Development of an artificial articular cartilage.
We have attempted to develop an artificial articular cartilage on the basis of a new viewpoint of joint biomechanics in which lubrication and load-bearing mechanisms of natural and artificial joints are compared.  We investigated poly(vinyl alcohol)-hydrogel (PVA-H) which has been recognized as a rubber-like gel and have improved the mechanical properties of this gel through a new synthetic process. In this article we report the biocompatibility and various mechanical properties of the new, improved PVA-H from the aspect of its usefulness as artificial articular cartilage.  As regards the lubrication, we measured the change of thickness and fluid pressure of the gap formed between a glass plate and the specimen under loading and found that the PVA-H had a thicker fluid film under higher pressure than polyethylene (PE).  The momentary stress transmitted through the specimen revealed that PVA-H had a lower peak stress and a longer duration of sustained stress than PE, suggesting a better damping effect.  The wear factor of PVA-H was approximately five times as large as that of PE.  Histological findings of the articular cartilage and synovial membranes around the PVA-H implanted for 8-52 weeks showed neither inflammatory nor degenerative changes.  The PVA-H artificial articular cartilage could be attached to the underlying bone using an osteochondral composite material.  Although there remain still some problems to solve, PVA-H seems to be a very interesting and promising material which meets the requirements of artificial articular cartilage.
Oka
M
M
Research Center for Biomedical Engineering, Kyoto University, Japan.
Noguchi
T
T
Kumar
P
P
Ikeuchi
K
K
Yamamuro
T
T
Hyon
S H
SH
Ikada
Y
Y
D000818:Animals; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular; D005782:Gels; D006801:Humans; D007595:Joint Prosthesis; D008153:Lubrication; D008422:Materials Testing; D011095:Polyethylenes; D011142:Polyvinyl Alcohol; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011817:Rabbits; D016474:Weight-Bearing