Yeung was told to just accept it as a fact of ageing.

"The doctor said, 'Your knee has completely degenerated. It can't be treated. Take care.'"

A 2000 study by Chinese University found that among Hongkongers aged 50 and above, 7 per cent of men and 13 per cent of women suffered from osteoarthritis. Back then, doctors prescribed painkillers to help patients cope with the discomfort.

Now, there is possibly a better option available. A drug manufacturer is bringing to Hong Kong a new treatment that addresses the joint itself; the Health Department has also developed a set of exercises to be done in water, and the results of tests were published in a recent issue of the .

But the problem remains: doctors say the demand for joint replacement, the last resort for this condition, is outpacing supply.

That can be seen in the "longer and longer waiting times in public hospitals, where it is not uncommon for patients to wait a few years before receiving the procedure," writes Dr Yuen Wai-hong of Queen Elizabeth Hospital's department of orthopaedics and traumatology, in the journal.

"This does not take into account the waiting time between the referral and the first orthopaedic consultation. Patients on the waiting list for TKR [total knee replacement] are usually in excruciating pain and have significant functional impairment," Yuen writes.

Yuen attributes the growing demand for knee replacements to Hong Kong's ageing population - more than 20 per cent of the population is expected to be 65 or older by the early 2020s.

But now younger Hongkongers are also affected, says Albert Lee, a professor and director of the centre for health education and health promotion at Chinese University.

During the past couple of years, Lee says, he and his colleagues have been getting more inquiries from younger people, some in late 30s, seeking help for joint pain. "It's a public health issue, not just a medical issue," Lee says.

Being overweight is an important risk factor because the knee and hip joints bear a person's entire body weight. More weight to bear means more stress on the joints. Lee says regular exercise is important, but for people with joint pain it can be hard.

"It's a vicious cycle, because of the pain, they cannot move around," he says. "It limits their movement."

That holds true for Yeung, who didn't dare travel with her family, and she had to hold on to something when going up stairs or slopes.

But now Yeung can move around without much pain, partly because she's been doing a different kind of exercise. Physiotherapists from the Health Department developed exercises to be done in swimming pools, including squats, jumps and arm movements.

The idea is that doing exercises underwater is less stressful than on land - plus there's the added benefit of resistance.

The physiotherapists tested the 10-week programme with 20 seniors suffering from osteoarthritis. Yeung was among them and, like most members of the group, her pain subsided.

She can now bend her knees more, and the weight that her leg muscles can support has more than doubled.

Some health centres for the elderly have already adopted the routine.

The greatest misconception about osteoarthritis is that it can't be treated, says Mary Lau, a physiotherapist at the Department of Health's Elderly Health Service, who led the study.

"People generally think: 'I'm getting old, joint pain is inevitable,'" she says. "But you can improve joint function and reduce the pain substantially, and even prevent it altogether."

Hongkongers will soon be able to buy a new gel, which its manufacturer claims can relieve osteoarthritis by lubricating the joint after it's applied to the skin. The product, Flexiseq, is already on sale in Britain, Germany and Malaysia.

If a patient's joints have deteriorated too severely, then the only option for a cure is to replace the joint, says Lee.

However, some say public hospitals in Hong Kong aren't exactly equipped for an influx of people needing joint replacements.

The government and the Hospital Authority have established two joint-replacement centres, at the Hong Kong Buddhist Hospital and Yan Chai Hospital, Yuen says in his article. But it also points out that the two centres are on the verge of becoming overcrowded, and hospitals with long waiting lists for the procedure are in need of extra resources.

In an statement, a representative from the Hong Kong Hospital Authority says a third joint-replacement centre will be set up at Pok Oi Hospital by next year.

Ma Kai-yiu, a doctor specialising in arthritis and other rheumatic disease, echoes the call for help.

"If a patient needs joint replacement at a government hospital, the waiting list is so long that it might take several months to more than a year," Ma says.

"By that measure, we don't have enough infrastructure to deal with the problem."
 

How to prevent joint problems:

carry anything that's more than 10 per cent of your body weight - that includes school bags and shopping bags.

something else after an hour of sitting or standing at work.

regularly.

stools that are too short for you. Bending your knees at an awkward angle means they have to bear several times your body weight.

shoes that support your weight; avoid high heels.

a doctor if your joints hurt.