P - Neuropathic Foot Flashcards
what are 2 major risk factors for neuropathic ulcer
loss of protective sensation
mechanical stress
what pathology is neuropathic ulceration the most common thing you will see in that patient population
DM
what does neuropathic ulceration result from in DM
poor glucose control
what are 2 characteristics of peripheral vascular dz that increase the risk of neuropathic ulceration
tissue breakdown
delayed wound healing
what is the sequence that leads to lower extremity amputation
minor injury
ulceration
faulty ulcer healing
infection
spreading
amputation
how does loss of protective sensation become a significant risk factor for neuropathic ulcers
- limited awareness of foot injury d/t dec sensation
- fail to initiate injury avoidance behaviors
- delay seeking medical treatment –> don’t realize there is a problem until it is significant
how is protective sensation tested
semmes-weinstein nylon 5.07 filament (10g of bending force)
what does the classification for risk of plantar ulcer and amp in neuropathic foot test
for loss of protective sensation
what are the category classifications for determining the risk of plantar ulceration and amp in the neuropathic foot
Category 0 - normal
- lo loss of protective sensation
Category 1 - loss of protective sensation (5.07 filament) at any areas of foot tested
Category 2 - loss of protective sensation and evidence of high presssure
- callus, deformity, joint limitation
Category 3 - hx of plantar ulceration
what are examples of evidence of high pressure that you might see in a category 2 (risk of plantar ulcer and amp)
callus
deformity
- bunion
- hammer toe
- claw toe
joint limitation
- lack of DF, midfoot motion, great toe ext
-> changes the mechanics of wt bearing and walking
what are types of mechanical factors (4)
pressure
shear
intrinsic
extrinsic
pressure vs shear mechanical factors
pressure = compressive
- vertical
- fairly easy to measure
- can measure barefoot or in shoe
shear = horizontal forces
- harder to measure
intrinsic vs extrinsic mechanical factors
intrinsic = bone or joint deformity
extrinsic = environment around foot (ie shoe)
what are intrinsic factors that are associated w high foot pressure
bone deformity
joint limitation
what are examples of bone deformities as an intrinsic mechanical factor (6)
bunion
claw toe
rearfoot varus/valgus
forefoot varus/valgus
charcot foot
partial amp
what is often the underlying component for a bone deformity
intrinsic ms weakness (small plantar intrinsics)
how does a bony deformity like a claw toe inc risk for ulceration
intrinsic ms weakness
MT heads become more prominent –> curl down and get more load and pressure on head –> MT head not designed to take load –> toe ulceration
what is a common location for ulcers associated with claw toe
toe ulcers
what determines the degree of ulceration in rearfoot and forefoot varus/valgus deformities
degree of compensation
- amt of ROM determines amt of compensation possible and thus determines amt of load
what risk factor for ulceration are rearfoot and forefoot varus/valgus deformities associated with
abnormal foot pressures
what is a charcot foot
collapse of tarsal bones leading to midfoot ulceration
- radiographic changes at talonavicular &/or calcaneal cuboid joints
what is type of path is charcot foot considered
neuropathic osteoarthropathies
where is ulceration expected in charcot foot
midfoot
where is ulceration expected in forefoot varus (compensated)
1st or 5th MT head
where is ulceration expected in forefoot varus (uncompensated) and why
5th MT head
rigid varus/inverted position, WBing stays in same lateral part of foot
what will active ortho pts w uncompensated forefoot varus present as often to PT
stress fx at 5th MT head
- not meant to bear weight on the lateral side of our foot
where is ulceration expected in forefoot valgus and why
1st MT head
valgus/everted position, medial side of forefoot, plantar side of big toe hitting ground early in gait
how is a partial amputation an intrinsic factor for ulceration
results in greater loading force on residual limb
how is great toe amputation an intrinsic factor for ulceration and why
inc pressure on remaining 1st ray segment
- in gait heel strike, then pronate to push thru great toe
transfer lesion
- load shifts to 2nd MT -> not meant to take load
what limitations in motion can be intrinsic factors for ulceration
1st MTP ext
PF 1st ray
ankle DF
where is there increased stress with limited 1st MTP extension
IP joint during propulsion
-> toe ulceration
what role does 1st MTP extension play in gait
need 65deg or >
as move thru end of stance phase and heel comes off ground –> get DF there
- if don’t have that motion get load there and at toes earlier in gait cycle (propoulsion) or in later stance phase
where is there increased stress with rigid PF 1st ray
on 1st MT head
where is there increased stress with limited ankle DF (ankle equinus)
forefoot & risk of ulceration there
in general ortho pop, what problems will you see with limited ankle DF and why
when DF stops, heel comes up early and force on forefoot earlier in gait cycle and there for longer duration than meant to be
-> metatarsalgia
-> plantar surface foot pain
what are reasons for limited ankle DF
restricted talocrural joint
restricted GS complex
motor neuropathy in peroneal n. distribution vs tibial n. distribution: common pt pop, ROM limitations, areas of inc stress
peroneal = forefoot
- common in DM
- foot equinus, hallux limitus
high forefoot stress
tibial = rear foot
- common in SCI
- limited PF
high stress at heel
what are 3 levels of stress that can cause injury
momentary high
repetitive mod
cont low
what is the most common MOI to an insensate foot
repetitive mod stress from walking
what is the response to repetitive mod stress from walking in normal vs loss of protective sensation
normal - alter behavior
- stop activity, shift WBing stress to another area
no protective - cont activity
- in same manner until # of reps exceeds a tolerable stress threshold resulting in skin breakdown
what are 2 integumentary concerns if person is at risk for ulceration
noncompliant dry skin
hyperkeratosis (callus)
why is noncompliant dry skin an integumentary concern
breeding grounds for infection
-> cracking & ulceration
what causes hyperkeratosis (callus)
response to tissue stress
why is hyperkeratosis (callus) an integumentary concern
inc pressure –> injury
can mask underlying ulceration
removal of heavy callus shown to dec foot pressure
what are causes of tissue atrophy
ms or connective tissue atrophy
fat pad migration from bony areas
what can impact a person’s ability to self inspect feet
obesity
vision loss
joint limitation
(common in elderly)
what are 3 other factors impacting the risk for ulceration
inability to self inspect feet
high impact exercise
skin temperature
how can high impact exercise impact risk for ulceration and what is recommended in pts w DM
abnormal stress levels
low impact exercise
- stationary bike
- swimming, UE exercies
what is an elevated skin temperature predictive of
ulceration and charcot fx in pts w DM
what can elevated skin temp be d/t
inflammation
- soft tissue stress
- infection or bony injury
what skin temperature change is significant
should be symmetric b/w limbs
- significant if >1-2deg C
what are 4 steps to foot screening
test for sensory loss
identify signs of skin lesions
assess ROM and strength
inspect footwear
