Table 1.

Depth-dependent material properties of human patellar and distal femoral articular cartilage. Properties ξ (fiber modulus), E (ground matrix modulus) and k (hydraulic permeability) were obtained by refitting experimental data from unconfined compression stress-relaxation tests reported previously ³⁰ and averaged over six specimens; the power-law exponent for the fiber response was set to β=2.15 and Poisson’s ratio for the ground matrix was set to ν=0. Mean and standard deviations are reported at normalized depths z/h through the articular layer of the patella and distal femur (z/h=0 at subchondral bone and 1 at articular surface). The full thickness of the articular layers at the test sites was h=2.55±0.39 mm for the patella and h=2.41±0.22 mm for the femur.

	layer	z/h	ξ (MPa)	E (MPa)	k (×10−3 mm4/N·s)
patella	4	0.82±0.03	24.6±25.1	0.20±0.12	1.11±0.88
	3	0.54±0.06	13.2±5.3	0.38±0.14	1.05±0.51
	2	0.33±0.04	10.2±6.4	0.67±0.19	1.17±0.64
	1	0.11±0.01	11.9±5.4	0.83±0.30	0.95±0.65
femur	4	0.76±0.04	17.7±5.8	0.25±0.10	1.14±0.29
	3	0.43±0.06	21.1±4.2	0.76±0.27	0.55±0.23
	2	0.25±0.03	12.4±0.7	0.54±0.17	0.96±0.55
	1	0.08±0.00	17.9±0.3	1.06±0.21	0.53±0.05