MEDIAL CANTHOPEXY - AN EXPERIMENTAL AND BIOMECHANICAL STUDY

Medial canthopexy is associated with a significant failure rate. A cad averic study was undertaken to evaluate the biomechanics of the medial canthal tendon and three types of fixation devices for medial canthop exy. Eight medial canthal tendons were assessed in 4 fresh-frozen cada ver heads. The medial canthal tendon was found to be much stronger tha n previously suspected, with an average breaking strength of 36 newton s and an elongation of 6.25 mm. The tendon-bone complex was noted to b e closely matched biomechanically. Three medial canthopexy techniques were then assessed: transnasal wire over a button, 1.7-mm screw fixati on into the medial orbit, and the Mitek GII anchor. Their respective h olding strengths were 74%, 92%, and 97% of that of the contralateral i ntact medial canthal tendon. The three types of fixation devices all p rovided excellent ultimate biomechanical strength.