Mechanical strength evaluation.
The realization that increases in bone mass do not always reflect fracture reduction in humans and the infeasibility of observing low-impact fractures in animal models have made ex vivo mechanical testing imperative.31 Three-point bending, 4-point bending, and torsion testing are used frequently to assess bone mechanical strength.70 However, these tests can only be done in diaphyses of long bones, in sites where osteoporotic fractures are rare. New tests have been developed to assess the vertebral (compression testing) and femoral head (cantilever testing) mechanical strength, sites where osteoporotic fractures are common in humans.61,7