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Home , Chondrocalcinosis, Osteoarthritis, Osteophyte

Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. EIW N COMMENTARY AND REVIEWS Radiographic Evaluation of : Degenerative 1

and Variations Ⅲ EIWFRRESIDENTS FOR REVIEW

Jon A. Jacobson, MD In the presence of joint space narrowing, it is important to Gandikota Girish, MD differentiate inflammatory from degenerative conditions. Yebin Jiang, MD, PhD The presence of , sclerosis, and subchon- Brian J. Sabb, DO dral cysts and the absence of inflammatory features such as erosions suggest . Typical osteoarthritis involves specific at a particular patient age. When osteoarthritis involves an atypical joint, occurs at an early age, or has an unusual radiographic appearance, then other causes for destruction should be consid- ered, such as trauma, crystal deposition, neuropathic joint, and hemophilia. There are several types of arthritis, such as juvenile chronic arthritis and gouty arthritis, that may have a variable appearance compared with that of other common inflammatory arthritides.

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1 From the Department of , University of Michi- gan Medical Center, 1500 E Medical Center Dr, TC-2910L, Ann Arbor, MI 48109-0326. Received Decem- ber 11, 2006; revision requested February 7, 2007; revi- sion received July 25; accepted September 12; final ver- sion accepted November 7; final review by J.A.J. April 20, 2008. Address correspondence to J.A.J. (e-mail: [email protected] ).

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Radiology: Volume 248: Number 3—September 2008 737 REVIEW FOR RESIDENTS: Radiographic Evaluation of Arthritis Jacobson et al

adiography is commonly used in In part 1 of this review (1), common level of physical activity. For example, the evaluation for arthritis. A ba- inflammatory arthritides were dis- one of the first joints that may demon- Rsic algorithm based on radio- cussed. The present review will first fo- strate osteoarthritis is the acromiocla- graphic findings can be followed to cus on degenerative joint , vicular joint, where minimal reach a final and usually correct diagno- which include typical osteoarthritis as formation may be seen in the 4th de- sis (Fig 1). While it is impossible to well as less typical forms of osteoarthri- cade of life and beyond, owing to the include all forms of arthritis with their tis, as may be seen with trauma, crystal stresses that occur at this joint (Fig 4). variations into one scheme, this algo- deposition disease, and hemophilia. Fi- Another site of typical osteoarthritis is rithm can be used as a framework for nally, variations from the algorithm will the first carpometacarpal joint, often evaluation, as it encompasses the most be discussed, including conditions such beginning after the 5th decade of life, frequent radiographic features of com- as juvenile chronic arthritis, inflamma- owing in part to stresses related to con- mon arthritides. tory osteoarthritis, and gouty arthritis. stant use of opposing thumbs or joint The starting point for the algorithm laxity (Fig 5a) (3). Osteoarthritis also is joint space narrowing. The next step characteristically involves the interpha- is to determine if the joint process is Degenerative Joint Disease langeal joints of the after the 4th inflammatory or degenerative. While an A degenerative process is suspected or 5th decades of life; this is related in inflammatory condition is suggested by when joint space narrowing, osteophyte part to degree of use and overuse (Fig and soft-tissue swelling, it is formation, bone sclerosis, and subchon- 5b) (4). the presence of bone erosions that is the dral cysts are seen in the absence of Involvement of the metacarpopha- characteristic finding of inflammation. inflammatory changes (Fig 3). When langeal joints is not infrequently associ- Early erosions will appear as disconti- degenerative joint disease involves a sy- ated with osteoarthritis of the interpha- nuities of the thin, white, subchondral novial articulation, the term osteoar- langeal joints, although this type of in- bone plate, commonly involving the thritis or osteoarthrosis is used. Com- volvement is usually of lesser severity. joint margins (Fig 2). Uniform joint monly, joint space narrowing from osteoar- Unlike in larger joints, joint space nar- space narrowing may also be present. In thritis is associated with osteophyte rowing of the interphalangeal and meta- contrast, a degenerative cause of joint formation, especially in the (2). carpophalangeal joints in osteoarthritis space narrowing is characterized by os- With the and , a weight- may be symmetric. Osteoarthritis of the teophytes; bone sclerosis; subchondral bearing radiograph will improve detec- first metatarsophalangeal joint is com- cysts, or geodes; asymmetric joint space tion of early joint space narrowing. The mon beginning in the 5th decade of life narrowing; and lack of inflammatory finding of marginal osteophytes is typi- (Fig 6) and may be associated with hal- features such as bone erosions (Fig 3). cally used to detect osteoarthritis, while lux . the findings of joint space narrowing, As a person ages, osteoarthritis is bone sclerosis, and subchondral cysts identified involving the knee joints and are used to assess severity (2). As the joints, beginning after the 4th or 5th Essentials joint space narrows, the osteophytes decade of life (4). With regard to the Ⅲ With joint space narrowing, it is become larger, bone sclerosis in- knee joints, joint space narrowing is important to differentiate inflam- creases, and subchondral cyst, or ge- typically asymmetric and most com- matory from degenerative causes. ode, formation may be seen. When os- monly involves the medial femorotibial Ⅲ Typical osteoarthritis involves teoarthritis is identified at , compartment, possibly with the patel- specific joints at a particular pa- it is important to consider the joint in- lofemoral compartment (Fig 7) (5). tient age. volved, the age of the patient, and the Similarly, hip joint space narrowing is Ⅲ Osteoarthritis of an atypical joint, radiographic appearance as the next asymmetric, with superior migration of at an early age, or with an atypi- step in the algorithm. the femoral head more common than cal appearance suggests other less medial migration (Fig 8) (6). Underlying common causes for cartilage de- Typical Osteoarthritis acetabular dysplasia is associated with struction. Osteoarthritis is typically the result of superolateral migration. With early hip Ⅲ An atypical appearance of osteo- articular cartilage damage and wear and osteoarthrosis, a frog leg view will often arthritis can be due to trauma, tear from repetitive microtrauma that crystal deposition disease, neuro- occurs throughout life, although ge- pathic joint, and hemophilia. netic, hereditary, nutritional, meta- Published online Ⅲ Juvenile chronic arthritis and bolic, preexisting articular disease, and 10.1148/radiol.2483062112 gouty arthritis are two types of body habitus factors may contribute in Radiology 2008; 248:737–747 arthritis that have an appearance some cases. This process tends to in- that is different from that of other volve specific joints during specific de- Abbreviation: CPPD ϭ calcium pyrophosphate dihydrate common inflammatory arthrit- cades of a person’s life and depends in ides. part on the patient’s body habitus and Authors stated no financial relationship to disclose.

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reveal a rim or collar of osteophytes that can appear as atypical cally involves the radiocarpal joint of that may be more difficult to visualize on osteoarthritis. Although radiographic the wrist and the second and third an anteroposterior radiograph. findings of CPPD appear somewhat sim- metacarpophalangeal joints of the The sequence of osteoarthritis de- ilar to those of osteoarthritis, they are hands (Fig 10) (6). scribed above can be somewhat vari- atypical because of joint distribution, of the triangular fibrocartilage is com- able. Regardless, when osteoarthritis is extensive subchondral cyst formation, mon, although calcium deposition in the identified, it is important to consider and associated calcium deposition, in- intrinsic carpal (in particular which joint is involved, the severity of cluding chondrocalcinosis. For exam- the lunotriquetral ) and joint the radiographic changes, the distribu- ple, CPPD arthropathy characteristi- capsules is also seen (7). In the knee, tion of osteoarthritis, and the age of the patient to make the distinction between typical and atypical osteoarthritis. Figure 1

Atypical Osteoarthritis If radiographic findings of osteoarthritis are identified but the involved joint is not one commonly affected by osteoar- thritis, the severity of the findings are excessive or unusual, or the age of the patient is unusual, then other less com- mon causes for cartilage damage and osteoarthritis should be considered. Possible causes for this atypical appear- ance of osteoarthritis include trauma, crystal deposition disease, neuropathic joint, and hemophilia. Other possible causes include congenital and develop- mental anomalies, such as dysplasia, that disrupt normal biomechanics. Trauma is the most common cause for atypical osteoarthritis. This may be a sequela of (a) a prior traumatic event that causes cartilage damage and accel- erated osteoarthritis or (b) an unusual Figure 1: Flow chart shows approach to radiographic evaluation of arthritis. Algorithm begins with joint and excessive repetitive , which space narrowing and initially uses differentiation between inflammatory and degenerative findings to reach the may be seen in an athlete or may be final diagnosis. (Reprinted, with permission, from reference 1.) occupational. For example, a remote athletic injury may produce an acceler- ated appearance of knee or hip osteoar- Figure 3 throsis. The clue for diagnosis is the Figure 2 relatively young age of the patient, in- volvement of an atypical joint (Fig 9), marked unilateral asymmetry of lower extremity joint involvement, or unusual severity. Another example of atypical osteoarthritis is due to excess occupa- tional stresses and repetitive injury that is atypical because of patient’s age and involvement of an unusual joint, such as the elbow. Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease may cause chondrocalcinosis and calcifica- Figure 2: Inflammatory arthritis (rheumatoid Figure 3: Osteoarthritis. Posteroanterior radio- arthritis). Posteroanterior radiograph shows dis- graph shows interphalangeal joint space narrow- tion of the synovium, , ten- continuity of bone cortex, representing marginal ing, subchondral sclerosis, and osteophyte forma- dons, and ligaments. In addition, CPPD erosions (arrows). tion (arrows). crystal deposition disease may cause an

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which is the joint most commonly af- Because the finding of chondrocalci- pends on the cause of the neuropathy. fected by CPPD crystal deposition dis- nosis alone is nonspecific (other causes For example, involvement of the mid- ease, disproportionate patellofemoral include hemochromatosis and hyper- is characteristic with mel- degenerative change is characteristic parathyroidism, among others), it is the litus, where findings of joint space nar- (Fig 11) and is associated with chondro- coexistent finding of CPPD arthropathy rowing, bone sclerosis, and osteophytes calcinosis, which affects the fibrocarti- that suggests CPPD crystal deposition are seen (Fig 13). The findings of coex- lage menisci and (8). disease as the cause. It is important to isting arterial calcifications further sug- Calcium deposition in the gastrocne- consider the diagnosis of hemochroma- gest the diagnosis of neuropathic joint, mius tendon origin is another finding tosis when the radiographic findings of and correlation with patient history is seen with CPPD crystal deposition dis- CPPD are identified, as there is substan- important. Other causes of neuropathic ease in the knees (Fig 11) (8). Other tial overlap in their radiographic find- joint include syphilis or tabes dorsalis sites of chondrocalcinosis include the ings. In hemochromatosis, more exten- (involving the lower extremity joints pubic symphysis and the hip labrum (9). sive involvement of the second through and spine) and syrinx (involving bilat- fifth metacarpophalangeal joints has eral shoulder joints). Figure 4 been described, and metacarpal radial Repetitive intraarticular hemorrhage, hooklike or drooping osteophytes are as seen with hemophilia, may cause car- more common (Fig 12) (9). tilage destruction and radiographic fea- Another cause for an atypical ap- tures of atypical osteoarthritis (Fig 14). pearance of osteoarthritis includes an Although bone erosions due to second- early neuropathic joint. In this situation, ary synovial inflammation may be seen, the loss of feedback mechanisms of sen- often the osteophytes, bone sclerosis, sation and proprioception leads to joint and subchondral cysts are most appar- instability and degenerative changes ent. The combination of bone erosions during daily activities. While the char- and osteophyte formation creates an ir- acteristic findings of a neuropathic regular appearance to the articular sur- joint—namely sclerosis, fragmentation, face. When one sees these degenerative and —are obvious in the changes, it is the possible atypical joint Figure 4: Osteoarthritis. Anteroposterior acro- later stages of this process, the early distribution and young age that are in mioclavicular joint radiograph shows joint space changes of a neuropathic joint will often contrast to characteristics of typical os- narrowing, sclerosis, and osteophyte formation appear as atypical osteoarthritis (10). teoarthritis (Fig 15). Other features of involving the acromioclavicular joint (arrow). The primary clue to the diagnosis of an hemophilia include somewhat more early neuropathic joint is the distribu- symmetric joint space loss, the pres- tion of radiographic changes, which de- ence of excessive subchondral cyst for-

Figure 5 Figure 6

Figure 6: Osteoarthritis. Anteroposterior foot Figure 5: Osteoarthritis. (a) Posteroanterior and (b) oblique radiographs show joint space narrowing, radiograph shows first metatarsophalangeal joint sclerosis, and osteophyte formation of (a) first carpometacarpal (arrow) and (b) interphalangeal and metacar- space narrowing, sclerosis, and osteophyte for- pophalangeal joints. mation (arrows).

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Figure 7 Figure 8

Figure 7: Osteoarthritis. Anteroposterior knee radiograph shows joint space narrowing, sclero- sis, and osteophyte formation (arrow) predomi- Figure 8: Osteoarthritis. (a) Anteroposterior and (b) frog-leg hip radiographs show superolateral joint space nately involving the medial compartment. narrowing, sclerosis, subchondral cyst, and osteophyte formation (arrow) with buttressing of the femoral .

Figure 11

Figure 9

Figure 10

Figure 9: Atypical osteoarthritis due to trauma. Mortise radiograph shows joint space nar- rowing, sclerosis, subchondral cyst, and osteo- phyte formation (arrow). mation, and possible dense effusion from hemorrhage. In addition to os- teopenia, epiphyseal overgrowth is seen, due to chronic hyperemia in child- Figure 10: CPPD crystal deposition disease in hood (11). In the knees, elongation or the hand. Posteroanterior radiograph shows sec- Figure 11: CPPD crystal deposition disease in squaring of the and widening of ond and third metacarpophalangeal joint space the knee. (a) Anteroposterior and (b) lateral radio- the intercondylar notch may be seen narrowing, sclerosis, subchondral cyst, and os- graphs shows chondrocalcinosis involving the (Fig 14). Repeated hemorrhage may teophyte formation (arrowheads). Note chondro- menisci (arrowhead) and hyaline cartilage, pre- calcinosis of the triangular fibrocartilage (arrow), dominant patellofemoral joint osteoarthritis produce a large expansile and destruc- and severe osteoarthritis of the first carpometacar- (straight arrow), and calcification of the gastrocne- tive abnormality known as hemophiliac pal joint. mius tendon origin (curved arrow). pseudotumor, most commonly involving

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Figure 12 the femur and osseous pelvis. There is Figure 12: Hemochromatosis. often overlap between the radiographic Posteroanterior hand radiograph features of hemophilia and those of ju- shows osteoarthritis of metacar- venile chronic arthritis; however, knee, pophalangeal joints, with hooklike ankle, and elbow involvement are more osteophytes (arrowheads). common in hemophilia. Correlation with patient history is also important in the diagnosis of hemophilia. Other less common causes for an atypical osteoarthritis appearance in- clude epiphyseal dysplasia, ochronosis,

Figure 14

Figure 13

Figure 13: Neuropathic joint. (a) Anteroposterior and (b) lateral foot radiographs show joint space narrowing, sclerosis, subchondral cyst, and osteophyte formation (arrows). Note plantar navicular tilt and pes planus. Figure 14: Hemophilia. Anteroposterior knee radiograph in 20-year-old man shows joint space narrowing that is somewhat symmetric, sclerosis, subchondral cyst, and osteophyte formation (ar- rowheads), with widening of intercondylar notch (arrows). Note flattening of distal femoral condyle surfaces.

Figure 15

Figure 15: Hemophilia. Lateral foot radiograph shows joint space narrowing, sclerosis, and os- teophyte formation (arrows).

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Figure 16

Figure 16: Juvenile chronic arthritis: Still disease. (a) Posteroanterior hand radiograph shows joint space narrowing and inflammatory changes at several joints, with epiphyseal overgrowth and other growth disturbances due to early epiphyseal fusion. (b) Bilateral anteroposterior knee radiographs show uniform joint space narrowing (arrows), osteopenia, and epiphyseal overgrowth with widening of the intercondylar notch (arrowheads). Note secondary osteoarthritis.

Figure 17 Figure 18 Figure 17: Early osteoarthritis. Posteroanterior radiograph of the fingers shows proximal and distal interphalangeal joint space nar- rowing with minimal subchondral sclerosis and relatively few osteo- phytes.

Figure 18: . Anteroposte- rior knee radiograph shows diffuse uniform joint space narrowing.

romegaly, other radiographic findings include spade-shaped distal phalanges, and . With epiphyseal dys- nosis, a term that describes abnormal initial widening of joint spaces, in- plasia, multiple joints will be involved, pigmentation in the disorder alkap- creased heel pad thickness, posterior with irregular articular surfaces and ab- tonuria, is associated with characteris- vertebral scalloping, and mandibular normal shape of the epiphyses. Ochro- tic multiple disk calcifications. With ac- and sinus enlargement.

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Variations to Algorithm joint space narrowing is seen. How- villonodular and synovial os- ever, there are several conditions that teochondromatosis may cause second- In the presented algorithm as an ap- do not precisely fit into the algorithm; ary osteoarthritis with pressure ero- proach to the diagnosis of arthritis on these include juvenile chronic arthri- sions, especially if the condition is radiographs, joint space narrowing tis, inflammatory arthritis with sec- was used as an arbitrary starting ondary osteoarthritis, erosive or in- point, primarily to emphasize the im- flammatory osteoarthritis, , and Figure 21 portant distinction between inflamma- systemic lupus erythematosus. Al- tory and degenerative arthritis when though not discussed here, pigmented

Figure 19

Figure 19: Rheumatoid arthritis with secondary early osteoarthritis. Posteroanterior hand radiograph shows uniform joint space loss of each metacarpophalangeal joint. Note small erosions (arrowheads) and small osteophytes (arrows). Figure 21: Inflammatory or erosive osteoar- thritis. Posteroanterior finger radiograph shows joint space narrowing, sclerosis, and osteophyte formation of distal interphalangeal joint with prominent central erosion (arrow).

Figure 20

Figure 22

Figure 20: Rheumatoid arthritis with secondary osteoarthritis. Anteroposterior pelvis radiograph shows Figure 22: Gout. Posteroanterior hand radio- joint space narrowing of each hip joint. Note small erosions (arrowheads) and osteophytes (arrows). Sacroil- graph shows sclerotic erosion (arrow), with soft- iac joint involvement is also present with narrowing, irregularity, and sclerosis. tissue swelling and wide joint space.

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Figure 23 longstanding and involves a joint of small capacity. Figure 23: Gout. Anteroposte- rior foot radiograph shows multi- Juvenile Chronic Arthritis ple punched-out sclerotic ero- The category of juvenile chronic arthri- sions (arrows), with soft-tissue tis (or juvenile rheumatoid arthritis) swelling. consists of Still disease (or seronegative chronic arthritis), juvenile-onset adult- type rheumatoid arthritis, juvenile-on- set , psoriatic ar- thritis, arthritis of inflammatory bowel disease, other seronegative spondyloar- thropathies, and miscellaneous arthritis (12). This discussion will primarily fo- cus on Still disease because it is the most common type, accounting for 70% of cases of juvenile chronic arthritis. Still disease has three subtypes: pauciarticular, polyarticular, and sys- temic. The most common is pauciarticu- lar disease (60% of cases), which in- volves the larger peripheral joints such as the knees, , elbow, and wrists and affecting one to four joints (13). Another subtype includes polyarticular disease (20% of cases), commonly af- fecting bilaterally the hands, wrists, knees, ankles, and feet (Fig 16). A third subtype, systemic disease (20% of cases) may or may not be associated with arthritis but is characterized by fe- Figure 24 Figure 25 ver, rash, lymphadenopathy, hepato- splenomegaly, pericarditis, myocardi- tis, and anemia. Common radiographic features of arthritis in Still disease include soft-tis- sue swelling and osteopenia; however, there are several distinct differences when compared with adult rheumatoid arthritis. These differences include de- layed joint space narrowing and erosive changes, possible periostitis, growth disturbances, and, later, joint fusion (Fig 16). The presence of periostitis is due to the relatively loosely adherent periosteum in children compared with Figure 24: Gout. Posteroanterior finger radio- that in adults. Growth disturbances in- Figure 25: Gout. Anteroposterior knee radio- graph shows substantial destruction centered at clude osseous overgrowth of the epiph- graph shows punched-out sclerotic erosion (ar- distal interphalangeal joint (arrow). yses due to chronic hyperemia and bone row) and soft-tissue swelling (arrowheads). undergrowth due to premature growth plate fusion. phytes are present in the setting of joint narrowing, and secondary signs of in- Joint Space Narrowing without Erosions space narrowing. In the absence of ei- flammation to arrive at the correct diag- or Osteophytes ther erosions or osteophytes, one must nosis. For example, if joint space nar- In the presented algorithm, the first rely on the distribution of joint involve- rowing involves the distal interphalan- step is to determine if erosions or osteo- ment, the characteristics of joint space geal joints in a 60-year-old patient

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without periarticular osteopenia or soft- is involvement of a joint not typically af- thritis in that it commonly involves the tissue swelling, then early osteoarthritis is fected by osteoarthritis, such as the meta- interphalangeal joints of the hand, and likely (Fig 17). If joint space narrowing carpophalangeal joints. When osteo- osteophytes are quite obvious. The addi- involves the knee but symmetrically in- phytes are identified in this situation, one tional characteristic feature is a central volves the joint with periarticular os- may initially consider causes for atypical erosion that produces two convexities of teopenia, then an inflammatory arthritis osteoarthritis. However, other findings of the joint surface, likened to the wings of a such as rheumatoid arthritis is suggested underlying inflammatory arthritis are of- seagull (Fig 21). This central erosion (Fig 18). If joint space narrowing involves ten present, such as symmetric joint should not be confused with the marginal a single joint with soft-tissue swelling and space loss and evidence for erosions (Fig erosions of rheumatoid arthritis. Prolifer- periarticular osteopenia, then early septic 19). Healed erosions may demonstrate a ative synovitis is present, and consequent joint must be considered. smooth or sclerotic margin. The charac- inflammation of the involved joint can re- teristic distribution of joint abnormalities sult in (14). Inflammatory Arthritis with Secondary with inflammatory arthritis may also be Osteoarthritis seen, such as bilateral, symmetric, prox- Gout A patient with chronic and possibly imal involvement of the extremities or bi- Gouty arthritis is caused by monosodium treated inflammatory arthritis may de- lateral fifth metatarsophalangeal joint in- urate crystals, which display strong nega- velop secondary changes of osteoarthri- volvement, as seen in rheumatoid arthri- tive birefringence at polarized light exam- tis. Assessment using the presented algo- tis. The finding of symmetric joint space ination. The radiographic features of gout rithm becomes difficult in this situation, loss with osteophytes also suggests in- do not fit into the presented algorithm, in because a combination of erosions and flammatory arthritis with secondary os- that joint space narrowing occurs late osteophytes may be present involving the teoarthritis (Fig 20). (Fig 22). In addition, the erosions are same joint. There are several radio- characteristic in that they are frequently graphic features that indicate inflamma- Inflammatory or Erosive Osteoarthritis near a joint but not specifically marginal tory arthritis with secondary osteoarthri- Inflammatory or erosive osteoarthritis and they have sclerotic margins that pro- tis. Many times, the most obvious feature can be viewed as a variation of osteoar- duce a punched-out appearance (Fig 23) (15). Periarticular osteopenia is also ab- sent. Another clue to the diagnosis of gout Figure 26 is the presence of marked soft-tissue swelling from gouty tophus deposition. Calcification of such tophi is uncommon in the absence of coexisting renal disease. Marked bone destruction occurs in se- vere cases, with substantial soft-tissue swelling (Fig 24). The most common site for gout involvement is the first metatar- sophalangeal joint of the foot. Other joints, such as the interphalangeal joints of the hands and feet are not uncommon, although gout can occur in other joints as well (Fig 25). Another characteristic site for gouty erosions are the tarsal . Rounded lucencies about a joint may rep- resent erosions or intraosseous tophi. Gout may also produce soft-tissue swell- ing from , such as olecranon bur- sitis. Because the radiographic findings may at times be confusing and appear quite unusual, it may be helpful to re- member, “When in doubt, think gout.”

Systemic Lupus Erythematosus The radiographic features of systemic lupus erythematosus (SLE) may not be obvious, in that joint space narrowing Figure 26: Systemic lupus erythematosus. (a) Posteroanterior and (b) oblique hand radiographs show and erosions are not frequent. The most reducible subluxation and swan-neck deformities at several joints (arrowheads). common finding with SLE is the pres-

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ence of reducible metacarpophalangeal matory conditions. Radiology 2008;248(2): crystal deposition disease. Radiology 1995; joint subluxation without erosions; such 378–389. 196:547–550. findings are often identified only on 2. Kijowski R, Blankenbaker DG, Stanton PT, 8. Yang BY, Sartoris DJ, Resnick D, Clopton P. oblique radiographs and are absent on Fine JP, De Smet AA. Radiographic findings Calcium pyrophosphate dihydrate crystal posteroanterior views (Fig 26). Periartic- of osteoarthritis versus arthroscopic findings deposition disease: frequency of tendon cal- ular osteopenia and soft-tissue swelling of articular cartilage degeneration in the cification about the knee. J Rheumatol 1996; tibiofemoral joint. Radiology 2006;239:818– 23:883–888. may be seen. 824. 9. Steinbach LS, Resnick D. Calcium pyrophos- 3. Sonne-Holm S, Jacobsen S. Osteoarthritis of phate dihydrate crystal deposition disease Conclusion the first carpometacarpal joint: a study of revisited. Radiology 1996;200:1–9. radiology and clinical epidemiology—results Once joint space narrowing is recog- 10. Aliabadi P, Nikpoor N, Alparslan L. Imaging from the Copenhagen Osteoarthritis Study. nized, the presence of erosions suggests of . Semin Musculo- Osteoarthritis Cartilage 2006;14:496–500. an inflammatory arthritis, while the skelet Radiol 2003;7:217–225. 4. Arden N, Nevitt MC. Osteoarthritis: epide- presence of osteophytes indicates a de- 11. Kerr R. Imaging of musculoskeletal compli- miology. Best Pract Res Clin Rheumatol generative arthritis. When osteoarthri- cations of hemophilia. Semin Musculoskelet 2006;20:3–25. tis is suggested, it is important to take Radiol 2003;7:127–136. 5. Preidler KW, Resnick D. Imaging of osteoar- into account the distribution of joint in- 12. Resnick D. Diagnosis of bone and joint disor- thritis. Radiol Clin North Am 1996;34:259– volvement, the severity of disease, and ders. 3rd ed. Philadelphia, Pa: Saunders, 271, x. age of the patient to consider less com- 1995;972. 6. Bencardino JT, Hassankhani A. Calcium py- mon causes of cartilage damage. One 13. Azouz EM. Arthritis in children: conven- rophosphate dihydrate crystal deposition must also be familiar with the arthriti- tional and advanced imaging. Semin Muscu- disease. Semin Musculoskelet Radiol 2003;7: des that do not cleanly fit into the algo- loskelet Radiol 2003;7:95–102. 175–185. rithm, such as gouty arthritis. 14. Greenspan A. Erosive osteoarthritis. Semin 7. Yang BY, Sartoris DJ, Djukic S, Resnick D, Musculoskelet Radiol 2003;7:155–159. References Clopton P. Distribution of calcification in the 1. Jacobson JA, Girish G, Jiang Y, Resnick D. triangular fibrocartilage region in 181 pa- 15. Gentili A. Advanced imaging of gout. Semin Radiographic evaluation of arthritis: inflam- tients with calcium pyrophosphate dihydrate Musculoskelet Radiol 2003;7:165–174.

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