WHEN it comes to new and innovative ideas, Hong Kong is rarely slow to adopt them. However, in the field of treating male impotence, it is unlikely a popular therapy in the United States will soon catch on in the territory. Across the Pacific men suffering impotence - the inability to sustain an erection - are referred to surrogate partners. These are women who treat their ''patients'' by having sex with them, using sexual therapy techniques to progressively prolong their erections over a series of sessions. ''It is a bit like aerobics - the more you practise the longer you can keep at it,'' mused a Hong Kong doctor with a broad smile. ''Sometimes there are things that you cannot get from your wife.'' Hong Kong and Asia's infinitely more conservative mores are unlikely to countenance such a practical method of trying to solve a condition estimated to affect more than one in 10 men worldwide. But almost a year after several urologists opened a facility to treat impotence at the Hong Kong Adventist Hospital it appears more Hong Kong men than ever before are coming forward to seek treatment for what has for so long been a taboo subject. One doctor from the Adventist, who cannot be named because of Hong Kong regulations prohibiting doctors from what may be regarded as advertising, says there is still much ignorance among members of the public about impotency and sexual dysfunction in general. ''It is strange; there is nothing shameful about impotency; if your eyes are not working properly you go to a doctor, and so on,'' the doctor said. ''Sex is for pleasure, it is for procreation and it has a very important link with friendship and in a marriage. You should also remember that 95 per cent of erectile disorders can be treated.'' Impotency can be caused by psychological and physical conditions - anything from stress, depressive illness and psychotic disturbances to diabetes, heart problems and other vascular conditions or else injuries that lead to crushing of the pelvis or slipped discs that may affect the nerves supplying sensation to the groin area. Although Hong Kong is often said to be in a class of its own when it comes to stress, the doctor said it was not a cause of impotence any more than in other major cities like New York, Paris or London. Formerly, treatment for impotence was exclusively the province of psychologists and psychiatrists. Given the reluctance of Asian men to openly discuss what they felt was a sexual failing, it was not surprising impotency was not widely discussed in Hong Kong. What the doctor termed ''national and cultural inhibitions'' were still preventing many men from coming forward with their complaints about impotency. ''Men do not want to admit there is something wrong. They will say they are working at 70 per cent of their sexual capacity, while their wives will tell you separately that it is more like 20 per cent,'' the doctor said. Advances in medical treatment over the past two decades have seen urologists becoming far more involved in treating impotence, although counselling, rest and sex therapy are still the best methods for dealing with temporary impotency. There are three devices used to physically aid men to get erections. The simplest is a vacuum device that fits over the penis and draws blood into the erectile tissue with a rubber ring placed on the base of the organ to prevent draining. Patients can also be taught to inject themselves with drugs that draw blood into the organ, with the dosage being varied according to the age and the level of the patient's circulation. The most advanced - and the most expensive - method is the use of prostheses, either semi-rigid bendable plastic rods, silicon cylinders that are pumped up and down with saline solution from a reservoir inside the scrotum, and implants that can cost up to $50,000 including the surgeon's fees and hospitalisation. But the doctor warns none of the techniques are perfect. The vacuum is somewhat uncomfortable and the rubber ring can only be worn for 30 minutes before the penis becomes starved of fresh, oxygenated blood. The amount of the injection must be carefully scrutinised and administered, or else there is a danger of the organ remaining rigid and the blood clotting, causing permanent damage. Complications can result from surgery, including infection and, in two to three per cent of cases, failure. Still, according to the doctor, most men are pleased with the results of their treatment. ''They tell me they wish they had done it earlier.''