Collateral ligament reconstruction of the unstable metatarsophalangeal joint: an in vitro study.

Anatomic reconstruction of the collateral ligaments of the lesser metatarsophalangeal joints is proposed for certain cases of metatarsophalangeal instability. The suggested reconstruction involves replication of the attachments of the collateral ligaments. As an example of such a reconstruction, the interosseous tendon was used in this study as a graft for anatomic replacement of the collateral ligaments. The tendon was left attached distally where its attachments include the volar plate and proximal phalanx, thereby resembling the distal attachment of the collateral ligament. The proximal portion of the tendon was inserted into the metatarsal head, replicating the attachment of the collateral ligament at that location. Preliminary testing of such a reconstruction shows that it can re-establish stability caused by loss of the collateral ligaments. Such a procedure may be applicable in select cases of crossover toe deformity and straight vertical instability.