Diagnosis: patellafemoral artrosis or something else?

Dear sir, madam,

I am 35 years old, used to be sportive, but for 10 years or so I'm having a knee injury that slowly begins to worsen. In the last years I've been following treatment several times by doing exercises. Now I am doubting if the diagnosis is correct and if the treatment is adequate.

My pain is mostly on the front of my knee, on the left side, at the lump. I have marked this place on the photos below. When I bend my knee, something "jumps" or skips there, just before I have completely bent my knee. I can feel something on the outside moving to the left, sliding over something hard.

I especially have pain * after * efforts such as cycling, climbing stairs and walking. During the activity I often have little or no trouble, unless I exceed my normal limit. The worst pain usually comes the day after exercise, especially while sitting. It is a nagging pain that I estimate a 5 a scale of 1-10. I suffer the most after cycling. I can no longer do a 20 km walk or bike ride, unless I cycle very slowly, around 10 mph. For comparison, a few years ago I regularly cycled 75 miles with 5,000 altitude meters on a day. I no longer do mountain biking. I haven't run for years, either. These days I swim. That goes well, but doing a short sprint also causes pain the next day. The pain is so annoying that it mentally bothers me by now.

What helps with pain is stretching my leg, putting ice on it, and taking painkillers such as acetaminophen and ibuprofen. I don't see any swelling and the knee never locks. My office chair and bike saddle are at the right height and my footwear is in order

In recent years I have visited several physiotherapists and an orthopedist. According to my physiotherapist's latest diagnosis, I probably have patella femoral arthrosis. If I understand correctly, in normal words, it's wear of the cartilage. Currently I have been following a program at the physio for four months where I am doing leg press, blank extensions and step-ups exercises to improve strength and coordination. In my opinion, this has yielded little or no improvement so far. My physical therapist says that this can take a few months before I notice something.

In the past, physiotherapists all reckoned that the pain has to do with my patella. All think that the spur of my kneecap is not good. Three years ago a physiotherapist told me that I have Patella Femoral Pain Syndrome. When it turned out that the exercises were not very effective, he referred me to a orthopedist. I then had an MRI made on his advice. He saw nothing remarkable, just some arthrosis, but that was minimal. Then I ended up with my current physical therapist, because the pain hinders me in daily life, even when I am not exercising.

Now I doubt whether the patella or arthrosis is the *cause* of my pain, because none of the specialists can explain why something is jumping or skipping on my knee. They pay no attention to that, even though I have indicated on several occasions that my pain is more *on* my knee and not so much *inside* my knee. I find it strange that they can't explain what this is and whether it has anything to do with it, but I can't do anything with that, so that's why I follow the exercise program.

Now what's strange is that when I first do a stretching exercise, and then bend my knee completely a few times, nothing jumps/skips for a while. I mean when I do a standing quadricep stretching exercise, where I fully bend my knee. It looks like my quadricep is going too tightly over my knee, but that it goes well if I stretch it in advance. According to all specialists, this does not matter.

Now my questions are:
- Do you think the diagnosis made by the specialists is correct? (I understand that this is difficult to determine remotely)
- Does the treatment I follow make sense?
- Can the jumping/skipping of a tendon / muscle be the cause of my pain?
- How can I find out if that is indeed the case with me?
- If so, what can I do about it?

Thank you very much for your help.