Abstract
Traumatic anterior instability of the shoulder is commonly treated with the Latarjet procedure, which involves transfer of the coracoid process with a conjoint tendon to the anterior aspect of the glenoid. The two most common techniques of the Latarjet are the classical and congruent arc techniques. The aim of this study was to evaluate the difference in force required to dislocate the shoulder after classical and congruent arc Latarjet procedures were performed. Fourteen cadaveric shoulders were dissected and osteotomised to produce a bony Bankart lesion of 25% of the articular surface leading to an "inverted pear-shaped" glenoid. An anteroinferior force was applied whilst the arm was in abduction and external rotation using a pulley system. The force needed to dislocate was noted, and then the shoulders underwent coracoid transfer with the classical and congruent arc techniques. The average force required to dislocate the shoulder after osteotomy was 123.57 N. After classical Latarjet, the average force required was 325.71 N, compared with 327.14 N after the congruent arc technique. This was not statistically significant. In this biomechanical cadaveric study, there is no difference in the force required to dislocate a shoulder after classical and congruent arc techniques of Latarjet, suggesting that both methods are equally effective at preventing anterior dislocation in the position of abduction and external rotation.