First Ray Surgery

First Ray Surgery


Stage I

Subclinical subluxation of the first metatarsal joint

Stage II

Development of clinical hallux abduction deformity

Stage III

Development of metatarsus primus adductus deformity

Stage IV

Clinical subluxation/dislocation of the first MPJ

Metatarsus Adductus Angle

Normal is 15°.

Values less than 15° represent a rectus foot.

At birth, MTA angle is around 30°.

At one year (begin walking), it is around 20°.

By age 4 years, the MTA angle reaches its adult normal value of 15°.


Intermetatarsal Angle

Also known as metatarsus primus adductus angle, metatarsus primus varus

Normal is 8° to 12° in a rectus foot and 8° to 10° in an adductus foot.

Base wedge osteotomies are indicated in feet with an IM of 15° or higher in a rectus foot or 12° or higher in an adducted foot.

When metatarsus adductus is present, the foot functions as if the IM angle is larger. The formula to account for this metatarsus adductus and find the “true IM angle” is as follows:

True IM angle = IM angle + (metatarsus adductus angle – 15°)


Hallux Abductus Angle

Also known as hallux valgus angle

Normal 0° to 15°


PASA (Proximal Articular Set Angle)

Also known as DMAA (distal metatarsal articular angle)

Normal 7.5° to 12°


DASA (Distal Articular Set Angle)

Normal 7.5°


Hallux Abductus Interphalangeus Angle

Normal 10°


Metatarsal Protrusion Distance

Normal (+ or -) 2 mm


Tibial Sesamoid Position

Normal 1 to 3



Nov 20, 2018 | Posted by in ORTHOPEDIC | Comments Off on First Ray Surgery
Premium Wordpress Themes by UFO Themes