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#4 Surg > 60 - Radiographic Planning for HAV Surgery > Flashcards

60 - Radiographic Planning for HAV Surgery Flashcards

1
Q

Hallux abducto valgus (HAV) evaluation

A
  • Clinical and radiographic pictures don’t always match
  • May seem to have large deformity clinically but is smaller radiographically
  • Use radiographs for surgical planning to choose best procedure
  • Radiographs MUST be WB to evaluate foot correctly
  • Angles will likely change with WB
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2
Q

Radiographic evaluation

A

NOTE: look at radiographs systematically***

  • Soft tissue first
  • Then bone and cartilage
  • Then angles and alignment
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3
Q

Soft tissue evaluation on radiographs

A

o Edema
o Masses
o Air
o Foreign bodies

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4
Q

Bone and cartilage quality evaluation on radiographs

A 
o	Osteopenia
o	Cysts/Tumors
o	Erosions
o	Joint space narrowing
o	Exostosis
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5
Q

Example of radiograph evaluation (on slides)

A
  • Example of osteoporotic bone and bone cysts within the 1st metatarsal head
  • Example of joint space narrowing and exostosis
  • AP radiographic views – straight down on top of the foot (This is where most of our x-ray measurements will be taken)
  • Lateral radiographic view
  • Sesamoid axial view – there is a block you put the foot up on, they go up on the ball of the foot (This is important in terms of the rotation of the 1st metatarsal)
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6
Q

Hallux interphalangeus angle

A
  • Definition: Angle formed by the longitudinal bisection of proximal phalanx
    and distal phalanx of the hallux
  • Normal angle is
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7
Q

Hallux abductus angle (HAA)

A
  • Definition: Angle formed by bisection of the longitudinal axis of the proximal
    phalanx and 1st metatarsal
  • Normal range is
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8
Q

Distal articular set angle (DASA)

A
  • Definition: Angle formed by longitudinal bisection of the proximal phalanx of
    the hallux and the perpendicular of the line formed by marking the medial and
    lateral aspects of the cartilage of the base of the proximal phalanx
  • Looks at angular deviation of the cartilage of base of the proximal phalanx
  • Normal is 0-8 degrees
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9
Q

Proximal articular set angle (PASA)

A
  • Definition: Angle formed by a line perpendicular to longitudinal bisection of
    the 1st met and a line formed by marking points of medial and lateral aspects
    of 1st met head cartilage
  • Evaluates position of articular cartilage of the 1st met head
  • Normal is 0-8 degrees
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10
Q

Intermetatarsus angle (IM)

A
  • Definition: Angle formed by longitudinal bisection of the 1st metatarsal
    and the second metatarsal
  • This angle is the “powerhouse” which determines which procedure to do
  • Normal = 0-10 degrees
  • Mild/moderate deformity = 10-15 degrees (In this case a head procedure is typically done)
  • Severe deformity = > 15 degrees (In this case a more proximal procedure is typically done)
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11
Q

Metatarsus adductus angle

A
  • Helps determine if all metatarsals are going off to the side or just the first one
  • Definition: Angle formed by line perpendicular to midfoot bisection and
    longitudinal bisection of the second
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12
Q

Metatarsus adductus angle: Points used to create perpendicular of midfoot are

A

o Medial most aspect of 1st met cuneiform joint or talonavicular joint
o Lateral most aspect of calcaneal cuboid joint or 4th met cuboid joint
(some texts will use 5th met cuboid joint)

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13
Q

Metatarsus adductus angle: Reference values for metatarsus adductus

A

o 0-15 = normal
o 16-25 = mild
o 26-35 = moderate
o > 35 severe

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14
Q

Metatarsus adductus angle: Alternative method to measure

A

o Angle formed by longitudinal bisections of the intermediate cuneiform and the 2nd metatarsal
o Normal is a little higher for this form of measurement
o Usually 5-10 degrees higher

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15
Q

Importance of metatarsus adductus angle

A
  • In patients with increased met adductus, patient may have severe bunion deformity even with mildly increased IM angle
  • If met adductus angle > 15 degrees
  • True IM = (met adductus – 15) + IM
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16
Q

Now we are moving on to alignment and other considerations

A

FYI

17
Q

Joint positions

A

Defined by the relationship of a line representing the effective
articular surface of the first metatarsal head and a line
representing the effective articular surface of the proximal phalanx:
o Congruous joint-lines are parallel
o Deviated joint-lines intersect outside the joint space
o Subluxed joint-lines intersect inside the joint space

18
Q

Types of deformity WENT THROUGH ENTIRE CHART

A
  • Structural deformity
  • Positional deformity
  • Combined deformity
19
Q

Structural deformity

A
  • Angle formula: PASA + DASA = HAA
  • PASA/DASA abnormality: PASA +/- DASA abnormal
  • Joint is congruent
20
Q

Positional deformity

A
  • Angle formula: positional deformity

- PASA/DASA abnormality: PASA + DASA

21
Q

Combined deformity

A
  • Angle formula: PASA + DASA
22
Q

Notes on chart

A
  • Structural deformity = deformity due to bone
  • Positional deformity = deformity due to soft tissue contraction/adaptation
  • HAA = hallux abductus angle
23
Q

Shape of metatarsal head

A
  • Round = most unstable
  • Square (oblique) = relatively stable
  • Square with ridge = most stable
24
Q

Metatarsal protrusion distance

A
  • A measurement for relative length of patterns of 1st and 2nd metatarsals
  • Normal is +/- 2mm
25
Q

Medial cuneiform obliquity

A
  • May or may not be relevant. Study by Hatch et al that is awaiting publication, did not find correlation.
  • If x ray angle different than 15, can change the perceived angle.
26
Q

Tibial sesamoid position

A
  • The is the relationship of the tibial sesamoid to the
    bisection of the shaft of the first metatarsal:
  • Normal = positions 1,2,3
  • Abnormal = positions 4,5,6,7
  • Used an indication for removal of fibular sesamoid
27
Q

What to look for in lateral view radiographs

A
  • 1st ray elevation
  • Hammer toes
  • Hallux crossing over second
28
Q

Conclusion

A
  • Develop a systematic approach to evaluating radiographs
  • Radiographic angles and alignment give you the guidelines needed for procedure choice
  • Treat the patient, not the x-ray
29
Q

CASE STUDY 1 (look at slides)

A
  • Weight bearing x-rays: by appearance, IM angle looks to be above 15°
  • Tibial sesamoid position looks to be a 7 (not touching midline)
  • The 2nd metatarsal is protruding beyond the normal arc – positive for metatarsal protrusion
  • 1st metatarsal elevatus is present (1st metatarsal is elevated)
  • Procedure of choice: Lapidus because of high IM angle with phalanx wedge to straighten toe
30
Q

CASE STUDY 2 (look at slides)

A
  • Weight bearing x-rays
  • By appearance, the IM angle looks to be below 15°
  • Tibial sesamoid position looks to be at a 3 (at midline)
  • There is not significant protrusion of the 2nd metatarsal – negative for metatarsal protrusion
  • Procedure of choice: Austin

#4 Surg (14 decks)

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