I have been researching into knee injuries generally following surgery on my knee for Patellar Teninopathy and have found some information which others may find of interest.
There is significant evidence now by respected researchers (Khan and Cook are the most famous), which suggests that most cases of Tendonitis are in fact Overuse tendinosis, and I have been pursuaded that this was in fact the case with my injury.
A classic symptom of both patellar tendonitis and tendinosis is pain near the lower end or inferior pole of the patella.
Patellar tendonitis is an inflammation of the tendon at the inferior pole of the patella. This, if rested, usually clears up within a few weeks.
Patellar tendinosis is nothing to do with inflammation, but in fact is where the Collagen fibres in the tendon, which give it its strength and run longitudinally, have broken down and their poercentage make up of the tendon has decreased. Instead of the collagen fibres being properly aligned, they are disoriented. The actually percentage of Collagen fibres is less than it was before.
It is therefore believed that this injury will not heal with just resting, because the Collagen fibres will not reproduce and realign unless the tendon is worked on by doing strengthening exercises (single leg squats and calf raises), which re-align them and instigate Collagen production.
Useful references can be found on www.findarticles.com, by looking up "patellar tendinopathy" and/or Khan or cook, although the links below are the best articles I could find.http://www.physsportsmed.com/issues/2000/05_00/khan.htm
Other places to research include the American Journal of Sports Medicine website where free abstracts can be obtained.
The recovery rate following open surgery (arthroscopic surgery recovery is slightly less)are not as good as I was lead to believe by my surgeon. He said 97% success, but the research says 80%, but this % relates to recovery being no more pain, not return to exercise. The figure for return to previous level of sport is 50%, which to be fair is pretty low. Recovery after surgery for those who do recover is 6 to 12 months - a very long time!
So persist with the physio, use surgery really as a last option.
Good luck all.