Abstract
1. Pathological hallux valgus may be differentiated from an increase in the normal valgus alignment of the great toe by the relationship to each other of the articular surfaces of the first metatarso-phalangeal joint; these are congruous in the normal joint, but displaced on each other in the pathological.
2. The earliest change is lateral deviation of the proximal phalanx on the metatarsal head, which may progress rapidly to subluxation.
3. Subluxation is an early change in a high proportion of cases, and is frequently present when the patient is first seen in adolescence.
4. Once subluxation has occurred progression of the deformity is likely.
5. Metatarsus primus varus and hallux valgus increase pari passu. There is not enough evidence to be certain which of these is the primary change, but such as there is suggests that lateral deviation of the great toe occurs first, and increase in the intermetatarsal angle is secondary to this.
6. It is suggested that hallux valgus should be regarded primarily and fundamentally as a subluxation, or tendency to subluxation, of the first metatarso-phalangeal joint.
