Radiografi Assessment

JULY 15, 2001 / VOLUME 64, NUMBER 2 www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 279

asymmetric joint cartilage loss, subchon-dral sclerosis (increased bone density),marginal osteophytes and subchondralcysts is the same in younger and olderadults.1 Primary osteoarthritis is themost common form and is usually seenin weight-bearing joints that have under-gone abnormal stresses (e.g., from obe-sity or overuse).13-16 The precise etiologyof osteoarthritis is unknown, but bio-chemical and biomechanical factors arelikely to be important in the etiology andpathogenesis.1 Biomechanical factorsassociated with osteoarthritis includeobesity, muscle weakness and neurologicdysfunction. In primary osteoarthritis,the common sites of involvement in-clude the hands, hips, knees and feet13,17

(Figure 1). Secondary osteoarthritis is acomplication of other arthropathies orsecondary to trauma. Gout, rheumatoidarthritis and calcium pyrophosphatedeposition disease are correlated with theonset of secondary osteoarthritis.

Clinical ManifestationsOsteoarthritis is primarily assessed

through a history and physical examina-tion. The cardinal symptom of osteo-arthritis is pain that worsens during

Worldwide, osteoar-thritis is the mostcommon form ofarthritis.1 It is amongthe most prevalent

and disabling chronic conditions in theUnited States.2 The prevalence increaseswith age, and by the age of 65, approxi-mately 80 percent of the U.S. population isaffected.3-5 The functional impairmentssecondary to osteoarthritis also occurmore frequently in older adults. Pain andlimitation of motion restrict the indepen-dence of older adults by impairing theirperformance of activities of daily living.6,7

As a result, dependence is especially com-mon for ambulation, stair climbing andother lower-extremity functions.8

Costs directly attributable to osteo-arthritis are considerable in the UnitedStates, with work loss accounting for morethan one half of the estimated annualexpense of $155 billion (in 1994 dollars).9

Another major expense is the number ofjoint arthroplasties performed in patientsin the advanced stage of the disease.10-12

Etiology and Risk FactorsAlthough osteoarthritis is especially

common in older adults, its pathology of

Osteoarthritis is one of the most prevalent and disabling chronic conditions affecting olderadults and a significant public health problem among adults of working age. As the bulkof the U.S. population ages, the prevalence of osteoarthritis is expected to rise. Althoughthe incidence of osteoarthritis increases with age, the condition is not a normal part of theaging process. More severe symptoms tend to occur in the radiographically moreadvanced stage of the disease; however, considerable discrepancy may exist betweensymptoms and the radiographic stage. Roentgenograms of involved joints may be usefulin confirming the diagnosis of osteoarthritis, assessing the severity of the disease, reas-suring the patient and excluding other pathologic conditions. The diagnosis ofosteoarthritis is based primarily on the history and physical examination, but radiographicfindings, including asymmetric joint space narrowing, subchondral sclerosis, osteophyteformation, subluxation and distribution patterns of osteoarthritic changes, can be helpfulwhen the diagnosis is in question. (Am Fam Physician 2001;64:279-86.)

Radiographic Assessment of OsteoarthritisDANIEL L. SWAGERTY, JR., M.D., M.P.H., and DEBORAH HELLINGER, D.O.University of Kansas Medical Center, Kansas City, Kansas

COVER ARTICLERADIOLOGIC DECISION-MAKING

Coordinators of this series areMark Meyer, M.D., at the Uni-versity of Kansas School ofMedicine, Kansas City, Kan., andWalter Forred, M.D., Universityof Missouri-Kansas City Schoolof Medicine, Kansas City, Mo.

The editors of AFP welcome thesubmission of manuscripts forthe Radiologic Decision-Makingseries. Send submissions to JaySiwek, M.D., following theguidelines provided in Informa-tion for Authors.

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activity and improves with rest. Instability ofjoints is a common finding, especially of theknees and first carpometacarpal joints. Earlymorning stiffness is common and characteris-tically lasts one hour or more, depending onseverity. Stiffness may occur following periodsof inactivity. Musculoskeletal examinationmay reveal swelling, deformities, bony over-growth (referred to as Heberdens nodes wheninvolving the distal interphalangeal joints andBouchards nodes when involving the proxi-mal interphalangeal joints of the hands),crepitus and limitation of motion. Musclespasm, and tendon and capsular contracturesalso may be observed, depending on the siteand duration of involvement.

Pain caused by osteoarthritis may develop inany part of the involved joint or tissue. Typi-cally, pain progresses gradually over time andincreases with weight bearing. A patient withprimary osteoarthritis seldom has any attribut-able systemic symptoms (e.g., fatigue or gener-alized weakness). The progression of symp-toms in patients with osteoarthritis is fairlyconsistent. Mild discomfort first occurs in ajoint when it is in high use, but the pain isrelieved by rest. Symptoms progress to constantpain on use of the affected joint and finally,with more advanced joint involvement, painoccurs at rest and at night. Generally, little ten-derness occurs outside the joint, but pain canoccur with extremes in range of motion. Limi-tation of motion is often prominent.

Other pathologic processes should not beoverlooked when evaluating patients withpainful joints. Osteoarthritis can often be dif-ferentiated from other processes by the historyand physical examination (Table 1),6 as well aslaboratory studies and radiographic findings.

Cervical and lumbar pain may result fromarthritis of the apophyseal joints, osteophyteformation, pressure on surrounding tissueand muscle spasm. Nerve root impingementcauses radicular symptoms. Cervical and lum-bar stenosis develop when facet joints hyper-trophy, the disc degenerates and bulges, andthe ligamentum flavum becomes lax and

280 AMERICAN FAMILY PHYSICIAN www.aafp.org/afp VOLUME 64, NUMBER 2 / JULY 15, 2001

FIGURE 1. Common sites of involvement in primary osteoarthritis.

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The Authors

DANIEL L. SWAGERTY, JR., M.D., M.P.H., is associate professor in the Departments ofFamily Medicine and Internal Medicine, and associate director (Education) of the Cen-ter of Aging at the University of Kansas School of Medicine, Kansas City, Kan. Hereceived his medical degree and completed a family practice residency and a fellow-ship in geriatric medicine at the University of Kansas School of Medicine.

DEBORAH HELLINGER, D.O., is assistant professor and chief of musculoskeletal radiol-ogy in the Department of Radiology at the University of Kansas School of Medicine.She received her medical degree from the University of Health SciencesCollege ofOsteopathic Medicine, Kansas City, Mo. Dr. Hellinger completed a residency in diag-nostic radiology at Tulsa Regional Medical CenterOSU.

Address correspondence to Daniel L. Swagerty, Jr., M.D., M.P.H., Department of FamilyMedicine, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS66160-7370 (e-mail: [email protected]). Reprints are not available from the authors.

widens. The spinal canal narrows and com-presses the cord. Posterior vertebral osteo-phytes may also contribute to cord compres-sion. Patients may develop lumbar pain,extremity weakness, gait ataxia or abnormalneurologic findings. Pseudoclaudication is acharacteristic feature of lumbar stenosis and isdescribed as pain in the buttocks or thighsoccurring with ambulation and relieved byrest. Hip pain is usually felt in the groin or themedial aspects of the thigh; however, it can bereferred to the knee or buttocks and may bemisdiagnosed as lumbar stenosis.

Radiographic FindingsThe diagnosis of osteoarthritis is often sug-

gested on physical examination. Plain film

radiographs are usually adequate for initialradiographic evaluation to confirm the diag-nosis or assess the severity of disease if surgi-cal intervention is being considered. Twoviews of the involved joint should beobtained, with the possible exception of thesacroiliac joints and the pelvis. The two viewsshould be obtained in orthogonal planes to

Osteoarthritis


The radiographic hallmarks of primary osteoarthritis includenonuniform joint space loss, osteophyte formation, cyst formation and subchondral sclerosis; however, in earlyosteoarthritis, minimal nonuniform joint space narrowingmay be the only radiographic finding.

TABLE 1

Clinical Findings Differentiating Osteoarthritis from Other Causes of Painful Joints

Condition History Physical

Primary Gradual progression of pain Bony enlargement of joints: DIP, PIP, first osteoarthritis Morning stiffness of one hour or more carpometacarpal, hips, knees, feet

Pain increasing with weight bearing Usually no wrist, elbow, ankle or involvement Night pain of MCP No systemic symptoms

Bursitis / Pain increased with movement No joint abnormality or swellingtendonitis Pain worse at night Certain passive maneuvers produce pain

No systemic symptoms Pain on resisted active range of motion of Pain on some maneuvers, not others affected muscles

Mechanical Recurrent joint swelling Pain and limitation at certain points of flexion intra-articular Joint locks or extensionconditions Joint gives way Pain on combined rotation and extension of

Intermittent pain with pain-free intervals the knee

Rheumatoid Often insidious onset Involvement of MCP, wrist, elbows, anklesarthritis Morning stiffness of one hour or more Synovial thickening

Systemic symptoms Classic deformities:Associated symptoms (e.g., Raynauds Swan neck

syndrome, skin rash) BoutonniereUlnar deviation

Loss of range of motion of wrist, elbows

DIP = distal interphalangeal joint; PIP = posterior interphalangeal joint; MCP = metacarpal phalangeal joint.

Information from Bagge E, Bjelle A, Eden S, Svanberg A. A longitudinal study of the occurrence of joint com-plaints in elderly people. Age Ageing 1992;21:160-7.

one another (i.e., anteroposterior [AP] andlateral). Additional views of weight-bearingjoints (knees, hips) may be necessary. Corre-lation of radiographic evidence of degenera-tive joint changes and symptoms described bypatients vary by joint. Abnormalities detectedin the knees correlate with pain in 85 percent

of patients, the fingers and carpometacarpaljoints in approximately 80 percent and thehips in 75 percent.6

The radiographic hallmarks of primaryosteoarthritis include nonuniform joint spaceloss, osteophyte formation, cyst formationand subchondral sclerosis. The initial radi-ographs may not show all of the findings. Atfirst, only minimal, nonuniform joint spacenarrowing may be present. The involved jointspaces have an asymmetric distribution. Asthe disease progresses, subluxations mayoccur and osteophytes may form. Subchon-dral cystic changes can occur. These cysts mayor may not communicate with the joint space,can occur before cartilage loss and have a scle-rotic border. Subchondral sclerosis or sub-chondral bone formation occurs as cartilageloss increases and appears as an area ofincreased density on the radiograph. In theadvanced stage of the disease, a collapse of thejoint may occur; however, ankylosis does notusually occur in patients with primaryosteoarthritis.

KNEE

When evaluating patients with osteoarthri-tis of the knee, AP and lateral radiographsallow an adequate evaluation of the medialand lateral joint spaces. To adequately assessthe joint space, the AP view should be obtainedwith the patient in a standing position. The lat-eral view also allows evaluation of thepatellofemoral joint; however, an additionalview, known as the sunrise view, can offer evenmore information about this joint space.

Radiographic findings in patients withosteoarthritis include medial tibiofemoraland patellofemoral joint space narrowing, aswell as subchondral new bone formation.18,19

Next, lateral subluxation of the tibia occurs,and osteophyte formation is most prominentmedially. Lateral joint space narrowing canalso occur but not as prominently as themedial narrowing (Figures 2a and 2b). Carti-lage is lost, and subchondral bone formationoccurs. Marked osteophyte formation also


FIGURE 2. Osteoarthritis of the knees. (A) Anteroposterior view of theleft knee of patient 1 shows medial joint space narrowing (arrow). (B) Lateral view of the left knee shows sclerosis with marked osteo-phyte formation (arrows). The osteophytes are best seen in this view.(C) Patient 2 has marked osteoarthritic changes with medial jointspace narrowing (white arrow) causing a varus deformity of the kneeand collapse of the joint space with destruction of the medial cartilageand the subchondral cortex (open arrowheads). (D) Subchondral cysts(solid arrowhead) are noted.

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occurs (Figures 2c and 2d), and osteophytesare seen anteriorly and medially at the distalfemur and proximal tibia, and posteriorly atthe patella and the tibia.

HAND

The hand can be evaluated with AP andoblique views; however, more detail is evidentwith magnified views of the entire hand or ofa specific joint. Magnification views are par-ticularly helpful in evaluating the soft tissuesand the fine detail of specific bone. The mostcommonly involved joints in the hand andwrist are the first carpometacarpal joints, thetrapezionavicular joint and the proximalinterphalangeal and distal interphalangealjoints. Joint space loss is nonuniform andasymmetric (Figure 3). Erosive changes arenot seen in primary osteoarthritis. In caseswhere an underlying disease process (such asan inflammatory arthropathy) is present, sec-ondary osteoarthritis can occur. Post-menopausal women may have a variant ofosteoarthritis, known as erosive arthritis.20

Only erosive osteoarthritis has erosions andankylosis. The distribution in the hands andthe feet is similar to that of osteoarthritis.

HIPS AND PELVIS

AP views of the pelvis can be used to assessarthritic changes in the hips as well as thesacroiliac joints (Figure 4). Changes associatedwith the hip include superolateral joint spacenarrowing with subchondral sclerosis. Thesuperolateral portion of the joint is theweight-bearing portion. Cystic changes canoccur, and the femoral head can appear to beirregular.

The true synovial joint space of thesacroiliac joint occurs anteriorly and inferi-orly. In osteoarthritis, bridging osteophytesdevelop and extend from the ilium to thesacrum. Sclerotic changes are also noted, butankylosis or erosions do not usually developas they do in spondyloarthropathies such asankylosing spondylitis, psoriasis or Reiterssyndrome.

SPINE

Lateral and AP lumbar spine radiographsare adequate to allow identification of osteo-arthritic changes in the apophyseal joints.Decreased joint space is noted between thesuperior and inferior facets. Sclerosis and cystformation occur in osteoarthritis of the spine.Neural foraminal narrowing may result fromthe osteophyte formation. These changes canbe seen on computed tomographic (CT)

Osteoarthritis


Postmenopausal women may have a variant of osteoarthritisknown as erosive arthritis; the distribution in the hands andfeet is similar to that of osteoarthritis.

FIGURE 3. Oblique (left) and AP (right) views of the hand demonstratedecreased joint space and subchondral sclerosis at the first carpalmetacarpal joint (white arrows). There is old joint space loss at the PIPand DIP joints with relative sparing of the MCP joints. Osteophyte for-mation with soft tissue swelling and subchondral sclerosis is noted atthe 2nd and 3rd DIP joints compatible with Heberdens nodes (openarrows). (PIP = proximal interphalangeal; DIP = distal interphalangeal;MCP = metacarpal phalangeal)

scans. Figure 5 illustrates neural foraminalnarrowing caused by facet osteophyte forma-tion. Similar changes are seen in the cervicalspine. Primary osteoarthritic changes are notcommonly seen in the thoracic spine. Osteo-arthritis of the spine is often associated withdegenerative joint disease.

FOOT

In the foot, AP and lateral radiographs areadequate to assess osteoarthritic changes, butoblique and magnified views may be helpfulif a detailed view of a joint space is required.The most common joint involved is the firstmetatarsophalangeal joint. Again, subchon-dral sclerosis, osteophyte formation and cys-tic changes are common. Lateral subluxationof the great toe results in a hallux valgusdeformity. Osteoarthritic changes elsewherein the foot, such as the subtalar joint, are usu-ally caused by altered mechanics from con-genital or acquired abnormalities (e.g., pesplanus, fusion of two bones) or are secondaryto another underlying arthropathy (e.g., pso-riasis, Reiters syndrome).

Disease ProgressionFollow-up radiographs are unnecessary in

evaluating progression of the disease but canbe helpful, especially if surgical intervention isplanned or a fracture is suspected. Imagingbeyond plain films is not warranted for rou-tine follow-up; however, in the appropriateclinical situation, additional types of imagingmay be useful. Nuclear medicine bone scanscan show radiopharmaceutical localizationbut are nonspecific in areas of increased boneproduction. Tomography is only helpful if anoccult fracture is suspected, but routinetomography is not indicated to monitorosteoarthritis.

While a CT scan is not indicated for an ini-tial evaluation or as routine follow-up, it maybe helpful in the evaluation of the lumbarspine to check facet hypertrophy in the man-agement of low back pain and spinal stenosis.This evaluation can also be accomplished with


FIGURE 4. Serial anteroposterior views of the pelvis demonstrating pro-gressive osteoarthritic changes of the hips. (Top) The first film,obtained in 1997, demonstrates bilateral, superolateral joint space nar-rowing (arrows) at the hips that is worse on the left side. Subchondralsclerosis (solid arrowhead) and cyst (open arrowhead) formation arealso noted on the left side. (Center) The March 1999 film shows theinterval increase in joint space loss (arrow) and sclerosis (solid arrow-head). (Bottom) A third film, obtained in December 1999, reveals lefthip arthroplasty (arrow).

magnetic resonance imaging (MRI) studies,although the osseous detail is better appreci-ated with CT scan. MRI also can be helpful inevaluating cartilage loss but often is unneces-sary because plain films provide adequateinformation. MRI studies should not be rou-tinely performed in diagnosing osteoarthritisunless additional pathology is suspected (e.g.,post-traumatic injuries, malignancy, neuralforaminal impingement, infectious process).Ultrasonography can be helpful in diagnosingcystic changes in the soft tissue about the

joints but is not useful in the initial diagnosisof osteoarthritis.

Differential considerations are based, inpart, on which joint is being examined. Ingeneral, the major differential diagnosisincludes rheumatoid arthritis, psoriaticarthritis, calcium pyrophosphate depositiondisease, ankylosing spondylitis and diffuseidiopathic skeletal hyperostosis (Table 2).20

The authors indicate that they do not have any con-

flicts of interest. Sources of funding: none reported.

Osteoarthritis


FIGURE 5. (Left) Axial computed tomographic images of the lumbar spine at the level of L4-5demonstrating hypertrophy of the facets (solid arrowhead) with sclerosis (black arrow). (Right)Facet hypertrophy, with or without a disc bulge, can cause stenosis of the neural foramina (openarrowhead) and nerve root impingement. Subchondral cyst formation (white arrow) is evident.

TABLE 2

Radiographic Findings Differentiating Osteoarthritis from Other Causes of Painful Joints

Condition Bone density Erosions Cysts Joint space loss Distribution Bone production

Osteoarthritis Normal overall No, unless Yes, Nonuniform Unilateral and/or Yes; osteophytes; erosive subchondral bilateral; asymmetric subchondral sclerosisosteoarthritis

Rheumatoid Decreased Yes Yes, synovial Uniform Bilateral; symmetric Noarthritis

Psoriatic Normal Yes No Yes Bilateral; asymmetric Yesarthritis

CPPD Normal No Yes Uniform Bilateral Yes; osteophytes; chondrocalcinosis; subchondral

Ankylosing Earlynormal Yes No Yes Bilateral; symmetric Yesspondylitis Latedecreased

DISH Normal No No No Sporadic Flowing osteophytes; ossification oftendon, ligaments

CPPD = calcium pyrophosphate deposition disease; DISH = diffuse idiopathic skeletal hyperostosis.

Information from Brower AC. Arthritis in black and white. Philadelphia: Saunders, 1998:23-57.

Osteoarthritis

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12. Madhok R, Lewallen DG, Wallrichs SL, Ilstrup DM,Kurland RL, Melton LJ 3d. Trends in the utilizationof primary total hip arthroplasty, 1969 through1990: a population-based study in Olmsted County,Minnesota. Mayo Clin Proc 1993;68:11-8.

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17. Brander VA, Kaelin DL, Oh TH, Lim PA. Rehabilita-tion of orthopedic and rheumatologic disorders. 3.Degenerative joint disease. Arch Phys Med Rehabil2000;81(3 suppl 1):S67-72.

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19. Petersson IF, Boegard T, Saxne T, Silman AJ, Svens-son B. Radiographic osteoarthritis of the knee clas-sified by the Ahlback and Kellgren & Lawrence sys-tems for the tibiofemoral joint in people aged35-54 years with chronic knee pain. Ann RheumDis 1997;56:493-6.

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