Q3: Biomechanics & Components Proximal to the Knee Flashcards
1
Q
Knee: Type of Joint and Inhibitors
A
Joint:
* Modified Hinge Joint (2-6 DOFs)
Limiters:
* Menisci
* Ligaments/Muscles
2
Q
Main Knee Motion
A
Sagittal Plane (Flex and Ext)
3
Q
Initial Contact
Knee Mechanics
A
Approaching neutral; extensors are active
0 degrees
4
Q
Midstance
Knee Mechanics
A
Slight flexion; extensors are active
0 degrees
5
Q
Terminal Stance
Knee Mechanics
A
Approaching neutral
0 degrees
6
Q
Preswing
Knee Mechanics
A
Rapid flexion is initiated
40 degrees flexed
7
Q
Hip: Type of Joint and Inhibitors
A
Joint:
* Ball & socket
Limiters:
* socket depth
* muscles/ligaments
8
Q
Acetabulum
Hip Joint
A
Acetabular labrum - fibrocartilaginous rim
Transverse ligament - closes the upside down “U”
Capitis femoris ligament - limits adduction
9
Q
When standing…
Hip Forces and ligaments
A
0.3x bodyweight
10
Q
When standing on 1 limb…
Hip Forces and ligaments
A
2.4-2.6x bodyweight
11
Q
When walking…
Hip Forces and ligaments
A
1.3-5.8x bodyweight
12
Q
When running…
Hip Forces and ligaments
A
4.5+ times bodyweight
13
Q
Ligamentous Support
Hip ligaments
A
Iliofemoral (Y-lig)
* strongest in the body
Ishiofemoral
* limits ext. and abduction
Pubofemoral
14
Q
Parastance
Hip Forces
A
standing using GRF; moves it posteriorly
15
Q
Inital Contact
Hip Mechanics
A
Flexed 30 degrees; extensors active
16
Q
Midstance
Hip Mechanics
A
Close to neutral; abductors active for balance
If abductors are weak, Trendelenberg will be (+)
17
Q
Terminal Stance
Hip Mechanics
A
Extended 10 degrees
18
Q
Preswing
Hip Mechanics
A
Rapid Flexion Initiated
19
Q
Early/Mid Swing Phase
Hip Mechanics
A
Flexion continues; Flexors are active
20
Q
Terminal Swing
Hip Mechanics
A
Hamstrings are active to slow tibia and prevent excessive hip flexion
21
Q
Antalgic Gait
Hip Joint
A
Painful Hip may cause…
* PF for shock absorption
* Flex., Abduct, external rot. combo - optimize femoral head position
* pivot met. heads to avoid forceful push off in late stance
22
Q
Initial Contact
GRF
A
Ankle - PF
Knee - Ext.
Hip - Flex
23
Q
Loading Response
GRF
A
Ankle - PF
Knee - Flex
Hip - Flex
24
Q
Midstance
GRF
A
Ankle - DF
Knee - Ext.
Hip - Ext.
25
Terminal Stance
| GRF
Ankle - DF
Knee - Ext.
Hip - Ext.
26
Preswing
| GRF
Ankle - DF
Knee - Flx
Hip - Ext
27
Goals
| KAFO
* Control tibia and femur
* correction
* prevention
* muscle compensation
* increase stability
* decrease pain
28
Sagittal Indications
| KAFO
* Quads MMT - 3+ or less
* Genu Recurvatum - > 30 degrees
* Knee flexion contractures
29
Coronal Indications
| KAFO
Genu varum and valgum
30
Transverse Indications
| KAFO
Rotary and/or triplanar instability
31
Other Indications (not plane of motion related)
| KAFO
Proprioception or Sensory impairment
32
Types/Styles
| KAFO
Conventional, Thermoplastic, Hybrid
33
Thermoplastic
| KAFO
Increased contact, cosmesis, control
Decreased weight
34
Common Components
| Conventional KAFO
* Proximal thigh band
* Distal thigh band
* Knee joints/Sidebars
* Calf band
* Ankle joints
35
Types of Ankle Joints
| KAFO
* Double action
* Dorsi assist - swing phase help
* Free motion - coronal control
* Limited motion - stops PF
36
Solid Stirrups
| KAFO
Direct attachment to shoe
Strong - continuous piece of metal
Can be hard to align mech. and anatomical joints
37
Split Caliper Stirrup
| KAFO
Not as strong as solid (3 parts)
Easier to align
Can use multiple shoes
38
Hybrid AFO NYUCBL
Increased foot control while avoiding proximal contact
39
T-Strap
| KAFO components
Address pronation or supination based on orientation
Sup. - attached laterally
Pron. - attached medially
40
Straight Knee Joints
| Knee Joints
Uses ring/drop locks with a ball retainer; used for patients with UE issues
41
Swiss/Cam/French Lock
| Knee Joints
Hands free lock; uses a bail release
| Can disengage accidentally
42
Posterior Offset Joints
| Knee Joints
Mech. joint is set posteriorly to provide knee stability
Indicated for hyperextention
Allows for flexion is swing phase
43
Dial Lock
| Knee Joints
adjustable for knee deformities/contractures
44
Step (Ratchet) Lock
| Knee Joints
hands free with incremental locking; self adjusts to available knee ROM
45
Key Lock
| Knee Joints
Like a step lock but only locks in full extension
46
Stance Control KAFOs
* Free flexion in swing phase
* Locked knee in stance phase
Weight line shifts anterior to the knee after temporal midstance
| Usually locked from IC to Midstance
47
Ankle Driven
| Stance Control KAFO
Requires DF at Mid to Terminal stance to unlock
| Cannot be used with solid ankle
48
Positional
| Stance Control KAFO
Locks/Unlocks based on tibial inclination and hip positon
| can be overly safe; knee can unlock early going downhill
49
Microprocessor
| Stance Control KAFO
based on MP prosthetic knee technology; expensive
50
Spreader Bars
| KAFO components
Controls hip motion when using B/L KAFOs
51
Axial Resist KAFO
Uses prosthetic principles to load limb proximally
Weight through:
* Ischial Tuberosity
* Scarpa's triangle
| Locked knee
52
Indications
| Axial Resist KAFO
* Malunion
* Fx distal to midshaft of femur
* post-op
* arthritic conditions
53
Indications
| Hip Orthoses
* Dysplastic disorders
* Trauma
* Post-Op
54
Unilateral or Bilateral Pelvic Bands
| Hip Ox Components
* Midpoint from Iliac Crest to Greater Troch
* Rigid portion is 33% of circumference
* Anterior trimline - 30mm medial ASIS
* Posterior trimline - posterior midline
55
Free Motion
| Hip Joints
Free sagittal motion;
controls coronal and transverse motion
56
Ring (Drop) Locks
| Hip Joints
Hold in all planes
57
Trigger Lock
| Hip Joints
Automatic locking
58
Adjustable (Dial) Lock
| Hip Joints
Used when variable sagittal ROM is needed; 6 degree increments
59
Abduction-Flexion Joint
| Hip Joints
used when variable sagittal/coronal ROM is needed
Indications:
* S/P hip replacement
* Hip dislocation
* lumbar fusion
60
Twister Cables
| Transverse Hip Motion
Controls hip rotation; attaches to a pelvic band and shoe
Usually in small children
| Contraversial
61
Walk About/Up & About Systems
Articulation proximal and medial to anatomical hip joint
* facilitate reciprocating gait but not forward progression
62
Landmarks
| HKAFO
* Iliac Crest
* ASIS
* Greater Trochanter
* Anatomical Hip Joint
63
Anatomical Hip Joint
12 mm anterior & 25 mm proximal to the greater trochanter
64
Advantages of Crossing the Hip
* Increase coronal control
1. adductor issues
* Increase transverse control
1. int./ext. rotation issues
65
Rationale
| HKAFO
* Allow weight bearing (contracture prevention)
* Seat femur in acetabulum
* delay deformites (pediatrics)
* Post-Op
* stability
* transverse control
| Usually short term and unilateral
66
Paraplegic Patient Goals
| HKAFOs
* Therapeutic
* Improve Independence
* Hold alignment
* achieve external stability
67
Swing to/through
| HKAFOs Gait Possibilities
Most efficient pattern
68
Swivel Walking
| HKAFOs Gait Possibilities
Very slow but easy; may not require aids
69
Reciprocal Walking
| HKAFOs Gait Possibilities
* Appears more normal
* Increased stability
* Less energy consumption, but more training
70
Standing Frames
| Static HKAFOs
* SCI L3 or higher
* Need to have head control and seated balance
* Independent standing (FREE HANDS)
* Gravity affects bone density/GI tract
* reduces contractures
71
Parapodium
| Static HKAFOs
Mech. Hip & Knee joints for sit to stand
* independent mobility
* swivel walker adaptation can be used
72
ORLAU Swivel Walker
| Static HKAFOs
No joints; Swivels by laterally shifting weight
* allows for forward progression
* adjustable growth
* used only on flat ground
73
Connection methods
| RGO
*Reciprocating Gait Ox*
1. Isocentric Bar
2. Double Cable
3. Single Push-Pull System
74
Ambulatory Progression
| RGO
* Lateral shift
* Trunk extension
* Contralateral leg advancement
* Lateral shift
* repeat
*gait training is important*
75
Common Assistive Devices
| RGO
Lofstrand Crutches
76
Indications
| RGO
* Spina Bifida
* Paraplegia
* Atrophy
* MS
* CP
* Polio (not common anymore)
77
Contraindications
| RGO
* contractures
* spasticity
* poor UE strength
* obesity
* ulcers
* poor bone density
* poor conditioning (cardio)
* lack of motivation/support/compliance
* hemiplegia
78
Advantages
| RGO
Independent Locomotion;
Gravitational Benefits
79
Disadvantages
| RGO
Expense,
issues with clothing,
and difficulty don/doffing
80
Gait Training Ox
| GTO
Provides pelvic and trunk support; pt. can move hips and legs to facilitate progression
81
Indications
| GTO
* CP
* Developmental Delay
* Step ability when unweighted
* Low weight (<74 lbs)
* plantigrade feet
* knee contractures up to 20 degrees
* stable hips
82
Contraindications
| GTO
* Contractures
* Spasticity
* Lack of motivation, support
* Poor cognitive skills
83
Benefits
| GTO
* Hands-free mobility
* guidance and control
* independence increases
* improves bowel/bladder function
* improves bone density
* self esteem and social interaction
84
Alignment and Fit
| GTO
* Flat heel and sole with ground
* joint congruency (mech. and anat.)
* horizontal joint axis
* adequate confromity to pt. anatomy
85
Trimline Criteria
| KAFO
* 35mm distal to perineum
* 10mm distal to troch.
Knee clearance:
* medial - 6mm
* lateral - 3mm
86
Fitting Criteria
| KAFO
* Distal thigh & calf strap = equal distance from knee center
* min. 105 degrees knee flexion
* If thermoplastic, then Total Contact fit
* If conventional, then 3-6mm clearance
* If conventional ankle, then 5-6mm clearance
| Use appropriate foot plate length
