Posterior four-part fracture-dislocations of the proximal humerus: clinical and functional evaluation of osteosynthesis treatment.

Objective: To evaluate patients diagnosed with posterior four-part fracture-dislocations of the proximal humerus, that were surgically treated with osteosynthesis, regarding their clinical and functional outcomes.

Methods: A prospective observational study of eight patients from the same hospital institution in the interior of São Paulo State (Brazil), through individual interviews using the UCLA, DASH, and Constant international scores. The active movements included in the scores plus the range of motion of the affected and non-affected limb were measured.

Biomechanics of four techniques for fixation of the four-part humeral head fracture.

Objective: To carry out a biomechanical study of four techniques for fixation of four-part humeral head fractures.

Methods: The fracture was reproduced in 40 plastic humeri, divided into groups of ten according to the fixation technique, each one employing different fixation resources, in different configurations. The humeral models were mounted on an aluminum scapula, with leather straps simulating the rotator cuff tendons, and submitted to bending and torsion tests in a universal testing machine, using relative stiffness as an evaluation parameter.