| Background: Acetabular fractures are very common in orthopaedic practice. Its functional outcome depends on the quality of reduction and attainment of joint congruity. However fracture reduction and fixation are extremely difficult because of its complex anatomy and difficulty in exposure especially quadrilateral plate. Furthermore there are no appropriate implants to fix the fracture of quadrilateral plate. The complicated anatomy, difficulty in exposure, thin wall of the quadrilateral plate and its situation near the joint makes it difficult for reduction and fixation. Based on the acetabulum anatomic research foundation, we attempted to design a T-shaped reconstruction plate for the anterior column and quadrilateral plate fracture and compare it biomechanically with the reconstruction plates available in the market so as to obtain better fixation in future.Object: To design T-shaped reconstruction plate for quadrilateral plate fracture and evaluate it biomechanically.Methods: Acetabulum is a complex structure and because of its complex anatomy it is extremely difficult to reduce and fix the fracture especially quadrilateral plate. In this series we have designed a reconstruction plate which is applicable to the three dimensional structure of the acetabulum. We harvested 12 samples of the pelvis and the proximal portion of the femur. Each of them was sectioned sagittally through the midline of the sacrum and the pubic symphysis. This produced 24 hemipelves for our research. All of these specimens were visually examined and then X-rayed to exclude any skeletal diseases or the acetabular dysplasia. All muscles and connective tissues, including the hip capsule were dissected keeping the articular labrum intact, we divided them in two groups, 12 samples were used for fracture of quadrilateral plate, 12 samples were used for transverse and inner wall fracture . Then we divided them in two groups randomly according to their sides. One group was an experimental group while other was a control group. We made an inner wall and transverse and inner wall fracture using scroll saw with a blade having 0.5 mm thickness. An osteotomy perpendicular to the femoral neck was made. The femoral heads were preserved. Then we fixed these models with 10 holes reconstruction plates (GP) and the newly designed T-shaped reconstruction plates (NP) using 3.5mm×40mm cortical screws (manufactured by Anyang Weili Medical Instrument Company) according to the AO principles. We followed biological mechanical testing methods of the Shazar. Each model was kept on the clamp with acetabulum on its top, and then the force was applied through the femoral head which was connected to a transition bar. This biomechanical study was performed by a biomechanical test machine (Model: AGS-10KNG, Daojin Company, Japan). We then measured acetabular displacement on different loads. Finally statistical analysis was done using T-test.Results: Biomechanical test was done on two different kinds of fracture model fixed with two different reconstruction plates and screws by carrying load, and then acetabular deformation was measured. The result displayed the deformation on the experiment group was smaller than that of the control group using the similar loads which was statistically significant (p<0.05).Conclusion: T-shaped three dimensional reconstruction plate is a good choice for the stable fixation of the fracture. Its mechanical performance is superior, safe and reliable. These type of plates are malleable .We think these T-shaped reconstruction plates are a better option for the fracture of the quadrilateral plate .
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