Pl. Mente et Jl. Lewis, ELASTIC-MODULUS OF CALCIFIED CARTILAGE IS AN ORDER OF MAGNITUDE LESS-THAN THAT OF SUBCHONDRAL BONE, Journal of orthopaedic research, 12(5), 1994, pp. 637-647
The elastic moduli of calcified cartilage and subchondral bone tissues
were measured experimentally with use of a three-point bending test.
Specimens were obtained from a bovine patella and the distal end of a
bovine femur, from two different animals. Fifteen specimens were teste
d as ''pure'' subchondral bone beams, and 15 were tested as composite
calcified cartilage/subchondral bone beams. A least-squares optimizati
on scheme was used to obtain modulus values from the composite beams.
The elastic modulus for subchondral bone calculated from the ''pure''
subchondral bone beams was 2.3 +/- 1.5 GPa (3.9 +/- 1.5 GPa for specim
ens from the femur and 1.6 +/- 0.7 GPa for specimens from the patella)
. The composite beam optimization resulted in a modulus for subchondra
l bone of 5.7 +/- 1.9 GPa and a modulus for calcified cartilage of 0.3
2 +/- 0.25 GPa. The modulus for the calcified cartilage was more than
an order of magnitude lower than the modulus of the underlying subchon
dral bone. This supports the idea that the zone of calcified cartilage
forms a transitional zone of intermediate stiffness between the artic
ular cartilage and the subchondral bone.