P R E S S   R E L E A S E

Chinese Version
- Chronic endocrine disorders
6 March 2001

Osteoarthritis in Hong Kong Chinese - Prevalence, aetiology and prevention

Osteoarthritis is a common degenerative joint condition that usually occurs at the hip, knee or hand.  Osteoarthritis of the knee is particularly common among Hong Kong Chinese and accounts for most of the disability of the elderly in Hong Kong.  Very often, joint replacement is required in many patients.

A study by the Faculty of Medicine of The Chinese University of Hong Kong reveals that the prevalence of osteoarthritis knee is as high Hong Kong as in western countries.  With a aging population and as osteoarthritis has the feature of suddenly becoming very common in the knee and hip joints in women after menopause, it is envisaged that osteoartritis will become a very major public health problem in Hong Kong, and in particular to women.  Early prevention is very important.

Osteoarthritis of the knee can be diagnosed by persistent knee pain together with the following symptoms:
- Crepitus when the joint is moved
- Morning stiffness of <½ hour
- Bony enlargement

The Chinese University of Hong Kong surveyed 426 adult men and 621 adult women in Hong Kong in 2000.  The study found that among men aged 50 years and older, 17% had persistent knee pain and 7% can be diagnosed to have osteoarthritis of the knee.  Among women aged 50 years and older, 24% had persistent knee pain and 13% can be diagnosed to have osteoarthritis of the knee. These findings are very similar to the Framingham study in America.  As arthritis and stroke are the major cause of disability in people who were originally healthy, the findings reveal the severity of the problem and indicated public concern over osteoarthritis should be raised.

A second study in 2000 investigated 650 hospital patients with osteoarthritis of the knee and 650 normal subjects.  The three main aetiological factors for osteoarthritis of the knee were: overweight, knee joint injury and lifting heavy load at work.  64% of patients investigated were overweight and overweight subjects were 5 times more likely to develop osteoarthritis of the knee.  26% of patients had previous knee injuries.  Subjects with a previous knee joint injury were 7 times more likely to develop osteoarthritis of the knee.  Moreover, subjects working in jobs entailing lifting heavy loads were 5 times more likely to develop osteoarthritis of the knee, and 56% of the patients worked in such jobs.  

Contrary to popular belief, recreation sports activities such as jogging, ball games and dancing did not cause osteoarthritis of the knee.  Rather safe sport should be promoted to prevent the disease.
The Chinese University recommends the followings for the primary and secondary prevention of osteoarthritis of the knee.

1 Weight reduction
- A weight reduction of 10 lbs reduces 50% absolute risk of osteoarthritis of the knee.

2 Injury prevention
- Professional sports players (e.g. soccer players) should avoid high impact bodily contact.
- Injuries must be treated by specialists and with adequate rehabilitation.

3 Workers in load-bearing jobs
- Government should establish policy and guidelines for occupational lifting.
- Employers should provide lifting aids to workers.
- Simple measures such as strengthening of the quadriceps muscles are recommended for workers.

4 Recreational sports activities should not be avoided.  Appropriate physical activity is beneficial for rehabilitating subjects with established osteoarthritis.