Well, turns out I need to have my ACL (anterior cruciate ligament) replacement surgery re-done.
It turns out that a combination of the first surgery being done badly and woefully inadequate NHS physio afterwards means that the knee is rubbish. They drill holes through the bones top and bottom of the joint to feed the new ligament through. Unfortunately the surgeon who did the job drilled the lower tunnels too far back which means that the ligament is too loose and the joint is therefore loose as well. I turn, this means that the loose ligament moves about in the tunnel and makes it wider and so the problem compounds itself.
The revision surgery is even more of a bugger than the first one, as it may be that it can't all be done in one go. If there is no room to have another tunnel drilled I will need a bone graft from my hip and have to wait 6 months before being able to do the other part of the surgery. As it is, I will lose the hamstring ligaments (which is what they use in place of the knee ligament) from my left leg as well as they've already used the one from my right leg.
I'll need four to six weeks off work and months of physio.
At least it's covered by the PMI insurance at work so I can have private treatment.
I'm feeling very sorry for myself just now.