BACKGROUND: Split fracture of greater tubercle of humerus is usually fixed with screw and tension band. The pull of supraspinatus muscle and infraspinatus muscle on the greater tubercle can easily cause the fracture to move upward and backward, resulting in reduction loss, acromial impingement and external rotation disorder. These two kinds of fixation strength are limited, which is not conducive to early functional exercise of patients, and shoulder joint dysfunction is prone to occur after operation.

OBJECTIVE: To determine the strongest internal fixation method for split type greater tuberosity fracture of humerus by hook plate, screw and tension band technique using biomechanical test.

METHODS: A new split type greater tuberosity fracture model was established with 30 fresh pig humerus with supraspinatus muscle (purchased from local abattoir). The models were divided into three groups (n=10 per group). The fracture of the greater tuberosity was fixed by hook plate, screw and tension band technique. The supraspinatus muscle was pulled. The loads required to produce 3 mm and 5 mm of displacement, as well as complete failure were recorded in the three groups.

RESULTS AND CONCLUSION: (1) The load required to produce 3 mm and 5 mm displacement was (510±114) N and (932±159) N in the hook plate group, (170±57) N and (284±82) N in the screw group, (98±48) N and (158±72) N in the tension band group. Under the same displacement, the force required by hook plate group was greater than that of screw group and tension band group (P < 0.05). (2) The average failure load of hook plate group was significantly higher than that of screw group and tension band group [(1 050±286), (470±108), (285±89) N, P < 0.05]. (3) The results have demonstrated that the hook plate has better biomechanical stability than screw and tension band fixation for split type greater tuberosity fracture, which provides a better choice for clinical treatment of split type greater tuberosity fracture.