For the presence of subdislocation of the first MTPJ, 99 feet were subdislocated whereas 107 feet were assumed normal [Table 1].
Theoretically, a larger PASA would indicate a better likelihood of the first MTPJ retaining normal alignment.
PASA could allow for the normal alignment of the first MTPJ when the proximal phalange deviates laterally, but only within a certain angle (no more than 15[degrees]).
Haines and McDougall, [sup] and Lane [sup] all considered the medial eminence to be a component of the distal first metatarsal instead of skeletal proliferation, and that it becomes conspicuous simply because when the surface of first MTPJ decreases, the sagittal groove deviates laterally, and this leads to increased exposure of the medial eminence.
1,3) The plantar plate and collateral ligaments aid in static stabilization of the lesser MTPJ.
Many intrinsic and extrinsic factors have been identified that contribute to second MTPJ instability.
A variety of treatments have been proposed for second MTPJ instability, the choice of which depends on the degree of deformity.