TT and TF Biomechanics

Question 1

Prosthetic fit comes into play during _______ and ______ phase of gait.

Answer 1

swing and stance

Question 2

Why is prosthetic fit important in stance phase?

Answer 2

Weight-bearing and proper fit to not get breakdown of areas.

Question 3

Why is prosthetic fit important in swing phase?

Answer 3

Is the prosthetic going to stay on the limb/ disallow “pistoning”

Question 4

TRANSTIBIAL BIOMECHANICS

Answer 4

TRANSTIBIAL BIOMECHANICS

Question 5

In PTB (patellar tendon bearing) sockets, emphasis of weightbearing on pressure ________ areas such as what areas?

Answer 5

• tolerant
• patellar tendon, pretibials, posterior distal aspect of residuum, popliteal fossa, lateral shaft of fibula, tibial flares

Question 6

In casting, areas that are meant to be weight-bearing will be made ________. Why?

Answer 6

tighter, to increase weight-bearing in those areas

Question 7

Do we want total contact of the socket on the limb?

Answer 7

Yes, but want to enhance weight-bearing areas tighter.

Question 8

For TT medial/lateral stabilization we want to ATTEMPT to replicate the normally occurring _____ at the knee. How is this done?

Answer 8

• Varus

- They will shift the pylon/foot 0.5” medial to center during bench assignment.

Question 9

Whichever way the residual limb goes, the head/arms/trunk go the ______ direction, but the distal end of the residual limb go the _________ direction.

Answer 9

• same

- opposite

Question 10

Why do we want to AVOID knee valgus at the knee during bench alignment?

Answer 10

If shifting proximal-lateral in the socket, this will create pressure at the fibular head and peroneal nerve.

Question 11

For anterior/posterior stabilization place the socket in 5 degrees _______ to enhance PTB (patellar tendon bearing). Also place the foot slightly ________ to center of socket.

Answer 11

• flexion

- posterior

Question 12

The way they get PTB in the socket is by promoting _________.

Answer 12

flexion

Question 13

If the foot is so far posterior, because this position creates a _______ moment at the knee, it can create knee ___________ causing falls.

Answer 13

• flexor

- instability

Question 14

If the foot is too far anterior it creates an _________ moment at the knee, causing a loss in the benefits of the PTB.

Answer 14

extension

Question 15

If the foot is posterior it creates a ________ proximal pressure and _________ distal pressure.

Answer 15

• posterior

- anterior

Question 16

If you see that someone is having breakdown on the anterior aspect of their tibia, what 3 things should we think it could be.

Answer 16

• fit
• weakness
• foot is too far posterior

Question 17

If a patient is having knee instability, they will be extending their ______ to try and get stabilization at mid-stance. If they are extending their knee in an open chain, what does this cause?

Answer 17

• quads

- banging of knee into socket “bell-clapping”

Question 18

If the foot is too far anterior (hyperextension moment) we will see antero________ and postero_______ pressures and possible bottoming out.

Answer 18

• anteroproximal

- posterodistal

Question 19

If the foot is too far postierior (flexion moment) we will see postero_________ and antero______ pressures.

Answer 19

• posteroproximal

- anterodistal

Question 20

If the foot is too far laterally, we will see lateral ________ and medial ________ pressures.

Answer 20

• lateral proximal

- medial distal

Question 21

If the foot is too far medially, we will see lateral ________ and medial ________ pressures.

Answer 21

• lateral distal

- medial proximal

Question 22

• Anterior socket = _________ foot

- Lateral socket = _________ foot

Answer 22

• posterior
• medial

Same in opposite directions

Question 23

TRANSFEMORAL BIOMECHANICS

Answer 23

TRANSFEMORAL BIOMECHANICS

Question 24

One of the main things to consider when talking about TF amputations is what?

Answer 24

Knee stability because patient feels like they are going to fall or the leg is unstable.

Question 25

In TF amputations, if the prosthesis is not aligned properly and the socket is rotating on the limb, the _____ will not be in the proper position to function optimally.

Answer 25

knee

Question 26

What are 3 things we can do to minimize rotation of the socket in a TF amputation?

Answer 26

1. ) Maintain pelvis in a posterior tilt on posterior rim
2. ) Incorporate ischial/gluteal weightbearing
3. ) Adductor longus tendon housed in a groove

Question 27

Do prosthetics above or below the ischial tuberosity allow for more stability?

Answer 27

Above (ischial containment sockets), allows for more control and stability over limb

Question 28

With medial/lateral stabilization, patients are not stable until their limb contacts the ______ wall when transferring into weight acceptance. What is done to counter this with the prosthetic?

Answer 28

• lateral
• the lateral wall of the prosthetic is cut into to allow less time for the limb to be unstable and reach the closed-chain situation faster.

Question 29

With medial/lateral stability patients need good _______ wall support and _______ contact with the socket.

Answer 29

• lateral

- abductor

Question 30

For medial/lateral stability, points of force in proximo________ direction and distero________ direaction to prevent lateral shifting in socket.

Answer 30

• proximomedial

- distolateral

Question 31

With medial/lateral stability, the center of the heel is under or slightly lateral to _______ _______ to promote slight valgus.

Answer 31

ischial tuberosity

Question 32

• If the foot is too far medial it creates excessive pressure in the ________ and ________.
• If the foot is too far lateral it creates excessive pressure ______lateral and ______medial.

Answer 32

• groin and distolateral

- proximolateral and distomedial

Question 33

In TF amputations the GRFV must stay ______ to the knee. How is this done?

Answer 33

• anterior

- 5 degrees of flexion is built into the socket

Question 34

What does building 5 degrees of flexion into the socket do for the patient?

Answer 34

• enhances firing of gluteals

- allows knee extension while avoiding hyperlordosis

Question 35

What is a static checkout?

Answer 35

Looking for basic fit principles

Question 36

What things are checked in a static checkout?

Answer 36

• soles of feet flat (no plantar or dorsi)
• socket fit well (playdoh in socket)
• user comfortable
• is suspension adequate
• are bony landmarks level (could lead to joint/back pain)
• vertical pylon in stance
• are tissue rolls minimal
• gapping between leg and socket
• does residuum have distal contact
• normal heel center spacing
• is knee stable

Question 37

Do you have to worry about pressure sensitive/tolerant areas in TF amputations?

Answer 37

Not as much because it is so fleshy, common breakdown at groin or at adductor longus tendon.