How do you know when surgery is the best option and who makes the call? About a million orthopaedic surgeries are done each year in Australia. Many of these are joint replacements or spinal surgeries to treat osteoarthritis. Hip and knee replacements alone cost the health system more than any other hospital procedure – over $2 billion a year. And some of these surgeries are on the rise. A Victorian study found that between 1994 to 2014, the number of hip replacements done went up 175 per cent, while knee replacements went up 285 per cent. But the evidence for many commonly performed operations is far from clear cut. Research suggests that about half of orthopaedic procedures have no scientific evidence to prove they work better than non-surgical treatments, and another quarter are no more effective than alternatives such as physiotherapy, exercise and weight loss.