Biomaterial Database

Sustained loading increases the compressive strength of articular cartilage. 1998

M A Adams, and A J Kerin, and M R Wisnom

Department of Anatomy, University of Bristol, UK.

BACKGROUND When synovial joints are subjected to sustained or repetitive loading, fluid is driven from the articular cartilage so that it is less able to equalise compressive stress between opposing joint surfaces. We test the hypothesis that sustained loading reduces the compressive strength of cartilage-on-bone. METHODS Forty specimens of articular cartilage-on-bone, approximately 15 mm square, were removed from the patella groove of mature bovine knees. Specimens were loaded on a materials testing machine using a 5 mm-diameter plane-ended indentor. Controlled loading/unloading cycles of 1s duration, and of increasing severity, were applied until failure was evident on the force-deformation graphs. Half of the specimens were 'creep loaded' for 30 at 2 MPa before their strength was assessed. After testing, damage was investigate using ink staining of the cartilage surface, and histology. RESULTS Sustained loading reduced cartilage thickness by 45% and creep-loaded specimens were 21% stronger (P = 0.01). Most specimens appeared to fail by fissuring of the cartilage surface zone. CONCLUSIONS Sustained loading strengthens cartilage by expelling water from it, reducing the tendency of the surface zone to rupture in the manner of an over-inflated car tyre.

UI	MeSH Term	Description	Entries
D001834	Body Water	Fluids composed mainly of water found within the body.	Water, Body
D001842	Bone and Bones	A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principal cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.	Bone Tissue,Bone and Bone,Bone,Bones,Bones and Bone,Bones and Bone Tissue,Bony Apophyses,Bony Apophysis,Condyle,Apophyses, Bony,Apophysis, Bony,Bone Tissues,Condyles,Tissue, Bone,Tissues, Bone
D002358	Cartilage, Articular	A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.	Articular Cartilage,Articular Cartilages,Cartilages, Articular
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D019245	Compressive Strength	The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)	Compressive Strengths,Strength, Compressive,Strengths, Compressive
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In