The medial crosssover toe: a cadaveric dissection.

UNLABELLED: The development of a medial crossover second toe (second toe crossing over the first toe) is not a rare clinical condition. It often occurs in the setting of hallux valgus, although not exclusively so. The resulting displacement of the second toe can cause pain in shoes, with surgical correction being problematic. The pathologic anatomy of this condition has not been fully described. In an effort to better understand it, dissection of a cadaveric specimen with a full crossover toe is presented. The dissection revealed findings not previously documented. They include medial displacement of the flexor tendons and plantar plate along with deformity of the plate itself. These changes are in addition to contracture of the medial collateral ligaments and the previously described rupture of the lateral collateral ligaments. Both the plantar plate and the collateral ligaments, the two major static soft tissue stabilizers of the lesser MP joint, were found to be significantly involved. Pull on the flexor tendons only accentuated the malalignment of the toe.

CLINICAL SIGNIFICANCE: The extensive soft tissue changes explain the difficulty in achieving a successful long term correction of a full medial crossover toe with a soft tissue procedure. With attenuation of the plantar plate and medial displacement of the flexor tendons, there is an imbalance of muscle forces across the MP joint. This muscle imbalance would not be corrected by release of the medial collateral ligament, dorsal capsular release or extensor tendon lengthening. Reconstruction of the collateral ligament is at risk for incomplete correction since it is unlikely to resolve deformity in the plate if already present.