61/62/63: HAV Surgery - Feilmeier Flashcards
hallux abductus valgus means …
- The great toe (hallux) is deviated away from the midline of the body in the transverse plane (abducto) and rotated away from the midline of the body in the frontal plane (valgus)
- *Tri plane description using frontal plane definition of valgus
why would you call a bunion metatarsus primus varus?
- The distal portion of the first metatarsal (metatarsus primus) is deviated toward the midline of the body (varus)
- This descriptor refers to the transverse plane in the foot
review of actions in planes
hick’s ROM first met
adduction, dorsiflexion, inversion/varus
BUT current research suggests it may actually be adduction, dorsiflexion, eversion/valgus
seasamoids pointing toward second met
valgus
sesamoids more toward midline = varus
describe what a bunion really is
hallux = hallux abducto valgus
metatarsal = metatarsus primus adducto valgus
- use tri-axial orthogonal coordinate system
- describes multi-planar position
what is happening in coronal plane in HAV?
- valgus metatarsal rotation (pronation)
- pronation of the first met is third plane of deformity
larger the bunion (greater IM angle) …
more frontal plane rotation (generally)
true or false: the first met is supinated/varus in a bunion deformity
false
this goes against Hick’s definition
what might you find on AP studies of a foot with bunion?
***
- lateral rounding of met head
- lateral displacement of sesamoids
- lateral roudning of met shaft
- lateral shift of plantar tuberosity
capsulorrhapphy
medially tightening the capsule to brings sesamoids more medial and in-line with the met
deformity correction goal: line up anatomic and mechanical axis
define mechanical and anatomic axis
define CORA
- CORA = center of rotation angulation
- Intersection of the Proximal Anatomic Axis (PAA) and Distal Anatomic Axis (DAA) of the two segments being corrected
- Bunion CORA = at the metatarsal cuneiform jt
- axis of correction of angulation ACA in met will produce a new deformity
define PASA
- change in where the cartilage of 1st met head is located realtive to met itself
- measured by putting transverse line through cartilage, anatomic axis, line perpindicular to anatomic axis. Normal 0-8
- some consider PASA to be radiographic artifact, least reliable measurement
- IF PASA is intirinsic to bone, should not change follwoing proximal correction procedures (reverden procedure at head should be only way to fix, distal procedure options should not work- they do)
Concepts to consider as causes for
less than optimum outcomes
- Disregard for the level of deformity
- Not fixing the original deformity at the CORA
- Failing to restore the anatomy in all three planes
- Focusing solely on the transverse plane of the deformity
- Inaccurate representation of PASA
- This transverse plane measurement may be just an artifact
- Unpredictability of soft tissue balancing as a component of the corrective procedure
- MTPJ capsular balancing for correction of sesamoid and hallux alignment does not offset the lack of alignment produced by the osteotomy and deteriorates in time