TO all outward appearances, the complex of wards and laboratories that make up the showplace Prince of Wales Hospital in Sha Tin appears to run like any institution of eminent reputation. It is big, and scrupulously sterile, and for Hong Kong set out in spacious surroundings. White-coated staff stride about the place authoritatively, or disappear into offices that look extremely organised. The doctors are of excellent academic pedigree. The best universities from Oxford and Cambridge to Boston and Sydney, appear after the names of the staff, and their collective practical experience encompasses most of the famous hospitals of the English-speaking world. In short, it appears to be the right place to be treated when you are seriously ill and need the best medical staff. But all is not as it appears in the Sha Tin medical kingdom. Especially among the upper echelons of the medical hierarchy. During the last 18 months, the medical faculty has become factionalised. Rivalries that had been accepted as tolerable medical politics in the past have intensified and begun to surface in the public arena. At the centre of the dispute is the intention of the Department of Surgery, within the Faculty of Medicine, to re-commence the controversial ox valve programme later this year. No date has been publicly announced for the resumption of the use of the animal tissue replacement valve but individual surgeons at POWH have been told: ''It will be in a few weeks''. This, in itself, is not particularly hot news. In May this year, Dr Jonathan Ho, the cardiac surgeon in charge of the ox-valve project, was expected to announce the re-start of the programme, but for yet unexplained reasons it did not go ahead. The rumours, however, produced their own form of fall-out that has added new controversy in the medical ethics debate about ox valve surgery. Twelve months earlier, the ox valve programme at the hospital, after a life of six months, ceased to function. No official explanation was given for the cessation but it did not take the cardio-medical community by surprise. The ox valve programme has been controversial since its introduction at POWH in January 1992. Until then, patients who suffered from rheumatic heart disease received metal valve replacements and the procedure was not perfect. Patients were put on a programme of life-long medication and prognosis could include development of thrombosis. The animal tissue ox valve, a refinement of the Baruah valve developed by a doctor of the same name in India, appeared to solve many of these problems. The pioneering artificial valve, produced from the cover of ox hearts, appeared to induce fewer long term side effects and require less outpatient monitoring. But other cardiac surgeons in Hong Kong were not convinced that the project should continue because they claimed it was experimental. Surgical procedures, which are either experimental or accepted as conventional procedures, can be performed on patients. Both are permitted but there can be disputes about whether a surgical technique has shifted from experimental status. At the first press conference on the project, on May 1, 1992, Dr Ho reported that 10 patients who had received ox valves were doing well. Investigations later revealed that at least two patients in the programme had died between January and May 1992. In January 1992, the wife of a Gurkha soldier died on the operating table during the process of receiving an implant and a second patient died in April 1992, two days after ox valve surgery. Some time after the press conference, Dr Ho said that six of the 12 patients who had received ox valve implants had died. Visiting senior lecturer, Dr John Sanderson, began an internal inquiry into the programme in September and confirmed the mortality rate, but said that only one death was related to the ox vale implant. Since then Dr Sanderson has completed his internal report, and Professor Arthur Li Kwok-cheung has spoken out in defence of Dr Ho and his team, and the Department of Surgery. He accused his critics of being jealous of the programme in an article in the Chinese language Next magazine earlier this year, and said that the criticisms were based on rivalry. His comments have been the subject of an inquiry by the local Medical Council after other doctors objected to them. The inquiry is believed to be continuing but the results of the findings are not circulated publicly. This week, The South China Morning Post attempted to contact Professor Li to confirm that the programme will be re-started. He did not make himself available for comment.