Hallux valgus

Question 1

Hallux valgus deformity
- deformity
- aetiology
- examination
- xray

Answer 1

definition: complex deformity with lateral deviation of the great toe and medial deviation of the 1st MT

Aetiology
Multifactorial, more common in women
Intrinsic
- idiopathic
- familial
- hyperlaxity
- inflammatory - RA and gout
- congenital - Down’s
- neuromuscular - CP

Extrinsic
- footwear
- tight fitting shoes
- pointed toes/ high heels

Pain
EXTRINSIC PAIN
- due to deformity - rubbing on footwear

INTRINSIC PAIN
- joint incongruence
- degeneration
- synovitis - MTPJ/ Sesamoid joint

Examination
- achilles tendon tightness
- lesser toe deformity
- correctability
- pain/painless/ transfer metatarsalgia
- TMTJ instability

Classification
HVA: mild <20deg, moderate 20-40deg, severe >40deg
IMA: <11deg, moderate 14-20deg and severe >20deg

Question 2

Pathophysiology of hallux valgus

Answer 2

Pathophysiology
- medial structure attenuation
- valgus deviation of hallux
- plantar movement of abductor hallucis
- unopposed adductor hallucis
- FHL, FHB and EHL lateralise
- sesamoid subluxed laterally
- pronation of hallus - when HVA >30deg
- lateral contractures - deformity becomes fixed

sequelae of hallux valgus
Hallux valgus deformity defunctions the 1st ray
- load transfer to the lesser rays
- transfer metatarsalgia
- plantar plate rupture
- clawing of lesser toes

Question 3

Management of hallux valgus

Answer 3

Goals of treatment:
- correct the deformity - shoeable foot
- pain relief
- refunction the 1st ray
- reduce transfer metatarsalgia (shortening MT)

Non-op
- splints
- shoe with increased toe box

Goals of surgery
- correct HV, IMT angles and interphalangeus
- correct or maintain congruence
- avoid MT shortening or elevation
- avoid plantar resection to prevent MT head avn
- relocate sesamoids under MT head

operative
Distal osteotomy
- chevron - mild HV > 30 IMT<12
- risk loss of position and osteonecrosis (plantar/lateral BS)

Diaphyseal osteotomy
- Scarf - moderate to severe (HVA =25-40) - multi-planar
- perpendicular to GRF - 60deg cuts
- risk of stress fracture

proximal osteotomy
- ludloff - long oblique dorsal prox to plantar distal
- very severe deformity

TMTJ fusion
- modified lapidus (original MT1-MT2)
- hypermobile, OA, TMTJ instability or recurrence

McBride’s soft tissue release
- lateral release - adductor hallucis
- medial capsuloraphy
- combined procedure
- risk of hallux rigidus

1st MTPJ fusion
- severe HV with OA
- HV with neuromuscular disorder/ spasticity/ inflammatory arthritis
- severe deformity with osteoporosis
- salvage post-failed op or infection

Question 4

what are the normal angles for the hallux?

Answer 4

Interphalangeus - between proximal and distal articular surfaces of the PP1 <10
HVA - between MT1 and PP1 <15
IMA - between MT1 and MT2 <9
DMAA - distal metatarsal articular angle - between MT articular surface and MT axis

Question 5

how do you perform a scarf osteotomy?

Answer 5

**Scarf osteotomy **
- medial longitudinal midline incision MT shaft to base of PP
- protect dorsomedial branch of saphenous nerve
- capsule divided midline and reflected dorsally
- plantar dissection avoided - AVN risk
- shaft exposed and bunion excised
- Z cut osteotomy parallel to ground = perpendicular to GRF - transverse cuts 60 deg
- lateralise dorsal fragment to correct IMA
- rotate distal fragment - correct DMAA
- fixed with two variable pitch screws (barouk screws)

risks
- fracture
- dorsomedial branch of saphenous nerve
- transfer metatarsalgia

Akin osteotomy
- medial closing wedge osteotomy
- bone cut - perpendicular to axis of the phalanyx
- avoid cock up deformity and protect great toe tendons
- staple fixation