Figure 3.

Mechanical testing analysis of fractured femurs from COX-deficient mice. Fractured femurs and contralateral control femurs were collected from COX-1-null, COX-2-null, wild-type and mice heterozygous for the COX-2-null allele after 4 weeks of healing. The femurs were analyzed for structural (peak torque and maximum rigidity, a and b) and material properties (maximum shear stress and shear modulus, c and d) by torsional mechanical testing to failure. Each fractured femur value was normalized to its contralateral femur value as a percentage and the means with standard errors for each genotype are shown (n≥9). For the COX-2-deficient mice, all values were significantly less than the values from other genotypes (P<0.05). However, no significant differences were detected between the COX-1-null mice and controls.