Puccio FD, Mattei L. Biotribology of artificial hip joints. World J Orthop 2015; 6(1): 77-94 [PMID: 25621213 DOI: 10.5312/wjo.v6.i1.77]
Corresponding Author of This Article
Lorenza Mattei, MD, PhD, Department of Civil and Industrial Engineering, University of Pisa, Largo Lazzarino, 56126 Pisa, Italy. l.mattei@ing.unipi.it
Research Domain of This Article
Orthopedics
Article-Type of This Article
Topic Highlight
Open-Access Policy of This Article
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World J Orthop. Jan 18, 2015; 6(1): 77-94 Published online Jan 18, 2015. doi: 10.5312/wjo.v6.i1.77
Table 1 Geometrical characteristics of hip implants: head diameter Dh and diametrical clearance Cl
Head/cup
Dh (mm)
Cl (μm)
MoP
22.2-44
160-400
CoP
22.2-36
160-400
MoM
22.2-54
50-150
MoMRHR
42-62
50-300
CoC
22.2-44
20-100
Table 2 Implant material properties: Young’s modulus E, Poisson’s ratio v and surface roughness Ra
Material
E (GPa)
n
Ra (μm)
P
UHMWPE
0.5-1
0.4
0.1-2
M
CoCrMo
230
0.3
0.01-0.05
C
Biolox delta
350
0.26
0.001-0.005
Table 3 Experimental estimations of coefficient of friction for different bearing types, obtained using 25% and 100% bovine serum as lubricants (test conditions: load range 0.1-2 kN, rotation ± 25°, frequency 1 Hz)[32,33]
Head/cup
COF 25% Bovine serum
COF 100% Bovine serum
MoP
0.062 (+ 0.008)
0.064 (± 0.01)
CoP
0.056 (+ 0.01)
0.06 (± 0.012)
MoM
0.12 (± 0.02)
0.096 (± 0.012)
MoMRHR
0.098 (± 0.02)
0.079 (± 0.011)
CoC
0.04 (+ 0.007)
0.056 (± 0.01)
Table 4 Theoretical estimation of the lubrication regime according to equation (17)
Head/cup
hmin (μm)
Ra (μm)
λ
Lubricationregime
MoP
0.065-0.144 (0.105)
0.1-2
0.1-1
Boundary to Mixed
CoP
0.076-0.107 (0.092)
0.1-2
0.05-0.9
Boundary to Mixed
MoM
0.020-0.061 (0.041)
0.014-0.071
0.6-2.9
Boundary to Mixed
MoMRHR
0.082-0.049 (0.066)
0.014-0.071
0.9-4.6
Boundary to Fluid-film
CoC
0.035-0.045 (0.04)
0.0014-0.0071
5.7-28.3
Fluid-film
Table 5 Typical wear rates reported in clinical studies (when available, the average value is indicated in the brackets)
Head/cup
hclin (μm/Mc)
Vclin (mm3/Mc)
MoP
50-500 (50)
10-500 (80)
CoP
30-150
15-50
MoM (RI)
1-50
0.1-25
MoM (SS)
0.1-1
0.05-4
MoMRHR (RI + SS)
0.2-10
0.2-2.9
MoMRHR (ADT)
1.5-46
0.2-95
CoC
0.01-1
0.005-2
Citation: Puccio FD, Mattei L. Biotribology of artificial hip joints. World J Orthop 2015; 6(1): 77-94