TT and TF Biomechanics Flashcards
Prosthetic fit comes into play during _______ and ______ phase of gait.
swing and stance
Why is prosthetic fit important in stance phase?
Weight-bearing and proper fit to not get breakdown of areas.
Why is prosthetic fit important in swing phase?
Is the prosthetic going to stay on the limb/ disallow “pistoning”
TRANSTIBIAL BIOMECHANICS
TRANSTIBIAL BIOMECHANICS
In PTB (patellar tendon bearing) sockets, emphasis of weightbearing on pressure ________ areas such as what areas?
- tolerant
- patellar tendon, pretibials, posterior distal aspect of residuum, popliteal fossa, lateral shaft of fibula, tibial flares
In casting, areas that are meant to be weight-bearing will be made ________. Why?
tighter, to increase weight-bearing in those areas
Do we want total contact of the socket on the limb?
Yes, but want to enhance weight-bearing areas tighter.
For TT medial/lateral stabilization we want to ATTEMPT to replicate the normally occurring _____ at the knee. How is this done?
- Varus
- They will shift the pylon/foot 0.5” medial to center during bench assignment.
Whichever way the residual limb goes, the head/arms/trunk go the ______ direction, but the distal end of the residual limb go the _________ direction.
- same
- opposite
Why do we want to AVOID knee valgus at the knee during bench alignment?
If shifting proximal-lateral in the socket, this will create pressure at the fibular head and peroneal nerve.
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.
- flexion
- posterior
The way they get PTB in the socket is by promoting _________.
flexion
If the foot is so far posterior, because this position creates a _______ moment at the knee, it can create knee ___________ causing falls.
- flexor
- instability
If the foot is too far anterior it creates an _________ moment at the knee, causing a loss in the benefits of the PTB.
extension
If the foot is posterior it creates a ________ proximal pressure and _________ distal pressure.
- posterior
- anterior
If you see that someone is having breakdown on the anterior aspect of their tibia, what 3 things should we think it could be.
- fit
- weakness
- foot is too far posterior
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?
- quads
- banging of knee into socket “bell-clapping”
If the foot is too far anterior (hyperextension moment) we will see antero________ and postero_______ pressures and possible bottoming out.
- anteroproximal
- posterodistal
If the foot is too far postierior (flexion moment) we will see postero_________ and antero______ pressures.
- posteroproximal
- anterodistal
If the foot is too far laterally, we will see lateral ________ and medial ________ pressures.
- lateral proximal
- medial distal
If the foot is too far medially, we will see lateral ________ and medial ________ pressures.
- lateral distal
- medial proximal
- Anterior socket = _________ foot
- Lateral socket = _________ foot
- posterior
- medial
Same in opposite directions
TRANSFEMORAL BIOMECHANICS
TRANSFEMORAL BIOMECHANICS
One of the main things to consider when talking about TF amputations is what?
Knee stability because patient feels like they are going to fall or the leg is unstable.
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.
knee
What are 3 things we can do to minimize rotation of the socket in a TF amputation?
- ) Maintain pelvis in a posterior tilt on posterior rim
- ) Incorporate ischial/gluteal weightbearing
- ) Adductor longus tendon housed in a groove
Do prosthetics above or below the ischial tuberosity allow for more stability?
Above (ischial containment sockets), allows for more control and stability over limb
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?
- 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.
With medial/lateral stability patients need good _______ wall support and _______ contact with the socket.
- lateral
- abductor
For medial/lateral stability, points of force in proximo________ direction and distero________ direaction to prevent lateral shifting in socket.
- proximomedial
- distolateral
With medial/lateral stability, the center of the heel is under or slightly lateral to _______ _______ to promote slight valgus.
ischial tuberosity
- 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.
- groin and distolateral
- proximolateral and distomedial
In TF amputations the GRFV must stay ______ to the knee. How is this done?
- anterior
- 5 degrees of flexion is built into the socket
What does building 5 degrees of flexion into the socket do for the patient?
- enhances firing of gluteals
- allows knee extension while avoiding hyperlordosis
What is a static checkout?
Looking for basic fit principles
What things are checked in a static checkout?
- 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
Do you have to worry about pressure sensitive/tolerant areas in TF amputations?
Not as much because it is so fleshy, common breakdown at groin or at adductor longus tendon.
