Depending on the type and severity of damage, knee pain can be a minor annoyance, causing an occasional twinge when you kneel down or exercise strenuously. Or knee pain can lead to severe discomfort and disability.
Many relatively minor instances of knee pain respond well to self-care measures. More serious injuries, such as a ruptured ligament or tendon, may require surgical repair.
Severe knee pain that comes on suddenly (acute pain) is often the result of injury. Some of the more common knee injuries include the following:
- Ligament injuries
- Tendon injuries (tendonitis)
- Meniscal Tears
- Loose bodies
- Knee cap dislocations
- Iliotibial band injuries
- Osgood-Schlatter disease
- Septic arthritis
Chronic knee pain can often be the result of arthritis, either rheumatoid, or osteoarthritis. An underlying injury can also be at the root of chronic knee pain. Of course, Gout can also be a cause of arthritis and knee pain as well.
Signs and Symptoms
Pain is usually over the inside, front, or outside aspect of the knee, and can be worsened with activity. If the knee itself feels unstable, a physician should be consulted as soon as possible.
Ligaments are large bands of tissue that connect bones to one another. In the knee joint, four main ligaments link the femur to the tibia and help stabilize your knee as it moves through its arc of motion. These include the collateral ligaments along the inner (medial) and outer (lateral) sides of your knee and the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), which cross each other as they stretch diagonally from the bottom of your thighbone to the top of your shinbone.
Other structures in your knee include:
- Tendons. These fibrous bands of tissue connect muscles to bones. Your knee has two important tendons, which make it possible for you to straighten or extend your leg: the quadriceps tendon, which connects the long quadriceps muscle on the front of your thigh to the patella, and the patellar tendon, which connects the patella to the tibia.
- Meniscus. This C-shaped cartilage, which curves around the inside and outside of your knee, cushions your knee joint.
- Bursae. A number of these fluid-filled sacs surround your knee. They help cushion your knee joint so that ligaments and tendons slide across it smoothly.
Many knee injuries are due to overuse, problems with alignment, sports or physical activities, and failure to warm up and stretch before exercise. But they can also result from trauma, a fall, or a direct blow to your knee.
Common knee injuries and their causes include:
- Ligament injuries. You're most likely to tear your collateral ligaments in sports that require quick stops and turns. Collateral ligaments can also be damaged by repeated stress, which causes them to lose their elasticity, much like an overstretched rubber band. Most ACL injuries are sports-related.
- Tendon injuries. Inflammation of the quadriceps tendon (tendonitis) can occur from physical activity. It can also result from inflammatory diseases that occur throughout your body, most notably rheumatoid arthritis.
- Meniscus injuries. A meniscus tear can result from aggressive pivoting or sudden turns — any activity that twists or rotates your knee. Occasionally, you can tear your meniscus while lifting something heavy.
- Bursitis. Sometimes called housemaid's knee or carpet layer's knee, prepatellar bursitis often occurs after an activity that requires you to kneel for long periods — scrubbing floors, gardening, or installing tile or carpet, for example. It can also result from an infection or as one of the signs of arthritis or gout.
- Dislocated kneecap. Kneecap (patellar) dislocations can occur in contact sports and in activities that require you to change direction while running, such as tennis, racquetball and volleyball. If your knees tend to turn inward or your kneecaps are higher than normal, you may be more prone to this injury.
- Osgood-Schlatter disease. This condition can develop in athletic young people during the years when their bones are growing rapidly — usually ages 10 to 15 for boys and 8 to 13 for girls. Osgood-Schlatter disease results from repeated tugging of the patellar tendon on a growth plate at the top of the tibia.
- Hyper extended knee. This usually results from an awkward landing after a jump or from a contact injury.
- Iliotibial band syndrome. This is a common cause of lateral knee pain in runners. You're more likely to develop iliotibial band syndrome if you have biomechanical problems such as unequal leg length or weak hip abductors, the muscles responsible for sideways leg motion. Exercising on concrete surfaces or uneven ground, increasing the intensity or duration of your exercise too quickly, wearing worn or ill-fitting shoes and excessive uphill or downhill running also can contribute to knee pain.
Seeking Medical Advice
Some types of knee pain require more immediate medical care. Call your doctor if you:
- Can't bear weight on your knee
- Have marked knee swelling
- See an obvious deformity in your leg or knee
- Have worrisome pain
- Have a fever, in addition to redness, pain and swelling in your knee, which may indicate an infection
Screening and Diagnosis
A magnetic resonance imaging (MRI) test may aid in the diagnosis.
Unlike an X-ray, which isn't useful for viewing ligaments, tendons and muscles, an MRI can help identify injuries and damage to soft tissue. Depending on the type of injury, other imaging tests include:
- X-ray. Can help detect bone fractures and degenerative joint disease.
- Computerized tomography (CT) scan. Creates cross-sectional images of the inside of your body, may help diagnose bone problems and detect loose bodies.
Commonly referred to by the acronym P.R.I.C.E., self-care measures for an injured knee include:
- Protection. For most minor injuries, a compression wrap is usually sufficient. More serious injuries, such as a torn ACL or high-grade collateral ligament sprain usually require crutches and sometimes also a brace to help stabilize the joint with weight bearing.
- Rest. Taking a break from your normal activities reduces repetitive strain on your knee, gives the injury time to heal and helps prevent further damage.
- Ice. A staple for most acute injuries, ice reduces both pain and inflammation. 15 to 20 minutes three times a day is usually sufficient. Although ice therapy is generally safe and effective, don't leave ice on longer than recommended because of the risk of damage to your nerves and skin. After two days, you might try switching to heat to relax your muscles and increase blood flow.
- Compression. This helps prevent fluid buildup (edema) in damaged tissues and maintains knee alignment and stability. It should be tight enough to support your knee without interfering with circulation.
- Elevation. Because gravity drains away fluids that might otherwise accumulate after an injury, elevating your knee can help reduce swelling.
- Anti-inflammatory medications. Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, ibuprofen (Advil, Motrin, others) and naproxen sodium (Aleve, Naprosyn), can help relieve pain. What's more, NSAIDs can have side effects, especially if you take them for long periods or in amounts greater than the recommended dosage. Even small doses may cause nausea, stomach pain, stomach bleeding or ulcers; and large doses can lead to kidney problems and fluid retention.
When self-care measures aren't enough to control pain and swelling and promote healing in an injured knee, other options include:
Normally, the goal of physical therapy is to strengthen the muscles around your knee and help you regain knee stability. Training is likely to focus on the muscles in the back of your thigh (hamstrings), the muscles on the front of your thigh (quadriceps), and your calf, hip and ankle. In the early stages of rehabilitation, you work on re-establishing full range of motion in your knee. Finally, you work on training specific to your sport or work activities, including exercises to help you prevent further injury.
There's no single best way to treat most knee injuries. Whether surgical treatment is right for you depends on many factors, including:
- The type of injury and amount of damage to your knee
- The risk of future injury or damage if you don't have surgery
- Your lifestyle, including which sports you play
- Your willingness to modify your activities and sports
- Your motivation to work through rehabilitation to strengthen your knee after surgery
Before making any decision, consider the pros and cons of both nonsurgical rehabilitation and surgical reconstruction in relation to what's most important to you. Nonsurgical treatment isn't an option if you have cartilage damage that interferes with your range of motion (locked knee) or if the blood supply to your knee is severely compromised.
If you choose to have surgery, your options may include:
- Arthroscopic surgery. Arthroscopy may be used to remove loose bodies from your knee joint, repair torn or damaged cartilage, reconstruct torn ligaments and occasionally correct damage from degenerative joint diseases such as arthritis.
The advantage of the procedure is that you're likely to recover more quickly and with less discomfort than you would with open surgery.
- Partial knee replacement surgery. If you have considerable knee damage from degenerative arthritis but still retain some healthy cartilage, and conservative measures such as lifestyle changes, medication and physical therapy fail to help your symptoms, you may be a candidate for a partial knee replacement.
In this procedure (unicompartmental arthroplasty), your surgeon replaces only the most damaged portion of your knee. The surgery can usually be performed with a small incision, and your hospital stay is typically just one night. You're also likely to heal more quickly than you are with surgery to replace your entire knee. Unfortunately, many people who opt for knee replacement surgery have damage too extensive for unicompartmental arthroplasty. In addition, long-term results may not be as good as they are with a total knee replacement.
- Total knee replacement. In this procedure (total knee arthroplasty), your surgeon cuts away damaged bone and cartilage from your thighbone, shinbone and kneecap, and replaces it with an artificial joint (prostheses) made of metal alloys, high-grade plastics and polymers. Total knee arthroplasty can improve knee problems associated with osteoarthritis, rheumatoid arthritis and other degenerative conditions such as osteonecrosis — a condition in which obstructed blood flow causes your bone tissue to die.
You may be a candidate for total knee replacement if you have a severely damaged, arthritic knee that limits your mobility and function, you're older than 55 and in generally good health, and conservative measures fail to improve your symptoms.
In recent years, a number of nonsurgical treatments for knee pain that results from arthritis have been investigated or become available.
- Orthotics and bracing. Arch supports, sometimes with wedges on the inner or outer aspect of the heel, can help to shift pressure away from the side of the knee most affected by osteoarthritis.
- Glucosamine and chondroitin. These substances, found naturally in cartilage, are also available as over-the-counter dietary supplements. Both may help relieve the pain of osteoarthritis of the knee. Glucosamine appears to decrease the rate of cartilage destruction.
- Corticosteroid injections. Injections of a corticosteroid drug into your knee joint may help reduce the symptoms of an arthritis flare and provide pain relief that lasts a few months. The injections aren't effective in all cases and cause some of the same side effects that oral steroid medications do, including an increased risk of infection, water retention and elevated blood sugar levels.
- Hyaluronic acid. This thick (viscous) fluid is normally found in healthy joints, and injecting it into damaged ones may ease pain and provide lubrication. Injected hyaluronic acid, which is derived from rooster combs, was first used in the 1970s to treat arthritis in racehorses. The Food and Drug Administration (FDA) approved it for human use in 1997. Experts aren't quite sure how hyaluronic acid works, but it may reduce inflammation. Relief from a series of shots may last as long as six months. There are currently three inject able forms available; Hyalgan, Synvisc, and Euflexxa. Euflexxa is the only one not derived from rooster combs allowing it to be safely used in patients with egg allergies.
- Topical painkillers. A lidocaine patch applied to arthritic knees can provide significant pain relief. The FDA has approved an over-the-counter product, capsaicin, for the temporary relief of arthritis pain. It's sold under several names, and many pharmacies also carry their own brands.
- Keep extra pounds off. Maintaining a healthy weight is one of the best things you can do for your knees — every extra pound puts additional strain on your joints, increasing the risk of ligament and tendon injuries and even osteoarthritis.
- Get strong, stay limber. Because weak muscles are a leading cause of knee injuries, you'll benefit from building up your quadriceps and hamstrings, which support your knees. Try knee extensions, hamstring curls and leg presses to strengthen these muscles. Balance and stability training helps the muscles around your knees work together more effectively. And because tight muscles also can lead to injury, stretching is important. Try to include flexibility exercises in your workouts.
- Be smart about exercise. If you have osteoarthritis, chronic knee pain or recurring injuries, you may need to change the way you exercise. That doesn't mean you have to stop being active, but it does mean being smart about when and how you work out. If your knees ache after jogging or playing basketball or other sports that give your joints a real pounding, consider switching to swimming, water aerobics or other low-impact activities — at least for a few days a week. Sometimes simply limiting high-impact activities will provide relief.
- Make sure your shoes fit well. If the shoe fits, you'll be a lot safer. Choose footwear that's appropriate for your sport. Running shoes aren't designed for pivots and turns, for instance, but tennis and racquetball shoes are.
- Baby your knees. Wearing proper gear for knee-sensitive activities can help prevent injuries. Use kneepads when playing volleyball or laying carpet and buckle your seat belt every time you drive. Most shattered kneecaps occur in car accidents.
- Listen to your body. If your knees hurt, or you feel fatigued, don't be a hero — take a break. You're much more likely to injure yourself when you're tired.