Ch 6 - Prosthetic and Orthotics: Lower Limb Flashcards
What is the most common cause of lower extremity amputation?
Peripheral arterial disease (PAD), also referred to as peripheral vascular disease (PVD)
What is Ankle-Brachial Index (ABI)?
Ratio of ankle systolic pressure to brachial systolic pressure
What are the scales of Ankle-Brachial Index (ABI)?
– ABI 0.91 to 1.30: Normal
– ABI 0.71 to 0.90: Mild PAD
– ABI 0.41 to 0.70: Moderate PAD
– ABI 0.00 to 0.40: Severe PAD
What does a Ankle-Brachial Index (ABI) >1.30 suggest??
Calcified, noncompressible vessels, which can produce false negative results. This is common in diabetics
When is Doppler velocity waveform analysis used?
If screening ABI is abnormal, Doppler waveform analysis is performed to localize the lesion
Describe Doppler velocity waveform analysis.
Doppler waveforms are obtained at multiple sites and a change in waveform from one level to the next is indicative of PAD
What is the gold standard imaging for PAD?
Intraarterial contrast angiography
What is Myodesis?
Muscles and fasciae are sutured directly to bone through drill holes
When is Myodesis contraindicated?
Severe dysvascularity in which the blood supply to the bone may be compromised
What is Myoplasty?
Opposing muscles are sutured to each other and to the periosteum at the end of the cut bone with minimal tension
What is the procedure of choice in severe dysvascular residual limbs (myodesis vs. myoplasty)?
Myoplasty
Describe a partial toe amputation.
Excision of any part of one or more toes
Describe a toe disarticulation.
Disarticulation at the metatarsophalangeal (MTP) joint
Describe a Partial foot/ray resection.
Resection of a portion of up to three metatarsals and digits
Describe a Transmetatarsal amputation (TMA).
Amputation through the midsection of all metatarsals
Describe a Lisfranc amputation.
Amputation at the tarsometatarsal junction
Describe a Chopart amputation.
Midtarsal amputation—only talus and calcaneus remain
Describe a Syme’s amputation.
Ankle disarticulation with attachment of heel pad to distal end of tibia; may include removal of malleoli and distal tibial/fibular flares
Describe a Long BKA (transtibial) amputation.
> 50% of tibial length
Describe a standard BKA (transtibial) amputation.
20% to 50% of tibial length
Describe a Short BKA (transtibial) amputation.
<20% of tibial length
Describe a knee disarticulation.
Amputation through the knee joint, femur intact
Describe a Long AKA (transfemoral) amputation.
> 60% of femoral length
Describe a Standard AKA (transfemoral) amputation.
35% to 60% of femoral length
Describe a Short AKA (transfemoral) amputation.
<35% of femoral length
Describe a hip disarticulation.
Amputation through hip joint, pelvis intact
Describe a hemipelvectomy.
Resection of lower half of the pelvis
Describe a hemicorporectomy.
Amputation of both lower limbs and pelvis below L4, L5 level
What are unsatisfactory levels for elective sites of lower limb amputation?
Distal 2/5’s of tibia
Very short BKA proximal to tibial tubercle
Very high AKA
What are causes of toe, metatarsal ray or TMA amputations?
Trauma to the toes Loss of tissue due to an infection, or gangrene Frostbite Diabetes Arterial sclerosis Scleroderma Buerger’s disease
What function does a TMA amputation maintain?
Preserves the attachment of the dorsiflexors and plantar flexors and their function
What is a Pirogoff amputation?
Vertical calcaneal amputation
What is a Boyd amputation?
Horizontal calcaneal amputation
What do patients with Lisfranc and Chopart amputations develop?
Foot often develops a significant equinovarus deformity resulting in excessive anterior weight bearing with breakdown
What can prevent equinovarus deformity in amputees?
Adequate dorsiflexor tendon reattachment with Achilles tendon lengthening
What are pros to a Symes amputation?
- Maintains length
- Heel pad for WB
- Early fitting of prosthesis
- Partial WB after the procedure with a proper rigid casting (~ 24 hours)
What are cons to a Symes amputation?
Poor cosmesis
Prosthesis fitting difficult
Describe functional ability of elderly patients after BKA.
50% worse function
5% improve function
What are advantages of BKA over AKA?
Dec energy expenditure
Dec mortality rates d/t better healing and tissue viability
Describe the proper cuts through bone in BKA.
Fibula cut 2 to 3 cm shorter than the tibia
Tibia beveled anteriorly
When is a knee disarticulation preferred over BKA?
Severe flexion contracture (> 50°)
Limb is ischemic
What is a Modified knee disarticulation?
Moderate trimming of the femoral condylar prominences and patellofemoral arthrodesis in the intercondylar notch
What degree of hip flexion contracture can be accommodated in a socket?
20 degrees
What is the ideal shape for transtibial residual limb?
Cylindrical
What is the ideal shape for transfemoral residual limb?
Conical
What is a removable rigid dressing (RRD) for the transtibial amputee?
Plaster or fiberglass cast suspended by a stocking and supracondylar cuff
How should elastic bandages be applied to residual limb post op?
Figure-8 wrap
What size elastic bandages should be used on residual limbs?
Double length 4-inch for transtibial limb
Double length 6-inch for transfemoral limb
When should elastic shrinker socks be used?
Once staples or sutures removed for 24 hrs/day
Fit to groin in AKA’s
When can shrinker socks be stopped?
Once fit for definitive prosthesis
Can use for edema at night