P&O Flashcards
What is stride length?
Linear distance b/w corresponding successive points of contact of the same foot
What is step length?
Linear distance in plane of progression b/w corresponding successive contact points of opposite feet
How much time percent wise in gait cycle are you in stance vs. swing? What about double-limb vs. single-limb support in normal gait cycle?
60 stance, 40 swing;
20 double-limb vs 80 single-limb
Center of gravity typically located
5 cm anterior to the S2 vertebra
Subdivisions of stance phase?
- Initial contact (heel strike)
- Loading response (Foot flat); lowest COG
- Midstance (Midstance); highest COG
- Terminal stance (Heel off)
- Preswing (Toe off)
Subdivisions of swing phase?
- Initial swing (Acceleration)
- Midswing (Midswing)
- Terminal swing (Deceleration)
6 determinants of gait?
- Pelvic rotation
- Pelvic tilt
- Knee flexion in stance
- Foot mechanisms (ankle flexion/extension mechanisms)
- Knee mechanisms
- Lateral displacement of pelvis
When is iliopsoas active during gait cycle?
Concentric with terminal stance, preswing, initial swing, midswing
When is glute max active during gait cycle?
Initial stance, eccentric
When is glute med active during gait cycle?
Eccentric during initial stance, loading response, midstance, terminal stance
When are hamstrings active during gait cycle?
Eccentric during initial stance and loading response (similar to pretibial muscles); also during swing phase
When are quads active during gait cycle?
Eccentric during initial stance and loading; also during preswing and initial swing
When are pretibial muscles active during gait cycle?
Eccentric during initial stance and loading response; concentric during swing phase
When are calf muscles active during gait cycle?
Eccentric during mid stance;
concentric during terminal stance and pre-swing
What does excessive trunk lateral flexion b/w loading response and preswing suggest?
Ipsilateral glute med weakness (compensated Trendelenburg gait)
Primary disturbance in Parkinson’s gait? Other key features?
Reduced step length;
Stooped posture, festinating gait, shuffling, freezing, decreased arm swing
Consequences of hip flexion contracture on gait?
Increased anterior pelvic tilt, increased knee flexion, also increased energy consumption
Compared to ambulation in normal patients, those propelling WC showed ______ increase in energy expenditure
9%
Muscles needed for crutch walking?
UE:
Latissimus dorsi, triceps, pec major;
LE:
Quads, hip extensors, hip abductors
Major risk factor for LE amputations?
Diabetes
Leading cause of UE amputations?
Trauma
When to do amputation for mangled hand?
Irreparable damage to four of the following:
- Skin
- Vessels
- Skeleton
- Nerves
- Extensor tendons
- Flexor tendons
Percentile ranges for transradial amputation?
Very short: residual limb less than 35%;
Short: 35-55
Long: 55-90
Percentile ranges for transhumeral amputation?
Humeral neck: Residual limb less than 30%;
Short transhumeral: 30-50;
Standard transhumeral: 50-90
What is the most common and practical type of terminal device?
Body-powered voluntary opening device
In prosthetic wrist unit, what does wrist flexion unit allow with terminal device?
To be in flexed position, facilitating ability to perform activities close to the body. Important for b/l UE amputees
Two types of wrist units?
Friction wrists, locking wrists
What does transradial amputation prosthesis require?
- Harness and control system
- Upper arm cuff/pad
- Elbow hinge
- Socket
- Wrist unit
- Terminal device
What transradial prosthetic socket can be used with a figure-9 harness for control purposes?
Muenster socket
What is the most commonly used trans-radial harness?
Figure-8 (O-ring) harness
When is the single-control vs. dual-control cable system used?
Single-control for transradial single-control cable system;
Dual-control for transhumeral and very short transradial split-socket prosthesis
What is the harness used most frequently for transhumeral prostheses?
Modifications of the basic figure-8 and chest strap patterns used with transradial prostheses
How does the dual-control cable system operate?
One cable with two functions:
- Flex elbow unit when elbow is unlocked
- Operate terminal device when elbow locked
For body-powered vs myoelectric control systems, what are advantages to both?
Body-powered: less expensive, lighter, more durable, easier to repair, sensory feedback;
myoelectric: better cosmesis, stronger grasp force, less harnessing
For body-powered vs myoelectric control systems, what are disadvantages to both?
Body-powered: Mechanical appearance, depends on your motor strength, difficult to use;
Myoelectric: More expensive, heavier, decreased durability due to other components
Myoelectric transradial prostheses use _______ ______ to activate the prosthesis
muscle contractions
Most common causes of LE amputations per age group
0-5: congenital
5-15: Cancer, trauma
15-50: Trauma
Over 50: Vascular, infection
Define myodesis vs myoplasty?
Myodesis: Muscles and fasciae sutured directly to bone;
myoplasty: Opposing muscles sutured to each other and to periosteum
Where does Lisfranc amputation happen? Chopart? Consequence of these amputations?
Tarsometatarsal junction;
tarsals and metatarsals;
can get equinovarus deformity with excessive anterior weight bearing with breakdown
Advantages of Syme’s?
- Maintains length of limb
- Preserves heel pad
- Early fitting of prosthesis
- Partial weight bearing possible
In elderly, approximately _____ of patients have worse functional ability after BKA
50%
When is one instance when knee disarticulation would be the procedure of choice?
Severe flexion contracture (over 50 degrees) and limb ischemic
Ideal shape for transtibial residual limb is _________, and ideal transfemoral limb is ___________
cylindrical;
conical
Ideal dressing for post-op residual limb management? How long should a shrinker be worn daily? Contractures to worry about?
Removable rigid dressing;
24 hours a day except bathing;
hip flexion, hip abduction, and knee flexion contractures
Prosthetic feet available for Syme’s amputation?
- Solid ankle cushion heel (SACH)
- Stationary ankle flexible endoskeleton (SAFE)
- Energy-storing carbon fiber foot
What is the standard socket used for the average BK amputee? What is it characterized by?
Total-contact patellar tendon bearing socket;
bar in the anterior wall designed to apply pressure on the patellar tendon
Pressure-tolerant areas?
- Patellar tendon
- Pretibial muscles
- Popliteal fossa (gastroc-soleus muscles)
- Lateral shaft of fibula
- Medial tibial flare
Pressure-sensitive areas?
- Tibial crest, tubercle, condyles
- Patella
- Fibular head
- Distal tibia and fibula
- Hamstring tendons
Which suspension design includes silicone or other gel insert or liner with use of one-way expulsion valve?
Suction suspension
Key features of SACH foot?
Compressible heel, wooden keel;
can get motions of ankle in normal walking without actual ankle movement occurring
Difference in motion for single-axis vs multiaxis?
Single-axis moves in DF and PF; K1
multi-axis for PF, DF, inversion, eversion, rotation; K2
Two examples of flexible-keel foot?
SAFE (stationary ankle flexible endoskeleton);
STEN (stored energy)
Example of energy-storing foot/dynamic response?
Flexfoot, good for K3 and K4 users
Difference in polycentric vs single-axis knee?
Polycentric has instantaneous center of rotation that changes, prox and posterior to knee unit itself;
allows greater knee stability, more symmetrical gait, and equal knee length when sitting
(PPP)
Ischial containment socket is also known as _________; what position does it keep the femur in?
Narrow medio-lateral socket;
keeps femur in adduction to keep hip abductors in more stretched and efficient position
What is characteristic of the quadrilateral transfemoral socket?
Narrow AP, wide ML;
reliefs for adductor longus, hamstring, greater trochanter, gluteus maximus, rectus femoris
Manual locking knee provides what benefit?
Ultimate knee stability in stance phase (knee kept extended throughout gait cycle); for geriatric patients
What is the mechanism of the constant friction knee?
Uses friction mechanisms, ultimately decreasing incidence of high heel rise in early swing and decrease terminal impact in late swing
Key disadvantages with stance-control knee?
Have to unload fully to flex, so can’t use in b/l AKA;
activities requiring knee motion under weight bearing, like step-over-step descent, not possible with this knee
What can polycentric/four-bar knee be used for?
Knee disarticulation and long residual limb; provides excellent knee stability
What do fluid-controlled knee units allow for? Advantages?
Allows for either swing phase, or swing and stance phase control;
variable cadence, smoothest gait, also stable
Key difference with microprocessor-control hydraulic knee compared to fluid-controlled knee units?
Computer-programmed custom settings for each individual; re-calibrates stability of the knee 50 times per second
What is choke syndrome?
Proximal prosthetic socket too tight and lack of total contact b/w residual limb and socket impairing venous return
What is verrucous hyperplasia?
Wartlike skin overgrowth, usually of residual distal limb, due to inadequate socket wall contact with subsequent edema formation
Causes of excessive knee flexion with transtibial amputee?
- Increased ankle DF
- Excessive anterior displacement of socket over foot
- Excessive posterior displacement of foot relative to socket
- Heel cushion too hard
- Knee flexion contracture
Causes of excessive knee extension with transtibial amputee?
- Increased ankle PF
- Moving socket posteriorly relative to foot
- Moving foot anteriorly relative to socket
- Too soft heel cushion
- Quad weakness, distal anterior tibial discomfort
Causes of lateral trunk bending to prosthetic side in transtibial amputee?
Prosthesis too short, prosthesis in abduction; amputee with hip abduction contracture, very short residual limb
Causes of abducted gait in transtibial amputee?
Prosthesis too long, too much abduction; amputee with hip abduction contracture
Causes of circumducted gait?
Prosthesis too long, inadequate suspension, abduction contracture of residual limb
How frequently to replace prostheses in pediatric amputee?
First 5 years of age: Yearly;
Ages 5-12: every 18 months;
ages 12-21: every 2 years
Who is more likely to experience bony overgrowth after an acquired amputation, kids or adults?
Kids more so than adults
Cane measurement/prescription?
20- to 30-degree elbow flexion, or height of greater trochanter of hip for cane height
What is a University of California Biomechanics Lab orthosis useful for?
Controlling flexible calcaneal deformities (rearfoot valgus or varus) and transverse deformities of the midtarsal joints (forefoot abduction or adduction); provides effective longitudinal arch support and re-aligns a flexible flat foot
What is a rocker bar and what is it used for?
Strip placed posterior to metatarsal heads;
can relieve metatarsal pain, quicken gait cycle, or assist DF
What is a heel wedge used for?
Place medially to rotate hindfoot into inversion, or laterally to rotate hindfoot into eversion
Heel lift useful for
compensation of fixed pes equinus deformity, or leg length discrepancy more than 1/4 to 1/2 inch.
Where does the line of gravity pass through in LE?
- Just posterior to hip joint to passively extend hip joint
- Just anterior to knee joint to passively extend the knee
- Anterior to ankle joint to dorsiflex ankle
What are options for single channel ankle joints for AFO’s with hinged ankle joints?
- Spring in channel for dorsiflexion assist
- Inserting steel pin for plantar flexion stop
- Pin and spring for dorsiflexion assist and plantar flexion stop
What is characteristic of dual channel ankle joints?
Posterior channel functions exactly as a single channel joint;
anterior channel provides option of adjustable steel pin for dorsiflexion stop or to lock joint in fixed position
What LE orthosis would be good for an obese patient with quads weakness?
KAFO with double metal uprights and posterior offset knee joint
Scott-Craig orthosis designed for who? What does it allow for?
Ambulation in adults with paraplegia (neuro level at L1) who want to stand and ambulate;
Unsupported standing
What is the RGO?
Special design of HKAFO; used for upper lumbar paralysis where active hip flexion is preserved
What can be added to a knee immobilizer to decrease rotational instability of the knee?
Footplate
What is purpose of an opponens orthosis?
Immobilize the thumb and first MCP joint to promote tissue healing and/or protection or for positioning of weak thumb in opposition to other fingers
Purpose of long opponens orthosis? Classic examples?
Similar to short opponens orthosis but will cross the wrist;
long opponens splints and thumb spica splints
When is wrist-driven prehension orthosis used?
C6 complete tetraplegia; need wrist extensors at least 3+ or better to use body-powered tenodesis
What is a balanced forearm orthosis?
Shoulder-elbow-wrist-hand orthosis (SEWHO) with forearm trough and mount;
supports forearm and arm against gravity, allowing patients with weak shoulder and elbow muscles to move arm horizontally and flex elbow to bring hand to mouth
What type of orthosis is a sterno-occipital mandibular immobilizer?
Cervicothoracic orthosis (CTO)
When is the Minerva CTO useful?
Management of unstable cervical spine
When is the Halo vest CTO used? Risks?
Management of unstable C-spine fx;
pressure ulcers with bedrest
TLSO can help increase
intra-abdominal pressure
Purpose of Taylor brace?
Flexion/extension control TLSO
Purpose of Knight-Taylor Brace?
Similar to Taylor brace; for post-surgical or non-surgical management of stable T- or L- fx
Purpose of Jewett brace?
Permit upright position and prevent flexion after compression fx of TL spine;
also for TL Scheuermann’s disease and thoracic osteoporotic kyphosis
Purpose of CASH TLSO brace?
Similar to Jewett; has cross picture
When to use CTLSO?
Milwaukee brace good for scoliosis, when apex located superior to T8;
also for thoracic Scheuermann’s disease kyphosis
