foster piston action, and prolonged use may produce pressure atrophy of the thigh.
30
Question
What factors affect the ease of donning a prosthesis with a thigh corset?
Answer
It is more difficult to don due to a series of pressure closure hook-and-loop straps that must be fastened.