AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Background

Osteoarthritis, the most common type of joint disease, is a heterogeneous group of conditions that result in common histopathologic and radiologic changes. It is a degenerative disorder that results from the biochemical breakdown of articular cartilage in the synovial joints. Although osteoarthritis is thought to be largely due to excessive wear and tear, secondary nonspecific inflammatory changes may also affect the joints.

Historically, osteoarthritis has been divided into primary and secondary forms, although this division is somewhat artificial. Secondary osteoarthritis is conceptually easier to understand. It refers to degenerative disease of the synovial joints that results from some predisposing condition, usually trauma, that has adversely altered the articular cartilage and/or subchondral bone of the affected joints. Secondary osteoarthritis often occurs in relatively young individuals. This form of the disease is beyond the scope of this article.

The definition of primary osteoarthritis is more nebulous. In the broadest sense of the term, primary osteoarthritis is an idiopathic phenomenon, occurring in previously intact joints, with no apparent initiating factor. Primary osteoarthritis is related to the aging process and typically occurs in older individuals. Some clinicians limit primary osteoarthritis to the joints of the hands (specifically the distal interphalangeal joints, proximal interphalangeal joints, and joints at the base of the thumb), whereas others include the knees, hips, spine (apophyseal articulations), and hands as potential sites of involvement. This article primarily focuses on osteoarthritis of the hand, knee, and hip joints.

The term primary or idiopathic osteoarthritis may become obsolete as underlying causes of osteoarthritis are discovered. For instance, many investigators believe that most cases of primary osteoarthritis of the hip may, in fact, be due to subtle or even unrecognizable congenital or developmental defects.

Pathophysiology

Although, by definition, the etiology of primary osteoarthritis is unknown, the pathology and pathogenesis of osteoarthritis has been extensively studied.

The normal articular surface of synovial joints consists of hyaline cartilage, which is composed of cells (ie, chondrocytes), surrounded by an extracellular matrix that includes various macromolecules, most importantly proteoglycans and collagen. The cartilage protects the underlying subchondral bone by distributing large loads, maintaining low contact stresses, and reducing friction at the joint.

A variety of factors, most notably age, lead to the development of primary osteoarthritis; however, primary and secondary osteoarthritis are not separable on a pathologic basis. Most investigators believe that degenerative alterations primarily begin in the articular cartilage, as a result of either excessive loading of a healthy joint or relatively normal loading of a previously disturbed joint. External forces accelerate the catabolic effects of the chondrocytes and disrupt the cartilaginous matrix.

Enzymatic destruction increases cartilage degradation, which is accompanied by decreased proteoglycans and collagen synthesis. Changes in the proteoglycans render the cartilage less resistant to compressive forces in the joint and more susceptible to the effects of stress. The decreased strength of the cartilage is compounded by adverse alterations of the collagen. Elevated levels of collagen degradation place excessive stresses on the remaining fibers, eventually leading to mechanical failure. The diminished elastic return and reduced contact area of the cartilage, coupled with the cyclic nature of joint loading, causes the situation to worsen over time.

Microscopically, flaking and fibrillations develop along the normally smooth articular cartilage surface. The loss of cartilage results in the loss of the joint space. Progressive erosion of the damaged cartilage occurs until the underlying bone is exposed. Bone denuded of its protective cartilage continues to articulate with the opposing surface. Eventually, the increasing stresses exceed the biomechanical yield strength of the bone. The subchondral bone responds with vascular invasion and increased cellularity, becoming thickened and dense (eburnation) at areas of pressure.

Furthermore, the traumatized subchondral bone may undergo cystic degeneration, due to either osseous necrosis secondary to chronic impaction or the intrusion of synovial fluid. At nonpressure areas along the articular margin, vascularization of subchondral marrow, osseous metaplasia of synovial connective tissue, and ossifying cartilaginous protrusions lead to irregular outgrowth of new bone (osteophytes). Fragmentation of these osteophytes or of the articular cartilage itself results in intra-articular loose bodies (joint mice).

Frequency

United States

Approximately 80-90% of individuals older than 65 years have evidence of primary osteoarthritis.

Mortality/Morbidity

Osteoarthritis typically develops slowly and progresses over several years. Usually, the pain slowly worsens over time, but it may stabilize in some patients. Osteoarthritis of the knee is a leading cause of disability in elderly persons. Osteoarthritis also causes millions of Americans to miss work because of back pain.

Race

Primary osteoarthritis affects all races, although the prevalence and patterns of the disease appear to differ.

• The disorder is more prevalent in Native Americans than in the general population.
• Disease of the hip is seen less frequently in Chinese patients from Hong Kong than in age-matched white populations.
• In persons older than 65 years, osteoarthritis is more common in whites than in blacks.

Sex

In individuals older than 55 years, the prevalence of osteoarthritis is higher among women than men.

• Women are especially susceptible to osteoarthritis in the distal interphalangeal joints of the fingers.
• Women also have osteoarthritis of the knee joints more frequently than do men, and they are more prone to erosive osteoarthritis (see Clinical Details below), with a female-to-male ratio of about 12:1.

Age

Osteoarthritis occurrence appears to increase with patient age, in a nonlinear fashion. The prevalence of the disease increases dramatically after the age of 50 years, likely because of the following factors:

• Age-related alterations in collagen and proteoglycans that decrease the tensile strength of the joint cartilage
• Diminished nutrient supply to the cartilage

Anatomy

Primary osteoarthritis occurs commonly in the hands, particularly in the distal interphalangeal joints, proximal interphalangeal joints, and first carpometacarpal joints. Clinicians who include involvement of other joints in the definition of primary osteoarthritis also see the disease in the hip joints, knee joints, first metatarsophalangeal joints, and lower lumbar and cervical regions of the spine (apophyseal articulations).

Primary osteoarthritis in other joints, such as the shoulder, elbow, wrist, and ankle, is less common.

Clinical Details

Signs and symptoms

Primary osteoarthritis is a common disorder of the elderly, and patients are often asymptomatic. Patients with symptoms usually do not notice them until after they are aged 50 years.

Deep, achy, joint pain exacerbated by extensive use is the primary symptom. Also, reduced range of motion and crepitus are frequently present. Joint malalignment may be visible. Heberden nodes, which represent palpable osteophytes in the distal interphalangeal joints, are characteristic in women but not men. Inflammatory changes are typically absent or at least not pronounced.

Subsets of primary osteoarthritis

Certain diseases are often categorized as subsets of primary osteoarthritis. These disorders include primary generalized osteoarthritis (PGOA), erosive inflammatory osteoarthritis, and chondromalacia patellae.

Kellgren and Moore described PGOA in 1952. The disease is characterized by familial and often premature development of Heberden and Bouchard nodes, as well as the precocious degeneration of the articular cartilage of multiple other joints, including the first carpometacarpal joints, knee joints, hip joints, and spine articulations. The radiographic appearance of PGOA is indistinguishable from that of nonfamilial primary osteoarthritis, although the disease typically progresses relatively rapidly and appears severe on images.

Erosive (ie, inflammatory) osteoarthritis is a form of primary osteoarthritis marked by a greater degree of inflammation, with erosive abnormalities and, in some cases, osseous ankylosis. The disease most commonly occurs in postmenopausal women, and it may be hereditary. Laboratory findings are generally uninformative. Erosive osteoarthritis is typically bilateral and symmetrical, and it occurs in the interphalangeal, particularly distal interphalangeal, joints of the hands (see Image 24). Rarely, patients may have erosive osteoarthritis at the base of the first metacarpal or even in the feet.

Radiographically, the erosions are centrally located (see Image 25), in contrast to the marginal erosions in rheumatoid arthritis. Osteophytes are present; consequently, interphalangeal joints may assume a gull-wing configuration, with central erosions flanked by raised lips of bone. Periarticular soft-tissue swelling is evident. Osseous fusion, which severely limits joint motion, may occur (see Image 26).

Chondromalacia patellae, which most commonly occurs in young adults, is a syndrome of crepitus and pain at the anterior knee associated with cartilaginous changes along the undersurface of the patella (see Image 17). Conventional radiographs provide little information. Although arthrography enables a more direct assessment of cartilaginous integrity, many consider MRI to be the initial imaging study of choice. Fast spin-echo images (eg, fast spin-echo T2-weighted fat-suppressed images) or gradient-echo images (eg, T1-weighted 3-dimensional fat-suppressed images) can be used for the detection of cartilaginous ulceration, which is classically focal and located along the medial facet of the patella.

Preferred Examination

Osteoarthritis is typically diagnosed on the basis of clinical and radiographic findings.

Limitations of Techniques

Radiographic findings may be normal in the early stages of the disease, because cartilage is not directly visualized. Eventually, cartilage loss manifests as joint-space narrowing.

Patient Education: For excellent patient education resources, visit eMedicine's Arthritis Center. Also, see eMedicine's patient education article Osteoarthritis.

DIFFERENTIALS

Section 3 of 12  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

RADIOGRAPH

Section 4 of 12  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

One important characteristic of primary osteoarthritis is that different abnormalities are found in the pressure (ie, contact) and nonpressure areas of the affected joint. In the highly stressed (ie, pressure) areas of the joint, radiographs can depict joint space loss, as well as subchondral bony sclerosis and cyst formation. In the areas without high contact pressures, osteophytes can be detected. Bilateral symmetry is often seen in cases of primary osteoarthritis, particularly when the hands are affected.

With the onset of osteoarthritis, articular cartilage loses its smooth texture and becomes coarsened. This change leads to a sharp increase in frictional forces. Subsequently, cracks and tears, which lead to cartilage softening and flaking, are noted histologically. The net loss of articular cartilage appears as a reduction of the joint space on radiographs.

In major weight-bearing joints, a greater loss of joint space occurs at those areas subjected to the greatest pressures; this effect is in contrast to that of inflammatory arthritides, in which uniform joint-space narrowing is the rule. In the osteoarthritic knee, for example, one commonly observes the greatest loss of joint space in the medial femorotibial compartment (see Image 1), although the lateral femorotibial compartment and patellofemoral compartment may also be affected. Collapse of the medial or lateral compartments may result in varus or valgus deformities, respectively. Hence, weight-bearing radiographs are preferred for evaluation of the osteoarthritic knee to depict such deformities, as well as to provide an accurate assessment of joint-space narrowing.

Radiographs of the entire lower extremity (ie, load-line views) are also useful for demonstrating varus or valgus malalignment. Axial projections are best for evaluating the patellofemoral joint. When the patellofemoral compartment is involved, the lateral facet of the patella is more frequently affected than the medial facet, and lateral patellar subluxation may be noted. Osteoarthritic changes of the patellofemoral articulation may be seen on lateral projections.

In the osteoarthritic hip, the superior aspect of the joint is typically the most narrowed (see Image 2); axial and medial migration of the femoral head is less commonly seen. In the small joints of the hand, radiographs often show narrowing of the entire joint (see Image 3). In some cases, the interphalangeal joint may be asymmetrically affected, and radial or ulnar deviation at the joint may be appreciated; volar subluxation, as seen with rheumatoid arthritis, seldom occurs. Valgus deformity often accompanies osteoarthritis of the first metatarsophalangeal joint (see Image 4).

As the cartilage is worn away, friction causes the exposed subchondral bone to become smooth and polished, giving it a shiny surface (eburnation). The bone also becomes rebuttressed and sclerotic, a finding that is seen radiographically, generally after visible joint space narrowing occurs. As degeneration progresses, sclerosis becomes more marked, infiltrating deeper into the bone. Sclerosis is often the most prominent radiographic finding when osteoarthritis affects the facet joints of the spine (see Image 5).

Cyst formation is a fundamental radiographic finding in patients with osteoarthritis. Osteoarthritic cysts are also referred to as subchondral cysts, pseudocysts, or geodes, the preferred European term. These lesions are generally 2-20 mm in diameter. On radiographic examination, communication with the articular space may or may not be seen. Osteoarthritic pseudocysts in the acetabulum are termed Egger cysts (see Image 2).

Later in the disease, the subchondral bone weakens and compresses; bony collapse may be seen radiographically. This finding is commonly seen in advanced cases of osteoarthritis of the hip, in which flattening of the superior aspect of the femoral head typically occurs (see Image 2).

The fundamental radiographic finding in the less-stressed areas of the osteoarthritic joint is osteophytosis. Osteophytes are mushroom-shaped bony outgrowths that are generally seen at the margins of the joint. These outgrowths are capped by cartilage that gradually ossifies. The osteophytes vary in size and may be smooth or jagged. In the knee, sharpening of the tibial spines and the more typical marginal osteophytes may be present (see Image 6). A bony prominence, known as the Parson bump, may develop just anterior to the tibial spines (see Image 7). Growth of osteophytes is one of the best indicators of disease progression. Fractured osteophytes result in intra-articular loose bodies. Flexed views (ie, tunnel views, skier views) of the knees often demonstrate these loose bodies particularly well.

As stated previously, primary osteoarthritis is most commonly seen in the hands. Bilateral symmetry is generally observed, with multiple fingers on each hand affected. Heberden nodes refer to bony prominences at the distal interphalangeal joints, whereas similar bony outgrowths at the proximal interphalangeal joints are called Bouchard nodes. Although they are generally present simultaneously, Heberden nodes are more common. On frontal radiographs, medial or lateral subluxation may accompany the wavy joint surface. In most patients with osteoarthritis of the interphalangeal joints, the first carpometacarpal joint is also affected (see Image 8), often with some degree of radial subluxation of the metacarpal. The scaphotrapezium and scaphotrapezoid joints may also be affected (see Image 9).

Small joint effusions are not uncommon in osteoarthritic joints. Chondrocalcinosis and periarticular calcium hydroxyapatite deposition may also be seen. Mucinous cysts arise from the capsules of interphalangeal joints and may present radiographically as small periarticular soft-tissue masses.

Degree of Confidence

Conventional radiographs remain the criterion standard for the imaging diagnosis of osteoarthritis. The diagnosis can be made with a high degree of confidence when joint narrowing, subchondral sclerosis, and osteophyte formation are seen. Several radiographic grading systems have been proposed, but currently, no single system is adequate for evaluation of osteoarthritis at all joints.

CT SCAN

Section 5 of 12  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

CT is rarely used for the diagnosis of primary osteoarthritis, although it may be used for the diagnosis of malalignment of the patellofemoral joint or the foot and ankle joints. It may also be useful in evaluating the osseous detail of the vertebral column, particularly the facet joints (see Image 10).

In patients who cannot tolerate MRI, CT scanning after the intra-articular injection of contrast material can be useful for the depiction of articular cartilage disease and the diagnosis of osteoarthritis or loose bodies in a variety of joints. CT is also well suited for the demonstration of hip joint osteoarthritis (see Image 11), but this examination is rarely ordered, except for preoperative planning.

MRI

Section 6 of 12  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

MRI can depict many of the same findings of osteoarthritis as those depicted on radiographs, including joint narrowing, subchondral osseous changes, and osteophytes (see Image 12). However, radiographs remain the imaging method of choice in the diagnosis of osteoarthritis, because they are more cost-effective than other methods and because they can be obtained more readily and quickly.

Unlike radiography, MRI can depict articular cartilage directly; this feature of MRI has been the subject of multiple research studies over the past several years, particularly focusing on the cartilage of the knee. A variety of pulse sequences have been described, but the most commonly used include spoiled gradient-recalled echo (SPGR) and fast spin-echo imaging. Three-dimensional gradient-echo images with fat saturation display the hyaline cartilage as high signal intensity tissue relative to bone, fat, and fluid (see Image 13). Abnormalities are seen as alterations of morphology of the normally bright cartilage, for example, fissuring (see Image 14) or thinning (see Image 15). With intermediate- or T2-weighted fast spin-echo images, normal articular cartilage is of intermediate signal intensity (see Image 16). Cartilage abnormalities can be seen as regions ofrelatively increased intrasubstance

signalintensity(see Image 17) or as morphologic defects such as fissuring (see Image 18) or thinning (see Image 19). Several systems have been advocated for use in the grading of focal cartilage change; however, a simple description of the extent of disease (ie, surface, partial-thickness, or full-thickness irregularity with or without underlying subchondral bony change) is generally sufficient and prevents confusion that occurs with numeric grading systems. In patients with osteoarthritis not related to prior trauma, diffuse cartilaginous thinning is often noted; this affects the medial compartment more so than the lateral or patellofemoral compartments early in the disease. Later, tricompartmental cartilaginous thinning may be appreciated.

Although subchondral sclerosis often has low signal intensity on both T1- and T2-weighted images, a bone-marrow edema pattern (low signal intensity on T1-weighted images, high signal intensity on T2-weighted images) may also be seen. Zanetti et al (2000) concluded, on the basis of histologic findings in osteoarthritic knees that were treated with joint replacement, that this pattern usually represents histologically noncharacteristic abnormalities such as bone marrow fibrosis, bone marrow necrosis, and trabecular abnormalities, whereas actual edema is only a minor constituent.

ULTRASOUND

Section 7 of 12  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

Currently, ultrasonography has no role in the clinical evaluation of osteoarthritis, although it is being investigated as a tool for monitoring cartilage degeneration.

NUCLEAR MEDICINE

Section 8 of 12  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

In joints affected with osteoarthritis, increased uptake of bone-seeking radiopharmaceuticals (see Image 20) may be seen before any radiographic abnormalities are apparent (see Image 21). Tracer accumulation (see Image 22) is concentrated in regions of bony eburnation and osteophyte formation (see Image 23).

However, scintigraphic studies are of limited use for the diagnosis of osteoarthritis because increased uptake of the radiotracer can also be seen in several other hypervascular articular diseases. Furthermore, the image resolution of bone scintigraphy is much less than that of other imaging modalities.

ANGIOGRAPHY

Section 9 of 12  

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• Differentials
• Radiograph
• CT SCAN
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• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Findings

Angiography is not routinely used for the diagnosis of osteoarthritis. Hypervascularity that accompanies the reparative response to osteoarthritis may be incidentally noted in affected bones and joints during studies performed for reasons other than the evaluation of osteoarthritis.

INTERVENTION

Section 10 of 12  

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• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Several treatment options are now available for slowing or stopping the progression of this common disorder. The patient is instructed to avoid placing excessive strain on the affected joint and to lose weight, if applicable. Physical therapy may be recommended to preserve joint motion and flexibility. Acetaminophen or anti-inflammatory agents are often prescribed to alleviate the pain associated with the disease. Intra-articular pharmacologic therapy includes corticosteroid injection and viscosupplementation.

Radiologists may aid in the treatment of osteoarthritis by administering image-guided intra-articular injections of steroids. After the introduction of the needle into the joint and prior to steroid administration, aspiration of as much synovial fluid as possible should be attempted. This procedure often provides symptomatic relief for the patient and allows laboratory evaluation of the fluid, if necessary. Infected joint fluid and bacteremia are contraindications to steroid injection.

If these treatments are ineffective, surgical intervention, which ranges from arthroscopic procedures to total joint arthroplasty, may be necessary in some patients.

MULTIMEDIA

Section 11 of 12  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

Media file 1:  Standing anteroposterior (AP) radiograph of the knees reveals bilateral medial femorotibial compartment narrowing and sharpening of the tibial spines; this finding is typical of osteoarthritis.
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Media file 2:  Anteroposterior (AP) radiograph of the hip reveals severe superior migration of the femoral head (which reflects loss of articular cartilage), subchondral sclerosis, prominent osteophytes, and a large Egger cyst in the superior acetabulum. Mild flattening of the superior aspect of the femoral head is present.
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Media file 3:  Posteroanterior (PA) radiograph of the hand reveals narrowing, osteophytes, and subchondral cysts affecting the distal interphalangeal joints; this finding is typical of osteoarthritis.
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Media file 4:  Radiograph of the foot reveals narrowing, subchondral sclerosis, and osteophyte formation affecting the first metatarsophalangeal joint. A mild valgus deformity is present as well.
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Media file 5:  Oblique projection demonstrates gradual narrowing and sclerosis of the facet joints as one progresses down the lumbar spine.
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Media file 6:  Standing radiograph of the knee reveals narrowing of the medial and lateral femorotibial compartments with marginal osteophytes.
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Media file 7:  Lateral radiograph of the knee in the patient in Image 6 reveals patellofemoral compartment narrowing and osteophytosis. A prominent Parson bump is also seen. Large ossified intra-articular bodies are evident.
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Media file 8:  Radiograph demonstrates narrowing and osteophytosis affecting the first carpometacarpal joint.
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Media file 9:  Close-up radiograph of the wrist shows osteoarthritic changes at the first carpometacarpal joint, with severe narrowing and sclerosis of the trapezium-scaphoid and trapezoid-scaphoid (triscaphe) articulations.
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Media file 10:  Transverse CT scan image obtained through the lower lumbar spine shows sclerosis of the facet joints.
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Media file 11:  Transverse CT scan image obtained through the superior aspect of the hip reveals joint narrowing, osteophyte formation, and subchondral cysts typical of osteoarthritis.
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Media file 12:  T1-weighted coronal MRI of the knee shows typical findings of osteoarthritis, including narrowing and subchondral changes at the medial femorotibial compartment and osteophyte formation.
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Media file 13:  Sagittal 3-dimensional gradient-echo fat-saturated MRI of the knee reveals normal hyperintense articular cartilage.
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Media file 14:  Sagittal 3-dimensional gradient-echo fat-saturated MRI of the knee reveals a full-thickness fissure of the articular cartilage of the patella.
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Media file 15:  Sagittal 3-dimensional gradient-echo fat-saturated MRI of the knee reveals full-thickness thinning of the articular cartilage of the lateral femoral condyle posteriorly with underlying degenerative subchondral marrow changes.
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Media file 16:  Transverse fast spin-echo T2-weighted fat-saturated MR image dipicts normal intermediate signal intensity patellar cartilage well outlined against joint effusion.
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Media file 17:  Transverse fast spin-echo T2-weighted fat-saturated MR image of the knee reveals increased signal intensity within the articular cartilage of the patella reflecting degeneration.
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Media file 18:  Transverse fat-suppressed fast spin-echo T2-weighted MR image reveals a fissure of the patellar cartilage filling with joint fluid.
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Media file 19:  Transverse fat-suppressed fast spin-echo T2-weighted MR image reveals a full-thickness defect of the articular cartilage along the medial facet of the patella with underlying degenerative subchondral marrow changes.
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Media file 20:  Spot delayed technetium-99m methylene diphosphonate (MDP) bone scintigram reveals focal increased radiotracer accumulation at the basilar joints and several interphalangeal joints (circles); this finding is compatible with osteoarthritis.
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Media file 21:  Radiograph obtained in the same patient as in Image 20 shows only tiny osteophytes at the basilar and scaphotrapezium joints.
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Media file 22:  Spot delayed technetium-99m methylene diphosphonate (MDP) bone scintigram reveals increased uptake of the radiopharmaceutical in the right hip joint.
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Media file 23:  Radiograph obtained in the same patient as in Image 22 shows severe osteoarthritic disease (joint narrowing, subchondral sclerosis, osteophytosis) that affects the right hip.
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Media file 24:  Close-up posteroanterior (PA) radiograph of the hand reveals narrowing and osteophytes affecting multiple interphalangeal joints. Note the "gull-wing" configuration of the distal interphalangeal joint of the middle finger due to central erosion. There is also ankylosis of the distal interphalangeal joint of the index finger.
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Media file 25:  Close-up radiograph of the fifth digit shows osteophytes and central erosions resulting in a "gull wing" appearance.
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Media file 26:  Close-up radiograph shows fusion of the distal interphalangeal (DIP) joint of the fifth finger; this finding is compatible with advanced erosive osteoarthritis.
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REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Ultrasound
• Nuclear Medicine
• Angiography
• Intervention
• Multimedia
• References

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• Phadke K. Regulation of metabolism of the chondrocytes in articular cartilage--an hypothesis. J Rheumatol. Dec 1983;10(6):852-60. [Medline].
• Radin EL, Paul IL. Response of joints to impact loading. I. In vitro wear. Arthritis Rheum. May-Jun 1971;14(3):356-62. [Medline].
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Article Last Updated: Jan 24, 2007