Patellar Tendonitis and Cartilage Issues in the Knee: A Comprehensive Guide - Orthopedics

Patellar tendinitis and irregularities in the cartilage on the posterior aspect of the knee?

---

Hello, doctor.
I currently have a knee joint issue and would like to consult you.
Two months ago, I fell off my bicycle (I realized my shoes were still clipped in when I stopped, and I fell to my left side, hitting my left knee).
At that moment, I continued to ride lightly with my right foot for 30 minutes until I returned to my bike.
After getting home, I applied ice.
Since then, my daily routine has been normal, but I haven't ridden my bike or engaged in any special exercise.
(For reference: Before the injury, I went on a multi-day hiking trip six months ago, where my knees felt sore while going downhill, and I used trekking poles.
However, I had no significant issues with daily activities like going up and down stairs.
I only ride my road bike on weekends and had no symptoms.) A week after the fall (counting from the accident), I noticed that after kneeling for a while, the upper part of my knee would feel sore.
I visited my family doctor, who suggested it might be patellar tendinitis and advised me to rest.
I started going out less (avoiding activities that required long periods of walking, like shopping) and made a conscious effort to keep my left leg straight and used it less, which led to some pain in my right leg.
A month after the fall (counting from the accident), I felt some improvement.
However, one time when I squatted to pick something up and then stood up, I felt a pull in the back of my knee that was somewhat painful.
I thought about doing some stretching exercises, and when I tried a butterfly stretch, I found that my knee still hurt.
The next day, I went back to my family doctor, who referred me to an orthopedic specialist.
The orthopedic doctor took X-rays and listened to my symptoms, diagnosing me with tendinitis and referring me for physical therapy.
Since I had been avoiding using my left leg, it had become stiff, and my quadriceps strength had weakened.
During physical therapy, the therapist had me do quadriceps training and manual massage.
During this time, my knee sometimes experienced recurrent inflammation (swelling).
Is this phenomenon normal? Sometimes my knee feels very sore; initially, I thought it was due to the weather, but it can also happen on good weather days.
Two months after the fall (so I had been in rehabilitation for a month by this time), I don't quite remember when it started after the injury, but due to my job requiring long periods of sitting, I elevated my left foot to the same height as my chair.
Just a week before my follow-up appointment, I tried sitting normally (with my thigh and calf at a 90 to 120-degree angle to the floor), as I felt stiff from keeping my foot flat for a long time.
However, I found that one position would become uncomfortable or slightly sore, prompting me to shift positions frequently.
After about two hours, I had to flatten my foot again, and afterward, my knee swelled (is this considered inflammation?).
Doing quadriceps exercises and applying ice at home helped reduce the swelling.
During my follow-up appointment, I explained this situation to the orthopedic doctor, who mentioned that there might be cartilage damage and ordered an MRI.
After the MRI, he said there were no other issues except for uneven cartilage on the back of my knee, but advised me not to worry too much.
He mentioned that if necessary, I could consider hyaluronic acid injections and to let him know.
When I asked him why my knee was swelling, he said there are many possible reasons for swelling, and it seemed he wasn't sure why I was experiencing it.
Five days after my follow-up, I tried sitting with my foot down again while working, and it still swelled.
Now I feel confused because I don't understand why my knee swells when sitting normally.
According to the doctor's initial assessment, it should be due to cartilage damage, but after reviewing the images, he felt it wasn't that serious.

1.
Why does my knee swell when sitting normally? Is it due to cartilage damage, tendinitis, or could there be other unknown causes?
2.
If the swelling when sitting normally is due to tendinitis, does that mean my physical therapy isn't effective? Initially (before seeing the orthopedic doctor), I could sit normally without pain or swelling, but now my condition seems worse, and it's been a month.
Could it be that my lack of exercise initially prevented inflammation or swelling?
3.
Given my current situation, what exercises can I do? Can I continue indoor cycling? If so, what precautions should I take, and under what circumstances should I stop to prevent worsening my condition?
4.
Regarding tendinitis, what should I be mindful of in my daily life? I currently keep my feet flat while sitting and try not to stand for long periods.
I go out less, only driving to work and occasionally shopping for essentials.
5.
I'm a bit worried about the uneven cartilage because I found information online suggesting it could be a precursor to chondromalacia.
Do you have any recommendations?
6.
Regarding hyaluronic acid, I would like to hear your opinion.
I've heard that it's usually administered in more severe cases.
Under what circumstances would you recommend a patient receive hyaluronic acid injections?
I hope you can provide me with some advice on what steps I can take next.
Thank you!

---

AL, 20~29 year old female. Ask Date: 2015/07/12