A shot in the dark, but has anybody tried this new method of addressing this common knee problem.
The article is on the Daily Mail so not point linking to it from here. Here is a quote from the article, on how the procedure helped rugby player Andy Goode:

“Mr Church suggested a novel treatment – an injection of botulinum toxin into the left hip muscle. The procedure would involve injecting Dysport – similar to Botox but using a different type of botulinum toxin – into the muscle to ‘switch it off’.
This would force the glutes to work harder, bringing the knee back into alignment.
While the effects of the treatment last only 12 weeks, the idea is that the patient has physiotherapy during that time to retrain the muscles permanently.
Patients usually need just one injection, but the treatment can be repeated if necessary. ‘Although I was supposed to take a few weeks off, I knew immediately that it worked because I could walk, bend and climb stairs without that shooting pain,’ says Andy, who lives in Gerrards Cross, Buckinghamshire.”