Pre Prosthetic Quiz

Question 1

In the sagittal plane, the transfemoral socket is always aligned with:

Answer 1

5 degrees of flexion if the patient has 0 degrees of extension and if there is a contracture, then the socket is pre-flexed to the measured degrees of the contracture plus 5 degrees of flexion

Question 2

If the prosthetic foot is positioned too far posterior in relation to the prosthetic socket:

Answer 2

• an excessive knee flexion moment will occur at loading response
• an insufficient knee extension moment will occurs at late midstance

Question 3

Operation of the elbow disarticulation prosthesis is identical to that of the standard transhumeral configuration and involves a fair-lead control cable with a dual control transhumeral figure of 8 harness. The control motion is primarily humeral flexion and also scapular abduction.

Answer 3

True

Question 4

The primary cause of lower limb amputation is:

Answer 4

Peripheral vascular disease

Question 5

Fluid resistance is ideal for meeting needs of the variable cadence patient because, as increased velocity attempts to force the knee into flexion more rapidly, the knee unit:

Answer 5

• responds with greater resistance to flexion
• engages a second cylinder used for extension resistance and resistance in this direction can be helpful in preventing terminal impact
• resistance is usually found to be greatest just before the point of maximal knee flexion and just before the point of maximal knee extension, due to the forces placed on the prosthetic knee during gait
• creates a more smooth and controlled gait via fluid resistance

Question 6

The hip joint and pelvic band provides a significant amount of mediolateral stability and rotational control but provides only minimal suspension

Answer 6

False

Question 7

The Canadian style prosthesis uses a two piece socket design as compared to the UCLA style which uses a one-piece socket design.

Answer 7

False

Question 8

There are two primary forms of grasp that we can make available to the patient: a cylindrical grasp and a pinch type grasp. The cylindrical grasp utilizes the thumb, second and third fingers in a three-jaw-chuck configuration.

Answer 8

False

Question 9

The general location of the mechanical joints should be:

Answer 9

Insert

Question 10

Due to the length of the knee disarticulation amputation, it is very difficult to place prosthetic components at the distal end of the socket and still have a cosmetic appearance of the prosthesis.

Answer 10

True

Question 11

Which of the following are muscles of the anterior leg?

Answer 11

• Tibialis anterior
• Extensor Digitorum Longus
• Extensor Hallicus Longus
• Peroneus Tertius

Question 12

At pre-swing the ground reaction line is as follows:

Answer 12

Anterior ankle, posterior knee, posterior hip

Question 13

If an AFO design is used, a rocker sole and cushioned heel modification to the shoe may be indicated to aid in smooth ambulation.

Answer 13

True

Question 14

A patient with weak ankle dorsiflexors may compensate by using steppage gait.

Answer 14

True

Question 15

Due to the changing position of the instantaneous center of rotation, the functional length of the shin segment changes. As the instantaneous center is located more proximally during full extension, the relative shin length is longer.

Answer 15

True

Question 16

SACH foot heel compression at loading response simulates:

Answer 16

Plantar flexion

Question 17

In the quadrilateral socket the function of the anterior wall is to maintain even pressure over the anterior residual limb and maintain the proper positioning of the ischial tuberosity on the posterior brim.

Answer 17

True

Question 18

In a quadrilateral socket, the ML dimension is calculated by taking the circumference at the ischial level and

Answer 18

Dividing it by 3 and subtracting 1/4”

Question 19

The primary etiology for a shoulder disarticulation his trauma (scarring usually present). This includes:

Answer 19

• farming/industrial accidents
• electrical burns
• amputation secondary to a brachial plexus injury

Question 20

Polycentric knee units can incorporate:

Answer 20

• constant friction dampening mechanism where the swing rate can be adjusted to the patient’s single cadence
• a feature that allows the instant center of rotation curve to be altered by the adjustment of an extension stop
• the capability of allowing from 110 to 160 degrees of flexion, depending on the unit selected
• distances from the knee articulation to the top of the knee unit that vary so much in the overall distance from knee center to the socket that not all are appropriate for the knee disarticulation patient, but can function well for the mediums to long transfemoral levels

Question 21

In the sagittal plane, the alignment of the single axis knee axis is posterior to the trochanter/ankle (TA) line. This can vary depending on the control mechanism being used. In most cases, the knee axis is placed posterior to the TA line by approximately

Answer 21

1/4”

Question 22

Axial rotational control of the prosthesis can be provided by:

Answer 22

• proximal PTB shape of the socket
• flattening the posterior brim to increase triangulation
• loading along the medial and tibial flares

Question 23

The transhumeral cable system is referred to as a “fair-lead” system. The cable housing:

Answer 23

Is split into two parts, creating the potential for elbow flexion

Question 24

The control of socket rotation is a significant consideration in transhumeral prosthetic design. The proximal brim for each of the transhumeral designs presented here will have

Answer 24

A “D” shaped cross-section at the axilla level in the socket

Question 25

Motions at the elbow, forearm and wrist are important for prepositioning the terminal device. For a partial hand amputation, wrist motion may be critical.

Answer 25

True

Question 26

Canted fingers on a terminal device

Answer 26

Permit better visualization of the work field when manipulating small objects

Question 27

A transradial figure of 8 harness is indicated as a standard harness of suspension design for transradial prostheses with flexible hungers or rigid hinges.

Answer 27

True

Question 28

The goals of transradial prosthetic socket design are:

Answer 28

• control of socket rotation
• facilitation of pronation and supination of terminal device
• appropriate socket trim lines
• selection of wrist shape

Question 29

Each patient should be interviewed carefully to assess their needs in terms of function and cosmetics regardless of gender.

Answer 29

True

Question 30

Possible causes for knee instability at initial contact (heel strike) in the transfemoral prosthesis include:

Answer 30

• heel cushion to firm
• knee set too far anterior
• insufficient socket flexion
• patient has weak hip extensors

Question 31

In quadrilateral socket design, the ischium rests on the brim, while in ischial containment sockets, it rests inside the brim.

Answer 31

True

Question 32

The K-level designation for a patient’s functional level can have a direct effect on:

Answer 32

• foot selection

- knee selection

Question 33

The primary indication for use of a Silesian belt is rotational control of the prosthesis.

Answer 33

True

Question 34

Select the foot from the list below which has the most coronal plane accommodation.

Answer 34

SAFE

Question 35

How do you correct an abrupt knee flexion moment at loading response?

Answer 35

Move foot anterior

Question 36

If a vascular patient is at risk for potentially having both lower extremities amputated, it is best to wait until both amputations are completed before prosthetic fitting commences.

Answer 36

False

Question 37

A partial foot amputation where only the talus and calcaneus remain is known as:

Answer 37

Chopart

Question 38

The goal of transtibial prosthetic socket design is to make sure all pressure tolerant areas are being utilized to support the patient’s weight and all non-tolerant weight bearing areas are relieved from pressure to prevent the patient from feeling pain.

Answer 38

True

Question 39

The standard starting place for PTB attachment point location is ___ and ___ to the sagittal midline of the socket at the level of the patella tendon “bar”.

Answer 39

1/2” posterior and 1/2” superior

Question 40

Gel type liners may be used with this type of suspension:

Answer 40

• neoprene sleeve
• suction sleeve
• locking pin

Question 41

The primary causes of amputation are:

Answer 41

• congenital deficiencies
• cancer
• trauma
• loss of vascularization

Question 42

The wrist disarticulation socket that is suspended by a Supra-epicondylar style socket will prevent axial rotation but allow pronation and supination.

Answer 42

False