What is osteoarthritis?

Osteoarthritis is a degenerative condition that mostly affects the hands, spine and joints such as hips, knees and ankles, and usually gets worse over time.

Normally healthy cartilage allows bones to glide over one another and helps absorb the shock of physical movement. In osteoarthritis the cartilage that covers the ends of the bones in the joints begins to break down and wear away, causing the bones to rub together, creating pain, swelling and loss of motion.

The main symptoms of osteoarthritis are pain, stiffness and limited joint movement. At first pain is felt during and after activity, but as the condition worsens pain may be felt during minor movements or even at rest. Affected joints may become enlarged and tender, affecting fine motor skills and leading to difficulty in performing everyday activities.


The symptoms of osteoarthritis can vary from one person to another, and for a particular person, can vary considerably over time, and in specific sites around a joint.

A range of factors contribute to the onset and progression of osteoarthritis [1,2,3], including:

  • being female
  • joint misalignment
  • joint injury or trauma (such as dislocation or fracture)
  • excess weight
  • repetitive joint-loading tasks (for example, kneeling, squatting and heavy lifting).

It is also the predominant condition leading to hip and knee replacement surgery in Australia [4]. Clinical guidelines in Australia recommend joint replacement surgery as a cost effective intervention for people with severe osteoarthritis who are unresponsive to medication and exercise [5].

The American College of Rheumatology guidelines strongly recommend people with osteoarthritis to participate in cardiovascular (aerobic) and/or resistance land-based and aquatic exercises [6].


  1. Chapman K & Valdes AM 2012. Genetic factors in OA pathogenesis. Bone 51:64–72.
  2. Lementowski PW & Zelicof SB 2008. Obesity and osteoarthritis 2008. The American Journal of Orthopaedics 37(3):148–151.
  3. Foley S, Ding C, Cicuttini F & Jones G 2007. Physical activity and knee structural change: a longitudinal study using MRI. Medicine and Science in Sports and Exercise 39:426–434.
  4. AOA (Australian Orthopaedic Association) 2011. Australian Orthopaedic Association National Joint Replacement Registry. Annual Report. Adelaide: AOA.
  5. RACGP (The Royal Australian College of General Practitioners) 2007. Referral for joint replacement: a management guide for health providers. Melbourne: RACGP.
  6. Hochberg MC, Altman RD, April KT, et al. 2012. American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip and knee. Arthritis Care & Research 64(4):465–474.