What is Knee Pain?
Knee Pain Explained by Las Vegas, Summerlin, and Henderson Nevada’s Top Pain Doctors
Knee pain is a common condition in which various structures that comprise the knee joint may be affected. The knee is described as the largest and most complex joint in the body as it consists of different bones, ligaments, muscles, and tendons as well as cartilage that provides a protective covering for the knee joint. There are four bones in the knee, which are the femur, tibia, fibula, and patella. These bones are connected to each other through ligaments such as the anterior cruciate ligament (ACL), which prevents the femur from slipping backward onto the tibia; the posterior cruciate ligament (PCL), which prevents the femur from slipping forward onto the tibia; and the medial and lateral collateral ligaments, which prevent the femur from moving sideways.
Learn About Knee Pain – Watch This Video
There are also quadriceps muscles located on the front of the knee joint and hamstrings located on the back of the knee; both of which provide additional support and stability. C-shaped sections of cartilage, known as the medial and lateral menisci, are located between the femur and tibia. The cartilage protects the knee by acting as a shock absorber and provides a gliding surface that promotes smooth movement. Furthermore, several membrane-lined sacs of synovial fluid, called bursae, are also located around the knee to ensure that it moves smoothly. Subsequently, when individuals are suffering from knee pain, one or more of these structures may be responsible for the pain that is being felt.
Each of these structures is susceptible to wear and tear from daily activities, overexertion of the joint, or injuries. Several environmental factors have also been identified as potential causes of long-term knee pain. For example, developing an infection or experiencing blunt trauma to the knee makes this joint more susceptible to future damage and chronic pain. Additionally, once knee pain begins, it may be somewhat difficult to determine the exact cause of the pain at first as some individuals experience mild and generalized pain, while others may experience sharp, localized pain.
Epidemiology and Impact of Knee Pain
According to a recent study, the incidence rate of knee pain and knee osteoarthritis has doubled in women over a span of 20 years and tripled in men. These findings, which were mostly observed amongst non-Hispanic Caucasian men, Mexican American men and women, and African American women, were independent of age and weight-related factors such as obesity. In general, chronic or periodic knee pain affects approximately 25% of adults by causing decreased mobility and stability as well as an impaired quality of life.
Osteoarthritis in particular, is the most common cause of knee pain in older individuals who are 50 years old or older. However, older individuals only have a higher incidence than younger individuals who do not engage in frequent recreational activities or sports (e.g., athletes). Athletes frequently suffer from knee pain due to injuries. A torn meniscus and iliotibial syndrome are quite common among cyclists, runners, and individuals who perform various types of sports and aerobics. Furthermore, adolescents, especially girls between the ages of 13 to 18 years of age, experience a high number of kneecap dislocations and this particular injury is often the result of sports activities.
Certain diseases also lead to knee problems in some age groups. Osgood-Schlatter disease, which is also called Schlatter’s disease or osteochondrosis, is one condition in particular that is frequently reported as a cause of knee pain in children between the ages of 10 to 15, especially boys.
The rate of knee replacements that have been performed has also increased greatly over the years, especially for individuals 65 years of age or older, due to chronic knee problems and pain. The number of knee replacements due to knee pain in younger individuals is also increasing, but at a disproportionate rate in comparison to older adults. Overall, it is estimated that 4 million adults in the United States have undergone a total knee replacement procedure. Approximately 1.5 million of these individuals are 50 to 69 years old.
Causes of Knee Pain
Knee pain is most often the result of an injury such as blunt trauma, sprained or strained ligaments and tendons, falling on the knees, bending the knees improperly, or twisting the knees in an abnormal manner. A torn meniscus, for instance, is a common knee joint injury that occurs from an unusually forceful twist or rotation of the knee joint. Various activities such as sports, recreation, or strenuous jobs often lead to knee problems as well.
More serious injuries such as a broken or fractured knee cap, femur, tibia, or fibula often occur from falling, improper twisting motions, or blunt trauma. These types of injuries may also cause nerve or blood vessel damage that can lead to numbness in the knee. Kneecap dislocation is another serious injury that causes severe knee pain. Pieces of tissue or bone, which may become dislodged due to this particular injury, can become stuck in the knee joint and cause mobility problems. Furthermore, dislocation is one of the most serious knee injuries and requires immediate medical attention.
Overuse or overexertion of the knee joint, which occurs during repetitive actions, or putting excessive pressure on the knee, can lead to various types of injuries. Activities that have been frequently associated with knee injuries and chronic pain include jogging, jumping, climbing stairs, and cycling. Bursitis, tendinitis, tendinosis, patellofemoral pain syndrome, plica syndrome, and iliotibial band syndrome typically develop from these types of repetitive actions.
Bursitis is characterized as the inflammation of the membrane-lined sacs in the knee which contain synovial fluid that lubricates the knee joint. Tendinitis is the inflammation of tendons, while tendinosis occurs from small tears in the tendons. Patellofemoral pain syndrome, which is the result of overexerting the knee or putting excess weight on the knee, causes pain that is felt in the front of the knee or in the kneecap. Plica syndrome is the abnormal folding or thickening of the ligaments that results in pain at the back of the knee.
Iliotibial band syndrome is characterized as inflammation of the iliotibial band, which is a network of fibrous tissue that provides stability for the knee joint and prevents dislocation. When the knee is overexerted, the iliotibial band may tighten, become overdeveloped, or rub up against the outer part of the knee. This leads to knee pain that is felt during movement and is a common syndrome amongst cyclists, runners, and individuals who perform various types of aerobics.
Knee problems may also develop from certain conditions such as osteoarthritis, autoimmune diseases, infections, and gout, among others. Osteoarthritis is the most common form of arthritis and is a chronic condition that is associated with damaged cartilage in the knee. The cartilage can become damaged as a result of wear and tear over a number of years or as the result of a specific injury. If the cartilage sustains sufficient damage, it begins to deteriorate, resulting in a high risk of bone rubbing directly against bone because the cartilage that previously separated the bones is no longer intact.
Autoimmune diseases, such as rheumatoid arthritis or lupus, are characterized by an atypical immune response to the body’s joints. Rheumatoid arthritis is inflammation of the tissue that lines the knee joint. Over an extended period of time, this condition can lead to the deterioration of cartilage, tendons, ligaments, and bone in the knee. Lupus is similar to rheumatoid arthritis in that it leads to inflammation, tissue damage, swelling of the joints, and joint pain, such as in the knee.
Fluid build-up, also referred to as knee effusion, can also develop within the knees as a result of inflammation. The fluid build-up is accompanied by moderate to severe pain in addition to inflammation. Furthermore, the formation of cysts such as the popliteal or Baker’s cyst cause pain and swelling, specifically in the back of the knee. Problems that originate in different parts of the body such as a pinched nerve in the hip or other hip problems may also cause pain in the knee.
Gout or pseudogout are characterized by the build-up of uric acid crystals or calcium pyrophosphate crystals, respectively. The build-up of these substances leads to pain in various joints such as the knee. Septic arthritis is a condition that is caused by a bacterial infection in the knee that causes pain and inflammation. A number of other infections such as hepatitis, influenza, and Lyme disease have also been associated with knee pain.
Osgood-Schlatter disease, which is also called Schlatter’s disease or osteochondrosis, is inflammation that affects the top of the tibia where tendons attach to the bone. This condition is frequently reported as a cause of knee pain in children between the ages of ten to 15, especially boys. Osteochondritis dissecans is another painful condition where a piece of cartilage or bone in the knee or a combination of both, loses its blood supply and dies, causing decreased mobility.
Some injuries and conditions cause immediate symptoms such as pain, swelling, or bruising, while others do not cause pain initially. The degree of pain that is experienced also varies among individuals.
Symptoms of Knee Pain
The specific symptoms of knee pain are widely varied. Some patients will experience pain that is a highly specific and sharp stab, while others will describe the pain as more generalized and widespread. Pain, swelling, and bruising may develop minutes after an injury and may worsen over a matter of hours or days.
Some common symptoms associated with knee pain include:
- Swelling and stiffness
- Numbness, a cold feeling, or tingling
- Discoloration (e.g., blue or pale color)
- Weakness or instability
- Popping, snapping, or grinding noises with movement
- Knee locks during movement
- Inability to straighten knee fully
Typical symptoms of a serious knee sprain include hearing or feeling a snap when the injury occurs, which indicates that a ligament may have partially torn. Swelling and moderate to severe pain may also be experienced as well as restricted movement. If the ligament was completely torn as a result of the injury, a deformity or bulge may be noticed at the injury site. The symptoms of a knee strain, which affects muscles or tendons, are quite similar to that of a knee sprain.
The symptoms of a knee fracture or dislocation include severe pain, swelling, and bruising, an unstable or loose knee joint, problems moving the leg or knee, a locked knee that cannot be bent or straightened, trouble standing or walking, and an abnormal appearance. More specifically, the knee may appear to be twisted, bent in an awkward manner, or in an abnormal position. This type of injury requires immediate medical attention.
Injuries that occur from overuse or exertion (e.g., bursitis, tendonitis, etc.) generally cause inflammation and serious pain during movement or when pressure is placed on the knee. Swelling also occurs due to increased fluid at the injury site as well as redness and skin that is warm to the touch.
Syndromes such as the patellofemoral pain syndrome and the iliotibial band syndrome are characterized by pain that occurs while sitting, squatting, jumping, or using the stairs, as well as knee buckling, grinding, or popping during movement.
Conditions such as osteoarthritis typically cause symptoms such as pain in the knees as well as the spine and toes, that tends to worsen after activity or at the end of the day. Individuals begin to experience pain while at rest as this condition progresses. Stiffness also occurs after periods of inactivity, especially in the morning; knee movement becomes limited, the knee joint may become enlarged, and tenderness may also be experienced due to fluid build-up around the joint.
While most cases of knee pain are not severe, you should contact your doctor if you experience any of the following symptoms along with the pain:
- Fever that is not associated with symptoms of the flu
- Unintentional weight loss of ten pounds or more
- Knee pain that is severe and is accompanied by other unexplained symptoms
- Knee pain that lasts for more than three days and has started to interfere with a daily routine (e.g. work or sleep)
Risk Factors for Knee Pain
Obesity has been labeled as a significant risk factor for knee pain as excessive weight can lead to knee joint inflammation and injuries. In individuals who are obese, even daily activities such as walking or using the stairs causes weight-related stress on the knees. Furthermore, aging and obesity are highly associated with the risk of developing knee osteoarthritis, but obesity in particular accelerates the degradation of cartilage in the knee.
Reports have also indicated that individuals who are obese and suffering from knee osteoarthritis lose an average of 3.5 quality-adjusted life years, especially in persons between the ages of 50 to 84. In addition, obesity is highly associated with total knee replacements, which individuals tend to undergo after experiencing knee pain and complications for extended periods of time. However, total knee replacement procedures also present potential risks such as persistent pain and complications, but this is not a common occurrence.
Physical abnormalities such as having flat feet, misaligned knees, or one leg that is shorter than the other, can make individuals more susceptible to knee problems and pain. Individuals who lack strength and flexibility in their muscles also tend to suffer from a high incidence of knee injuries. This is because muscles that are weak or too tight do not provide sufficient knee support and this leads to excess stress on the knee joint. Wearing flat-soled sandals or flip-flops on a daily basis or when going for long walks can also lead to poor arch support, which can cause pain in the knees.
Certain sports put a lot of pressure on the knees and greatly increase the risk of knee injuries. Activities that fall under this category include basketball pivots and jumps, running or jogging, and alpine skiing, which has a high potential for falling. In general, sports that cause a significant amount of pounding on the knees may lead to chronic knee pain and complications. Furthermore, a previous knee injury makes this joint more susceptible to further injury. Smoking also becomes a risk factor because it delays the healing process, reduces blood flow, and disrupts tissue repair.
Diagnosis of Knee Pain
Knee pain may be the result of injury or inflammation to one or more of the structures that make up the knee joint, so diagnosis involves pinpointing the exact location or structure that is causing the pain. However, knee pain can also occur in conjunction with a variety of conditions. Therefore, it is imperative that both the patient and physician accurately identify the cause of the pain prior to considering treatment options for knee pain.
Initial questions that are asked during the physical evaluation include:
- Where is the pain?
- Is the pain constant or periodic?
- Is the pain mild, moderate, or severe?
- Does the pain increase or worsen with movement or when the knee is touched?
- Was the pain the result of an injury?
- Was a pop heard when the injury occurred?
- Can grinding or popping be heard when the knee is moved?
These types of questions are asked because the location of pain may provide an indication of the structure that may have been affected. For instance, pain that is primarily felt on the side of the knee may indicate that the iliotibial band has been affected, while pain that is primarily felt in the front of the knee may be the result of patellofemoral syndrome. Furthermore, symptoms such as skin around the knee that is warm to the touch may indicate the presence of an infection. A description of how an injury occurred may also give a physician an impression of what structure may have been affected.
A physician may also use a checklist such as the one listed below in order to assess the presence of:
- Locking, clicking, or instability as this may be a sign that meniscal cartilage may have become damaged
- Pain under the kneecap in the tendon which indicates that tendinitis may be the cause of the pain
- Swelling which may indicate that more than one structure in the knee has been affected
- The sudden onset of symptoms which usually indicates that a traumatic event has occurred
- Throbbing pain in the knee as this may indicate that wear and tear or overexertion is causing the knee pain
- Pain while kneeling which may be an indication that the individual is suffering from arthritis
- Knee stiffness in the morning which may indicate that an individual is suffering from osteoarthritis
- Bony lump at the front of the knee, as in adolescents, this may be an indication of Osgood-Schlatter disease
- Tingling or numbness which is an indication that a serious injury has occurred such as nerve or blood vessel damage in the knee
A physician may also want to visualize the structures in the knee and may recommend having an x-ray of the knee joint. Additional imaging technologies that may be used to diagnose problems in the knee include computerized tomography (CT) scan, magnetic resonance imaging (MRI), or an ultrasound. An x-ray can help a physician detect fractures and degenerative joint disease. A CT scan allows for the detection of problems with the bone or loose structures (e.g., loose tissue or bone). An ultrasound and MRI allow soft tissue structures such as cartilage, ligaments, muscles, and tendons to be visualized.
When a physician suspects that an infection such as gout or pseudogout may be present, blood tests may be conducted. A procedure called arthrocentesis, which involves removing a small amount of fluid from the knee joint and having it analyzed, may also be performed.
Treatment for Knee Pain
Treatment for knee pain may include home treatments such as applying cold packs, resting, and using a brace; the use of over-the-counter or prescription medication; physical therapy; and surgery in some cases. However, the type of treatment that should be utilized depends on the type, severity, and location of the injury that is causing the knee pain as well as factors such as age, activity level (e.g., work schedule, sports, or hobbies), and health status.
The primary goal for the treatment of knee pain involves reducing or alleviating persistent pain and improving joint function. If the knee pain is mild to moderate and has not been caused by a serious injury such as a fracture, dislocation, or infection, home treatments may help relieve pain and improve additional symptoms such as swelling and stiffness. The following are recommendations for home treatments:
- Immediately apply cold packs or ice to the injury site to prevent and reduce swelling. Apply the cold pack or ice for 10 to 20 minutes, as tolerated, at least three times a day.
- Rest the knee joint and protect the injured or sore area from further injury through the use of a brace, for example. This means that activities which may be causing more pain and soreness should be discontinued for a period of time.
- Avoid taking a hot shower, using a hot tub, and applying hot packs for the first 48 hours after the injury has occurred.
- If the swelling is gone after 48 to 72 hours, heat can be applied to the injury site and the knee joint can be gently exercised. The application of moist heat can help restore flexibility.
- Health care professionals also recommend alternating between hot and cold treatments during this stage of recovery.
- Compressing or tightly wrapping the knee joint with an elastic bandage (e.g., Ace wrap) also helps decrease the swelling, but it should not be wrapped too tightly or this will cause additional swelling. Increased pain, numbness, swelling below the bandage, and tingling are signs that the bandage may be too tight. Remember that the bandage may help reduce swelling, but does not stabilize or protect the knee from further injury.
- Elevate the leg of the injured knee during periods of rest such as while sitting or lying down.
- Gently massage the knee in order to promote blood flow, but discontinue the massage if it causes more pain.
- Gently perform exercises such as a hamstring stretch and a knee-to-chest exercise in order to maintain flexibility, but avoid high-impact activities such as playing tennis, running, skiing, and snowboarding until the swelling and pain have stopped.
- Avoid smoking as this delays the healing process by decreasing the blood supply and delaying tissue repair in the knee.
Home treatments also vary slightly depending on the type of injury or condition that caused the knee pain. Treatment for a mild ligament sprain or muscle strain should involve immobilizing the knee joint by elevating it and resting, using ice packs, and an elastic compression bandage. Sprains or strains that cause moderate or severe pain should be evaluated by a medical professional in order to determine if approaches such as splint or cast, medication, physical therapy, or surgery may be necessary. If severe injuries are not properly treated, long-term pain may develop as well as reduced mobility or a deformity.
For a torn meniscus, treatment should focus on therapy that will help restore as much mobility as possible. Typical home treatment for this type of injury includes medication, hot and cold treatments, compression, and physical therapy. If surgery has to be performed, home treatments should be continued after the procedure.
Bursitis in the knee can be treated with applications of ice or cold packs, by resting, and by avoiding activities that further irritate the knee or increase pain. If the knee is red and warm to the touch, an infection may have developed that requires medical attention.
Symptoms of patellofemoral pain syndrome, which most commonly develops in athletes, teenagers, and manual laborers, can be improved by avoiding activities that cause the knee to frequently bend such as kneeling, squatting, or performing exercises that require the knee to be in a bent position. Nonprescription anti-inflammatory drugs (NSAID), resting, and applying ice to the knee also help relieve pain. Furthermore, physical therapy helps restore flexibility, stability, and strength in both the leg and knee muscles. A brace may also be necessary in order to stabilize the knee and if these types of treatment do not improve symptoms, surgery may be needed.
Iliotibial band syndrome can be treated by resting, taking medication that can help relieve pain and swelling, and performing stretching exercises that are recommended by a physician or physical therapist. Steroid injections have also been shown to be useful.
The pharmacological approach can help improve daily functioning by reducing pain. The first line of treatment for many cases of knee pain is a non-steroidal anti-inflammatory drug (NSAID). This class of drugs include acetaminophen (e.g., Tylenol), ibuprofen (e.g., Advil or Motrin), Naproxen (e.g., Aleve or Naprosyn), and aspirin (e.g., Bayer or Bufferin). These medications are recommended because of their ability to reduce inflammation within the joint and thereby, reduce pain. Oral corticosteroids, such as prednisone and cortisone, may also be recommended to reduce inflammation in the knee joint.
It is reported, however, that non-steroidal anti-inflammatory medication should not be consumed during the first 24 hours after an injury has occurred as these medications may increase the time it takes for blood clots to form if bruising develops under the skin. Taking this type of medication too early even has the potential to cause more severe bruising from blood that accumulates under the skin.
When over-the-counter medication does not help relieve knee pain, a physician may prescribe opioid medications, which are much stronger pain relievers than conventional medicine. Opioids such as morphine, codeine, and oxycodone are among the oldest classes of drug therapies that are available for treating pain. The pharmacological effects arise when opioids bind to the opioid receptors within the brain. Effective opioid treatment typically results in the decreased perception of pain, a delayed reaction to pain, and increased pain tolerance. Studies have provided ample support for the use of opioids for short-term relief of severe pain that had a sudden-onset. The misuse of opioids may lead to drug abuse, dependence, or an overdose, but this most often occurs with short-acting opioids. Prescribing long-acting opioids appears to decrease the occurrence of adverse side effects.
Individuals who are suffering from chronic knee pain may need to undergo more intensive forms of treatment in order to experience pain relief. Knee joint corticosteroid injections are a common procedure that has proven to be beneficial at reducing knee pain as well as inflamed tissue. Typically both a steroid and an anesthetic are injected into the affected region because the steroids lead to a reduction of inflammation, while the anesthetic leads to a reduction or elimination of pain. Some patients have reported experiencing immediate pain relief after receiving a corticosteroid injection. Steroid injections can also be repeated if necessary in order to improve the treatment outcome.
There are a number of different types of corticosteroid injections such as joint injections, which are often recommended for individuals with arthritis. This procedure is very common and involves an injection of steroids and an anesthetic directly into the joint, to relieve swelling and pain. Previous studies have shown that individuals receiving this intervention have reported significant pain reduction, along with an improvement in their quality of life and range of motion.
For patients suffering from knee osteoarthritis, medial branch blocks may become necessary. This procedure involves the insertion of a needle and a catheter into the spinal column in order to administer medication to nerve roots that are responsible for pain in the knee. A steroid and anesthetic, or a substance that disintegrates nerve tissue is injected in order to relieve chronic pain and this treatment method leads to long-term pain relief by blocking the transmission of pain signals to the knee joint.
Other Treatment and Management Strategies for Knee Pain
Spinal cord stimulation may also be considered for severe knee pain or knee osteoarthritis. During this procedure, implants are placed near the spine in regions where spinal nerves that regulate the transmission of pain signals are located. The implants transmit electrical impulses that can override pain signals that the brain normally receives. Nerve damage in the knee, which may occur from an injury or inflammation, may cause a higher number of pain-related impulses to be sent to the brain. Spinal cord stimulation has the ability to improve these impulses and help the body better control the knee pain.
In order to improve the safety and efficacy of the implants, the devices are made of soft, flexible material that makes their placement into the back easier. Furthermore, temporary stimulators are initially implanted during a brief trial period in order to ensure that the implants will work effectively. If no adverse side effects are observed during the trial phase, then the permanent devices are implanted. This procedure is more invasive than corticosteroid injections or medial branch blocks so it is only recommended for individuals who are suffering from neuropathy (nerve damage) in the knee that did not improve from other treatments or pain from a previous surgery that was unsuccessful. However, the effects of successful spinal cord stimulation are long-term.
Additionally, individuals who have suffered from serious knee injuries and chronic pain and did not experience relief from other forms of treatment may consider undergoing a total knee replacement. Joint replacement surgery is also an option for individuals with advanced knee osteoarthritis who have been suffering from chronic knee pain and complications that have significantly reduced their quality of life.
The initial stages of osteoarthritis can be treated through home remedies, but the symptoms associated with this condition tend to worsen over time and may eventually warrant the need for knee joint replacement. It has been reported that successful total knee replacement procedures have the ability to increase quality-adjusted life years by five to six years as opposed to individuals with severe knee problems who chose not to have this procedure performed.
Knee pain is a common condition that occurs when one or more of the structures that comprise the knee joint becomes damaged or inflamed (e.g., sprains, strains, fractures, or dislocations). The knee consists of different bones, ligaments, muscles, and tendons as well as cartilage and each of these structures is susceptible to wear and tear from daily activities, overexertion of the joint, or injuries. Several environmental factors such as developing an infection or experiencing blunt trauma to the knee have also been identified as potential causes of long-term knee pain. Furthermore, there are several risk factors associated with knee pain such as obesity, aging, physical abnormalities, wearing shoes with limited arch support, smoking, and previous injuries.
Reports of chronic knee pain and knee osteoarthritis have increased dramatically over a span of 20 years in both men and women. Furthermore, osteoarthritis is the most common cause of knee pain in individuals who are 50 years old or older. Adolescents, especially girls between the ages of 13 to 18 years of age, experience a high number of kneecap dislocations and Osgood-Schlatter disease is a common cause of knee pain in children between the ages of 10 to 15, especially boys.
There are a number of treatment options available for managing knee pain, but the initial diagnosis involves pinpointing the exact location or structure that is causing the pain. It is also important to determine whether a certain condition or infection may be causing the knee pain. In general, mild knee pain that may have been caused by a sprain or strain can be treated with home remedies such as elevation, cold packs, or non-steroidal anti-inflammatory drugs such as acetaminophen (e.g., Tylenol), ibuprofen (e.g., Advil or Motrin), or aspirin (e.g., Bayer or Bufferin). These types of approaches are often recommended before more intensive forms of treatment are attempted.
Individuals who experience severe, chronic knee pain, or injuries such as fractures or dislocations should seek immediate medical attention as treatments such as corticosteroid injections, medial branch blocks, spinal cord stimulation, or even surgery may be necessary in order to help relieve the knee pain. Overall, when it is suspected that a serious injury or condition is causing pain and discomfort, a physician should be allowed to examine the knee before starting treatment.
- Haviv B, Bronak S, Thein R. The complexity of pain around the knee in patients with osteoarthritis. Isr Med Assoc J. 2013;15(4):178-181.
- Hirsch G, Kitas G, Klocke R. Intra-articular corticosteroid injection in osteoarthritis of the knee and hip: Factors predicting pain relief-a systematic review. Semin Arthritis Rheum. 2013;42(5):451-473.
- Karlsson J, Söderström A, Augustini B, Berggren AC. Is buprenorphine transdermal patch equally safe and effective in younger and elderly patients with osteoarthritis-related pain? Results of an age-group controlled study. Curr Med Res Opin. 2013; in press.
- Kwofie MK, Shastri UD, Gadsden JC, Sinha SK, Abrams JH, Xu D, Salviz EA. The effects of ultrasound-guided adductor canal block versus femoral nerve block on quadriceps strength and fall risk: a blinded, randomized trial of volunteers. Reg Anesth Pain Med. 2013;38(4):321-325.
- Losina E, Walensky RP, Kessler CL, Emrani PS, Reichmann WM, Wright EA, Holt HL, Solomon DH, Yelin E, Paltiel AD, Katz JN. Cost-effectiveness of total knee arthroplasty in the United States: patient risk and hospital volume. Arch Intern Med. 2009;169(12):1113-1121.
- Losina E, Walensky RP, Reichmann WM, Holt HL, Gerlovin H, Solomon DH, Jordan JM, Hunter DJ, Suter LG, Weinstein AM, Paltiel AD, Katz JN. Impact of obesity and knee osteoarthritis on morbidity and mortality in older Americans. Ann Intern Med. 2011;154(4):217-226.
- Maricar N. Callaghan MJ, Felson DT, O’Neill TW. Predictors of response to intra-articular steroid injections in knee osteoarthritis-a systematic review. Rheumatology. 2013;52(6):1022-1032.
- Marks R. Obesity Profiles with Knee Osteoarthritis: Correlation with Pain, Disability, Disease Progression. Obesity. 2007;15:1867-1876.
- Nguyen US, Zhang Y, Zhu Y, Niu J, Zhang B, Felson DT. Increasing prevalence of knee pain and symptomatic knee osteoarthritis: Survey and cohort data. Am Intern Med. 2011;155(11):725-732.
- Porcheret M, Jordan K, Croft P, Treatment of knee pain in older adults in primary care: Development of an evidence-based model of care. Rheumatology.2007;46:638-648.
- Stein BE, Srikumaran U, Tan EW, Freehill MT, Wilckens JH. Lower-extremity peripheral nerve blocks in the perioperative pain management of orthopaedic patients: AAOS exhibit selection. J Bone Joint Surg Am. 2012;94(22):e167.
- Weinstein AM, Rome BN, Reichmann WM, Collins JE, Burbine SA, Thornhill TS, Wright J, Katz JN, Losina E. Estimating the burden of total knee replacement in the United States. J Bone Joint Surg Am. 2013;95(5):385-392.