O - Biomechanical Exam (Lab) Flashcards
when pt walks into clinic:
what type of pt is a supine exam important and why
someone walking toe in or toe out
* good to look to see if there is a long bone abnormality (femur or lower leg)
* is it bony or soft tissue
how can the knee influence the sagittal and frontal planes
sagittal: flexion contracture & recurvatum
frontal: varus & valgus
when is a better time to measure Q angle and why
dynamically - SL squat or step down
people could have normal alignment in static but valgus collapse dynamically
norms:
* females: 15-18deg
* males: 8-10deg
what is a malleolar position assessment? what are the norms? what would be abnormal?
tibial torsion/fibular migration
position of malleoli relative to table
norms: 15-25deg external malleolar torsion
abnormal: internal, <15, closer to 0 (likely toes in)
when born tib and fib straight across, as develop fib moves post which gives angle of TC joint
if you see someone toeing in or out, what is the process to figure out if it a bony abnormality
start at greater troch
palpate med and lat fem condyle
* in line w the table? or retro/anteverted?
* if retroverted, put them in neutral & do quad set to hold
malleolar prominent tips, looking up from bottom
* use inclinometer on one (number doesn’t really matter bc won’t write a goal to change it)
malleolar position:
* >25deg - likely out toe
* <15deg - likely in toe
what is the gold standard for measuring leg length
standing radiograph
unnecessary for most people
what are 2 things to do before measuring leg length and why
bridge - eliminate rotation
gentle traction - eliminate elevation
what are 2 ways to measure leg length and what are considerations of each
ASIS to medial malleolus
* problem is going over tissue bulk/swelling will make one seem longer than the other
hooklying w feet together, are knees level
* are femur or tibia longer
* this is subjective
what makes it true FF equinus as opposed to fake
stuck in position
* fake equinus - people will collapse into position in supine but can be moved out of the position
what is FF equinus
PF deformity of MTJ
lacking 10deg DF
what are the 3 ways to assess midtarsal joint mobility
longitudinal axis
oblique axis
lock-up
why is midtarsal joint mobility such a key piece to the assessment
if limitation in TC DF, pts collapse through midtarsal joint to compensate
if lacking TC mobility/DF, how will the pt’s gait present if MTJ is mobile vs rigid
mobile - pronation in late stance
rigid - early heel rise
how is MTJ mobility assessed in longitudinal vs oblique axis
longitudinal: FF inv and eve
oblique: FF DF-ABD, FF PF-ADD
why do you measure DF in a lock-up position
gives supinatory bias, inv calcaneus
* takes away mobility thru midfoot to assess TC specifically
in gait TC should be in neutral or slightly supinated when DF - measurement mimics needed function
oblique and longitudinal axises cross/are perp in sup –> more rigid foot
axises are parallel in pron –> more mobility
internal joint mechanics help dictate amt of mobility
what is the Feiss line
medial malleolus to where 1st MT hits ground
* assess position of navicular relative to line –> shows arch height
why are 1st and 5th rays assessed separately
each have their own axises
what is the significance of a PF 1st ray being mobile or rigid
PF 1st ray - hit ground early
mobile - ground will push ray up
* he doesn’t care bc the functional impact is basically 0
rigid - can’t move once hits ground
* problematic
norm for hallux DF in walking and stair climbing
walking - 65deg
stairs - 85deg
if sagittal plane restriction, difficult to smoothly transition over foot in gait
what is hallux abducto valgus (HAV)
medial deviation 1st MT head
lateral devation of hallux
lateral shift in position of sesamoids
laxity of medial capsule and ligaments
d/t oblique forces
HAV
what are 3 possible etiologies
family
footwear
faulty biomechanics
HAV
how can footwear be an etiology
pointed toe box provides ABD force
HAV
how can faulty biomechanics be an etiology
- unlocked midtarsal joint
- 1st ray unable to PF against GRF
- DF position of 1st ray tensioning plantar fascia creating functional hallux limitus
what are 8 components to a supine exam
- hip neutral (ante, retro, neutral)
- malleolar position (internal, external, normal)
- FF position
- MTJ mobility (longitudinal & oblique axis)
- arch height
- 1st & 5th ray positions / mobility
- hallux DF
- toe positions (HAV, Morton’s, claw, hammer)
when do the intermetatarsal and hallux ABD angles become important
if going to have surgery
* bigger the angle, the more aggressive the osteotomy
intermetatarsal angles
normal, mild, mod, and severe
norm: 6-8
mild: 8-10
mod: 10-15
severe: >15
halllux ABD angles
normal, mild, mod, and severe
normal: 5-20
mild: 20-30
mod: 30-40
severe: >40
morton’s toe
what is it
how does this impact biomechanics
what pathologies can result
1st MT shorter
dec stability
inc load on 2nd MT
intractable plantar keratosis
metatarsalgia
morton’s neuroma
what is it
what are sx
fibrotic tissue about plantar digital n.
* primarily b/w 2nd & 3rd or 3rd & 4th
sx: pain, burning, numbness
what is the likely cause of claw toes and hammer toes
abnormal shear happening thru rays of foot
what is talonavicular congruency
symmetrical feel of talar head in reference to navicular
* STJ not pronated or supinated
why do you load the forefoot after finding talonavicular congruency to assess alignment
locks MTJ in position of maximal pronation
ideal STJN
what is the normal rearfoot relationship
calcaneal position
normal calcaneal position 3-4deg varus
what is considered an abnormal RF
subtalar varus
* >3-4deg of calcaneal inv w STJ in neutral
ideal STJN
what is the normal RF to FF relationship
plane of MT heads is perpendicular to posterior calcaneal bisection
what is considered an abnormal FF
FF varus - MT head plane inverted relative to calcaneal bisection
FF valgus - MT head plane everted relative to calcaneal bisection
make sure you align calcaneal bisection before assessing this, significant STJ varus can trick you into thinking FF varus
what pt will you likely see lacking calcaneal eversion
hypopronatory foot
what is normal calcaneal mobility
20deg inversion/ADD
10deg eversion/ABD
what are 3 components to the prone exam and how are each assessed
STJN
* calcaneal & distal 1/3 leg bisections
* RF relationship
* FF relationship
calcaneal mobility
* inversion - ADD
* eversion - ABD
TC mobility
* knee ext & flex
if there is a leg length discrepancy, what happens up the chain on the long side
foot - pronation
* functionally shorten longer leg
knee:
* flex / hyper ext
* genu varum/valgum
pelvis
* inominate elevation
spine
* scoliosis
takes less effort to pronate than supinate, otherwise would see supination on shorter leg
what does measuring neutral tibial stance assess
total RF varum
* tibial varum w STJ varum would in camt of inversion when hitting the ground
how can calcaneal position be assessed in standing and what is the importance of this
in STJN (should be equal to prone)
relaxed stance (norm: 4-6deg pronation)
can measure amount of calcaneal excursion from STJN to relaxed stance (1:1 ratio)
* can help determine if compensated or uncompensated
hallux DF
how is it measured
what is normal vs abnormal
relaxed stance, passively ext hallux
norm: 20deg
functional hallux limitus <20deg w FWB
hallux DF
what is the windlass mechanism/test
how is this mechanism changed by pts who toe out
with DF, arch lifts up
* job of plantar fascia bc doesn’t elongate/stretch
* test: how much DF in relaxed stance
people who toe out, harder for plantar fascia to do its job
* get more tension
* some irritation
* more load on post tib, med gastroc, achilles tendon
what are 6 components to a standing exam
posture
tibial varus
calcaneal excursion (STJN -> relaxed)
FF position
navicular drop (STJN -> relaxed)
WBing hallux DF (windlass test)
