Hi. Need to rule out soft tissue pathology of the knee, osteoarthritis and spine trouble. Kindly get Xray done of both the knees AP in standing position and lateral views. Get X-ray of the LS SPINE AP and lateral views. Post x-rays after they are done.
Avoid sitting Cross legged.
Quadriceps Exercises- Lie straight, make a towel role and put it under the knee, press the keen against the role, hold it for 20 secs. Repeat 20 times twice a day. This will help relieve some pain.
Core Strengthening Exercise- Straight Leg Raised With Toes Turned Outward, repeat 10 times, twice a day.
what history you have provided is definitely not adequate to diagnose the problem, as you have said that you have seen so many doctors yet there is no relief is indicative is the accurate diagnosis of the patients condition may not be in place. the pain in knee is just a symptom which may arise due to many causes first and foremost being the wear and tear that happens in the knee as a result of ageing process casusing the condtion called ostearthritis, secondly it may be coming from the soft tissue in and around the knee which are the cartilages , meniscus and ligaments... there is also a possibility that the knee is absolutely fine in its structure but still trhere is the pain, this kind of trouble may arise when the nerve going ro your n]kneee is pinched and irritated at some point along its course,,,
doing hot water fomentation may help a bit , but its definitely help , but its not the complete treatment plan , its just a stop gap measure to buy some tyime so that the investigations can be performed with respect to your knee as well as lower back.
For conform diagnosis, i sugest you to go for MRI KNEE. At home you can do hot pack application 3-4 times a day for 10 min at one time. Ask her to wear knee cap except during sleep. Leg should not be in hanging position during sitting. Use pain killer oil like elegesic liniment over knee joint. Avoid prolong standing.