No one actually wants knee replacement surgery. Make certain you don’t need it.
HEALTH When it hurts to rise from a chair, stoop to the floor, ascend or descend stairs, you may be thinking this is either a normal part of aging or that it's time to begin interviewing osteopathic surgeons. If surgery is necessary, there are minimally invasive techniques available.
You may be surprised to discover, however, that the same symptoms are indicative of a treatable condition that can either be caused by trauma during vigorous workouts or sitting for prolonged periods. The condition is called Patellofemoral Pain Syndrome or Chrondromalacia Patella.  If you suspect you have this condition, see your doctor for an evaluation.
With each step on a level surface, the patella pushes against the femur at a force of 1.8 times body weight. The force increases to 3.5 times body weight when climbing stairs or 5 times body weight upon descent. Running or jumping increases the patellofemoral force over 10 times body weight. 
- Elastic knee support
- Walking on level ground
- Stationary cycling
- Apply ice packs for 20 minutes after exercising
Knee pain can also develop in people with bow legs. Overpronation is inward rolling of the foot. The force of each step does should properly center on the knee, down through the feet. A misalignment occurs in bow-legged individuals. This can be further aggravated by low arches and ill fitted shoes. Orthotic shoe inserts may be prescribed by a podiatrist.  Rehabilitation will likely involve some form of exercise. Weight reduction may also be advised to minimize knee pressure.
- Got Knee Pain? Maybe The Answer Is More Exercise. npr.org
- Rehabilitation for Patellofemoral Syndrome ‘Chondromalacia patella’ (pdf). sportmed.com
- 15 Home Remedies for Knee Pain. howstuffworks.com