Mechanical Basis of Metatarsalgia.

The 3-rocker mechanism of gait provides a framework to understand why patients have mechanical metatarsal pain and to differentiate between the various types of metatarsalgia. Clinical examination of the patient together with radiological findings allows identification of the type of metatarsalgia and the pathomechanics involved, and the planning of surgical treatment. Second-rocker/nonpropulsive metatarsalgia is related with an abnormal inclination of a metatarsal in the sagittal plane, either anatomic or functional (equinism). Third-rocker/propulsive metatarsalgia is related to an abnormal length of a certain metatarsal with respect to the neighboring metatarsals in the transverse plane.