Hugh asked The Guru for the following Physiotherapy Advice: In June I was diagnosed with a "spontaneous" osteonecrosis in the knee i.e. an oedema apparently caused by that. I'm a runner and was advised to rest up for 3 months and it would repair itself. That time is almost up and, although there is no pain any more, there is a sensitivity in the area sometimes when walking. Is it safe to start running again or should I ask for another MRI scan to check all is now ok?

Hi Hugh Hummm, osteonecrosis is when bone looses its blood supply, either on a temporary or permanent basis. I'm not sure that I've heard that oedema or swelling would cause this to the joint (but does at an intraosseal level ie inside the bone structure), but it may be a product of the bone death and joint reaction. The issue of bone dieing around a joint is that the joint surface and cartilage on that surface may suffer in the long to short term. Regardless of what you feel and what you can see I'd of thought an MRI would be imperative before you thought about going out running again....