Lecture 20 - Lower Limb Amputation Flashcards
causes of amputation by percent? and etiology?
- Men > women
- Amputation rates increase steeply with age
–dysvascular disease is #1 cause
describe Dysvascular disease as cause of amputation
PVD = something affecting blood flow to limbs, easier to happen farther from heart
Must have good vasculature to have a nerve
Healthy adult cartilage is aneural
describe Peripheral Vascular Disease + Peripheral neuropathy
Common complications of diabetes
–Not isolated to diabetes
Both are predisposing factors for LE amputation
–non-healing and/or infected neuropathic ulcers precede approximately 85% of non-traumatic LE amputations in individuals with diabetes
signs and symptoms of peripheral neuropathy
–deficits of sensation (vibratory & protective)
–loss of Achilles and patellar reflexes
–motor impairments (weakness and atrophy of the intrinsic muscles of the foot)
–autonomic dysfunction (inadequate or abnormal hemodynamic mechanism, trophic changes of the skin, and distal loss of hair)
what are Common subjective complaints of people with peripheral neuropathy?
1) “numbness” &/or “cold feet”
•feet may be warm and well perfused
2) Pain
“stabbing,” “pins and needles,” “shooting,” “electric shock”, “lancinating”
often worse at rest, particularly at night
N.B distinguish from Intermittent claudication
–cramping or aching pain, 1o in the calves, with walking
–relieved with rest (except in advanced stages)
–Sx of PAD
3) Muscular complaints
“night cramps,” “spasms,” or “aching”
*Note parasthesia is not numbness – parasthesia is like when you sit on your foot and it goes “numb”
describe sensory neuropathy
loss of thermal, pain, and protective sensation
increased vulnerability of the foot to acute, high-pressure and repetitive, low-pressure trauma
may be unaware of minor trauma
–pressure from poorly fitting shoes (sides and tops of feet)
–pressure from thickening plantar callus
–“I didn’t know anything was wrong until I saw a blood stain on my sock”
describe motor neuropathy
1) associated weakness and atrophy contribute to development of bony deformity of the foot
- bony prominences
- mal-alignment of joints
- altered weight-bearing pressure dynamics
2) may present with observable gait deviations
•peroneal neuropathy → weakness of ankle dorsiflexors (foot drop)
3) classic “intrinsic-minus” foot
- cocked-up toes (claw toes)
- prominent extensor tendons
- a high arch
- prominent metatarsal heads
4) associated with skin breakdown due to altered pressure distribution
- high plantar pressures (MT heads)
- dorsal surfaces of the proximal interphalangeal joint (rub against shoe’s toe box)
- distal tips of the toes (increased weight-bearing forces)
Describe the 2 types of Autonomic Dysfunction (sympathetic nerve damage)
Sudomotor dysfunction
- impairment in sweat gland function
- reduced hydration of the tissues
- skin of the foot becomes dry, less pliable, and much more prone to fissuring (enable entry of bacteria & infection)
Vasomotor dysfunction
- dilation of the arterioles of the foot
- hyperemia (↑ blood flow) of soft tissues and bone
- factor in the development of Charcot’s arthropathy
what is Charcot’s arthropathy?
Presentation in patient with neuropathy
–sudden onset of localized swelling, warmth, and erythema (redness of skin) in the absence of an open wound or anything else that would cause inflammation
what is the second leading cause of amputation and epidemiology/etiology?
describe the naming system of amputations
what are the 3 top levels of amputation?
1) toe, 2) transtibial, 3) transfemoral
what are the 2 foot level amputations?
what is the ankle level amputation?
what is the best location for transtibial level amputation?
- Surgeon tries to preserve as much of the limb as possible
- Long = better to fit prosthetic
- Greater lever arm = better (note quads and hamstrings still attached, gastrocs not)
- Larger area for prosthetic to attach to = better able to control it
- More likely to develop phantom limb pain with shorter
- Psychological impact
describe the types of knee level amputation
-B and c together = better option- no point in preserving because losing the insertion point of quads anyways.
describe the level of amputation - Transfemoral
- Shorter limb = preferable this time bc of where the prosthetic knee goes
- Transfemoral pref to knee disarticulaiton
- Bc of potential problem of skin breakdown
describe knee disarticulation vs. Transfemoral
describe the level of amputation effect on musculature
Preservation of musculature
Loss of distal insertion point requires surgical repair
- muscle-to-bone fixations (myodesis) - preferred
- muscle-to-muscle fixation (myoplasty)
- muscle-to-fascia fixation (myofascial)
Biomechanical effect
- altered line of pull of the muscles
- loss of force generating capacity (loss of muscle mass)
- altered / loss of distal connective tissue (tendon, etc.)
- shift in functional position on the length-tension curve
**note: Femur has muscle attachment pretty much the whole way, Attachment on bone (instead of muscle or soft tissue) is preferred
Picture:
Biggest muscle = most likely to not be preserved
- Gluteus max = greatest extensors, illiopsoas = flexion, glut min and med = greatest abdution
- *major abd, ext, flex and rotators of hip not as affected – adduction – MOST affected!!