[Resistance of the the coraco-clavicular ligaments to traction: clinical application]

One method for treating chronic incapacitating acromioclavicular dislocation is to resect the external extremity of the clavicle and to stabilise the stump by ligamentoplastic procedures, using the coracoclavicular ligament. The purpose of this work was to evaluate the mechanical quality of the ligamentoplastic approach. Twelve fresh cadavers, average age 80 years, were studied. The samples taken were 24 coracoclavicular ligaments, 24 coraco-acromial ligaments, 9 tendons from the palmaris longus muscle and 9 iliotibial tracts. The ligaments removed were tested in a Instron traction machine at a speed of 10 cm/mn. The mechanical properties of the coracoclavicular and coraco-acromial ligaments were studied. For comparison, those of the tendon of the palmaris longus muscle and the iliotibial tract were also studied. The results show the pre-rupture resistance of the coraco-acromial ligament to be 50% lower than that of the trapezoid and conoid parts of the coracoclavicular ligaments taken together. These results suggest the validity of ligamentoplastic treatment using the coraco-acromial ligament, but that reinforcement, using a tendon from the palmaris longus muscle or a piece of the iliotibial tract, may also be necessary, especially for subjects taking part in sports or with well-developed musculature.