Osteoarthritis

What is osteoarthritis?

Osteoarthritis is a chronic condition characterised by the breakdown of the cartilage that overlies the ends of bones in joints, which usually gets worse over time. It mostly affects the knees, hands, and hips, but can also affect other joints such as the spine and ankles.

As osteoarthritis progresses, it can become difficult to perform everyday tasks. 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 also become swollen and tender which can affect fine motor skills.

Many factors can contribute to the onset and progression of osteoarthritis (Palazo et al. 2016), including:

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

How common is osteoarthritis?

Osteoarthritis is the most common form of arthritis in Australia. Around 2.1 million (8.3%) people in Australia were estimated to be living with arthritis, according to self‑reported data in the 2022 Australian Bureau of Statistics (ABS) National Health Survey (NHS) (ABS 2023). This represented 57% of people living with any form of arthritis, excluding gout.

For more information about other forms of arthritis, see All arthritis, Rheumatoid arthritis, Gout, and Juvenile arthritis.

In 2022, osteoarthritis:

• prevalence increased substantially with increasing age, from 10% among people aged 45–54, to 30% of those aged 75 and over
• was more common among females compared with males (10% and 6.1%, respectively) (Figure 1) (ABS 2023).

Figure 1: Prevalence of osteoarthritis, by age and sex, 2022

Impact of osteoarthritis

Osteoarthritis can have a profound impact on every aspect of a person's life. Ongoing pain, physical limitations and depression can affect an individual's ability to engage in social, community and occupational activities (Briggs et al. 2016).

Older people living with osteoarthritis can also be more prone to falls compared with those without osteoarthritis. This increased risk is due to factors caused by osteoarthritis, such as decreased physical activity, joint instability, medication use and pain (Rosadi et al. 2022).

Measures of impact presented in this section include burden of disease, health expenditure and mortality data.

Burden of disease

In 2023, osteoarthritis accounted for 2.5% of total disease burden (also known as disability-adjusted life years or DALY), 4.7% of non-fatal burden (also known as years lived with a disability or YLD) and almost none (less than 1%) of the fatal burden (also known as years of life lost or YLL).

Within the musculoskeletal disease group, osteoarthritis accounted for:

• 19.8% of total burden (DALY)
• 20.3% of non-fatal burden (YLD)
• 2.8% of fatal burden (YLL) (AIHW 2023a).

Variation by age and sex

In 2023, the rate of burden from osteoarthritis:

• was 1.8 times as high for females compared with males (6.9 and 3.9 DALY per 1,000 population, respectively)
• was less than 0.1 DALY per 1,000 population for people aged under 20, then increased consistently to a high of 17.4 DALY per 1,000 population for people aged 75–79 (Figure 2). 

Figure 2: Burden of disease due to osteoarthritis, by age and sex, 2003, 2011, 2015, 2018 and 2023

Trends over time

After adjusting for different population age structures over time, the rate of osteoarthritis burden increased by 27% (from 3.5 to 4.5 DALY per 1,000 population) – or 1.2% per year on average between 2003 and 2023. Osteoarthritis burden was largely non-fatal and relatively stable over time. 

For more information, see the Australian Burden of Disease Study 2023.

Variation between population groups

In 2018, after adjusting for age differences, the rate of osteoarthritis burden:

• was highest for people living in Inner regional and Outer regional areas (each 5.0 DALY per 1,000 population) and lowest for people living in Remote and Very remote areas and Major cities (3.8 and 3.9 DALY per 1,000 population, respectively)
• was highest for people living in areas of most disadvantage (lowest socioeconomic areas) and lowest for people living in the least disadvantaged areas (highest socioeconomic areas) (5.0 and 3.1 DALY per 1,000 population, respectively) (Figure 3) (AIHW 2021).

For more information, see Australian Burden of Disease Study 2018: Interactive data on disease burden.

Figure 3: Burden of disease due to osteoarthritis for remoteness area and socioeconomic area by sex, 2011, 2015 and 2018

Health system expenditure

In 2020–21, an estimated $4.3 billion of expenditure in the Australian health system was attributed to osteoarthritis, representing 2.9% of total health system expenditure and 29% of expenditure for all musculoskeletal conditions (AIHW 2023b).

Where is the money spent?

In 2020–21, hospital services represented 86% ($3.7 billion) of osteoarthritis expenditure, which was more than the hospital proportion for all disease groups (63%). The private hospital services proportion of osteoarthritis expenditure was 3.7 times the proportion for all disease groups (61% and 17%, respectively) (Figure 4).

Figure 4: Osteoarthritis expenditure attributed to each area of the health system, with comparison to all disease groups, 2020–21

In 2020–21, osteoarthritis accounted for:

• 11% ($2.6 billion) of all private hospital services expenditure – ranking 1st of all diseases/conditions
• 2.3% ($104.7 million) of all medical imaging expenditure (Figure 5).

Figure 5: Proportion of expenditure attributed to osteoarthritis, for each area of the health system, 2020–21

Who is the money spent on?

The distribution of health system expenditure on osteoarthritis by age and sex reflects the prevalence distribution, with more spending for older age groups and females.

In 2020–21:

• 97% of osteoarthritis expenditure was attributed to people aged 45 and over
• 1.3 times more osteoarthritis expenditure was attributed to females compared with males ($2.4 billion and $1.9 billion, respectively), with a remaining $50.1 million (1.2%) unattributed to any sex.

In 2018–19, it was estimated that osteoarthritis expenditure per case was:

• 38% higher for males compared with females ($2,100 and $1,500 per case, respectively)
• 45% higher than musculoskeletal conditions as a group ($1,700 and $1,200 per case, respectively) (AIHW 2022a).

For more information, see:

• Health system spending per case of disease and for certain risk factors
• Health system spending on disease and injury in Australia, 2020–21.

How many deaths were associated with osteoarthritis?

Osteoarthritis was recorded as an underlying and/or associated cause for 2,314 deaths or 8.9 deaths per 100,000 population in Australia in 2022. This represented 1.2% of all deaths and 22% of all musculoskeletal deaths in 2022.  

Osteoarthritis was recorded as the underlying cause for 100 deaths (4.3% of osteoarthritis deaths) and an associated cause only, for 2,214 deaths (96% osteoarthritis deaths).

Variation by age and sex

In 2022, osteoarthritis mortality (as the underlying and/or associated cause) in comparison to all deaths, was more common among:

• older people (92% of osteoarthritis deaths were among people aged 75 and over, compared with 68% for total deaths)
• females (67% of osteoarthritis deaths were among females, compared with 48% of total deaths) (Figure 6).

Figure 6: Age distribution for osteoarthritis mortality, by sex, 2012 to 2022

Trends over time

After adjusting for different population age structures over time, mortality rates for osteoarthritis (as the underlying and/or associated cause) between 2012 and 2022 were:

• relatively stable, averaging 6.2 deaths per 100,000 population 
• 1.4 to 1.6 times as high for females compared with males (Figure 7). 

Figure 7: Trends over time for osteoarthritis mortality, 2012 to 2022

Variation between population groups

In 2022, after adjusting for age differences, mortality rates for osteoarthritis (as the underlying and/or associated cause) were 1.3 times as high for people living in:

• Outer regional areas compared with people living in Major cities (8.0 and 6.1 deaths per 100,000 population, respectively)
• areas of most disadvantage (lowest socioeconomic areas) compared with people living in the least disadvantaged areas (highest socioeconomic areas) (7.1 and 5.4 deaths per 100,000 population, respectively).

Treatment and management of osteoarthritis

At present there is no cure for osteoarthritis and the disease is long-term and progressive. Treatment for osteoarthritis aims to manage symptoms, increase mobility and maximise quality of life.

What role do GPs play in managing osteoarthritis?

General practitioners (GP) are usually the first point of contact in the health care system for people with osteoarthritis (RACGP 2018). GP management of osteoarthritis may include assessment and diagnosis, referral to other health services, prescribing medication and providing education about the condition. 

GPs can also provide advice and referrals, weight loss/management strategies and suitable exercise programs to help to manage as well as prevent osteoarthritis. Weight loss can help reduce symptoms whilst exercise can help improve symptoms (especially pain and joint stiffness) (RACGP 2018).

It is worth noting that there is currently no nationally consistent primary health care data collection to monitor provision of care by GPs. For more information, see General practice, allied health and other primary care services.

What medicines are used to treat osteoarthritis?

Treatment of osteoarthritis with medication aims to relieve pain, reduce inflammation and improve functioning and quality of life. Analgesics, or pain medications, are commonly used to manage the pain of osteoarthritis.

Corticosteroid injections may also be recommended for short-term pain relief for hip and/or knee osteoarthritis if appropriate (RACGP 2018). Opioids are not recommended for the treatment of hip and/or knee osteoarthritis (RACGP 2018).

What role do hospitals play in treating osteoarthritis?

Data from the National Hospital Morbidity Database (NHMD) show that in 2021–22, there were 285,000 hospitalisations with a principal or additional diagnosis (any diagnosis) of osteoarthritis, representing 2.5% of all hospitalisations.

The rest of this section discusses hospitalisations with a principal diagnosis of osteoarthritis, unless otherwise stated. However, charts and tables also include statistics for any diagnosis of osteoarthritis.

In 2021–22:

• there were 242,000 hospitalisations, representing 2.1% of all hospitalisations in Australia, and 940 hospitalisations per 100,000 population
• osteoarthritis accounted for 786,000 bed days, representing 2.5% of all bed days
• 53% of osteoarthritis hospitalisations were overnight stays, with an average length of 5.2 days (Figure 8).

Figure 8: Age distribution for osteoarthritis hospitalisations, by sex, 2015–16 to 2021–22

Variation by age and sex

In 2021–22, osteoarthritis hospitalisation rates were:

• highest for people aged 75–79 (4,600 hospitalisations per 100,000 population) 
• 1.3 times as high for females compared with males (1,000 and 830 hospitalisations per 100,000 population, respectively) (Figure 8).

Trends over time

For osteoarthritis hospitalisations from 2015–16 to 2021–22:

• rates remained relatively stable, around an average of 1,000 hospitalisations per 100,000 population, with notable volatility over the last few years
• the proportion of overnight stays changed little, with an average of 51%
• the average length of overnight stays decreased slightly from 6.2 to 5.2 days (Figure 9).

It should be noted that the rate of hospitalisations over the past few years may have been affected by the COVID‑19 pandemic.

Data prior to 2015–16 are not presented because rehabilitation hospitalisations were coded differently prior to this year.

Figure 9: Trends over time for osteoarthritis hospitalisations, 2015–16 to 2021–22

Between 2011–12 and 2021–22, for osteoarthritis:

• acute care hospitalisations ranged between 570 and 680 hospitalisations per 100,000 population, with increased volatility over the last few years, likely due to the COVID‑19 pandemic
• the hospitalisation rate for other care types (inclusive of sub-acute and non-acute care) increased until 2018–19 (prior to the COVID‑19 pandemic) and decreased thereafter

• the average length of stay for acute care decreased slightly from 4.5 to 4.0 bed days
• the average length of stay for non-acute care decreased from 4.6 days to 3.8 days (Figure 10).

Figure 10: Trends over time for osteoarthritis hospitalisations by care type, 2011–12 to 2021–22

The primary purpose of rehabilitation care is to improve functioning of a patient with an impairment, activity limitation, or participation restriction due to a health condition. 

In 2021–22, osteoarthritis was the most common reason for rehabilitation care with arthrosis of knee accounting for 22% and arthrosis of hip accounting for 9.4% of all rehabilitation hospitalisations (AIHW 2022b). 

Joint replacement surgery

Osteoarthritis is the most common condition leading to hip and knee replacement surgery in Australia (AOANJRR 2019). Joint replacement is a cost-effective and clinically effective treatment for severe osteoarthritis (RACGP 2018).

Clinical guidelines recommend considering joint replacement surgery for severe osteoarthritis if all conservative treatment options have failed (RACGP 2018).

In 2021–22:

• 53,500 knee replacements and 35,500 hip replacements were performed in hospitalisations with a principal diagnosis of osteoarthritis (210 and 140 hospitalisations per 100,000 population, respectively)
• the rate of knee or hip replacements increased sharply to 75–79 years, and then decreased (Figure 11)
• the average length of stay for knee and hip replacements both increased from around 4 days for people aged 45–49 to around 6 days for people aged 85 and over.

Figure 11: Age profile of total knee and hip replacements

Between 2011–12 and 2021–22 for hospitalisations where osteoarthritis was the principal diagnosis:

• crude rates of both hip and knee replacement surgeries increased slightly
• after adjusting for age differences, the rate of total hip replacement surgeries increased slightly, while the rate of total knee replacement surgeries remained stable
• age-adjusted rates and crude rates, for both hip and knee replacement surgeries were impacted by the COVID‑19 pandemic. Lower rates were observed when elective surgeries were cancelled during the pandemic, followed by increased rates once the surgery backlog was rescheduled. The rate in 2021–22 was higher than pre-pandemic, likely due to an increase in the ageing population (Figure 12).

Figure 12: Trends in total knee and hip replacements for osteoarthritis, 2011–12 to 2021–22