Osteoarthritis: Pathogenesis and clinical findings
Ehlers-Danlos Syndromes (connective tissue disorders, e.g., Familial Hypermobility Syndromes)
Damage of normal cartilage under abnormal loading
Authors: Sean Spence Modhawi Alqanaie Reviewers: Yan Yu Jennifer Au Mao Ding Gary Morris* * MD at time of publication
Single large traumatic event or repeated microtrauma
Damage to normal articular cartilage under normal loading (force put on a joint)
Genetic anomalies in cartilage production and inborn errors of cartilage metabolism
Damage of abnormal cartilage under normal joint loading
Destruction/attrition of articular cartilage
Osteoarthritis
A degenerative joint disease that can affect both load bearing joints (knee, hip) as well as in smaller joints (proximal inter-phalangeal, carpometacarpal joints in hand)
Repeated physical joint trauma
Aberrant bone deposition secondary to wear on subchondral bone
Formation of osteophytes (bony projections) and subchondral sclerosis (bone thickening)
Lack of cartilage
Direct contact between bony processes with movement of the joint
Inflammation alters the chemical milieu of joint tissue
Synovial fluid forced into bone
Damage to subchondral (under cartilage) blood vessels
Subchondral fractures
cytokines regulate hyaluronic acid synthase
Synovium makes lower molecular weight hyaluronic acids (a potent proinflammatory molecule)
↓ synovial fluid viscosity
↑ risk of infection
Increased secretion of proteolytic enzymes
↑ joint fluid production
Joint effusion
Disruption of normal joint architecture
Palpable bony hypertrophy
(ex. Bouchard’s nodes (bony bumps on the middle joints of the finger))
Impaction of osteophyte with normal joint structures during movement
Physical disability
Crepitus
(grating sound in a joint)
Joint movement with reduced lubrication stimulates joint nociceptors
Stimulation of joint nociceptors (sensory receptors that detect damaging stimuli) in subchondral bone
Pain with use of joint
Pain with motion
↓ Range of motion
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published November 1, 2012, updated May 18, 2023 on www.thecalgaryguide.com