Understanding Knee Pain

We ask a lot from our knees. They bear most of our body weight, and we expect them to be both flexible (while walking and bending) and rigid (when standing). When our knees start to hurt, it can really disrupt our daily activities. 

The knee joint is the most complicated joint in the human body. Because of its anatomical structure—it consists of three bones and two joints—it is extremely prone not only to injury, but also to wear and tear. Some of the most common knee problems we see include sprained and torn ligaments, meniscal tears, tendinitis, overuse injuries, and osteoarthritis.

The bones in the knee joint—the femur, tibia and patella—are capped by articular cartilage, which is a smooth, slippery, nerve-free surface that protects the bones and allows the joint to glide smoothly. With arthritis, the cartilage flattens out and looses elasticity, and degenerative damage to the cartilage will eventually expose the bone located underneath. The resulting inflammation causes pain, stiffness and swelling.

How Arthritis Progresses In the Knee Joint

Healthy Knee

Healthy knee joint

Unicompartmental OA

Unicompartmental osteoarthritis

Bicompartmental OA

Bicompartmental osteoarthritis

Tricompartmental OA

Tricompartmental osteoarthritis

How do you know if your joint pain is the result of arthritis or merely overuse?

In general, the pain associated with arthritis develops gradually, although sudden onset is also possible. The pain of arthritis may come from different sources. These may include inflammation of the synovial membrane (tissue that lines the joints), the tendons, or the ligaments; muscle strain; and fatigue.  A combination of these factors contributes to the intensity of the pain.

In knees, the joint may become stiff and swollen, making it difficult to bend or straighten the knee. Pain and swelling are worse in the morning or after a period of inactivity. Pain may also increase after activities such as walking, stair climbing or kneeling. The pain may often cause a feeling of weakness in the knee, resulting in a “locking” or “buckling” sensation. Many people report that changes in the weather also affect the degree of pain from arthritis.

When the arthritis is non-inflammatory, the pain is worse with use and usually worse at the end of the day. When the pain is due to inflammation, frequently pain and stiffness are greatest in the morning or after a long period of rest. Symptoms are relieved by heat and gentle exercise. Of course, the most important symptom of arthritis is decreased function, sometimes caused by pain, and sometimes because the joint does not move properly.

What’s a good rule of thumb for when to see a doctor about your knee pain?

If your pain is keeping you up at night, it’s time.

Frequently Asked Questions

What are alternatives to knee replacement?

There are more than 100 types of arthritis, and in general, each type of arthritis has different treatments. Although finding the right treatment may take time, it will enable you to lead an active lifestyle.  

Treatments for arthritis can be divided into several categories, including:    

  • Medication:  Many drugs, both prescriptions and over-the-counter medications, are used to treat arthritis.  Common medications are aspirin-free pain relievers, anti-inflammatories, corticosteroids, disease modifiers, and sleep medications. Hyaluronic acid injections are helpful for mild to moderate arthritis; they increase the viscosity of joint fluid and the elasticity of the joint cartilage, and are also thought to have a mild pain-relieving effect. 
  • Exercise and Physical Therapy:  The golden rule of joint health is that the more you move, the less stiffness you’ll have. Regular exercise is essential to keep the body moving and flexible.  Not only does it help lessen pain, increase mobility, and reduce fatigue, but it also helps you look and feel better. The best exercise choices are activities that don’t pound your joints, such as walking, bicycling, swimming and strength training.
  • Heat or Cold:  Use of heating pads or ice packs can provide short-term relief from pain and stiffness.    
  • Pace yourself.  Alternating periods of activity with periods of rest will help ensure that your joints don’t tire from the stress of repeated tasks. 
  • Ease the load on your joint: Avoiding excess stress on your joints can help protect them. When lifting and carrying items let your bigger muscles and joints support the weight.  The second method is walking with assistive devices.  Lastly, weight control helps ease pain by reducing stress on your joints.     
  • Develop Coping Skills:  Arthritis takes a physical, social, emotional and even financial toll on those who suffer from it. You can learn ways to better manage how arthritis affects you by talking about your feelings with family members and friends. Also, seek out your local arthritis support group; it may provide an environment where you can learn new ways of coping with your illness.    

When Should I Consider Surgery?

Knee replacement is a successful, life-enhancing surgery performed on over 700,000 people in the U.S. each year. More than 90% of people who’ve had a total knee replacement experience a dramatic improvement in their pain and knee function. Some soreness and stiffness will persist for weeks, or months for some patients, but ultimately most people are glad they had surgery. However, surgery is still surgery, and should only be undertaken on your time frame, and when less invasive treatments no longer bring you relief. 

Signs that it might be time for a Total Knee Replacement:

  • Your knee pain prevents you from sleeping.
  • Medication and using a cane aren’t delivering relief.
  • You’re no longer as mobile as you’d like to be, and you feel pain with activity.
  • You have difficult getting in and out of chairs, cars and bathtubs.
  • You are experiencing pain, swelling and stiffness in your knee(s)
  • You have difficulty walking or climbing stairs.
  • You feel a decrease in knee motion or the degree to which you’re able to bend.
  • You feel a “grating” of your joint.

The goals of surgery are to restore pain-free motion, correct deformity, release contractures, and prevent joint instability.

What do I need to know when considering a knee replacement?

  • Arthritis is a progressive disease. Once you have it, it will never get better, and it generally will get worse. There are no exercises, diets, vitamins, or minerals that will make any difference. 
  • The rate of joint deterioration varies greatly from person to person. As knee arthritis progresses, individuals will experience worsening pain and declining function, but some people will find this less debilitating than others.
  • Eventually, your pain and disability will no longer respond to medication. Although you often might experience days or weeks when your knee pain is minimal, this is not a sign your arthritis is “’getting better.”
  • Knee replacement surgery is an elective decision. You will never need a knee replacement if you are willing to live with the pain.
  • More than 98% of patients who have a knee replacement operation have no major complications.
  • There can be consequences to waiting too long: Trying to “save your knee” by becoming totally sedentary won’t slow down the disease’s progression; in fact, it will only accelerate the loss of muscle and bone strength.  
  • Surgery is much better at improving pain than nonsurgical treatments.  A recent study by the New England Journal of Medicine reports that 85 percent of patients who got artificial knee reported pain relief and functional improvement, compared with 68 percent of patients initially assigned to nonsurgical treatment.  
  • Full recovery from the surgery takes about three to six months. Factors influencing your recovery include the type of surgery performed, your overall health, and the success of your rehabilitation.
  • Thanks to improvements in surgical techniques, prosthetic designs, bearing surfaces and fixation methods, 85 percent of total knee implants last 20 years. With normal use and activity, every knee replacement implant begins to wear in its plastic spacer. Excessive activity or weight may speed up this normal wear and may cause the knee replacement to loosen and become painful.
  • One recent study found that 90 percent of patients report they are satisfied with the outcome of their total knee replacement one year after surgery—the highest rate for any type of major orthopaedic surgery.

What are the benefits of knee replacement?

In a total knee replacement, the worn and arthritic surfaces of the knee joint are replaced. Some patients have likened the procedure to resurfacing a road full of potholes—the damaged cartilage, along with a very small amount of bone, is removed, and the knee implant is then attached to the bone to provide an artificial surface.  In patients whose arthritis is limited to just one or two areas of the joint, a partial knee replacement surgery is performed, which helps to preserve the normal bone and cartilage in the rest of the knee.

  • Reduced pain and restored mobility. More than 90% of people who have total knee replacement surgery experience a dramatic reduction in knee pain and a significant improvement in knee function. But total knee replacement will not allow you to do more than you could before you developed arthritis.
  • Improved quality of life. With less pain and greater mobility, you should be able to perform daily tasks more easily and lead a more active, more independent life.

What are the potential risks and complications of knee replacement surgery?

Joint replacement in general is highly successful and has a low rate of complications. However, as with any major surgical procedure, it is important for patients to be well informed about the possible risks of joint replacement surgery.   These risks include:

  • Infection around an implanted joint
  • Dislocation or instability of an implanted joint
  • Damage to nerves or blood vessels. (Nerve injuries occur in less than 1% of knee replacement patients and usually result from scar tissue from previous surgeries forming around the nerve.)
  • Blood clots (deep vein thrombosis)
  • Fractures during surgery (more common in revision surgery)
  • Wound irritation
  • Limb length discrepancies