INTERVENTIONAL PROCEDURES IN MUSCULOSKELETAL RADIOLOGY I1 0033-8389198 $8.00 + .OO

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY

Piran Aliabadi, MD, Nancy D. Baker, MD, and Diego Jaramillo, MD

The value of contrast arthrography of the hip joint is well-documented in this century. Evaluation of the unossified structures of the hip in developmental dysplasia of the hip (DDH), Legg-Calve-Perthes (LCP) disease, and complex congenital malformations, such as proximal femoral focal deficiency was a major stimulus to the development of this imaging modality. In these conditions, arthrography demonstrates the femoroaceta- bular relationships in various positions. This information is not currently provided by static MR imaging, where the hips are studied in a neutral position, nor with CT or sonogra-

In 1939 Severin,46 working at the Orthopae- dic Clinic in Stockholm, was one of the first to report in the English-language literature on the usefulness of contrast arthrography in children’s hips. He was influenced by earlier investigators who, during the previous de- cade, reported this new technique in the French- and German-language literature. Flu- oroscopic monitoring of pediatric hip arthrog- raphy, as it became available, was advocated by OzonofPO in 1973. Notwithstanding the successful application of contrast arthrogra- phy in children, it was not until 1974 that

phy.21, 2628.41, 46

Razzano et a143 presented a method for adult hip arthrography.

Unexplained hip pain in adults, accompa- nied by normal radiographs, stimulated fur- ther expansion of arthrographic techniques, such as aspiration arthrography and anesthe- tic arthrography (hip block). Additional im- aging, such as CT arthrography, MR imaging arthrography, and radionuclide scintigraphy, soon followed. By the 1970s, adult hip arthrography included preliminary aspiration of the hip joint. Razzano et a143 reported a series of 66 patients with diagnoses such as infection, rheumatoid arthritis, osteoarthritis, neuropathy, dysplasia, avascular necrosis, and implant 10osening.~~

In 1974, subtraction arthrography, adapted from neurovascular radiology, was imple- mented for diagnosis of loose cemented joint replacements, allowing improved visualiza- tion of opaque contrast in barium-impreg- nated cement-bone interfaces and in metal- bone interfa~es.4~ The efficacy of arthrography in diagnosing synovial chondromatosis, adhe- sive capsulitis, and transient osteopenia was introduced in 1977. The need to exclude infec- tion by performing aspiration prior to arthrography in adhesive capsulitis and tran-

From the Department of Radiology, Harvard Medical School (PA, NDB, DJ); the Department of Radiology, Brigham and Women’s Hospital (PA, NDB), Boston; and the Department of Radiology, Children’s Hospital (DJ), Boston, Massachusetts

RADIOLOGIC CLINICS OF NORTH AMERICA

VOLUME 36 * NUMBER 4 * JULY 1998 673

674 ALIABADI et a1

sient osteopenia was empha~ized .~~ Aspira- tion prior to total hip revision was studied in a large series by O’Neill and and Barrack and H a r r i ~ . ~

The years from 1991 to 1994 saw the con- cept of the diagnostic usefulness of intra-ar- ticular bupivacaine (hip block) in distinguish- ing radicular pain (either from the spine to the hip or from the hip or spine to the knee) from pain arising within the hip joint or from the joint capsule.s, 30 Arthrography for labral pathology, in children as well as adults, is currently evaluated by CT or MR imaging. This article reviews hip arthrography, hip as- piration, hip block, and iliopsoas bursogra- phy. MR imaging and CT arthrography are not discussed.

TECHNIQUE

In 1973, OzonofP summarized the various needle approaches to the pediatric hip joint that had been used, including initial (unre- ported) blind methods that, with the advent of fluoroscopy, were promptly replaced by 90- degree direct-anterior, angled-anterior, supe- rior, and inferior-angled approaches at- tempted under fluoroscopic guidance. These techniques were apparently adapted to adult hip arthrography with few written acknowl- edgements. Much later, a lateral technique was presented.29

With the 90-degree direct-anterior ap- proach, the needle enters the joint immedi- ately below the acetabular rim, lateral to the fovea. A complication of this method is inad- vertent injection of the labrum with contrast. Therefore, a more lateral 90-degree direct-an- terior approach was substituted, with the nee- dle pointing to the lateral metaphysis, thus avoiding not only the labrum but also the round ligament and articular cartilage.

A short-bevel needle was recommended for these 90-degree direct-anterior injections to avoid extravasation of contrast outside the joint capsule while the tip of the needle is within the joint cavity. Use of a stylet was recommended to prevent the possible intra- articular placement of skin fragments and to prevent plugging of the needle during aspira- tion.

Various needle angles were subsequently described to minimize some of these compli- cations. One such method was anterior place- ment below the capital femoral epiphysis, with 15-degree medial and 15-degree superior angulation of the needle to avoid injecting or traumatizing the physis. This is similar to an anterolateral approach to the lateral aspect of the femoral neck, above the zona orbicu-

Hip arthrography in adults is currently a routine outpatient procedure, whereas in chil- dren it is used primarily as an intraoperative technique prior to immobilization or correc- tive surgery. In children, under most circum- stances it is therefore performed under gen- eral anesthesia. Because many patients with severe DDH and LCP have limitation of mo- tion, the infants or children are often placed in traction prior to arthrography to increase their range of motion. There are fewer ossi- fied landmarks in the infant than in the adult. The needle should be introduced 1 cm distal to the physis, and 1 cm medial to the lateral aspect of the femoral head. It is important to identify the femoral artery by palpation in order to avoid it during the puncture. The contrast is infused into the joint until capsular distention is attained. The volume of the joint space varies significantly with age and the laxity of the joint. Once the joint is opacified, images are obtained in the neutral position, with varying degrees of abduction (typically 20 and 40 degrees), with 5 degrees of adduc- tion, and with flexion and external rotation (frog lateral or Lauenstein projection) and ab- duction and internal rotation (von Rosen pro-

A 50-50 solution of 60% sodium diatrizoate meglumine and normal saline was reported initially (in children) with volumes ranging between 1 and 5 mL. Syringe suction during withdrawal of the needle was recommended at the end of the arthrogram to prevent leak- age of contrast.21, 27, 28, *O, 46

In 1992, Kilcoyne and K a ~ l a n ~ ~ suggested a direct-lateral approach under fluoroscopic guidance (in adults), using the greater tro- chanter as a landmark with the needle paral- lel to the table top, placed at the midpoint of the anteroposterior plane of the patient. The needle tip enters the lateral aspect of the fem-

jection).12,33,34,54

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 675

oral head-neck junction, where there is a small synovial recess. This method avoids puncture of the femoral neurovascular bun- dle, round ligament, labrum, and articular cartilage, and allows full-length visualization of the needle (particularly when there is a metallic femoral head that obscures the over- lying metal needle).

A recent modified needle technique for pa- tients with prosthetic hips resulted in a 98% success rate for aspiration in 185 patients. It calls for directing the needle vertically down to the , superolateral aspect of the prosthetic neck with the bevel of the needle touching the pro~thesis.~

CT-guided aspiration arthrography is pre- ferred when periarticular heterotopic ossifi- cation (HTO) interferes with needle place- ment. Chew et allo used CT for 97% accuracy in obtaining successful needle placement in hips with HTO.

In patients who have undergone prosthesis removal (Girdlestone operation) for infection and preliminary to implant revision, the au- thors find that directing the needle to the center of the acetabular cavity during aspira- tion is useful.

COMPLICATIONS

Joint infection caused by all types of arthrography is rare. Freiberger14 reports one such complication in 25,000 arthrograms. Fur- thermore, he encountered only 20 mild aller- gic reactions, consisting of urticaria appearing within 15 to 20 minutes after injection of con- trast in 25,000 arthrograms. These patients were treated with oral antihistamines. Arthrography was not performed in patients with known sensitivity to contrast agent. Oc- casionally an air-only arthrogram was per- formed (in the knee) but was deemed less satisfactory than the double-contrast study. No mention of air arthrography of the hip was made. Syncope during arthrography was treated with spirits of ammonia and Trende- lenberg position. Acute, painful, sterile effu- sion following arthrography, usually within 12 hours, occurred rarely. The patient was reaspirated and negative cultures confirmed the presence of a sterile ~yn0vitis.l~ Intraos-

seous injection of contrast, recognized by a persistent bone stain with transiently opaci- fied veins, can be avoided by rotation of the needle while withdrawing a millimeter at a time and simultaneously reinjecting.4O

NORMAL PEDIATRIC ARTHROGRAM

In infants and children, there is usually a discrepancy between the contour of the ossi- fied and cartilaginous structures. The femoral head ossifies at about 4 months of age in girls and 5 months in boys. In patients with DDH, ossification of the femoral head is usually delayed. Ozonoff41 identifies the following key arthrographic structures:

The radiolucent labrum at the lateral margin of the joint. The capsule extends just cephalad to the labral tip, and there is a recess between the superior surface of the labrum and the capsule. This re- cess fills with contrast and is seen as a ”rose thorn,” an important landmark to locate the tip of the labrum. The acetabular cartilage has a smooth surface, is concave inferiorly, and is in- creased in width in DDH.

3 . The femoral cartilaginous head is smooth, regardless of the shape of the ossified epiphysis. It should fit tightly within the acetabulum, with only a small amount of contrast between the two structures.

The only pooling of contrast occurs around the metaphysis but is contained by the orbic- ular ligament, forming a waist termed the zonu ~rb icu lar i s .~~

DDH

The goal of arthrography as a guide to operative treatment in DDH is to indicate the position of the femoral head during the reduction maneuver and to demonstrate any obstacles to reduction (Fig. l).I* These obsta- cles include the following34:

1. The pulvinar, a cushion of proliferating fibrofatty tissue within the acetabulum

676 ALIABADI et a1

Figure 1. Developmental dysplasia of the hip in a 6-month-old boy. A, Femoral head (open arrow) is dislocated laterally and superiorly. The acetabulum is empty (closed arrow). The ligamentum teres is very well visualized (arrowhead). 6, Following reduction, the head articulates with the acetabulum (arrow). The capsule is lax.

2. A hypertrophied ligamentum teres (Figs.

3. A redundant capsule with areas of in-

4. A hypertrophied transverse acetabular

5. A psoas tendon indenting the capsule

and lying between the acetabulum and the femoral head

6. An abnormal configuration of the ace- tabulum (Figs. 1, 2, and 3) and the ace- tabular labrum (see Fig. 2)

1 and 2)

folding

ligament The acetabular abnormality has been called

Figure 2. Developmental dysplasia of the hip in a 15- month-old girl. AP arthrogram shows femoral head dis- placed superiorly and laterally. Ridge of cartilaginous ace- tabulum (closed arrow) between the acetabular concavity and the femoral head is noted. A thickened ligamentum teres (open arrow) is seen within the joint cavity.

Figure 3. Developmental dysplasia of the hip: Arthrogram shows a discrepancy between the contour of the ossified acetabulum and the cartilaginous acetabulum, character- istic for severe dysplasia of the hip. The cartilaginous ace- tabulum and the cartilaginous femoral head have smooth, congruent contours. The femoral head is unossified.

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 677

an inverted labrum or limbus, but it is probably a more complex abnormality (see Fig. 2). His- tologic studies suggest that a true cartilagi- nous ridge develops within the acetabular concavity, creating two separate acetabular chambers.42 The labrum is a firm structure, which does not usually flip to lie between the femoral epiphysis and acetabulum. The interposition of the pulvinar is usually tran- sient, because the fibrofatty tissue usually re- cedes after the hip is located. Psoas interposi- tion is not reliably detected by arthrography. Imaging in abduction and internal rotation (von Rosen position) allows differentiation between a subluxed hip with intervening soft tissue and a dysplastic hip with increased femoral anteversion. Medial pooling of con- trast resolves in the von Rosen position with increased anteversion.12

LCP DISEASE

Arthrography is used to determine the op- timal position of the femoral head for immo- bilization during the process of epiphyseal healing. The orthopedic surgeon's goal is to maximize containment of the femoral head by the acetabulum20 while maintaining con- gruity. Arthrography can detect causes of de- creased containment and visualize the effect

of abduction and internal and external rota- tion on the articular relationships.16, 24 In LCP, lateral displacement of the femoral head is usually multifactorial. The epiphyseal cartilage is abnormally thick, and there is hypertrophy of the synovium and of the ligamentum teres (see Fig. 1). Occasionally, increased synovial fluid may contribute to the subluxation.

The goal of arthrography in LCP is to eval- uate containment and congruity in various positions. Unfortunately, the maneuvers that increase containment, such as abduction, also decrease congruity. This is manifested by pooling of contrast between the femoral head and acetabulum (Fig. 4). In cases of severe flattening of the femoral head, abduction leads to "hinging" of the head on the lateral acetabular margin. This is called hinge abduc- tion& and results in separation of the femoral head from the acetabulum, simultaneously re- ducing containment and congruity (Fig. 5). Arthrography can also be used to detect irreg- ularity of the articular cartilage, which is im- portant progn~stically.~~

NORMAL ANATOMY OF THE ADULT HIP JOINT PERTAINING TO ARTHROGRAPHY

The hip is a ball-in-socket synovial joint whose center lies 1 to 2 cm below the middle

Figure 4. Legg-Calve-Perthes (LCP) disease in a 6-year-old. A, Neutral position. There is flattening of the superior aspect of the cartilaginous head. Femoral head and acetabulum are congruous. Ligamentum teres (straight arrows) and orbicular ligament (curved arrow) are normal landmarks. 6, 40" of abduction. Note pooling of contrast between the acetabu- lum and the femoral head, indicating incongruity of the articular surfaces (straight arrows). The rose thorn (curved arrow) indicates the location of the acetabular labrum.

678 ALIABADI et a1

Figure 5. Legg-Calve-Perthes disease in an 8-year-old showing hinge abduction. The flattened femoral head hinges on the lateral aspect of the acetabuium (arrow). The medial aspect of the joint opens with abduction.

of the inguinal ligament. The head of the femur is covered with hyaline cartilage except at the insertion of the (round) ligament into the head (fovea). The acetabular cavity, except for the round ligament, the pulvinar (intra- articular fat), and transverse acetabular liga- ment, is covered with hyaline cartilage. The fibrocartilaginous labrum and transverse ace- tabular ligament add several millimeters to the circumference of the acetabulum and closely engage the femoral head. The synovial membrane covers the pulvinar, round liga- ment, and neck of the femur and folds up-

ward along the undersurface of the capsule and the retinacula or bands that contain the blood vessels supplying the head and neck of the femur. The fibrous capsule attaches above the acetabular margin and surrounds the head and neck of the femur. It is thickest at its superior-anterior portion, where it is reinforced by longitudinal fibers, iliofemoral, and iliopubic. Inferiorly, at the base of the femoral neck, circular fibers (orbicularis liga- ment) form a collar about the inferior margin of the 52

ADULT HIP ARTHROGRAPHY

In adult hip arthrography, as in children, a thin coating of contrast is also necessary to visualize the lateral margin of the labrum and the articular cartilage. Because most of the contrast collects at the base of the femoral neck, placing the hip in abduction and exter- nal rotation or traction on the leg redistributes the contrast for better visualization of these structures (Fig. 6).

Injection of a larger volume of contrast fur- ther distends the joint. The increased opacity of the contrast, however, may obscure small intra-articular bodies. Air bubbles should be avoided because they can mimic noncalcified bodies. Calcified joint bodies must be identi- fied on scout radiographs because they can be completely obscured by contrast.

The advantage of distending the joint is

Figure 6. Normal adult hip arthrogram. A, During injection. Filling of inferior recesses (arrows). €3, Oblique view shows rose thorn (curved arrow) adjacent to labrum and articular cartilage outlined (straight arrow).

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 679

Figure 7. Adult hip arthrogram with mild osteoarthritis. Full contrast-distention outlines labrum (straight arrow) and synovial folds (curved arrow).

better visualization of synovial hypertrophy (Fig. 7). Conventional tomography after arthrography can help outline intra-articular defects that might otherwise be obscured by contrast (Fig. 8).

Dilution of contrast is a means of obtaining distention without obscuring intra-articular pathology. Distention of thejoint with con- trast may be advantageous in of infec- tion, enabling one to open and demonstrate

Figure 9. Adult hip arthrogram with fistulous tract (straighf arrow) and lateral subluxation of the femoral head. Note filling of the iliopsoas bursa laterally (curved arrow).

fistulous track (Fig. 9). -Arthrography after a Girdlestone operation may demonstrate the space between the acetabular cavity and the femoral neck stump (Fig. 10).

Figure 8. Adult hip arthrotomography in pigmented villo- nodular syndrome (PVNS) outline large articular erosion (straight arrow) and pannus in the inferior articular recess (curved arrow).

Figure 10. Adult hip arthrogram after Girdlestone proce- dure. Needle and contrast have been placed in the ace- tabular cavity. Note pooling of contrast in the acetabular cavity (arrow). Note also the amputated femoral neck.

680 ALIABADI et a1

NORMAL APPEARANCE OF HIP ARTHROPLASTY

There are many varieties of hip prostheses. The femoral hemiarthroplasty replaces the femoral head, which articulates with the na- tive acetabular articular cartilage. The stem may be cemented (Fig. 11) or noncemented. The cup may be unipolar or bipolar. The total hip replacement may be cemented (Fig. 12); noncemented (Fig. 13); or hybrid (usually ce- mented femoral and noncemented acetabular components) (Fig. 14).

Cement may be radiolucent or opacified with barium. The demonstration of complica- tions that occur with the various types of implants may require specific imaging modal- ities.

Figure 12. Normal cemented acetabular component. Ce- ment-bone interface measures less than 2 mm in Zones I, II and Ill. Although Zone 111 is slightly wider than Zones I and II, it remains within the normal width of 2 rnm (arrow).

CEMENTED PROSTHESIS LOOSENING

Hip pain after arthroplasty using cement fixation may be due to loosening, infection, HTO, trochanteric bursitis, dislocation, bone fracture, cement fracture, or attenuation and prosthesis fracture.29 The most common causes of painful prosthetic hip are infection and loosening. Differentiation between in- fected and noninfected loosening is important and sometimes difficult. Findings on conven- tional radiographs suggesting loosening of cemented prostheses include component mi- gration, lucency at the cement-prosthesis in- terface, complete lucent zone more than 2 mm in width at the cement-bone interface, and component or cement fracture (Fig. 15).5, 35

Culture of hip joint aspirate is necessary to diagnose infection and to determine microbe sensitivity to antibiotics. Contrast arthrogra- phy following aspiration has been used to detect prosthetic loosening as well. Demon- stration of contrast material in the cement- bone interface is abnormal and may indicate loosening (Figs. 15 and 16). Maus et a135 fur- ther refined this criterion for loosening, b d i - eating that contrast in the cement-bbone inter- Figure 11. Normal cemented bipolar hemiarthroplasty.

Note native acetabular cortex (sfraiuht arrow1 and normal cement-bone interface (open arroq. face should extend past the intertrochanteric

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 681

Using the technique described by DeLee and Charnley,'l Maus et aP5 divided the ace- tabular component into three zones: (1) zone I is the lateral third, (2) zone I1 is the superior third, and (3) zone I11 is the medial third. Demonstrating contrast at the cement-bone interface in zones I and I11 may not indicate loosening, but contrast in zone I1 in combina- tion with either zone I or zone I11 is highly predictive for loosening. Furthermore, con- trast in all three zones or contrast in zones I or I11 measuring more than 2 mm in width indicates a high probability of loosening.

In rare instances, cement used for fixation may not contain barium and appears lucent on radiographs. Arthrography is necessary to evaluate the apparent wide interface between the component and the bone (Fig. 18).5, 11, 35

Figure 13. Normal noncemented total hip replacement with no demonstrable metal-bone lucent zone.

line of the standard femoral and halfway down the stem of the long-stemmed compo- nent.5, 35

Subtraction arthrography allows better dis- crimination of the opaque contrast material by eliminating the equally opaque cement. By using subtraction arthrography and refined criteria, Maus et al" reported sensitivity of 96% and specificity of 92% for demonstrating loosening of the cemented femoral component.

For cemented acetabular prostheses, criteria for loosening are not as clear. Demonstration of contrast in the cement-bone interface of the acetabular component may not indicate loosening, according to Murray and Ro- d r i g ~ . ~ ~ In 22% of asymptomatic patients, con- trast was demonstrated in the cement-bone interface Of the component and Only Of l2 predicted loose by arthrography were actually loose at surgery (Fig. 17).

Figure 14. Normal hybrid total hip replacement with no lucency at the acetabular metal-bone or femoral cement- bone interfaces.

682 ALIABADI et a1

Figure 15. A, Scout radiograph. Cemented components, with both acetabular and femoral cernent- bone widening and lucency in the femoral rnetal-cement interface (arrow). 13, Arthrogram. Contrast in acetabular (straight arrow), femoral cement-bone (short arrow), and femoral metal-cernent interfaces (cuwed arrow).

High-pressure arthrography has been re- ported to increase the rate of detection of loosening for both acetabular and femoral ce- mented components. Injection of contrast is stopped when the patient complains of pain or there is lymphatic filling.19, 35

The phenomenon of lymphatic filling dur- ing hip arthrography (Fig. 19) was studied in 1971 in 91 patients with osteoarthritis as the primary reason for hip replacement. There was no correlation with prosthesis loosening or infection. This nonspecific nature of lym- phatic filling contradicted an earlier report.18 Pseudocapsular irregularity may be demon- strated arthrographically by the presence of irregular areas of contrast accumulation (Fig. 20). Capsular irregularity and the presence of nonbursal cavities are more common in patients with infected arthropiasties.

Bursa1 filling (trochanteric, lateral acetabu- lar, or iliopsoas) during hip arthrography is not uncommon after hip arthroplasty (Fig. 21). The resultant relative diminution of con- trast volume within the joint may produce false-negative results (insufficient contrast volume to enter the cement-bone interface) in cases of prosthetic loosening.35 Conversely, the demonstration of irregular cavities or fis- tulous tracts aids in the arthrographic diagno- sis of infection (Figs. 22 and 23).

From 1984 to 1990, the usefulness of preop- erative arthrography of failed total hip re- placements in large series for both loogening and infection was found to be of greater sen- sitivity and specificity when arthrography was correlated with nuclear scanning, plain radiography, and subtraction arthrography for loosening and when clinical and labora-

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 683

Figure 16. A, Scout radiograph. Hybrid implant with widening of metal-cement interface in the femoral cemented component (arrow). 6, Arthrogram. Contrast in femoral metal-cement interface (arrows).

Figure 17. A, Scout radiograph. Cemented acetabular component showing widening of cement-bone interface, upward migration of the femoral head and disruption of the ring-marker. 6, Arthrogram. No contrast in cement-bone interface, but contrast does surround the fractured (lucent) polyethylene cup (arrow).

684 ALIABADI et a1

Figure 18. A, Scout radiograph. Acetabular component, cemented but without barium-impregnated cement (radiolucent cement). 6, Arthrogram. Contrast in the radiolucent cement-bone interface (arrow).

Figure 19. Arthrogram. Cemented prosthesis with con- trast entering lymphatic vessels (arrows).

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 685

Figure 21. Oblique arthrogram. Contrast-filled greater tro- chanteric bursa in Figure 20. Arthrogram: Irregular contour of pseudocap-

sule (arrows) in a noninfected hip arthroplasty. (arrows),

Figure 22. A, Arthrogram scout radiograph. Hybrid implant. 13, Contrast fills infected fistulous tract (arrows) filling from hip arthrogram.

686 ALIABADI et a1

Figure 23. Noncemented component with trochanteric osteotomy, showing filling of an infected fistulous tract (short arrow) from the femoral metal-bone interface through a cortical defect (curved arrow).

tory signs of infection, such as elevated eryth- rocyte sedimentation rate, were correlated with aspiration data.’, 17* 35, 39

ral implants in the presence of postoperative pain. This technique, however, is not com- monly used. When the intra-articular position of the needle is confirmed, a dose of 0.1 pCi

UNCEMENTED PROSTHESIS LOOSENING

Barrack et a16 reported relatively low sensi- tivity and specificity of contrast arthrography in detecting loose uncemented prostheses, with both false-positive and false-negative re- sults for both femoral (Fig. 24) and acetabular components. A sensitivity of 57% and a speci- ficity of 60% (femoral component) and a sen- sitivity of 29% and a specificity of 89% (ace- tabular component) were reported. There were false-positive and false-negative results for both components. They also showed limi- tation of arthrography for identifying the fix- ation status of uncemented implants. Simi- larly, Cheung et a19 reported low sensitivity and specificity of contrast arthrography for predicting loosening.

The combination of contrast arthrography and nuclear arthrography using indium-111 has been reported as an accurate method in determining loosening of uncemented femo-

indium-111 chloride in 2 to 5 mL saline is injected, followed by 15 mL of contrast agent. The nuclear arthrogram is considered positive if distal tracking of radionuclide is observed beyond the boundary of the pseudocapsule. Swan et a14* report a sensitivity of 90% when either contrast or nuclear arthrography is pos- itive. The specificity is 100% when both stud- ies are negative.

ASPIRATION

Aspiration of the prosthetic hip joint and culture of the aspirated synovial fluid has been widely used for evaluation of painful hip replacements and diagnosing infection as the cause of hip pain and loosening. There is also controversy, however, about the use- fulness of routine preoperative aspiration prior to revision. Tehranzedeh et a149 reported three negative aspirations in five surgically proved infected prostheses. Maus et a135 re- ported sensitivity of only 71%. Thirteen per-

*

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 687

Figure 24. A, Scout radiograph. Noncemented femoral component and cemented acetabular compo- nent, which is rotated vertically, indicating loosening radiographically. B, Contrast in metal-bone interface (arrows) below the intertrochanteric line, indicating loosening arthrographically.

cent and 21% false-positive results were ob- tained by Barrack and Harris5 and Barrack et al.4 Although some false-positive results could be excluded by repeat aspiration, in some cases differentiation between false-posi- tive and true-positive cultures was difficult. Kraemer et a131 studied 136 intraoperative cul- tures after revision arthroplasty. Nine of 98 cemented and 18 of 38 noncemented hip arthroplasties were found to be infected. In a recent report, Cheung et a19 found five true- positive results in six infected noncemented prostheses aspirated. There were no false-pos- itive results and only one false-negative. These authors agree with the recommenda- tion of Kraemer et a131 that aspiration of the joint and culture of fluid be considered in eval- uating all painful uncemented hip prostheses.

ANESTHETIC ARTHROGRAPHY (HIP BLOCK)

The value of anesthetic hip arthrography in patients with spine and hip pain to help

distinguish between pain originating from the hip and radicular pain from the spine is documented.8, 30 Kleiner et a130 reported favor- able results in 18 patients who subsequently underwent spine or hip surgery, based on the clinical response to the anesthetic arthro- grams. Two false-negative results (no relief of hip pain after hip block but no subsequent spine pathology at surgery) were felt to be due to increased intraosseous venous pres- sure in the femoral heads. One' was an early unrecognized osteonecrosis and the other was severe osteoarthritis of the hip with associ- ated intraosseous venous hypertension, nei- ther of which obtained relief of pain from the intra-articular anesthetic. As an explanation for this phenomenon, it has been postulated that patients with severe osteoarthritis of the hip with intraosseous pressure over 40 mm Hg may experience hip pain at rest, unre- lieved by intra-articular bupivacaine, re- sulting in the false-negative hip block?

Intra-articular injection of local anesthetic can also help in determining the cause of

688 ALIABADI et a1

postarthroplasty hip pain. Significant relief of pain suggests the involvement of an intracap- sular process. Persistence of pain is not a helpful diagnostic finding. Braunstein et als examined the differentiation of pain caused by prosthesis loosening from that caused by capsular dysfunction in postoperative hips using intra-articular bupivacaine. The postop- erative capsular pain was not relieved by in- tra-articular bupivacaine, whereas the pain due to implant loosening was relieved by the intra-articular anesthetic.

Published techniques for anesthetic arthro- gram are as follows: 10 to 15 mL of meglu- mine diatrizoate mixed with 7 mL of bupiva- caine and injected under fluoroscopic control using a 20-gauge spinal needle into the pseu- docapsule of the total hip prosthesisE; 10 mL of 0.25% bupivacaine injected into the hip joint using a 22-gauge needle.30 In patients with inflammatory arthritis, intra-articular in- jection of long-acting corticosteroids may be added.

ILIOPSOAS BURSA

The world literature on iliopsoas bursitis was reviewed in 1972 by Armstrong and Sax- ton.2 They noted that although the German and English journals from 1834 to 1972 re- ported a total of 85 cases, the first iliopsoas bursogram was not presented until 1972.47 A second case was published in 1975.51

NORMAL ANATOMY OF THE ILlOPECTlNEAt BURSA

The iliopectineal (iliopsoas) bursa lies ante- rior to the joint capsule between the iliofem- oral and iliopubic fibers. Anterior to the bursa are the iliacus muscle and the tendon of the psoas muscle, above which are the femoral nerve (L3 and 4), common femoral artery lat- erally, and the common femoral vein medi- ally. Medial to the vein is the femoral canal, which is superficial to the pectineus muscle. Two other common bursae in the hip region are the lateral acetabular and the (greater) trochanteric. Slightly lateral to the iliopsoas is the origin of the rectus femoris muscle from the anteroinferior iliac spine. Superficial to

Figure 25. Normal bursa. Note position of needle. (Cour- tesy of J. Tehranzadeh, MD, University of California, Ir- vine, Orange, California).

the rectus femoris lie the origins of the sarto- rius muscle and the tensor fascia lata muscle. The lateral femoral cutaneous nerve (L2) emerges from the lateral margin of the ingui- nal ligament to cross the origin of the sarto- rius muscle.38, 52

ILIOPSOAS (ILIOPECTINEAL) BURSOGRAPHY TECHNIQUE

The iliopsoas (iliopectineal) bursa, the largest and most constant bursa, lies between the iliacus muscle belly, the psoas tendon, and the anterior capsule of the hip joint and separates the tendon from the pubis. It aver- ages 5.5 cm in length and 2 cm in width and communicates with the hip joint in up to 15% of adults, particularly those with hip arthritis, most commonly rheumatoid arthritis. In chil- dren, the bursa rarely communicates with the joint. The distended bursa may impress or medially deviate the external iliac vein.3s, 50, 52

It was not until 1995 that a large series (12 patients having undergone 24 iliopsoas

HIP ARTHROGRAPHY, ASPIRATION, BLOCK, AND BURSOGRAPHY 689

bursograms) was reported by Vaccaro et al.50 These patients were evaluated for internal snapping hip syndrome and selected patients were also injected with 40 mg methylprednis- olone acetate and 5 mL bupivacaine hydro- chloride. A technique consisting of a 90-de- gree direct-anterior approach at the upper medial quadrant of the femoral head, directed to the anterior acetabular column, was de- scribed. With the patient lying in the supine position on the fluoroscopic table, the supero- medial quadrant of the femoral head is marked, the course of the needle being lateral to the femoral vessels and nerve. A 22-gauge spinal needle is advanced perpendicular to the anterior column, and medial and cepha- lad to the margin of the acetabulum. Retrac- tion of the needle, about 5 mm, usually posi- tions the tip of the needle into the bursa.50

The contrast-filled bursa is an elongated anterior structure that projects over the iliac fossa and hip joint (Fig. 25). It may be divided by the iliopsoas tendon (Fig. 26).

In 1996,21 cases of proved tenosynovial or bursal tuberculosis using radiography, arthrography, CT, and MR imaging were re- ported; 12 involved the wrist (tenosynovial) and nine were bursal, only one of which was in the iliopsoas. The remaining bursa were

Figure 26. Normal outline of iliopsoas tendon (arrows).

three subdeltoid, one retrocalcaneal, one ischio- gluteal, and three tr0chanteric.2~ Other causes of iliopsoas (iliopectineal) bursal enlargement include osteoarthritis, rheumatoid arthritis, ju- venile chronic arthritis, pigmented villonodular synovitis, and synovial chondromatosis.5l

Enlarged synovial cysts about the hips are rare, and have been described on MR imaging and ultrasonography. These may not commu- nicate with the joint and, therefore, are not visible on arthrography.22

CONCLUSION

Contrast hip arthrography and aspiration, one of the earliest radiographic interventional procedures, remains a viable and useful tech- nique today. It has retained its utility in hip dysplasia, LCP disease, and septic joint, and has gained new usefulness in joint replace- ment surgery and pain control.

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CIBA-GEIGY, 1989

Address reprint requests to Piran Aliabadi, MD

Department of Radiology Brigham and Women’s Hospital

75 Francis Street Boston, MA 02115