[Effect of sand therapy on femur mechanical properties of arthritis in rabbits and finite element analysis].
OBJECTIVE
To determine the effect of sand therapy on the changes the femur mechanical properties of arthritis in rabbits in treatment.


METHODS
Right knees of New Zealand rabbits were fixed for 6 weeks by plaster, and taken off after 6 weeks. The rabbits were divided into a sand therapy group and a control group. The sand therapy group was treated for 20 d, the control group did not receive any treatment. After 20 days, 7 workpieces were taken from the sand therapy group, and 5 from the control group. After compression experiment, sigma-epsilon curves were obtained.Finite element method was used to analyze the stress cloud and the deformation cloud.


RESULTS
The sand therapy group showed high compressive strength. The stress of the control group was lower than that of the sand therapy group (P<0.05). When the surface materials were destroyed, the workpieces from the sand therapy group still bore large load, which matched the property that bone material was a typical multi-storey composite material. The stress cloud also found that the long axle suffered larger stress than the short axle, and the workpieces were more likely destroyed from the long axle.


CONCLUSION
Sand therapy can improve the mechanical properties of the bone.