Consult with physio

Without any delay book an appointment with a orthopedic physiotherapist and start treatment under his/her guidance along with the suggestio your surgeon who. Performed your surgery for better recovery. Joint needs to in full function by now.  But it's not too late.  So start therapy Asap.

Consult a Physiotherapist and start the therapy sessions immediately. If u cause a delay there will be more stiffness. So without delay start ur therapy sessions.

Hot formantation and passive range of motion exercise and active range of motion

Visit your nearest Physiotherapist and start physio session under supervision. It will take atleast 3-4 months time to get full flexion.Don't try to bend it by yourself .

Physio will help you now

It is 45 days you should be able to bend your knee at least 90 degree up to know because no screws or plate are there at your joint

You need proper physiotherapy sessions with joint mobilization , Range of motion exercises, and strenthening exercise also it takes around 40 to 60 days to get full range. For pain physiotherapist will plan pain managment treatment also like TENS for swelling and pain and u have to use hot water for muscle relaxation. So pls go for proper physiotherapy sessions.

It cant be said like that How much tym will it take But if you start exercises under supervision of Physiotherapist you will Improve faster

Start Physiotherapy exercises CPM Strengthen exercises

Please don't delay the treatment visit the nearest physiotherapy center. Stiffness will increase. Do exercise which must be thought after surgery. Also consult ur Ortho Doctor .