Approach to a Swollen Joint

Authors: Dr Kenneth H. Fye University of California San Francisco 2008-08-12

Approach to a Swollen Joint: Swelling in the joint, whether or not accompanied by pain and tenderness, is a sign of disruption in articular anatomy or function.

Introduction

Bones are strong, generally tubular structures composed of a dense collagen architecture infused with calcium phosphate crystals. The central component, or marrow, of bone is filled with tissues that produce the cellular elements of blood. Because they have to be rigid enough to support and protect the vital internal organs, bones are not intrinsically flexible enough to allow movement or locomotion. A joint is a skeletal articulation, where two separate bones are held together by strong yet flexible soft tissues that allow components of the skeleton to move when muscles on opposite sides of the joint contract or relax. These crucial soft tissues include the joint capsule and ligaments that actually connect the opposing bones, the tendons that attach muscles to the bones, the cartilage which cushions the surfaces of opposing bones, the synovial membrane which secretes the nutrients and lubricating substances that allow the joint to move smoothly and efficiently, and menisci, which are extra fibrous cushions found in various joints throughout the body.

Swelling in the joint, whether or not accompanied by pain and tenderness, is a sign of disruption in articular anatomy or function. The problem must be correctly defined before any appropriate corrective action can be taken. Therefore, the first step in the approach to joint swelling is diagnosis (a diagnosis is simply the definition of a medical problem). The two medical disciplines specifically directed toward the study and care of disruptions in skeletal function are orthopedics, a discipline which concentrates on the surgical treatment of these disorders, and rheumatology, a specialty directed towards treatment of the medical diseases that affect the joints.

Diagnosis

The tools used by clinicians in arriving at a diagnosis include the history and physical examination, laboratory tests, imaging studies (x-ray, ultrasound, magnetic resonance imaging, etc), and biopsy. The sophisticated technologies now available to the clinician should not be used randomly. They are expensive, sometimes invasive, and should only be used in the proper clinical context. Therefore, the most important tool used by any physician is still the history and physical examination.

History and physical examination

A history is simply the story of how the problem began and how it is affecting the patient. A physical examination is the visual observation, palpation, and manipulation of the affected area. The trained clinician gains valuable information from the physical examination by comparing his or her observations of the patient to normal anatomy. Deviations from the norm help the clinician define the physical problem. Every joint has a unique anatomy, and over the years clinicians have developed a myriad of physical maneuvers designed to distinguish specific disruptions in normal anatomy (1).

The first question that has to be answered in the algorhythym used by clinicians in approaching a swollen joint is whether the problem is affecting the soft tissues surrounding the joint, the joint itself, or both articular and periarticular supporting structures. For instance, if the swelling of an ankle began during a game of basketball and the physical examination reveals pain with manipulation of the ankle but no significant bone tenderness, the clinician would probably suspect a sprained ankle. A sprain is the overstretching of a ligament, sometimes leading to a partial tear. If the forearm just above the wrist is askew after a fall, the patient probably has a fracture. The slow onset of painful swelling in the knee of an elderly patient may reflect the presence of osteoarthritis (2). If the swelling is accompanied by redness, heat, and tenderness, the clinician has to evaluate the patient for any of the many diseases that can cause an inflammatory arthritis. Inflammatory arthritides that typically affect just a single joint include the infectious or septic arthritides (3) and the crystal-induced arthropathies, such as gout (4). Examples of inflammatory polyarthritides (arthritic conditions that affect 4 or more joints) include the autoimmune diseases, such as rheumatoid arthritis (5) or systemic lupus Erythematosus (6), and the forms of arthritis associated with the human leukocyte antigen B27 (HLA-B27) gene, such as ankylosing spondylitis and the arthritis associated with the skin disease, psoriasis (7).

    Diagram of a Normal Diarthrodial Joint (a joint with a synovial membrane).

                      Courtesy of the American College of Rheumatology

 

Laboratory

Sometimes the history and physical examination are so characteristic that no further diagnostic studies are needed, and appropriate therapy can be initiated. However, usually the history and physical examination just provide clues as to the nature of the underlying problem and further investigations are needed to adequately define the problem. The laboratory can provide the clinician with crucial diagnostic information through the examination of various body fluids, including blood, urine, sputum, or even feces. One of the most important laboratory tests available to the clinician evaluating a swollen joint is the analysis of synovial fluid (8). Synovial fluid is the lubricating and nutrient-filled fluid produced by the lining cells of the joint. Normally there is just enough fluid to coat the inner surfaces of the joint, so if joint fluid is detected on physical examination, there is something amiss. The physician can use a needle and syringe to withdraw synovial fluid from a swollen joint so that it can be analyzed. The number and type of inflammatory cells, the amount of protein, the presence of abnormal crystals, or the presence of invading microbes can all be determined by synovialysis (a term meaning analysis of synovial fluid) and can provide the clinician with invaluable diagnostic data. Using special stains of synovial fluid samples bacterial or mycobacterial invaders can be detected by normal light microscopy. Cultures of synovial fluid are also used to detect infections of the joint. Using polarized light with a red compensator, monosodium urate crystals (diagnostic of gout) or calcium pyrophosphate dihydrate crystals (typical of pseudogout) can be distinguished. The analysis of other bodily fluids, such as blood or urine, may be required to identify any of the many systemic medical problems that can cause arthritis. For instance, the presence of rheumatoid factors or elevated anti-cyclic citrullinated anti-body levels would be typical of a patient with rheumatoid arthritis (9). Patients with systemic lupus erythematosus have elevated antinuclear antibodies (a positive ANA) and depressed serum complement levels (10).  

Imaging

Generally, at some point in the evaluation of a swollen joint an imaging study of some kind will be done (11). It is difficult to envision the practice of modern medicine in general, let alone the practice of orthopedics or rheumatology, without x-rays. X-rays can be used to demonstrate or rule out a fracture. They can be used to detect the damage done to joints by erosive forms of arthritis, such as gout or rheumatoid disease. They can demonstrate the deposition of soft tissue calcifications in patients with tendonitis of the shoulder or in systemic rheumatologic disorders like scleroderma. Although very effective in the evaluation of boney or calcified structures, x-rays do not image soft tissue abnormalities very well. A number of new and sophisticated technologies have been developed that allow us to assess soft tissues throughout the body. Ultrasound machines use high frequency sound waves that rebound off soft tissue interfaces to outline soft tissue structures around joints. The images obtained by ultrasound are becoming better and better as our technology evolves. Computer assisted tomography (CAT) scanning, as the name implies, uses the computer to analyze a series of x-rays taken at different levels of the target organ, providing dramatic pictures of the inside of the body. No less dramatic are the images obtained by magnetic resonance imaging (MRI). With the help of powerful computers, these machines can detect differences in the magnetic resonances produced by the spin of nuclei in molecules found in different tissues throughout the body. These computers then produce detailed images that allow clinicians to visualize normal and abnormal soft tissue structures as never before. These tools can be used to identify torn ligaments, tendons, or menisci. They are used by clinicians to detect or quantify the amount of synovial proliferation or fluid in an inflamed joint or to detect boney fractures or erosions that are too subtle to be seen on x-ray. Other newer techniques, such as proton emission tomography (PET scanning) or single photon emission computed tomography (SPEC scanning) have not yet found a place in the routine evaluation of joint problems.

Biopsy

Some disorders that affect the joint and periarticular supporting structures are difficult to diagnose without microscopic examination of histologic material obtained by biopsy (8). Some chronic infectious processes, such as tuberculosus of the joint, can often only be diagnosed by biopsy. A few chronic inflammatory arthropathies, such as sarcoidosis affecting the joint, some benign neoplastic processes, such as pigmented villonodular synovitis, and even some malignancies that affect the joints, such as sarcoma, lymphoma, or metastatic disease, can only be definitively diagnosed by biopsy. Advances in the technology of arthroscopy have led to the development of small flexible instruments that can be introduced into a joint space and have made biopsies much easier to obtain. Fortunately, the diagnosis is usually made using much less invasive techniques. 

Treatment

Basically, there are 3 treatment modalities available to patients with swollen joints. The first is physical therapy. The second is pharmacologic therapy, meaning the use of appropriate anti-rheumatic medications. The third, reserved only for those patients who do not respond to more conservative therapies or for whom physical and pharmacologic therapies are not appropriate, is surgery.

Physical therapy

Physical therapy basically means temperature manipulation, the creation of the proper ratio of rest and exercise, the use of appropriate adaptive devices, and utilization of a variety of technological modalities (12). Physical therapy can be valuable in the treatment of both acutely or chronically swollen joints and periarticular supporting structures. It is used in the treatment of trauma or intrinsic articular disease. Both increased and decreased temperatures can be used to relieve muscle spasm and decrease pain. Cold is frequently applied to an acutely injured joint to prevent or decrease swelling, as well as to alleviate pain. However, one has to be careful with the use of ice because of the possibility of localized skin or subcutaneous cold-induced trauma. Ice treatments should be limited to no more that 20 minutes at a time and should be applied no more often than 3 times a day. Heat is easier to use but can also be dangerous if used inappropriately. Heat can be applied in the form of a hot shower, a hot pack, an electric heating pad, or even a hot towel. Acute burns can result from any of these modalities if the treatment is too hot. Prolonged application of even low dose heat to a localized area, such as the low back, can result in a form of chronic skin damage, termed erythema ab igne.

An acutely swollen joint should generally be immobilized. As the problem begins to respond to therapy it is important to mobilize the affected joint to prevent scarring and contractures of periarticular supporting structures that may result in decreased range of motion of the joint, even after the acute problem has resolved. Range of motion exercises can be done by the patient or, in patients unable to accomplish these exercises on their own, by a physical therapist. With continued improvement, progressive strengthening exercises against resistance are indicated to prevent or correct the muscle weakness often seen after immobilization of a joint.

Adaptive devices of various types are often extremely valuable in helping patients deal with joint problems. Support devices range from ace bandages to splints to braces to casts, depending on the problem and the target joint. An ace bandage may suffice if the problem is a sprained ankle, while an articulated brace may be necessary to help a patient with osteoarthritis of the knee function effectively. Chronic erosive arthropathies may result in significant joint destruction, making normal function impossible. A variety of adaptive functional devices have been developed to help such patients. These devices include long handled prongs to help patients retrieve objects out of reach, modified cooking and eating utensils to aid patients at mealtime, and even devices to aid patients insert and turn keys. Canes, crutches, scooters, and wheelchairs, some even motorized, are available to help patients whose ambulation has been hindered by their joint problem.

Some articular or periarticular problems respond to any of a number of mechanical modalities. Ultrasound is used to apply deep heat and to relieve muscle spasm. Transcutaneous electrical neurostimulation (TENS) is used to treat chronic musculoskeletal pain. Ionophoresis combines the use of transcutaneous neurostimulation and cutaneous corticosteroid administration to treat soft tissue problems, such as tendonitis or bursitis. Other devices, such as diathermy, have fallen into disuse because of either lack of proven efficacy or unacceptable toxicities.

           

Pharmacologic Therapy

When a swollen or painful joint does not respond to physical therapies and is associated with unacceptable levels of discomfort, the pharmacologic agents most often used first are analgesics (13). Acetaminophen is a non-narcotic, therefore non-addicting, analgesic agent that works centrally to decrease pain perception. It is available without prescription, and, when taken in recommended doses, is safe and well tolerated. It is often combined with narcotic agents, such as codeine, hydrocodone or oxycodone, for use in patients with more severe pain. Low dose non-steroidal anti-inflammatory agents(NSAIDs), such as naproxen, ibuprofen, or diclofenac, are also available without a prescription. The doses of these many agents vary enormously, but all doses recommended for over-the-counter NSAIDs are only analgesic and have no anti-inflammatory effects (14). The effective treatment of inflammatory rheumatic conditions requires the use of anti-inflammatory doses of these agents. The doses required to achieve anti-inflammatory effects also vary widely and are dependent on many factors, such as weight, age, and co-morbid conditions. The larger anti-inflammatory doses, available only by prescription, decrease swelling and pain by inhibiting the ability of enzymes of the cyclo-oxygenase family to produce other enzymes, called prostaglandins, that mediate many of the manifestations of inflammation. Although fairly well tolerated for short periods of time, when used chronically 10 percent of patients can develop gastrointestinal side effects, ranging from dyspepsia to heart burn to peptic ulcers. Rare side effects include rash, hepatitis, or renal failure. Low dose non-steroidal anti-inflammatory agents, such as ibuprofen, have, like acetaminophen, been added to narcotic agents for use in controlling the pain associated with articular disease.

When prescribed in the treatment of rheumatic conditions, aspirin is now most often used in low doses as an analgesic agent. At higher doses aspirin is an effective non-steroidal anti-inflammatory agent, but so many patients develop gastrointestinal, neurologic, renal or hepatic side effects when taking anti-inflammatory doses of aspirin it has generally been replaced by more benign non-steroidal anti-inflammatory agents. It is now commonly used as an anti-platelet agent in the treatment of cardiovascular disease.

Severe forms of chronic joint disease can now be treated with any of a number of slow acting disease modifying anti-rheumatic drugs (15). These agents have been shown to significantly decrease inflammation and to delay or even prevent joint destruction. They have a variety of modes of action. Some, such as the tetracycline related anti-biotics, work by inhibiting the production and release of matrix metalloproteases (enzymes that cause inflammation and joint damage). Some, such as hydroxychloroquine, may interfere with cytosolic functions. The anti-metabolites, like methotrexate, the purine antagonists, like azathioprine or mycophenolate mofetil, and the pyrimidine antagonists, like leflunomide, inhibit new nucleic acid production and thereby inhibit inflammatory cell function. The cytotoxic agents, like cyclophosphamide, decrease inflammation by killing inflammatory cells. Advances in genetic engineering have resulted in the development of the newer biologic agents which work by targeting specific mediators of joint inflammation without killing inflammatory cells, which are still necessary to fight off foreign invaders and protect us from our environment. All of these medicines have the potential of significant side effects, some life-threatening, and should only be used under the supervision of a skilled physician. However, the efficacy and “relative” safety of the newer agents, including the new biologics, have significantly improved the long term outlook of patients with chronic arthritic disorders.

The corticosteroids have proved to be invaluable in the treatment of rheumatic conditions, both articular and periarticular (16). Local corticosteroid injections are used for tendonitis, bursitis, nerve compression syndromes, such as carpal tunnel syndrome, and for many forms of arthritis, both degenerative and inflammatory (17). Systemic corticosteroids are used to treat severe joint inflammation and to control the systemic manifestations associated with many forms of arthritis. The side effects of systemic corticosteroids can be daunting, but they are time and dose dependent. These side effects include, but are not limited to, fluid retention, hypertension, weight gain, centripetal obesity, osteoporosis, poor wound healing, increased susceptibility to infection, stretch marks, hypokalemia (low potassium), insomnia, mental changes, “moon facies” with plethoric complexion, and thinning of the skin with easy bruisability. Side effects can be minimized by using low doses and by minimizing the length of time patients are exposed to the drug. Unfortunately, some forms of chronic arthritis require long term corticosteroid therapy, so patients and their physicians need to take steps to deal with the side effects that do develop. 

Surgical Therapy

The first surgical intervention in the treatment of a painful or swollen joint is local injection of corticosteroid (17). In an effort to decrease the discomfort associated with an injection, local analgesics, such as lidocaine, can be administered along with the therapeutic agent. Corticosteroids are anti-inflammatory agents used in both degenerative and inflammatory arthritic conditions. Orthopedists will often inject preparations of hyaluronic acid (the major lubricating substance in synovial fluid) into knees afflicted with degenerative arthritis. Local corticosteroids are particularly helpful in acute problems, and they may offer temporary relief in the treatment of chronic problems, but a recalcitrant condition might require more aggressive surgical therapy (18).

A number of soft tissue problems, such as trigger finger, carpal tunnel syndrome, or sclerosing tenosynovitis, can be surgically corrected using soft tissue techniques. Surgical arthroscopy is the use of a small bore fiberoptic instrument to enter the joint space through a small cutaneous incision. Arthroscopy can be used to examine the inner surface of a joint, to biopsy synovial membrane, to wash out the debris within a degenerative joint, or to repair anatomic derangements of articular structures, such as a torn meniscus or cruciate ligament. Surgical arthroscopy can also be used in some soft tissue procedures, such as carpal tunnel release. Some joints can be replaced if the damage caused by arthritis is too great. The replacement procedure, called an arthroplasty, is particularly successful in the knee and the hip. The shoulder and the proximal small joints of the fingers can often be replaced, but the long-term surgical outcomes are not always as good as those seen in the knee and the hip. There are no universally accepted prostheses for the elbow, wrist, or ankle. On rare occasions, a joint will be damaged to such a degree the bone cannot adequately support a prosthetic device. Such a joint may require a fusion, a procedure called an arthrodesis. The joint will no longer provide flexibility, but a fused joint is stable and painless. Osteotomy is an old procedure once used in the treatment of osteoarthritis. It has largely been replaced by surgical arthroscopy or arthroplasty.

Conclusion

A swollen joint can be a painful, debilitating problem. Fortunately, modern diagnostic techniques have enabled physicians to quickly define the vast majority of articular and periarticular problems, and modern therapies have enabled physicians to successfully treat the majority of swollen joints. Even chronic forms of arthritis that cannot be cured can be effectively controlled. 

Related Web Sites

1.                  American Association of Orthopedic Surgeons Web Site (http://orthoinfo.aaos.org)

2.                  American College of Rheumatology Web Site (http://www.rheumatology.org/)

 

References

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