Q: My 26 years old friend has got bone infection after a knee replacement surgery. What can be the reasons of infection in an orthopaedic surgery and measures to be taken to ensure sterile operation theatre environment?

A:Reasons of infection are the same for all surgeries, orthopaedic or otherwise. You have to realise that the development of infection is a balance between the bacterial load and the host defence. The bacteria may come from- a. the patients skin, b. the operation theater (OT) environment, c. the patients own body itself. In a conventional knee surgery, presuming proper care, the chances of a, b, and c are roughly equal. A, b, and c are preventable up to a point. For example, cleaning the patient with antiseptic solutions decreases the bacteria by about 97% or better. However, only strong caustics can lower the bacteria by 99%, and these strong caustics will damage the patients skin. If 3% of bacteria remain, you may think that the number is small, but remember that the absolute bacterial count is still thousands of billions. OT floors, equipment, etc can be cleaned with caustic solutions, and usually is. The OT atmosphere can be cleaned with a special laminar flow setup. Major hospitals now have a laminar flow system for its critical areas. However, this setup is extremely expensive, and makes about a 1% change in infection rates, perhaps less. The patients own bacteria can be decreased with antibiotics. Preoperative antibiotics again make a difference of only about 1% in infection rates in the type of surgery that you are talking about. Surgeons wear autoclaved gowns while operating. These gowns are sterilized, that means completely (100%, not 97%) bacteria free. They wear gloves, which again are sterile. If a surgeon did not wear such a gown or such gloves, that would be unpardonable, but I have never seen this happen in even the smallest hospital, and this is extremely improbably in a canter that conducts knee replacements. The bottom line is, the OT must follow standard norms for prevention of infection. With these norms infection can be minimized but not totally prevented. If you wish to take legal action against the hospital/ surgeon, you will need to show that the surgeons infection rate is more than average, or that the hospital did not follow standard norms. I think that the average for this operation should be 1-2%, but I am not certain.