Comparative biomechanical study of five systems for fixation of the coracoid transfer during the Latarjet procedure for treatment of anterior recurrent shoulder instability.

This work compares the biomechanical resistance of five modes of fixation coracoid bone-block fixation during Latarjet open-air or arthroscopic procedures. The hypothesis is that these systems are equivalent. Latarjet procedures were performed on cadavers, then the samples were subjected to an increasing tension until the fixation failed. Five systems were tested: two malleolar screws, one screw with washer, two 3.5-mm self-compressive screws, one 4-mm self-compressive screw associated with one 3-mm self-compressive screw, and endobutton. The main judgment criterion was the strength necessary for the failure of the fixation. The secondary criterion was the stiffness of the assembly. The single malleolar screw fixing has a lower breaking threshold than other fixings. There is no difference in strength concerning the other systems. The average strength is greater than the stresses of a shoulder during daily life activities. There is no difference regarding the secondary criterion. The use of a single screw is insufficient, but the other systems seems reliable. The use of small diameter self-compressive cannulated screws can provide a better result. This biomechanical work must be validated in clinical studies.