Lesser metatarsophalangeal joints: intra-articular distension, volumetric measurements, and changes of position.

Plantarflexion of the second metatarsophalangeal (MTP) joint with intra-articular injection has previously been observed and commented upon, and the purpose of this study was to determine motion of the lesser toes with direct fluid infusion into the lesser MTP joints. Fluid distension was found to cause variable postural changes in all lesser toes; the most consistent change was plantarflexion of the second metatarsophalangeal joint. Dorsiflexion of the third, fourth, and fifth MTP joints was observed, but less reliable than plantarflexion of the second MTP joint. The average volume in each of the lesser MTP joints was less than 1 cc. Plantarflexion of the second MTP joint was usually, but not always, indicative of intra-articular distention. Aspiration of these joints (given their small volume capacity) may not be a reliable or therapeutically useful technique.