RESUMEN
BACKGROUND: Polymethylmethacrylate (PMMA), commonly known as bone cement, has been widely used in the orthopedic surgery. It ensures the immediate stability of prosthesis and the minimal micromotion at the cement-bone interface, allowing early weight-bearing after surgery. OBJECTIVE: To investigate the biomechanical performance of Sanders type III fracture of the calcaneus by using PMMA bone cement as a treatment. METHODS: Eight adult cadaveric ankle and calcaneus specimens were selected and served as normal controls after detection of biomechanical properties. Another eight specimens were collected and randomized into experimental group and control group to make a model of Sanders type III fracture in the calcaneus. In the experimental group, PMMA bone cement was injected into the defect area. In the control group, the artificial bone was implanted in the defect area and a steel plate was used to fix the lateral calcaneus. Biomechanical properties of the specimens in the experimental and control group were detected. RESULTS AND CONCLUSION: (1) Strain and stress of the calcaneus: The stress distribution of the calcaneus in the normal control group was consistent with that in the experimental group, and there was no significant difference between the two groups. The stress of the calcaneus in the experimental group was similar to that in the control group with no significant difference. (2) Displacement and axial stiffness of the calcaneus: Compared with the normal control group, the calcaneal displacement in the experimental group only decreased slightly, and there was no significant difference between the two groups, and likewise, the calcaneal displacement in the control group increased slightly. In the experimental group, the axial compression strength was (21.98±1.88) MPa and the axial compression stiffness was (1 633±150) N/mm. Therefore, there was no significant difference between the experimental group and the normal control group (P > 0.05). (3) Contact strength of the subtalar joint: Fractures basically recovered with good outcomes after PMMA bone cement injection. To conclude, by using PMMA bone cement in the treatment of calcaneus fractures, the scientific validity and clinical utility can be ensured.