Knee Osteoarthritis

Overview

The knee joint is the meeting point of 3 bones – the femur (thigh bone), tibia (shinbone), and patella (kneecap). Each of these bones is covered by articular cartilage, the hard, slippery tissue that covers the ends of the bones where they meet to form the joint. Cartilage protects the joint from the impact of everyday movements by allowing the bones to glide over each other smoothly. Osteoarthritis of the knee is caused by the gradual loss of the cartilage in your knee joint.

When enough cartilage wears away, the bones rub against each other, causing pain, swelling, loss of motion, and joint changes.

The body responds to the loss of cartilage by producing more fluid in the lining of the joints to cushion it. However, the additional fluid can cause the joint to swell, limiting motion and causing pain. This is called an effusion, or fluid on the knee.

Friction between the bones may cause small deposits of bone called bone spurs to form on the edges of the joint. Cartilage can also break off and float around inside the knee joint, causing more pain and damage

Symptoms
The primary symptom of knee osteoarthritis is pain in the knee joint that gets worse when you are active and gets better with rest. If you have advanced osteoarthritis, you may also experience pain when you are resting. Symptoms usually progress gradually over time, although your symptoms may suddenly get worse if you aggravate your arthritis by doing too much or you injure your knee. Other common symptoms include

Stiffness It is very common to feel stiff, especially first thing in the morning. Stiffness usually lasts for about 30 minutes after you get up and can recur during the day if you are inactive for a while. Stiffness can make it difficult for you to go about your usual daily routine. For example, you may have difficulty

Walking
Climbing stairs
Squatting or kneeling
Standing up after sitting on a chair
Getting out of a bathtub

Tenderness. Touching the knee joint can be painful. Your knee may hurt to the touch even if there is no visible evidence of inflammation

Swelling. Your knee joint may swell with fluid, as your body attempts to make up for the loss of cartilage. Sometimes there is so much fluid that it begins to build up in the back of the knee, a condition known as a Baker’s cyst
Crackling or grating. You may feel a crackling or grating sensation when you move the joint. This is thought to be caused by roughening of the normally smooth cartilage inside the joint

Bone spurs. You may be able to feel bone spurs under the skin near the affected joints. These get larger over time

Causes and Risk Factors

There are a number of factors that may increase your risk for developing osteoarthritis in any joint. Risk factors that make it more likely that you will develop osteoarthritis in the knee specifically include

Kneeling and squatting. Work that requires frequent squatting and kneeling, such as construction and housework, may be a cause

Stress on the knee. This can be caused by

Heavy work. Carrying heavy items (tool belt, briefcase, purse, etc.) puts extra stress on the knees and hips, which causes more wear and tear on your joints

Being overweight. Carrying extra weight on your frame also places extra stress on your knees, and it can cause you to develop arthritis at a younger age and worsen your symptoms if you already have arthritis

Diagnosis

We evaluate the results of a physical examination and your description of your symptoms in order to diagnose osteoarthritis of the knee
Medical history

We will ask you a number of questions about your symptoms

?What kind of work do you do? What kind of work have you done in the past? What sports and other hobbies do you participate in

؟Have you ever injured your knee

?When and how did your symptoms start, and how have they changed over time

?How much pain are you having, and does it come and go, or is it constant
?When do you feel pain or stiffness, and how long does it last
?DOyou feel a grinding or grating sensation when you bend or straighten your knee
?Do you have family members who have experienced joint problems

?What medications are you taking now? What medications have you taken in the past

Physical examination
During the physical examination, we will examine your knee and look for
Swelling or fluid around, or behind, the knee joint

Tenderness over your knee

Bony enlargement of the knee joint

Any redness or warmth over the knee, which may indicate infection

Loss of ability to fully bend or straighten your knee

Imaging studies

We will look at X-rays of your knee in order to determine how severe the osteoarthritis is. An X-ray can reveal a number of knee joint characteristics that can help us confirm osteoarthritis. These include

The space between the thigh bone and shin bone is narrowed due to the loss of cartilage

Bony spurs, also called osteophytes

Cysts on the bone

Treatments

Our goals for treatment are
To decrease your pain and minimize swelling

To improve the function of the knee

To help you maintain a healthy body weight

To improve your quality of life and help you achieve a healthy lifestyle

There are a number of ways to treat osteoarthritis including exercise and physical therapy, weight management, medication, joint injections, and, in severe cases, surgery. We recommend a combination of treatments specifically for osteoarthritis of the knee joint
Limit the activities that may aggravate your knee; for example, running, fast walking, carrying heavy items, and standing for extended periods of time

Exercise and physical therapy

A combination of body-strengthening and aerobic exercise has been shown to reduce pain and improve quality of life. Gentle midrange movement makes arthritic joints feel more comfortable. Inactivity can make joints feel stiffer. Exercise can also improve your mood, energy levels, quality of sleep, weight control, heart health, and muscle tone and strength. It is important to choose the right kind of exercise and to limit activities that aggravate your knee. Running, fast walking, carrying heavy items, and standing for extended periods of time can all increase stress on the knee. We can help you choose the most appropriate form of exercise

Physical therapy

Physical therapy may improve the flexibility of your knee joint and strengthen the muscles that support the knee. As part of your physical therapy, we will teach you exercises that avoid hurting the joint or causing you more pain. It is important that you continue these exercises at home to maintain your progress. A physical therapy plan for the knee usually includes

Exercises to strengthen the quadriceps, or main thigh muscles. For some individuals, this increases the stability and mobility of the knee joint and reduces pain

Aerobic exercise. We can help you choose the most appropriate form of exercise. For example, if you are a runner, we may suggest that you try swimming or cycling on a stationary bike instead to reduce impact on your knee

Steroid injections

If oral pain medications are not effective, we may consider injecting the knee joint with steroid medication. Steroid injections can provide short-term improvement, usually for a few weeks to several months. We may repeat injections about every 6 months if they remain effective for you. Side effects of joint injections include pain and swelling after the injection

Surgery

We may recommend surgery if less invasive treatments have not been effective. Surgical procedures for osteoarthritis include knee arthroscopy, total joint replacement, partial joint replacement, and osteotomy

Arthroscopic Surgery

In many cases, we can evaluate and make some repairs to an arthritic knee joint using an arthroscope. This approach avoids the need for a large incision. An overview of this procedure includes the following
We make 2 or 3 small incisions in the knee joint

We then insert an arthroscope – a lighted device with a camera and surgical instruments attached – into the joint itself

The scope allows us to see the structures inside the knee and any debris, such as bone spurs and loose cartilage that have collected in the joint

We insert small instruments into the other incisions and use them to trim torn articular cartilage and/or remove debris that may be causing pain

Total Knee Replacement Surgery
We may recommend replacing your knee joint entirely if your osteoarthritis has not responded to other medical treatments and is so severe that it is affecting your ability to perform everyday activities

Total knee replacement is a very successful procedure that significantly reduces pain for many people and enables them to get back to the activities they enjoy. Replacement knee joints can last 15 years or more. How quickly they wear out will depend on the amount of pressure you put on your knee and how active you are

Not everyone is a candidate for knee replacement surgery. We will consider a number of factors while evaluating you for this type of surgery. It is crucial that you, and your joints, are healthy enough to recover from surgery and participate in a comprehensive rehabilitation program

The replacement knee joint is usually made of metal and/or plastic and has 3 components

A femoral component that attaches to the femur. This is usually made with polished metal

A tibial component. This is the part that is attached to the top of the tibia. It is usually made of plastic and metal

Kneecap – or patellar – component

The surgery
Knee replacement surgery takes between 1 and 3 hours. We usually perform the procedure using spinal anesthesia. You will be awake but numb from the waist down. Alternatively, we may recommend a general anesthetic


During the procedure, we make a vertical incision along the kneecap. We then prepare the bones so that the replacement implants fit well. We do this by removing some of the bone from the ends of the tibia and the femur and then drilling small holes into the ends of those bones. Next, we install the replacement knee. We use a special bone cement to attach the joint. Finally, we close the incision with stitches or staples, which we usually remove 2 to 3 weeks after the surgery

Recovery and rehabilitation


We will work with you to develop a graduated exercise program to restore mobility to your knee and to strengthen the muscles that stabilize the knee. We can advise you how and when to resume normal activities such as sitting, standing, and climbing stairs and discuss the most appropriate place for you to begin your rehabilitation. If you do not have anyone at home who can help you, we may recommend that you stay at a skilled nursing facility to begin your physical therapy. If you do go home, a physical therapist will visit for 4 to 6 weeks to make sure that you are progressing well. We will also talk to you about preventing falls. This is particularly important, as any fall can damage your new knee and require more surgery

Partial Knee Replacement

We may recommend a partial knee replacement if osteoarthritis has damaged only one area, or compartment, of your knee. During surgery, we replace only the damaged compartment of the knee – the medial, lateral, or patellar (kneecap) compartment. 
Partial knee replacement is a simpler and less invasive surgery that requires a smaller incision. You may recover and get back to your normal activities much more quickly than you would after a total knee replacement. We don’t usually recommend this procedure for younger, active patients as they are likely to put too much stress on the replacement, causing too much wear and tear. A partial replacement may be a good option for older slim patients who have less active lifestyles

Osteotomy

We may recommend a different procedure known as an osteotomy if you are young and not yet ready for a total knee replacement. Delaying a total knee replacement is particularly valuable for younger people because replacement knees tend to last, on average, about 15 years. Replacing your knee earlier in life may mean that you have to have knee replacement surgery several times during your lifetime.
During the procedure, we remove a section of bone from your knee. Removing bone from a specific area of your knee pushes your weight onto an area of the joint that does not have osteoarthritis damage. For example, if you have lost more cartilage in your inner knee, we may remove bone from the outside of your tibia, closest to the knee. The resulting unevenness tips your body weight toward the outer knee, which has healthier cartilage

Prevention

Although you can’t prevent osteoarthritis, you can decrease your risk of developing severe problems in your knee. A few things that you can do are
Maintain a healthy weight. Carrying excess weight places extra stress on your knee. Talk to us about weight management resources and classes

Exercise. Regular exercise will keep your muscles strong and your ligaments flexible. Try exercises that do not stress your knee like swimming, stationary bicycling, elliptical machines, or water aerobics

Wear shoes that support and cushion your feet

Avoid falls at home by keeping your home well lighted, using handrails on staircases, and using sturdy ladders or foot stools if you need to reach for items on high shelves. Do not use a chair or step on the counters

Avoid prolonged and repetitive kneeling, squatting, or frequent knee bends

Use walking sticks if you have to walk up and downhill