Knees & Hips: A troubleshooting guide to knee and hip pain

 | November 14, 2006

Knees & Hips: A troubleshooting guide to knee and hip pain

Have you always dreamed of playing a round of golf at Pinehurst? Or strolling Newport's famous cliff walk? Or maybe you've reached the point where simply climbing a set of stairs is a dream. If these goals seem to be further away than ever, you may be one of the millions of people with pain in the knees or hips.

Your knees and hips are your largest joints. They support your body's weight and they must work in close coordination to provide the mobility most people take for granted until injury, arthritis, or other problems interfere. One in 5 Americans age 60 and older has experienced significant knee pain on most days over the last six weeks, and 1 in 7 reports significant hip pain. Each year, Americans make about 15 million visits to doctors for knee pain and 6 million visits for hip pain.

Depending on the cause of your pain, the solution might be a set of exercises designed to strengthen and stretch the muscles that support the joint, taking some of the stress off the joint itself. Minor surgery may also help. But for many people, knee and hip problems become so intractable that the best solution is to replace a worn-out knee or hip with a mechanical joint. In the United States in 2003, there were 451,000 knee replacement and 364,000 hip replacement procedures performed. The average age at which a person has such surgery is 65 to 70, although many older people gain pain relief and improved mobility from these procedures.

Physically, your knees and hips are closely interdependent, located as they are at either end of the thighbone. This proximity means the angle of your hip affects the pressure on your knee. A hip disorder may cause knee pain, and knee disorders can aggravate hip problems.

People live longer than they used to, so joints need to stay strong and healthy through those additional years. But both knees and hips are subject to repetitive trauma wear and tear as you age, and you can traumatize them further if you increase your physical activity suddenly.

Medical care has changed. Doctors used to follow surgery by immobilizing the joint with a plaster cast. Weeks of immobility caused the muscles to weaken and shorten, resulting in long-lasting stiffness and poor function. Today, you can wake up from surgery with your knee already being gently bent and straightened by a machine. In addition, knee and hip replacements have freed thousands of patients from life in a wheelchair or on crutches.

Surgical techniques have also advanced. More surgery is performed through tiny incisions using an arthroscope, often on an outpatient basis. Pain relief has moved away from mind-clouding narcotics toward pain relievers that tackle the twin problems of pain and inflammation. Whether you've just started to experience pain or have been battling it for years, this report can help you make informed decisions about maintaining your mobility for years to come.

Knees in motion

Knees suffer injury more often than any other joint. Between the ages of 25 and 75, your chance of having disabling knee pain or injury is about 50%. What makes the knee so vulnerable? One factor is anatomy. Often described as a simple hinge, the knee is actually a complicated network of bones, cartilage, muscles, tendons, and ligaments (see Figure 1).

Figure 1: Strong and flexible The knee is more than a simple hinge. Along with the strength to raise and lower your body weight, this joint also has the supporting structures to allow you to twist and turn.

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Evaluating knees

Diagnosing knee problems can be complicated. In some situations, a physical examination and the information you provide is sufficient. But most diagnoses require at least an x-ray, and for others the doctor may need to use more sophisticated imaging techniques and laboratory tests to determine the cause and extent of damage (see "Testing for knee and hip problems").

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Overuse injuries

The knee can be compared to an expensive sports car a finely tuned machine that is capable of great power but also highly vulnerable to breakdown. Over time, many things can go awry as a result of illness, mishap, and misuse of the joint. Overuse injuries occur over a period of time rather than after a single injury or illness. They may result from repeated overwork or from doing too much in a single day. As we age, overuse injuries become more common. Even normal age-related changes, such as reduced muscle mass and bone density, can make you more prone to knee injury as you get older.

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Tears in supporting tissues

Just as muscles can tear, the supporting tissues surrounding the knee can split under the pressure of injury or overuse.

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Kneecap problems

Kneecap problems involve the interface between your femur (thighbone) and patella (kneecap). As you bend and straighten your knee, the patella rides up and down a groove in the front of the femur called the trochlea. The patella is actually inside the quadriceps tendon and is firmly attached to the strong quadriceps muscles. At the bottom, it connects to the tibia (shinbone) via the patellar tendon. A variety of conditions can throw off the patella's position and movement, causing pain and other symptoms.

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Osteoarthritis of the knee

Osteoarthritis is a disease that causes the breakdown of articular cartilage, the tissue that covers and protects the ends of bones. Arthritis can appear in any joint, but the knee is particularly vulnerable because it is a weight-bearing joint that is subject to daily wear and tear as well as sudden injury. In people who are genetically predisposed, osteoarthritis of the knee can result from normal daily use, perhaps interspersed with minor injuries, or from one or more significant injuries (such as damaged ligaments) that may seem unrelated because they occurred so long ago.

Cartilage is about 75% water. It compresses under the pressure of each step and resumes its original thickness when the force is released, much like a very tough sponge. When articular cartilage breaks down (see Figure 5), the result is pain and disability. Osteoarthritis is rare in young adults, but one in three people over age 62 has some amount of osteoarthritis in one or both knees. In addition, genetic differences in bone and cartilage seem to make some people more susceptible to osteoarthritis.

Figure 5: Osteoarthritis of the knee Age, mechanical wear and tear, genetics, and biochemical factors all contribute to the gradual degeneration of the cartilage and the meniscus. In this illustration, the articular cartilage of the condyles (knobs at the lower end of the thighbone) is degraded. Tenderness and morning pain that lasts less than 30 minutes are telltale signs of this condition.

Early in the process of knee osteoarthritis, the space between your tibia and femur decreases as the cartilage wears away. Once the cartilage disappears, bone rubs on bone, causing intense pain and often the formation of bone spurs around the joint.

For many people with osteoarthritis, pain tends to worsen as muscles tire during the day. It's common for a person to feel fine and move about without discomfort for several hours in the morning. Pain may arise in the afternoon, steadily worsening to the point where, by evening, walking becomes impossible.

To diagnose your condition, the doctor will ask you about your symptoms and medical history and may suggest laboratory tests and x-rays. If the osteoarthritis has progressed far enough, x-rays may show a reduction in the joint space in the knee or the presence of bone spurs. There is no specific blood test for osteoarthritis. The results of blood tests that indicate general inflammation, such as the erythrocyte sedimentation rate and the level of C-reactive protein, are often normal in osteoarthritis patients, but may be elevated if you have rheumatoid arthritis, a different form of joint disease. If your knee is suddenly swollen for no apparent reason, the doctor may remove some of the synovial fluid in the joint to check for signs of infection or arthritis.

Symptoms of knee osteoarthritis Intermittent or steady pain Swelling or tenderness Stiffness when you get up from sitting or lying down Grinding or crunching sounds

Treating osteoarthritis of the knee. So far, osteoarthritis has no cure. Although it is possible to regrow cartilage in the laboratory, doctors have not yet been able to get implanted cartilage to grow in an osteoarthritic knee. Like healthy plants in unhealthy soil, the implants eventually die. Doctors focus on three things when treating osteoarthritis: relieving pain, protecting joints, and improving muscle tone to help stabilize joints and prevent deformity.

For pain relief, acetaminophen (Tylenol) or NSAIDs can be effective. A combination of pain relievers, such as acetaminophen and ibuprofen, may bring more relief than using one of these medications alone. Since ibuprofen can cause stomach irritation, especially on an empty stomach, one option is to take ibuprofen with meals and acetaminophen between meals and before bed. Pain relievers have a variety of side effects, so it's important to discuss your personal health risks with your doctor when considering the regular use of these medications and to refrain from taking more than the recommended dose.

Occasionally, a doctor may inject a corticosteroid drug into a joint to ease pain. However, repeated injections may speed degeneration of cartilage.

Self-help for osteoarthritis of the knee. Exercise is a crucial component of osteoarthritis treatment. It can reduce pain and also improve your balance and your ability to walk and do everyday tasks. Regular exercise is important because the muscles surrounding the knee are prone to atrophy when not used. Swimming and cycling are usually good options. Walking is more problematic because it puts full weight-bearing stress on your knees, even while working the hip muscles harder than the knees. Using weight machines, such as Cybex or Nautilus, strengthens muscles surrounding the knee. The quadriceps are often weak, even before symptoms occur. Range-of-motion exercises help maintain joint function and relieve stiffness.

Because the knee bears the entire weight of your body, weight loss is particularly helpful in easing the discomfort of knee osteoarthritis. In addition, well-cushioned shoes can help reduce the impact on your knees as you walk. You can also take weight off the knee by using a cane or other walking device. If osteoarthritis affects the patellofemoral joint, a physical therapist can show you how to tape your knee to relieve pain and support your quadriceps. The therapist can also show you how to use walking aids such as crutches or canes, if needed, and devise an exercise plan that best suits your condition. Your local Arthritis Foundation chapter may have an arthritis self-management program including exercise, information, and support (see "Resources").

Surgery. Several surgical procedures are used for knee osteoarthritis, including arthroscopic surgery and knee replacement surgery.

New England Journal of Medicine Your orthopedic surgeon may recommend arthroscopic surgery to remove torn cartilage and small bone spurs (debridement) and to flush out the joint with a saline solution (lavage). While some studies have shown benefit from this frequently performed surgery, others have not. A 2002 study in the found that during two years of follow up, patients who had arthroscopic procedures reported no less pain or better function than the placebo group.

As a result of this and similar findings, arthroscopic surgery for osteoarthritis is now performed less often. However, some surgeons believe it can be effective in selected cases, such as when loose fragments of cartilage also known as "joint mice" are floating within the knee.

If knee osteoarthritis becomes severely limiting and nonsurgical means no longer control pain, you might consider total knee replacement. If the osteoarthritis affects only one compartment of the knee, partial knee replacement is an option.

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Hips

Watch a ballet dancer and you can appreciate the hip joint's ability to move in almost any direction, if only the muscles are willing. Like the shoulder, the hip is a ball-and-socket joint with a remarkable range of motion. It has basically the same joint design as that used to maximize your car's steering.

Like your knee, your hip is a network of bones, cartilage, ligaments, and muscles. People tend to perceive of their hips as just the part of the bone you can feel on the side of your body. It's important to recognize that the hip is actually a large region that extends to your thigh and groin. A malfunction anywhere in this large area can cause pain and decrease mobility.

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Evaluating hips

During an examination, the doctor will ask questions about pain and other symptoms. Be sure to describe sensations in the entire leg: A hip problem may cause pain in the front, side, or back of your hip, in the groin, and even in the knee. Mention any physical labor or sports you participate in and falls or injuries you have experienced. Even if you landed on your knees rather than your hip, you may have jolted your hips. (See "Evaluating knees" for a list of questions your doctor may ask.)

During the physical examination, the doctor will watch you walk to observe unevenness or changes in your gait. Hip pain or muscle weakness can change how you walk. Speak up if any portion of your stride hurts. The doctor may examine your shoes for signs of abnormal wear. The doctor may also observe how far you can flex your knee toward your chest and extend your hip out behind you, and how readily you can move your leg out to the side (abduction) and across your midline (adduction). As you lie on your back, the doctor will measure how far you can rotate your hip externally (letting the knee fall toward the outside of your body) and internally (letting your knee turn toward your midline). As you move or try to resist pressure applied by the doctor during different maneuvers, the doctor will assess pain, muscle strength and restrictions, and any grinding or snapping in the joint.

Along with the hip exam, the doctor will examine the position of your pelvis, compare your leg lengths, test nerve function in your legs, and check your feet and ankles for swelling that might indicate impaired circulation. He or she will also examine your spine for curvatures or conditions (such as a pinching of the sciatic nerve) that can cause hip pain.

In addition, the doctor is likely to use x-rays or other imaging techniques to diagnose hip problems (see "Testing for knee and hip problems").

Quick quiz: Are you hip? Test your knowledge of hips. Which hip bone is shaped like a deep socket? A. ilium B. acetabulum C. femur D. trochanter Low bone density results in the condition known as ______________. A. osteoarthritis B. bursitis C. osteoporosis D. tendinitis It's a good idea to apply ____________ to your hip right away if you stumble and bruise it. A. heat B. steam C. ice D. butter The success rate for total hip replacement surgery is __________. A. 55%65% B. 70%75% C. 80%85% D. Over 90% What is the average age of a person undergoing total hip replacement? A. 55 B. 65 C. 75 D. 82 True or false: If they're in good overall health, people in their 80s usually show significant improvements in mobility after hip replacement surgery. True False The prosthesis used for hip replacement usually lasts ____________. A. 510 years B. 1520 years C. 2530 years D. indefinitely True or false: More than half of people who take oxycodone (OxyContin) to control pain following hip surgery become addicted. True False Which of the following occurs commonly after hip replacement surgery? A. infection B. dislocation C. differing leg length D. paralysis Answers B C C D B True B False C

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Overuse injuries

Muscles of your thighs, abdomen, and buttocks attach at your hip joints. You can injure these muscles and nearby tendons when you overexercise or participate in activities that you don't do regularly or for which you lack sufficient conditioning.

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Hip fracture

One in seven women fractures a hip at some point in life, as does 1 in 17 men. For many of these people, life will never be the same. A year afterward, only 41% regain their previous ability to walk even if they were alert, healthy, and mobile beforehand.

Without active effort to reduce the risk among older people, hip fractures and disability will continue to surge as life expectancy increases and people spend more time in the high-risk years. Nine of 10 hip fractures result from falls, with most others from car accidents or other traumas. The risks for hip fractures can be divided into two categories those that make you more likely to fall and those that make your hip more likely to break if you do fall.

The risk of hip fracture is higher in someone with low bone density. Very low bone density results in the condition known as osteoporosis (see Figure 10). Someone with severe osteoporosis can actually break a hip just from the stress of walking. The risk of hip fracture rises with age in both men and women, with more than 90% of fractures occurring in people over 50. A man's risk is equivalent to that of a woman about five years younger. Fracture risk is higher for people on dialysis and remains high the first few years after a kidney transplant.

Figure 10: A fragile state Osteoporotic bone is more porous and less dense than healthy bone. The result is bone that is fragile and more vulnerable to breaks. In fact, osteoporosis contributes to more than 1.5 million bone fractures a year. Spinal, wrist, and hip fractures are most common, with hip fractures being the most serious of all. About two-thirds of those who break a hip permanently lose some of their ability to perform ordinary daily activities, and half aren't able to walk without assistance.

A possible hip fracture needs immediate evaluation. An x-ray is likely to show a fracture if one exists. But if it doesn't and if your symptoms strongly suggest a fracture, an MRI can reveal a break that has not moved out of place or a fracture involving the hip socket rather than the femur.

The two most common types of hip fracture involve the femur. A femoral neck fracture occurs in the horizontal section of the femur, about 12 inches from the ball of the hip joint. An intertrochanteric fracture occurs in the femur 34 inches below the ball of the hip. Fractures of the hip socket are less common.

The severity of a hip fracture is judged by how far the bone has moved out of place. If the bone has cracked but not separated, it is described as nondisplaced. If the bone has shifted slightly, it is classed as minimally displaced. If the bone is completely detached at the break site, it is said to be displaced.

Symptoms of hip fracture Severe pain in the hip or groin A turned-out leg that may appear shorter Swelling, tenderness, and bruising around the hip Inability to stand up (from either weakness or pain) Deformed appearance to the hip Hip too weak to lift the leg

Treating hip fracture. The goal of treatment is to reconnect the broken bone and hold it in place so the hip works properly until it has time to heal about three months. Surgery within 24 hours is usually necessary to make this repair. If you must wait for surgery, the hip may be held in traction (using weights to extend the muscles around the hip).

If you have a femoral neck fracture in which the pieces are not displaced, the orthopedic surgeon may connect the bone with surgical screws. If the bone has moved well out of place, or if you are older and not active, your surgeon may replace the head of the femur with a metal device, a procedure called a hemiarthroplasty or partial hip replacement. Or the surgeon may perform a total hip replacement (see "Hip replacement procedure") if pre-existing arthritis is noted. An intertrochanteric fracture is stabilized by screws and a device that holds the broken bone in place while allowing the ball to move normally in the hip socket.

In general, nonsurgical treatment for hip fracture is reserved for people who are at high risk for serious complications during surgery and whose medical condition is such that imperfect healing of the fracture would be acceptable for example, someone who is already bedridden and not in much pain.

After surgery, it can take several months for the hip to heal completely. Initially, you'll use crutches or a walker, putting weight on the leg only as permitted by the doctor. How soon you can put weight on the leg depends on the type of pinning or other device used in the repair. The goal of rehabilitation is to get you back on your feet as soon as possible. In the first few days of rehabilitation, you learn to use assistive devices safely and begin muscle strengthening and range-of-motion exercises in bed and while sitting. Gradually you'll begin to walk and perform more vigorous exercise with the physical therapist.

To prevent another fall, your physical therapist will work to help you develop a secure, balanced gait and will suggest other safety measures. To help prevent a second fracture, you should be evaluated for osteoporosis and treated if necessary.

Your doctor may also prescribe a drug from a class of antiresorptive agents called bisphosphonates, which increase bone density by slowing the rate of bone loss. Drugs in this class include risedronate (Actonel), alendronate (Fosamax) which are available in daily and weekly doses and ibandronate (Boniva), which comes in daily or monthly doses.

These drugs have been shown to reduce the risk of spine, wrist, and hip fractures by 40% to 50%. They are generally well tolerated, but they can irritate the esophagus and stomach, causing heartburn and nausea. Another drawback is that once a person starts taking them, he or she needs to continue taking them for life or risk a sharp drop in bone density.

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Osteoarthritis of the hip

The hip joint is one of the most common sites for osteoarthritis. This condition begins with a small amount of cartilage disintegration, resulting in some local inflammation. The process continues as the cartilage erodes and bone spurs form.

While there is no ironclad way to prevent this from occurring, most doctors believe the best way to avoid hip osteoarthritis is to maintain a healthy lifestyle. In particular, keeping a healthy weight from early adulthood on and exercising regularly to maintain muscle tone will help keep your hip joints strong.

Hip osteoarthritis is more common among the elderly and those who have had hip injuries. Obesity also places extra stress on the hips; in the Nurses' Health Study, an ongoing study of thousands of women, those who were in the heaviest group at age 18 had five times more risk of developing severe hip osteoarthritis than those who were in the lightest group. Recreational physical activities, including running, have not been shown to raise the risk of hip osteoarthritis.

To diagnose your condition, your doctor asks you about your symptoms and performs a physical exam. Although an x-ray will not show cartilage damage, it may reveal other changes related to osteoarthritis, including decreased joint space, bone spurs, and cysts. A blood test for inflammation helps rule out other possible causes of your symptoms.

Symptoms of hip osteoarthritis Pain radiating to your buttocks or knee Pain in the groin or inner thigh Pain when you pivot or rotate the hip inward Stiffness after inactivity and first thing in the morning Difficulty bending Limping or other gait changes Apparent shortness of the leg on the affected side Difficulty with foot care Groin pain when you get out of a chair Difficulty getting in and out of a car

Treating osteoarthritis of the hip. The first line of treatment for mild osteoarthritis of the hip is a combination of over-the-counter or prescription pain relievers such as ibuprofen and acetaminophen. Using acetaminophen along with ibuprofen or another NSAID makes it possible to use a lower dose and thus minimize side effects. NSAID medications have a variety of side effects so it is important to discuss your personal health risks with your doctor when considering long-term use. Steroid injections are also sometimes used.

Exercise is important to help keep your hip joint limber. Water exercises are particularly suited for improving the hip's range of motion and promoting strength and flexibility in the muscles surrounding it. For exercise to be effective, you must make an ongoing commitment to exercising several days a week. In studies from the Netherlands, a 12-week supervised exercise program significantly improved pain and function in people with osteoarthritis of the hip or knee. If the people did not continue to exercise, however, the benefits disappeared within nine months. Talk with your doctor or physical therapist about a full program of hip-strengthening exercises.

Resting the hip when you feel pain is also important. A cane or a walking stick held in the hand opposite your bad hip can take pressure off the joint as you walk or do other activities that tend to aggravate the pain (see "Easing the strain with a cane"). Most people limit stair climbing and cut back on walking longer distances. When bathing, use a shower stool and hand-held nozzle to avoid standing.

Easing the strain with a cane For something so low-tech and simple in design, a cane performs complex functions. You hold the cane in the hand opposite the side that needs support, about 4 inches to the side of your stronger leg. This redistributes weight to improve stability, helps reduce demand on muscles that may be weak, and takes the load off weight-bearing structures such as the hip, knee, and spine. The bottom line is that a cane can help you maintain mobility and ward off further disability if you have arthritis of the knee or hip (as well as assist in recovery after surgery). So don't let self-consciousness stop you from using a cane if your doctor recommends you try one. A physical therapist or other clinician can help you select a cane, make sure it's the proper length, and show you how to use it. He or she may also suggest certain muscle-strengthening exercises before you start walking with your cane. Canes are available at medical supply stores and pharmacies, through specialty catalogs, and on the Internet. They generally come in standard, offset, and multiple-legged versions. Government or private insurance usually covers the cost of a basic cane if you have a written prescription from your doctor. Standard canes. These are low-tech, lightweight, and generally inexpensive. They usually come with a curved or T-shaped handle and a rubber-capped tip at the bottom. Many people find that a T-shaped handle is more comfortable than a curved one. A standard model is good for people who need help with balance but don't need the cane to bear a lot of weight. Offset canes. The upper shaft of an offset cane bends outward, and the handle grip is usually flat often a good choice for people whose hands are weak or who need a cane that bears more weight than the standard type. Multiple-legged canes. Multiple legs offer considerable support and allow the cane to stand on its own when not in use. One drawback to such canes is that for maximum support, all the legs must be solidly planted on the ground. Doing so takes time and can slow the pace of walking.

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Testing for knee and hip problems

Sometimes a physical exam and your symptoms provide sufficient information for your doctor to make a diagnosis. But when that's not enough, a variety of imaging techniques and laboratory tests can clarify the situation.

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Imaging techniques

Medical technology has expanded doctors' ability to create images of joint damage far beyond the simple x-ray. Each imaging technique offers something different, and the choice will depend on the type of joint damage your doctor suspects.

X-ray. A standard x-ray, the most commonly used imaging technique, gives a two-dimensional picture of the bones in your joints (see Figure 11). X-rays can show bone fractures, spurs, loose fragments, dislocation, reduced space between bones, and bone damage from arthritis. But standard x-rays don't show cartilage, ligaments, or tendons; it requires more sophisticated imaging techniques to see these. For a standard x-ray of the knee, you may be asked to lie down or stand while a technician takes several views with your knee in different positions. For a hip x-ray, you will probably be asked to lie down. Even if only one knee or hip causes you problems, your doctor may order x-rays of both to compare the appearance of the joint and joint space.

Figure 11: Hip x-ray This x-ray shows osteoarthritis of the left hip. The normal "ball-in-socket" shape has noticeably deteriorated.

CT scan. Doctors sometimes order a CT (computed tomography) scan to look for hidden fractures, bone on bone, and other structural abnormalities. A CT scan uses a rotating x-ray tube housed in a doughnut-shaped machine to take many cross-section x-rays of your anatomy. A computer assembles these "slices" into a three-dimensional picture. During the scan, which takes less than an hour, you lie on your back on a movable table that is raised, lowered and moved in and out of the scanner. The equipment doesn't touch you, and the test isn't uncomfortable. CT is expensive, but it provides an enhanced view of bone, allowing your doctor to better evaluate bone shape and diagnose some defects hidden on standard x-rays. CT does not show soft tissue.

MRI. This test uses a strong magnet and radio waves to evaluate cartilage, soft tissues, and bone marrow. MRI is more expensive than CT or standard x-rays, but it's the most accurate way to detect ligament damage, cartilage damage from arthritis, or tears in the cartilage or meniscus. It is also used to evaluate a possible pelvic fracture, tumor, or osteoporosis of the hip. During the exam, which lasts about 45 minutes, you lie on a scanning table that slowly moves you through the machine. (Many centers have smaller MRI machines that can focus on specific body parts, so if you're having your knee done you may need only insert your knee.) For a hip exam, your feet may be taped together to keep your hips in the desired position. For a knee exam, a wedge may keep your knees at the desired angle. In some cases, the radiologist may inject a dye to obtain better images. You cannot have an MRI if you have a pacemaker, aneurysm clips, or certain other metal implants.

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Laboratory tests

While imaging tests can give your doctor a good view of the damage in your knees or hips, laboratory tests are sometimes needed to determine what is causing the damage and how it might be halted.

Arthrocentesis. If you have sudden or unexplained swelling in a knee, hip, or other joint, your doctor may perform an arthrocentesis, removing a little synovial fluid for examination. Excess synovial fluid may indicate infection, crystal deposits, trauma, or inflammation. Before arthrocentesis, the skin is cleaned and an anesthetic spray or injection is used to numb the area. The doctor inserts a needle with a syringe attached into the joint space (you may hear a pop) and withdraws a fluid sample, which is sent to a laboratory for analysis. If you have pain afterward, your doctor may suggest ice and pain relief medication. The procedure may immediately lessen pain and pressure caused by excess fluid. Knee arthrocentesis can be done in the doctor's office. Hip arthrocentesis is performed by a radiologist, guided by fluoroscopy, a type of x-ray that shows internal structures in motion.

Rheumatoid factor. This blood test detects an antibody present in about 85% of people with rheumatoid arthritis, a systemic autoimmune disease. The same antibody is also present in other medical conditions and in about 3% of healthy people.

Erythrocyte sedimentation and C-reactive protein. These blood tests are general measurements of inflammation of any kind; the higher the result, the more severe the inflammation. Most people with osteoarthritis have normal values, but those who have inflammatory conditions, such as rheumatoid arthritis, usually have elevated levels. High rates may also be an early sign of infection after knee or hip surgery. High levels of C-reactive protein over the long term also indicate an increased risk for heart disease. The serum uric acid test measures uric acid in the blood, which can help diagnose gout, a condition caused by the accumulation of uric acid crystals in a joint.

Optical coherence tomography Optical coherence tomography, or OCT, is an imaging technology that may help doctors get a clearer picture of the knee, leading to more accurate diagnoses of problems such as meniscal tears and cartilage defects and better decisions about which patients will benefit from surgery. OCT uses infrared light to obtain extremely high-resolution three-dimensional images of bones and tissue. The images are much more detailed than a CT scan or MRI, enabling doctors to better see subtle anatomical changes that may be causing pain and affecting mobility. OCT is already used to diagnose eye problems and is expected to be available for knee evaluation before 2020. One drawback is that OCT requires a needle to be inserted into the knee, so it will probably be used mainly for cases where existing diagnostic techniques are inconclusive.

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Nonsurgical treatments for knees and hips

Whether it's your hip or your knee that's bothering you, your doctor is likely to recommend the least invasive treatment to alleviate pain and encourage healing of your condition before resorting to surgery. Reducing inflammation, relieving pain, protecting the joint from further damage, and building strength in the muscles that support the joint can often improve joint function. The following treatments are often recommended for hip or knee pain and discomfort.

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RICE

RICE which stands for rest, ice, compression, and elevation is a first-aid strategy for most musculoskeletal injuries, including those involving the knees and hips. It is sometimes the only treatment you need.

Rest. Continuing to put stress on a painful injury can make it worse. Injuries need rest in order to heal. Rest doesn't always mean inactivity, however. Depending on the condition, you may need to stay off a leg entirely, cut back the distance you can run or walk without pain, switch to low-impact activities, or exercise using other parts of the body. It's important to rest an injury or flare-up of pain for a few days, but long periods of inactivity can make ongoing knee and hip problems worse by decreasing flexibility and weakening the muscles that support and protect the joints.

Ice. Cold numbs pain and reduces swelling by constricting blood vessels. After surgery or injury, wrap an ice pack in a cloth and apply for 20 minutes, remove for 20 minutes, apply for 20 minutes, and so on. To prevent frostbite, do not apply ice directly to the skin. Your source for cold can be as simple as a bag of frozen peas wrapped in a towel, but you can also buy easy-to-secure neoprene wraps with pockets for gel packs that you keep in the freezer. Most elaborate are electric "continuous-flow cold therapy" devices that deliver cold through pads shaped for different joints; your doctor or physical therapist may recommend such a device after surgery.

Ice helps knee injuries of all types. For hip injuries, cold can't penetrate deep into the hip joint itself, but it is still effective for hip pain stemming from problems closer to the surface, such as trochanteric bursitis.

After injury, use ice alone for 2448 hours. After that, you can continue using ice, switch to heat, or alternate. Ice increases stiffness; you may find it beneficial to use warmth before stretching and other exercise, following with ice afterward to minimize swelling. You can give yourself an ice rub by freezing water in a paper cup. Peel back the paper a little so you can apply the ice while holding the paper covering.

Compression. After a knee injury, gentle pressure can reduce swelling and hasten recovery time. Wrap an injured joint in an elastic bandage, taking care that the wrap isn't so tight that the skin below the joint becomes cool or blue. Neoprene stretch knee supports provide compression and have a hole for the kneecap to prevent irritation.

Elevation. Elevating the injured area takes advantage of gravity to reduce the swelling and painful throbbing that occurs when lots of blood pools in the area. Prop your knee up on a stool with pillows to raise the height, or lie down with your knee on a pillow.

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Heat

Heat is a good way to reduce pain and stiffness in your joints and relieve muscle spasms. After an injury, wait a day or two for swelling to go down before using heat.

You can use a heat pack applied directly to the joint, or warm your knees and hips in a hot tub or whirlpool or with a 15- to 20-minute soak in a regular bath. Therapists recommend a warm shower or bath before exercising to relax joints and muscles. Dress warmly afterward to prolong the benefit. Heating pads are convenient, but moist heat penetrates deeper.

You can buy hot packs and moist-dry heating pads, but a homemade hot pack works just as well. Heat a damp folded towel in a microwave oven (usually for about 1060 seconds, depending on the oven and the towel's thickness) or in a conventional oven set at 300° F (for about 510 minutes).

To relieve muscle spasms, a physical therapist may use diathermy (deep heat), a technique that uses electromagnetic waves to deliver heat beneath the skin and to relax muscles. Electromagnetic waves cannot be used on people with pacemakers.

Cold and heat work well in combination. You may benefit from using heat early in the morning and before exercise and using cold after exercise and at the end of the day.

Warming warning Prevent burns when using a heat pack by testing the temperature on the inside of your arm before applying; it should feel comfortably warm, not hot. To be safe, wrap the heat pack in a thin, dry towel before placing it on the skin.

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Ultrasound, phonophoresis, and iontophoresis

Therapeutic ultrasound uses sound waves to reach deep tissues in order to increase blood flow, relax muscle spasms, and aid healing. To do an ultrasound, the technician applies a gel to your skin and rubs an ultrasound wand over the area. In a technique called phonophoresis, medication (often hydrocortisone) is added to the gel and the ultrasound transducer applied over it. Because the ultrasound encourages blood vessels to expand, this approach is thought to deliver more medication to the injured area.

Another technique, iontophoresis, uses electrical currents to speed the delivery of medication to the damaged tissue, or simply to reduce muscle spasms and irritation from muscle spasms. Patches similar to Band-Aids are placed on the skin, and a painless, low-level current is applied for about 1015 minutes. You may feel warmth or tingling during the treatment.

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Therapeutic exercise

Exercise is more than just a good health habit; it's also a specific and effective treatment for many knee and hip problems. Strength in the muscles around a damaged knee or hip can take over some of the joint's responsibilities. For example, your hips have to do less work to support your body weight if your quadriceps, gluteals, hamstrings, and abdominal muscles are stronger. Strong quadriceps can take over the shock-absorbing role usually played by the meniscus or cartilage in the knee. The proper balance of strength in the muscles can hold the joint in the most functional and least painful position. With any knee or hip problem, the first muscles to lose strength are the largest antigravity muscles, the quadriceps and gluteals, so an exercise plan for any injury is likely to focus on these.

Muscles work in pairs one contracts while the opposing one relaxes. For example, when you straighten your knee, your quadriceps on the front of your thigh work, and the hamstrings on the back relax. Imbalances in the function of paired muscles can cause joint problems and invite injury. If your hamstrings are tight, your quadriceps can't contract fully and may weaken, so exercise the quadriceps and hamstrings (the opposing muscles) equally. Flexibility exercises (to stretch and relax specific muscles) are an important part of an exercise plan to improve joint function.

Closed-chain exercising. Physical therapists have emphasized the distinction between open-chain and closed-chain exercises. The chain referred to is a series of body parts, such as a hip, knee, ankle, and foot. In a closed-chain exercise, the part farthest from the body is stationary; in an open-chain exercise, it moves. For example, a squat is a closed-chain exercise because your feet stay stationary while your quadriceps do the work. In contrast, a seated leg extension is an open-chain maneuver. Physical therapists are incorporating more closed-chain exercises into rehab programs and recommending them for people with painful joints because these exercises involve more muscles and joints and help to create stability around a joint. Try a wall sit to strengthen your quadriceps, a crucial muscle in maintaining knee stability. Stand with your back against the wall, with your feet together, and slide down into a sitting position (see Figure 3). If you go to a gym with a leg press machine, you can use it for another type of closed-chain quadriceps exercise. When doing knee exercises that involve weight, avoid locking your knees or, conversely, lifting weight with your knee bent all the way.

Exercising without stressing your hips and knees If you like to exercise regularly but need to give your hip or knee a rest while an injury heals, here are some exercises you can do in the meantime. You can combine these exercises to create a routine lasting 30 minutes or longer: floor exercises, including abdominal curls, crunches, push-ups, or leg lifts hand weight routines, including repeated lifting in different directions with small hand weights exercise ball routines, including stretches, abdominal curls, or leg lifts swimming gentle yoga

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Medication

Several types of medication are used for knee and hip problems, some to control pain and inflammation and others to interfere with various disease processes (see Table 1).

Table 1: Drugs to treat joint pain
Generic name (Brand name)	Uses		Side effects
Acetaminophen
acetaminophen (Tylenol and other brands)	Relieves joint pain caused by injury, osteoarthritis, or other abnormalities	Can be used in conjunction with NSAIDs. Less likely to cause gastric bleeding than other pain relievers but may cause nausea, vomiting, diarrhea, jaundice, rash, tiredness, weakness. Excess dosage can cause liver or kidney damage. Heavy alcohol consumption during long-term therapy may cause liver or kidney damage.
Nonsteroidal anti-inflammatory drugs (NSAIDs)
aspirin (Bayer, Bufferin, Ecotrin, and others) ibuprofen (Advil, Motrin, Nuprin, and others) nabumetone (Relafen) naproxen (Aleve, Anaprox, Naprosyn) oxaprozin (Daypro)	Reduce inflammation and relieve joint pain by inhibiting prostaglandins, which trigger the body's inflammatory response	Stomach pain, gastric bleeding or ulcers, weight loss, nausea, vomiting, drowsiness, dizziness, fluid retention, heartburn, diarrhea, constipation, blurred vision. High doses can cause ringing in the ears. People who are allergic to aspirin or who take blood thinners should not take NSAIDs. People who take high doses for a long time should have periodic blood tests to check for gastric bleeding and liver or kidney damage. Discuss your personal health risks with your doctor before using long-term.
COX-2 inhibitors
celecoxib (Celebrex)	Reduces inflammation and relieves pain by inhibiting prostaglandins	Stomach upset, fluid retention, gastrointestinal bleeding, cardiovascular events, stroke, skin reactions, plus side effects similar to older NSAIDs. Increased risk of heart attack and stroke. People allergic to sulfa drugs should not take celecoxib. Discuss your personal health risks with your doctor before using long-term.
Opioid medications
codeine oxycodone (OxyContin, Percocet, Percodan, Roxicodone) pentazocine (Talwin) propoxyphene (Darvon, Darvocet) tramadol (Ultram)*	Provide stronger pain relief by interacting with receptors in the brain; usually used only for brief periods before and after surgery or serious injury	Nausea, dizziness or lightheadedness, vomiting, euphoria, constipation, abdominal pain, rash, headache. May be habit-forming when taken over time in large doses. Should be used cautiously by people with peptic ulcers, blood-clotting disorders, and liver disease. Can cause convulsions.
Corticosteroids
Oral corticosteroids such as prednisone (Prelone, Cortan, Deltasone, Liquid Pred)	Reduce inflammation by suppressing the adrenal glands, which produce natural steroids	Fluid retention, weight gain, facial hair growth, easy bruising, peptic ulcer, loss of calcium from bones (increases risk of fractures), cataracts, acne, sleeplessness, muscle wasting and weakness, headache, glucose intolerance. If taken at low doses for a week or less, side effects do not usually occur; therapy for several months or years causes more noticeable and serious side effects, even at low doses. Must be reduced gradually, not abruptly.
Injectable corticosteroids	Relieve pain and suppress inflammation of bursitis, tendinitis, gout, chondrocalcinosis, osteoarthritis, and rheumatoid arthritis	Tenderness, burning, or tingling at injection site. Risk of joint infections or cartilage damage. When injected into joints, tendon sheaths, or bursae, undesirable systemic side effects of oral use seldom occur.
*Non-opioid with effects similar to opioids

Acetaminophen. For pain relief, acetaminophen (Tylenol) is generally the first choice because it is effective and easy on the stomach. Do not exceed the recommended dosage of acetaminophen, however, because it can damage the liver.

NSAIDs. Nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Anaprox), and several others may be more effective than acetaminophen, particularly during sudden flare-ups of pain, because they are superior at reducing inflammation. There are also a number of prescription NSAIDs such as nabumetone (Relafin) and oxaprozin (Daypro).

But this relief comes at a price. Regular use of NSAIDs can produce gastrointestinal bleeding and ulcers, often without warning. Each year, these drugs contribute to more than 16,500 deaths and 100,000 hospitalizations because of gastric bleeding. Combining acetaminophen with a smaller amount of an NSAID may provide equivalent pain relief with a reduction in side effects.

The class of prescription NSAIDs known as COX-2 inhibitors is now rarely used, following news in 2004 that these drugs significantly increase a person's risk of heart attack and stroke. The manufacturers of two popular COX-2 inhibitors, rofecoxib (Vioxx) and valdecoxib (Bextra), withdrew these drugs from the market. A third COX-2 inhibitor, celecoxib (Celebrex), remains available. Because concerns about its cardiovascular side effects remain, it should be used only in cases in which a patient does not have heart disease, has tried other pain relievers without success, and is taking blood thinners (anticoagulants such as warfarin).

Opioids. Another large class of pain-relieving drugs are the opioid medications such as codeine and oxycodone, which have morphine-like properties. The term opioid has, by and large, supplanted "narcotic" as the preferred term for these drugs because the latter term has legal and regulatory meanings. Opioids work by interacting with the receptors on brain and spinal cord nerves for the endogenous opioids, which are the body's natural painkilling substances. For orthopedic problems such as knee and hip conditions, opioids are used judiciously, often for only brief periods just before and after surgery, or in patients with severe pain who are not helped by or are unable to tolerate NSAIDs. Opioids are effective in masking pain but do not help inflammation. Care must be taken to avoid tolerance, which develops after just two weeks, and side effects such as dizziness can make it difficult for people to participate in physical therapy while taking these medications.

Corticosteroids. Corticosteroids, such as prednisone, reduce the body's ability to generate an inflammatory reaction. They relieve pain by reducing inflammation. Corticosteroids are credited with both treating and causing knee and hip problems. When first introduced in the 1950s, corticosteroids were regarded as miracle drugs because of the dramatic effect on patients with active rheumatoid arthritis, many of whom were able to literally throw down their crutches. But within a few years, the devastating effects of long-term use of oral corticosteroids became apparent: bone weakening, compression fractures of the back, diabetes, increased susceptibility to infections, cataracts, hypertension, and other health problems. Most side effects occur when these drugs are taken orally, but repeated corticosteroid injections into a joint can result in thinning of the cartilage and weakening of the ligaments. In the short-term, though, corticosteroids can sometimes provide quick and dramatic relief.

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Alternative approaches

Over the years, people have turned to a wide variety of remedies to cope with the frustrating problem of joint pain. The choices are many because joint pain has been around for many centuries and nearly every traditional culture has developed medicines or therapies to treat it. Many of these remedies lack scientific support. But so long as they are not harmful, there is no reason not to use traditional or complementary therapies that seem to bring you relief. A few complementary therapies have some demonstrated effectiveness.

Acupuncture. This ancient Chinese technique uses slim needles to stimulate points along the body's "energy meridians" to correct disease-causing imbalances. In the language of Western medicine, acupuncture may work by releasing endorphins, natural morphine-like chemicals in the nervous system.

In 1997, a National Institutes of Health consensus panel concluded that acupuncture is an acceptable alternative or adjunct for treating many kinds of pain, including that from osteoarthritis. Since then, a number of studies have offered positive results specific to knees and hips. A 1999 study indicated that acupuncture may also be useful in patellofemoral pain syndrome, and a small trial in 2001 looking at people with hip osteoarthritis showed that acupuncture helped them more than exercise did. A large 2004 study found that people with knee osteoarthritis who had acupuncture for six months reported less pain and better function than people who received sham acupuncture or participated in an arthritis education program.

Glucosamine and chondroitin sulfate. Glucosamine is a substance normally found in both cartilage and synovial fluid, and chondroitin sulfate is one component of a protein that makes cartilage elastic. It isn't clear how supplements of these nutrients might work, but it's possible that they may encourage cartilage formation and minimize further breakdown while also reducing inflammation. Some skeptics compare this theory to that of a balding person eating hair in the hopes that it will grow on his head. At the same time, some patients swear these supplements provide genuine improvements.

New England Journal of Medicine So far, research on these supplements' effectiveness has offered mixed results. A large 2006 study published in the concluded that glucosamine and chondroitin did not reduce pain effectively over all, but that the supplements did benefit a subgroup of patients with moderate to severe pain. Two earlier three-year studies in Europe found that people with knee osteoarthritis taking glucosamine had significantly less pain and narrowing of their joint space than those taking a placebo. Chondroitin sulfate seemed to decrease pain in a three-month trial.

Common side effects include intestinal gas and softened stools. Chondroitin sulfate structurally resembles the anti-clotting drug heparin; if you're taking blood-thinning medication, tell your doctor and monitor your blood-clotting time. Because glucosamine may worsen diabetes, watch blood sugar levels carefully. Glucosamine is manufactured from chitin found in the shells of crustaceans, so people with shellfish allergies may react to it. In addition, studies show that the amount of glucosamine present in the products available in stores varies widely among manufacturers and possibly from batch to batch within the same brand, so it's difficult to know how much you're getting when you use this product.

Over all, these supplements appear safe but there is still no consensus on their effectiveness. If your pain has not responded to other treatments, feel free to give them a try. Treatment usually costs a dollar a day or more, so prolonged therapy is probably not warranted if it doesn't seem to help in two or three months.

People with joint pain need to educate themselves and become wise consumers. Don't buy into any treatment that promises a cure. Think instead of managing your condition. There are many complementary therapies to choose from, some of which may have interactions with medications you may be taking. That means it's important to inform your doctor of any complementary therapies you use.

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Arthroscopy

Since the late 1970s, surgeons have been able to work inside a joint and make repairs without fully opening it up. By making small incisions (about a quarter-inch), a surgeon can insert a tiny video camera and miniature surgical instruments to diagnose and repair abnormalities.

This approach, called arthroscopy, made its first appearance in 1918 when Professor Kenji Takagi of Tokyo University, seeking a better view of the knee to diagnose joint stiffness due to tuberculosis, performed the first successful arthroscopy of the human knee on a cadaver. By 1936, Takagi had developed a way to obtain color pictures and video of the interior of the knee joint. The technique was first used on live patients a year later. The limitations of technology at the time hindered widespread use of the technique. By the 1980s, however, technology had improved enough for the technique to be used for surgery, and many new instruments and arthroscopy techniques were developed. With new research and technology, arthroscopic surgery was performed not only on the knee, but also on the shoulder, ankle, wrist, and elbow.

Arthroscopy is less invasive than traditional surgery, and it causes less pain and fewer complications. Today, about 3 million arthroscopic procedures are performed annually in the United States, including about 1.6 million on the knees. The technique has completely transformed the field of sports medicine. The number of hip arthroscopies is relatively small but is steadily increasing.

Uses for arthroscopy Diagnosing knee or hip conditions Treating osteoarthritis Treating rheumatoid arthritis Treating cartilage tears or deterioration Treating ligament strains and tears Removing bone chips or cartilage pieces

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Joint replacement

Joint replacement is nothing new. Experiments with arthroplasty (replacement of all or part of a joint) were under way as early as the 1930s. These efforts stalled because of major complications: serious infections, problems attaching the replacement joint, and lack of durable materials. By the late 1960s, technology provided solutions. Doctors were able to protect against infection by using antibiotics, and surgeons began using dental cement to secure joints made from new materials such as titanium, cobalt-chrome alloy, and high-density polyethylene, which are lightweight and strong enough to withstand years of wear.

Thanks to improved materials, better sizing, and precision surgical tools, the success rate for knee and hip replacement surgery is now 90% to 95%. About 220,000 total hip replacements and 418,000 total knee replacements are performed in the United States each year. Newer procedures including knee and hip resurfacing are also becoming available.

Still, people need to have realistic expectations about what joint replacement surgery can and cannot do. It's true that Jack Nicklaus returned to tournament golf after his hip replacement. But although your hip or knee replacement should allow you to engage in normal activities for your age, it won't enable you to run marathons, ski on moguls, or do more than you could before you became disabled. And joint replacement doesn't guarantee that you will be able to move or use the joint normally. Particularly at first, you will need to limit your range of motion to avoid dislocating the new joint. Many patients find the recovery period painful. Still, patients who are willing and able to participate in physical therapy can experience great improvement in function. The major consistent benefit is substantial relief from pain after you've healed from the surgery. Full recovery takes about three months.

Like a pair of shoes, an artificial joint has a limited life span. The more demand your activities place on the new joint, the quicker it will wear out. With normal activity, most last 1520 years. If you do regular high-impact exercise, your implant won't last as long. If possible, people under 60 are encouraged to delay the procedure because it is more likely that they will need later surgery to replace the implant particularly if they are extremely active or overweight. Surgery to replace an implant, called revision surgery, is more difficult because there is less bone to work with after removing the first implant.

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Choices in joint replacement

Work with your doctor to decide whether replacing your knee or hip joint is a good solution for you. Once you have answered that question, you'll need to make other decisions, including who will do the procedure, where to have it done, what type of implant to have, whether to replace one or two joints, and whether to do them both at once or one at a time.

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Undergoing joint replacement

Joint replacement is usually scheduled several weeks or months in advance. During the weeks preceding the surgery, your health care team will advise you on steps you can take to help ensure a successful outcome. Once the day of surgery arrives, you will follow a standard procedure at your hospital.

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Recovery in the hospital

Once you recover from the anesthesia in the recovery room, you're moved to a regular room. When you wake up, you'll find several tubes extending from your body a drain for the surgical area, a catheter to remove urine, and an IV for medications. You will also have elastic stockings or compression devices on your legs to help prevent blood clots. After hip replacement, your operated leg is suspended by a sling or special abduction pillow to keep the hip from dislocating (the ball slipping out of the socket). After knee replacement, your operated leg may be in a splint or in a continuous passive motion (CPM) device that gently bends and straightens the joint by a programmed amount.

Pain control. If you had an anesthesia line in your back, it may be left in place for a day or two to administer medication to keep your lower body pain-free. Otherwise you initially receive pain medication through an IV. If your doctor has recommended patient-controlled anesthesia, you push a button to administer pain-killing drugs into your IV tube as you need them; the machine is programmed so you cannot use too much medication. After a while, you switch to oral painkillers. Don't hesitate to use the medications. Pain is easier to control before it becomes intolerable. Taking medication 3060 minutes before physical therapy helps you perform the exercises. In addition, the medication can help relieve pain and swelling, particularly after activity.

Breathing. After surgery, small airways in the lungs can collapse and create an ideal environment for pneumonia to develop. To keep your lungs clear, the nurse will instruct you to cough several times an hour and to perform deep breathing exercises. You may be given a breathing exerciser called an incentive spirometer that lets you see how deeply you are breathing and challenges you to expand your lungs fully.

Blood clot prevention. One potential postsurgical danger is the development of a blood clot that travels to the lung, lodging there and blocking off your breathing (pulmonary embolus). To help prevent blood clots, your doctor may place compression devices around your legs and feet. These devices are hooked to a machine that regularly fills them with air to squeeze your calves, forcing blood up your legs to mimic the action that your muscles would provide if you were moving around. Elastic stockings (TED or anti-embolic stockings) worn on both legs keep pressure on your calf muscles (and thereby your legs) to enhance blood flow. A health care professional measures your calves to order the proper size and shows you how to put on the stockings, which can be tricky at first. Blood-thinning medications such as warfarin or heparin may be prescribed for the first several weeks after surgery.

You can help prevent clots by moving around as much as you are allowed. While in bed, increase blood flow by circling your ankles or alternately flexing and pointing your feet. Report any symptoms of a possible leg clot: increasing swelling, pain, tenderness, or redness in your calf. A clot that has reached the lung can cause shortness of breath or chest pain that comes on suddenly with coughing; if this happens, notify your doctor immediately.

Infection control. To prevent infection, patients undergoing joint replacement are routinely given antibiotics for 3648 hours. Still, it's important to follow your nurse's instructions about cleansing and bandaging your incision. Notify your health professional if you notice these signs of infection: redness, swelling, pain, tenderness, fever, and increasing or odorous drainage. An infection around your incision can usually be treated with antibiotics and scrupulous cleansing and dressing of the wound. In some cases, the surgeon may have to reopen the incision to remove infected tissue. Infections around the incision are taken seriously in order to avoid a deep infection around the prosthesis, which can necessitate removing the implant. This occurs in about 1 in 200 knee or hip replacements.

Steps to restore mobility. Your rehabilitation begins immediately. Grasp the overhead bar to shift around in bed and relieve pressure on your skin. Perform bed exercises as prescribed by your physical therapist.

Before you actively bend a knee replacement, your knee is placed in a CPM machine to bend and straighten it a programmed (and gradually increasing) amount. Use of the CPM device supplements but can't replace your participation in physical therapy.

By the day after surgery, a nurse or physical therapist helps you get out of bed and use crutches or a walker to move to a nearby chair. If you had hip replacement, an abduction pillow between your legs keeps your hips in a safe position while you sit; the first few nights, your leg may be returned to the sling. To prevent your hip from dislocating before the ligaments heal enough to stabilize the area, you must avoid specific movements in the hospital and for several weeks at home (see "After hip surgery: Four tips to avoid dislocation").

After hip surgery: Four tips to avoid dislocation Precautions against dislocating a new hip implant are quite limiting for about six weeks. It's important to follow them regardless of how well you feel, since a position can be risky without causing pain. Bend over as little as possible. Your hip should flex no more than 90 degrees, meaning you should not bend over farther than your waist. This rules out bending over to tie your shoes normally or pick up something you've dropped, and it also means you'll need a raised toilet seat and a chair or bed that is high enough that your knees don't rise above your hips when you sit. Be careful in bed. Lying down, you mustn't pull your knee toward your chest or reach down too far to get your covers. Rely on long-handled gadgets. Four devices can be helpful: a reacher to help you pull up pants or grab items that are out of safe range; a tool to pull on socks without bending over; a shoehorn to put on sturdy non-tying shoes; and a sponge to help you wash below your knees. Avoid movements that turn the operated leg in or out. Keep your feet pointed straight ahead when you sit and stand. Don't cross your legs, even at the ankle. Sleep on your back or on your side with your abduction pillow between your legs.

By the second day, you spend more time sitting up. You walk to the bathroom, and you start rehab exercises with the physical therapist. During the remainder of your hospital stay, you work with the physical therapist in the gym until you achieve certain goals. An occupational therapist or other professional teaches you how to bathe, dress, and get in and out of a car safely without jeopardizing your implant.

The average hospital stay following total knee and hip replacement is four days. Before you can safely go home, you are usually expected to perform the following: get into and out of bed, walk with crutches or a walker, go up and down a curb and the number of steps you must negotiate at home, perform your rehab exercises, and show you can do necessary tasks with little or no assistance (and, after hip replacement, without violating your hip precautions). If you had knee replacement, you should be able to straighten your knee and bend it 90 degrees. Depending on individual circumstances, these requirements may be altered. If you are medically cleared for discharge but not able to do these things, or if you need extra nursing care or have no assistance at home, you are discharged to a rehabilitation center. Many people who live alone choose this option.

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Recovery and rehabilitation

When you first arrive home, you need help a family member, friend, or person hired to assist with meal preparation, cleaning, bathing, shopping, and just fetching things you need. Depending on your medical condition, a visiting nurse or home health aide may be helpful.

Your degree of participation in a rehabilitation program is a major factor in the success of your implant. Think of yourself as an athlete training to come back from an injury. These first several weeks require much effort. Several times a day, you perform exercises your physical therapist has recommended to restore movement in the joint and strengthen the surrounding muscles (see Figure 14). You can do many of these exercises sitting or lying down. A physical therapist may come to your home or may schedule regular appointments for the first few weeks. In addition to formal exercises, gradually increasing the amount you walk and do normal tasks improves your strength and stamina.

Figure 14: Exercises after knee replacement Under the guidance of your physical therapist you'll gradually be able to do the following exercises: Sitting knee bends: Sit in a chair with a towel under the operated knee. Straighten your knee as far as possible and hold for 5 seconds. Repeat 10 times. Gradually work up to 25 repetitions. Standing knee bends: Hold onto a steady surface such as a table. Bend your operated knee back as far as it will go. Hold for 5 seconds, then lower the leg to the floor. Repeat 10 times. Gradually work up to 25 repetitions.

How long you will need to use crutches or a walker to keep weight off your implant depends on the type of implant you have and individual circumstances. Most people can put a little weight on a cemented implant right away. As postoperative pain decreases, they gradually build to full weight bearing and walking without crutches or a walker by four to six weeks. An uncemented implant isn't secure until bone grows into it; most surgeons will allow you to put only about half your weight on the joint for the first six weeks, after which full weight bearing is allowed. After about six weeks of healing, your rehabilitation goals shift toward restoring your ability to do normal activities, although you may still experience muscle pain and fatigue for several months as your tissues heal.

After six months you should be able to function pretty normally. You can expect to have as much movement as you had before the operation, but without the pain. Just don't expect to have better mobility than you previously had.

Post-surgical pain. Pain is usually well controlled while you're in the hospital, since doctors and nurses are nearby and can provide powerful medications intravenously. Once you return home, the pain level is hard to predict. Some people experience very little and can find relief with ordinary over-the-counter drugs. Others, however, have pain so severe that they describe it as the worst pain of their lives comparable to childbirth or passing a kidney stone and are reluctant to even get out of bed.

It's not always clear why a person may experience exceptional pain. It can be a matter of perception people's threshold for pain varies tremendously. In other cases, there may be an underlying problem causing the pain, such as a swollen tendon or an infection.

The important thing to remember is that you should never suffer in silence. If your pain level is unacceptable, see your surgeon. If there's an underlying cause, he or she can address it. For example, pain caused by a swollen tendon can be alleviated with a steroid shot, and infections can be cured with antibiotics. If there is no direct cause, the surgeon can prescribe a more powerful medication, such as oxycodone (Percocet, OxyContin). This drug is tightly regulated due to its potential for abuse, but it's unlikely to be misused by pain patients and is often effective.

Dos and don'ts These tips can help ensure that your return to mobility following surgery goes smoothly. Don't soak your wound. Upon returning from the hospital, do not soak your wound in water until it has thoroughly sealed and dried. Do eat right. Eating a healthy diet including lots of fruits, vegetables, and whole grains is important to promote proper tissue healing and restore muscle strength. Do learn the signs of blood clots. Warning signs of a leg clot include increasing pain, tenderness, redness, or swelling in your knee and leg. Signs a clot has traveled to your lung include shortness of breath and chest pain that comes on suddenly with coughing. Call your doctor if you develop any of these signs. Don't take risks that could cause you to fall. Be especially careful on stairs until your knee is strong. Use a cane, crutches, or a walker until you have improved your balance and strength. Do look for signs of infection. These include persistent fever, shaking chills, increasing redness or swelling of the knee, drainage from the knee wound, and increasing knee pain with both activity and rest. Do exercise wisely. Performing the exercises your physical therapist recommends is critical for restoring movement in your new joint and strengthening the surrounding muscles.

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Living with a replacement joint

Eventually, your knee or hip implant may feel like it is truly your own joint. However, complications can occur that shorten the life of an implant, and you may need to take certain precautions.

Infection. Your implant can become infected years after surgery, almost always because infection elsewhere in the body has spread to the area. Seek immediate treatment if you have symptoms of a urinary tract or other infection, and inform all your doctors that you have a joint replacement. At least for the first couple of years, you may be advised to take prophylactic antibiotics before medical procedures that often result in bacteria entering the bloodstream, such as invasive dental work (extractions, gum surgery, root canals, and any cleaning or procedure likely to result in bleeding), a colonoscopy, or any type of surgery. Your doctor can advise you how long to continue these precautions, which are particularly important for those who have an illness or have undergone medical treatment that impairs the immune system.

Leg-length discrepancy. A difference in leg length occurs only rarely after knee replacement but occurs frequently, at least temporarily, after hip replacement. Before surgery, one leg is often shorter than the other or feels shorter because the joint has deteriorated. Your orthopedic surgeon chooses an implant and plans surgery so that your legs will be equal in length after healing. After hip replacement, muscle weakness or spasm and swelling around the hip may temporarily cause an abnormal tilt to your pelvis and make you feel as though your legs are unequal in length. Stretching and strengthening exercises help restore your pelvis to its proper position (see Figure 15). It may be several months before you can tell if the discrepancy is real and needs to be addressed with the use of a lift in the shoe. When the discrepancy is accompanied by pain, surgery can correct both problems.

Figure 15: Exercises after hip replacement Check with your physical therapist before doing these exercises to strengthen your hip. Standing knee raise: Standing with the aid of a walker or holding a stable surface, lift your thigh to no more than 90° and bend your knee. Hold for 5 to 10 seconds. Straighten your knee and touch the floor with your heel first. Repeat until your leg feels fatigued. Hip abduction: Standing with your hand on a stable surface, lift your leg out to the side as far as you can and hold for 5 to 10 seconds. Keep your hip, knee, and foot pointing straight forward. Repeat until your leg feels fatigued.

Dislocation. In the weeks after a hip replacement, you'll need to take great care to keep from dislocating the implant before the surrounding tissues have healed enough to hold it in place. Even afterward, there is a chance of a painful dislocation. If your hip dislocates, your doctor gives you a sedative while he or she manipulates the implant ball back into the socket. A hip that dislocates more than once usually requires surgery to make the joint more stable.

Loosening. A replacement joint can loosen because the cement never secured it properly or eventually wore out, or because the surrounding bone never grew into the implant to create a tight attachment. This may require revision surgery.

Bone loss. As a joint implant suffers wear and tear, loose particles can be released into the joint. As your immune system attacks these foreign particles, it can also attack surrounding bone, weakening it in a process called osteolysis. This, in turn, may loosen the bone's connection to the implant. Osteolysis is a major factor leading to revision surgery after hip and knee replacement.

More mobility = weight gain Many overweight people who have painful knees or hips anticipate that having a joint replacement will ultimately help them shed weight by helping them be more active. Orthopedics While this expectation seems plausible, in many cases patients actually put on more weight after having surgery. A 2005 study in documented this phenomenon at least one year following hip or knee replacement surgery, patients gained an average of three pounds, with younger patients adding the most weight. Researchers aren't sure why this occurs one theory is that increased mobility after surgery leads people to eat out more often and to make more frequent trips to the refrigerator. Whatever the reason, don't assume that joint replacement surgery will automatically help you slim down. To lose weight, you'll need to adhere to a regular exercise program and reduce your total caloric intake.

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Revision surgery

If your implant fails, surgery to replace it takes longer and may be more complicated than your original operation. Look for a surgeon with experience doing both implants and revisions. Before you have revision surgery, your doctor will perform a thorough physical exam. If you're much older than the first time around, you may need to take more precautions. You may be advised to bank extra blood for the lengthy procedure.

During surgery, the surgeon removes the old implant and damaged bone or joint tissue surrounding it. Depending on the amount and condition of the remaining bone tissue, you may need bone repairs or a bone graft to create a stable site for the new implant. Rehabilitation is similar to the initial replacement but takes longer after revision, and the outcome is often inferior. For example, your range of motion in the joint may be more restricted or your leg alignment less even, and even after healing you may need to use a cane to keep full weight off the joint.

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Glossary

abduction: Movement of a body part away from the midline.

acetabulum: The socket of the hip's ball-and-socket joint, part of the pelvic bone.

adduction: Movement of a body part toward or across the midline.

arthroplasty: Joint replacement.

arthroscopy: The use of miniature scopes and other small instruments inserted through small incisions to diagnose and repair joint problems.

articular cartilage: Tough, rubbery tissue that forms on the surface of bones within joints.

bursae: Cushioning sacs containing lubricating fluid located at a point of friction between two moving structures, such as a muscle and a tendon.

bursitis: Inflammation of a bursa, causing swelling and pain.

chondrocalcinosis: Arthritis caused by calcium crystals.

chondromalacia: Softening or wearing away of the articular cartilage, common in the knee joint on the underside of the patella.

condyle: One of the bony knobs of the knee joint located at the lower end of the femur.

crepitus: Grinding sensation or sound when a joint (especially the kneecap) is moved.

femur: Thighbone.

fibula: The smaller bone of the calf, located in the back.

gout: Arthritis caused by uric acid crystals.

inflammation: A response to injury or foreign invasion designed to protect the body; the symptoms are heat, redness, swelling, and pain.

ligament: Fibrous tissue connecting bones and cartilage.

patella: The bone that forms the kneecap.

synovial fluid: Liquid medium that lubricates the joints.

synovium: A thin membrane lining joint capsules that produces synovial fluid.

tendinitis: Inflammation of a tendon, usually caused by injury, that may cause pain and restrict movement of the muscle attached to the tendon.

tendon: A tough, fibrous band of tissue that attaches muscle to bone.

tibia: The shinbone; the large bone of the calf.

trochlea: A groove in front of the femur where the patella moves as the knee bends and straightens.

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Resources

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Organizations

American Academy of Orthopaedic Surgeons www.aaos.org 6300 N. River Road Rosemont, IL 60018 800-346-2267 (toll free)

This professional organization for orthopedic surgeons provides patient fact sheets and booklets on numerous knee and hip problems. The Web site includes a physician locator.

American Academy of Physical Medicine and Rehabilitation www.aapmr.org 330 North Wabash Ave., Suite 2500 Chicago, IL 60611312-464-9700

This professional organization is for physiatrists, physicians who specialize in rehabilitation. The Web site includes a physician locator.

American Physical Therapy Association www.apta.org 1111 N. Fairfax St. Alexandria, VA 22314 800-999-2782 (toll free)

The national professional organization for physical therapists provides consumer brochures and other patient information.

Arthritis Foundation www.arthritis.org P.O. Box 7669 Atlanta, GA 30357 800-283-7800 (toll free)

This nonprofit organization produces more than 100 consumer publications. The Web site offers extensive information, including a large section on joint surgery. Local chapters advise about doctors and sponsor activities such as swimming and joint-health classes.

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Books

All You Need to Know About Joint Surgery: Get Ready for Surgery, Recovery and an Active New Lifestyle (Arthritis Foundation, 2002, 235 pages)

The Arthritis Foundation's official guide to joint surgery. In addition to surgical details and a step-by-step guide to preparation and recovery, the book describes nonsurgical treatments and offers advice on how to know whether (or when) surgery is right for you.

The American Physical Therapy Association Book of Body Maintenance and Repair Marilyn Moffat, P.T., Ph.D., FAPTA, and Steve Vickery (Henry Holt and Company, 1999, 288 pages)

This official APTA publication explains the mechanics of your body's moving parts (including chapters on knees and hips) and describes exercises to maintain optimal function and rehabilitate injuries. The illustrated exercises provide options to improve strength, endurance, and flexibility for beginners and those seeking greater challenges.

Knee Pain: The Self-Help Guide John Garrett, M.D., and Bob Reznik, M.B.A. (New Harbinger Publications, 2000, 251 pages)

With a knee surgeon as co-author, this book discusses a wide range of knee problems and treatments, using photographs to illustrate diagnostic tests, surgeries, and rehabilitation exercises.

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Review Date: 2006-09-01