Medial canthopexy: an experimental and biomechanical study.

Medial canthopexy is associated with a significant failure rate. A cadaveric study was undertaken to evaluate the biomechanics of the medial canthal tendon and three types of fixation devices for medial canthopexy. Eight medial canthal tendons were assessed in 4 fresh-frozen cadaver heads. The medial canthal tendon was found to be much stronger than previously suspected, with an average breaking strength of 36 newtons and an elongation of 6.25 mm. The tendon-bone complex was noted to be closely matched biomechanically. Three medial canthopexy techniques were then assessed: transnasal wire over a button, 1.7-mm screw fixation into the medial orbit, and the Mitek GII anchor. Their respective holding strengths were 74%, 92%, and 97% of that of the contralateral intact medial canthal tendon. The three types of fixation devices all provided excellent ultimate biomechanical strength.