The pathophysiology of osteoarthritis is related to excessive degradation of cartilage within the involved joint.  Elevated production of degradative metalloproteinases, including collagenases, result in tissue breakdown and disruption of the extracellular matrix. This in turn leads to functional compromise of the patient.  Commonly involved joints include:  hand PIPs, DIPs, and CMCs, hip, knee, and cervical and lumbar spine.

Predisposing factors include increasing age, female sex, genetic predisposition, major joint trauma, repetitive stress (i.e. vocational), obesity, congenital or developmental defects, prior inflammatory joint disease, and certain metabolic or endocrine disorders.