Knee Ligament laxity if you have problem in your legs then it might be due to ligament laxity where your legs would become very weak due to the old ligament injury and that should be treated immediately. Wear knee cap so that you will feel firm while walking or climbing stairs.
This is a general strain and for this you can follow these measures: one keep a pillow right under the knee while sleeping, next is you can keep ice in the painful area for about 5--10 minutes, if pain
still persists you can stretch your body by twisting the waist on both sides how we used to do in the school drill similarly you can try! One time you can do hot water fermentation that would help to reduce the muscle strain.
You have to do knee strengthening exercises, ie. Knee rehabilitation exercises which will strengthen your knee. Exercises will give you permanent cure than the surgery.
You can take Ultrasonic therapy in one of the nearby physiotherapy
clinics which would help to heal