RESUMO
BACKGROUND:The design of proximal femoral locking compression plate existed defects. Therefore, our team designed triangle truss locking plate with hyper-short arm according to proximal femoral locking compression plate (patent No. 201220051751.2). OBJECTIVE:To design and make triangle truss locking plate and evaluate its biomechanical properties. METHODS:Triangle truss locking plate with hyper-short arm was designed based on the support of two proximal screws of proximal femoral locking compression plate. Five pairs of fresh adult femur specimens were prepared, and the model of A3.1 (AO classification) reverse intertrochanteric fracture was established. Experimental group (right side) was fixed with triangle truss locking plate. Control group (left side) was fixed with proximal femoral locking compression plate. Stress distribution of the screws of proximal end of the plate, stress distribution of the fracture ends, the opening angle of fracture, and maximum load were detected. RESULTS AND CONCLUSION:(1) Stress distribution of the four screws of the proximal femoral locking compression plate was average in the experimental group, and the stress distribution of the two screws of triangle truss locking plate was close. Stress distribution of the four screws was not average in the control group. The proximal screw bearing stress was bigger in the control group than in the experimental group (P < 0.05). (2) Open angle under different loads were significantly smaler in the experimental group than in the control group (P < 0.05). (3) Maximum load was higher in the experimental group than in the control group (P < 0.05). Moreover, the position of damage was different between the two groups. The fixation in the experimental group was reasonable. These findings suggest that various biomechanic properties of the triangle truss locking plate with hyper-short arm were better than that of proximal femoral locking compression plate. Its fixation was reliable. Triangle truss locking plate could effectively reduce or avoid breakage of the plate and screw or coxa vara.