What Do These Reports Regarding Swelling And Pain In Knee Indicate?

Question : Hi DR,
My nephew(17 years old) is suffering from Right Knee pain and swelling for last 2 months. Initial MRI report says below
Fluid : Noted in retropatellar fossa,suprapatellar fossa, bilateral gutters and with in joint.
MRI Impression : Contusion in lateral condyle and intercondylar region of femur

Started medication accordingly, but pain is not in control and its increasing day by day, and currently he is not able to walk without any support. He is having pain 24 hours and at times(with any movements) he is getting unbearable pain and literally crying. We undergone orthoscopy(biopsy) with below findings
CULTURE: No bacterial growth.
Microscopy: section revealed denuded synovium with underlying clusters of acute inflammatory cells and fibrocollagenous stroma. No displastic or malignant cells seen.
Historical features are consistent with Septic Arthritis

Started giving septic arthritis medicines(oral). After 2-3 weeks of usage, his swelling got reduced to 50%, but pain was doubled. Various blood reports were taken and below are the same
HLAB27 - postive
Gram Stain - no bacterial forms,
RF IGM Antibodies - Negative
ESR : 63 (20 days back) and 38 (as of now)
CRP: 83 (20 days back) and 24 (as of now)
And all other things are normally.
Based on the above, doctors were concluding that because of more CRP would causes this pain and giving below medicines(after usage of the below crp and esr comes done as mentioned above).Started using the below for last 3 weeks but no improvement in the pain.
Augmentin 600mg (IV) - 3 times a day
Gentamicin -80mg(iV) - 2 times a day
Salazar 1gm(Oral) - 1 time a day
celadol 100mg - optional, based on pain.
Current Situation: Swelling reduced to 80% but heavy pain.

We got a doubt recently, bone(skeletal) TB would causes like these pain and we did a test for the same with Mantoux screening test(tuberculin sensitivity test) and found that no major rashes but slight senstive area and doctors considered that virus is present in body and (stoped above mentioned IV ) stated giving AKT 4(one complete strip daily) with Benadon 40mg(one tab per week) for last 2 weeks.

*with TB medicine if we use any pain killers /swelling reduce medicines, pain is gaining and almost one inch of increasing swelling for 2 days.
We are observing no side effects with TB medicines but we are in a crunch situation not understanding the issue for that pain.
Regards, XXXXXXX