Radiographs: Hallux Valgus

- Determine Congruency
- wt bearing AP & lateral radiographs:
- IMA: (nl < 10 deg)
    - note that this angle is highly dependent on the technique of measurement
           - some authors measure from down the metatarsal shaft, where as, other authors measure from the center of the metatarsal base to the center of the metatarsal head;

- distal metatarsal articular angle:
    - normally this is zero deg;
    - lateral deviation more than 10 deg is abnormal;
    - typically a moderately severe hallux valgus w/ a significantly increased DMA will be associated w/ a congruent bunion;

- hallux valgus angle:
    - normal < 15-18 deg;
    - when the valgus angle of the 1st MTP joint > 30-35 deg, pronation of the great toe results and other structures are also affected (plantar shift of abductor hallucis & lateral shift of sesamoid & intrinsics, and often hammering of the second toe);

- first metatarsocuneiform joint angle:
    - high angle of inclination or presence of a lateral facet at the base of the 1st MT shaft;
    - this mechanically blocks the the metatarsal from being brought into satisfactory alignment unless an osteotomy of the first metatarsal is carried out;

- sesamoids:
    - moderate subluxation:
           - lateral sesamoid is uncovered 50 to 75 % within 1st IM space;
           - medial sesamoid is located in a central position plantar to the first metatarsal head;
    - severe subluxation:
           - lateral sesamoid moves to the lateral aspect of the first metatarsal head is dorsal to the medial sesamoid;

- Misc:
    - generalized metatarsus adductus:
    - lengths of the 1st & 2nd metatarsals:
    - 1st talometatarsal angle (lat. x-ray):
    - degree of hallux interphalangeus
    - size of Medial Eminence
    - evidence of arthrosis of the 1st MP joint
    - obliquity of the first MT-cuneiform joint

Radiographic analysis of hallux valgus. A two-dimensional coordinate system.

Roentgenographic assessment in hallux valgus.

Metatarsophalangeal and intermetatarsal angle: different values and interpretation of postoperative results dependent on the technique of measurement.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, September 4, 2012 1:52 pm