Protrusio acetabuli in seronegative spondyloarthropathy

Protrusio Acetabuli in Seronegative Spondyloarthropathy By S i m 6 n E. Gusis, A u g u s t o M. R i o p e d r e , O m a r Penise, and Jos~ A. M a l d o n a d o Cocco Protrusio acetabuli (PA) is a complication of many disorders involving the hip joint. Its frequency and clinical features in seronegative sponyloarthropathy (SNSA) are unknown. The prevalence and characteristics of PA were studied in 50 adults and 25 children with SNSA (40 ankylosing spondylitis, 24 psoriatic arthropathy, and 11 Reiter's syndrome}. PA was considered present when the acetabular line medially exceeded the ilioischial line by 3 mm or more in men, 6 mm or more in women, more than 1 mm in boys, and more than 3 mm in girls. PA prevalence was 25% in the total group (19 of 75 patients}, 22% in adults, and 32% in children. There were no significant differences in seronegative disease type; PA was present with similar frequency

ACETABULI (PA) is a comp ~ROTRUSIO plication arising from a wide spectrum of disorders involving the hip joint. Some causes of this condition are Paget's bone disease, 1osteoarthritis,2 osteoporosis and osteomalacia,3 sicklecell anemia? rheumatoid arthritis (RA), 5,6juvenile rheumatoid arthritis ( J R A ) , 7-9 neoplasia, 1~ Marfan's syndrome,11,j2 trauma, 13 and idiopathic forms. 14,15Clinical involvement of the hip is a common problem that impairs functional capacity in patients with seronegative spondyloarthropathy (SNSA). 16 In the last diseases, PA has been described as a complication of adult ankylosing spondylitis (AS), 16 but its frequency and clinical features in other SNSA such as psoriatic arthropathy and Reiter's syndrome are unknown. Indeed, this complication has not yet been studied in children with SNSA. A variety of radiological methods have been developed for the diagnosis of this worrisome complication, from the gross intrusion of the femoral head within the pelvic cavity, 17,~8measurement of Wiberg's CE angle, 19presence and form of the teardrop, 14,2~ to acetabular line crossing medially to the ilioischial line.21 All these techniques have been used in adults, whereas only the penetration of a bone mass in the pelvic cavityTM and the crossing of the acetabular line medially to the ilioischial line 22 have been used to measure PA in children. Factors predisposing to the development of PA in chronic inflammatory joint disease have not been defined clearly, except for the inflam-

between genders and did not correlate with disease duration, clinical severity of hip involvement, or previous medication. Radiological damage was similar in adults and children and did not differ in those with and without PA. Similarly, functional capacity did not differ between groups. It is concluded that PA is a frequent complication in SNSA, however, its presence does not seem to modify the functional prognosis of these patients. Copyright 9 1993 by W.B. Saunders Company INDEX WORDS: Seronegative spondyloarthropathy; hip; protrusio acetabuli; ankylosing spondylitis; psoriatic arthropathy; Reiter's syndrome.

matory activity of the underlying disease 6 and certain drugs such as indomethacin23 and corticosteroids.6 The goal of this work was to study the prevalence of PA in adults and children with AS, psoriatic arthropathy, and Reiter's syndrome as well as its relation to clinical features of such diseases. MATERIAL AND METHODS

Retrospectively, 75 patients with SNSA, comprising 50 adults and 25 children, 40 with AS, 24 with psoriatic arthropathy, and 11 with Reiter's syndrome, all selected on the basis of anteroposterior radiographic study of the hip joint, were studied. Patients 16 years old or older at the onset of disease symptoms were considered adults. Cases of AS complied with New York criteria, 24 psoriatic arthropathy with Bennet's criteria, 25 and Reiter's syndrome with the criteria advanced by Willkens et al.26 Well-centered anteroposterior pelvic radiographic views were

From the Rheumatology Section, lnstituto de Rehabilitaci6n Psicofisica, Buenos Aires, Argentina. Sim6n E. Gusis, MD: Staff Physician; Augusto M. Riopedre, MD: Former Fellow in Rheumatology; Omar Penise, MD: Fellow in Rheumatology; Jos6 A. Maldonado Cocco, MD: Chief, Rheumatology Section. Address reprint requests to Sim6n E. Gusis, MD, Secci6n Reumatologfa, Instituto de Rehabilitaci6n Psicofisica, Echeverda 955, 1428 Buenos Aires, Argentina. Copyright 9 1993 by W..B. Saunders Company 0049-0172193/2303-000255. 00/0

Seminars in Arthritis and Rheumatism, Vo123, No 3 (December), 1993: pp 155-160

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available, projection of the coccyx coinciding with the pubic symphysis and with symmetrical obturator orifices. Absence of clinical hip compromise (limitation and/or pain) was not a reason for exclusion. All patients had negative rheumatoid and antinuclear factors. PA was considered present in adults when the acetabular line medially exceeded the ilioischial line by 3 mm or more in men and by 6 mm or more in women, in agreement with Armbuster et al. 21 PA was diagnosed in children when the acetabular line projected within the ilioischial line by more than 1 mm in boys and 3 mm in girls, in agreement with our findings 22 (Fig 1). Statistical tests used were X2, • with Yates' correction, z7 and Student's t test. as Suitable clinical data were obtained from each patient regarding the course of disease and dosage and duration of corticosteroid and nonsteroidal antiinfiammatory drug (NSAID) therapy. In each radiograph, the presence or absence of osteoporosis, joint space narrowing, erosions, cysts, subchondral sclerosis, osteophytes, periostitis, subluxation, bone ankylosis, and PA, as well as growth alterations, was evaluated. When several ameroposterior hip radiographs were available, the earliest one showing PA was chosen for study. Patients with PA were followed for 2 years to determine the progress of disease and whether hip surgery was required.

Fig 1: Schematic diagram of the pelvis, showing in the left hip joint the ilioischial (1) and acetabular (2} lines; *protruded area.

GUSIS ET AL

Table 1: Prevalence of PA in Adult and Juvenile SNSA Prevalence/ Laterality

Adult (n = 50)

PA prevalence

11/50 (22%) 5/11 (45%) 6/11

Unilateral Bilateral

(55%)

P NS NS

NS

Juvenile (n = 25)

Total (n -- 75)

8/25 (32%) 4/8 (50%) 4/8

19/75 (25%) 9/19 (47%) 10/19

(5O%)

(53%)

Abbreviations: PA, protrusio acetabuli; SNSA, seronegative spondyloarthropathy; NS, not significant.

Functional capacity was evaluated according to Steinbrocker's classification. 29 RESULTS

Nineteen of 75 patients with SNSA had PA (25%), unilateral in 9 and bilateral in 10 patients. PA was found in 11 of 50 adults with SNSA (22%)--unilateral in 5 and bilateral in 6--and in 8 of 25 children with SNSA (32%)-9unilateral in 4 and bilateral in 4 (Table 1). The prevalence of PA was 17% (4 of 24) in adults and 37% (6 of 16) in children with AS; 28% (6 of 21) in adults but entirely absent in children with psoriatic arthropathy; and 20% (1 of 5) in adults and 33% (2 of 6) in children with Reiter's syndrome. On comparison of adults and children for each disease, there were no significant differences in PA frequency (Table 2). Table 3 lists the clinical features of all patients with adult or juvenile SNSA; no statistically significant differences were found in gender (predominantly male), disease duration (8.5 years in adults, 7.7 years in children), clinical hip involvement (32% in adults, 48% in children), duration of hip symptoms (4.9 years in adults, 5.5 years in children), corticosteroid intake (22% in adults, 24% in children), indomethacin intake (54% in adults, 40% in children), or the presence of iridocyclitis as an extraarticular disease manifestation (10% in adults, 8% in children). Likewise, on comparison of patients with and without PA in adult and juvenile SNSA, there were no statistically significant differences in any of the features analyzed (Table 4). When adults with PA were contrasted with children, differences again proved negligible.

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PROTRUSIOIN SNSA

Table 2: Comparison of PA Prevalence in SNSA SNSA

Adult

Ankylosing spondylitis 4/24 (17%) Psoriaticarthropathy 6/21 (28%) Reiter'ssyndrome 1/5 (20%) Tota 11150 (22%)

Juvenile 6/16 013 216 8/25

(37%) (0%) (33%) (32%)

P NS NS NS NS

Abbreviations: PA, protrus~o acetabuli; SNSA, seronegative

spondyloarthropathy;NS, not significant.

Both adults and children evidenced a high frequency of radiological hip involvement: 88% (44 of 50) of adults and 84% (21 of 25) of children, with bilateral compromise in 41 of 44 (93%) adults and 21 of 21 (100%) children (Tabl e 5). In adults with PA, medial acetabular line crossing over the ilioischial line ranged from 3 mm to 15 mm; in children it ranged from 2 mm to 11 mm. One adult with AS required surgeiy for hip disease after 6 years of hip involvement, Furictional capacity was similar in the presence and absence of PA in adults and children (Table 6). When functional capacity was compared between adults with and without PA, no significant differences were found; the same was true for children. Table 3: Clinical Features of Adult and Juvenile SNSA Clinical Features Mean age, yr (range) Gender: male/total Mean disease duration, yr (range) Hip involvement Mean duration of hip symptoms, yr(range) Steroid drug intake Indomethacin intake Acute iridocyclitis

Adult (n = 50)

Juvenile

28.0 (16-53) 38/50 (76%) 8.5 (0.2-30) 16/50 (32%) 4.9 (0.5-20) 11/50 (22%) 27/50 (54%) 5/50 (10%)

11.2 (4-15) 20/25 (80%) 7.7 (0.2-30) 12125 (48%) 5.5 (0.1-30) 6/25 (24%) 10135 (4O%) 2/25 (8%)

(n = 25)

P

NS NS NS NS NS NS NS

Abbreviations: SNSA, seronegativespondyloarthropathy; NS,

not significant.

DISCUSSION

To our knowledge, only Dwosh et a116 have studied PA in AS using clinical and radiological evaluation of the hip joint in a series of 87 cases. They reported clinical involvement in 38% (33 patients) and radiological compromise in 48% (42 patients), with an overall PA frequency of 30%. This work, carried out in 1976, did not evaluate PA using the current methods developed by Armbuster et al zl in adults and by Gusis et al z2 in children. Patients with psoriatic arthropathy and Reiter's syndrome were excluded, and only adults were studied. 16 Radiological compromise was bilateral in 93% of cases and unilateral in 7%. In the series described herein, the overall frequency of PA in SNSA was 25% (19 of 75), with a greater percentage in children (32%, or 8 of 25) than in adults (22%, or 11 of 50), while bilateral and unilateral frequencies were almost identical. Thus, the frequency of PA in our study was similar to that found by Dwosh et al in adult AS. In adult RA, we reported that the frequency of PA was 23% (23 of 100), bilateral in 5 cases and unilateral in 18.5 In JRA, our percentage was 12% (9 of 73), bilateral in 5 cases and unilateral in 4. 30The frequency of PA is greater in children with AS than in adults (37% v 17%) and in juvenile Reiter's syndrome (33% v 20% in adults) but not in psoriatic arthropathy, in which adults predominate (28% v 0% in children). The last finding may be explained by the limited number of children with psoriatic arthropathy; only three cases of juvenile psoriatic arthropathy were observed and none of PA. Globally, PA is more frequent in children (32%, or 8 of 25) than in adults (22%, or 11 of 50). Comparative analysis of clinical features in adults and children did not show significant differences; males predominated as expected in both, with a slightly longer time of underlying disease duration (8.5 and 7.7 years, respectively). Patients had similar histories of drug intake (corticosteroids and indomethacin) and extraarticular manifestations (mainly acute iridocyclitis). Although differences were not statistically significant, there was greater clinical hip involvement in children than in adults, with similar disease duration. Given the retrospec-

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GUSIS ET AL

Table 4: Comparison of Adult and J u v e n i l e S N S A With and W i t h o u t PA Adult (n = 50) Clinical Features Mean age, yr (range) Gender: male/total Mean disease duration, yr (range) Hip involvement Mean duration hip symptoms, yr (range) Steroid intake Indomethacin intake Iridocyclitis

Juvenile (n = 25}

With PA In = 11)

Without PA (n = 39)

With PA (n = 8)

Without PA (n = 17)

28.8 (16-49) 8/11 (73%) 7.5 (1-20) 2/11 (18%) 1.5 (1-2) 0/11 (0%) 3/11 (27%) 1/11 (9%)

27.8 (16-53) 30/39 (77%) 8.8 (0.2-30) 14/39 (36%) 5.4 (0.6-20) 11/39 (28%) 24/39 (62%) 4/39 (10%)

10.5 (4-15) 7/8 (88%) 8.8 (3-30) 5/8 (63%) 8.8 (0.1-30) 1/8 (12%) 4/8 (50%) 1/8 (12%)

11.6 (8-15) 13/17 (77%) 7.2 (0.2-18) 10/17 (59 %) 3.8 (0-4.8) 5/17 (29%) 6/17 (35%) 1/17 (6%)

NS NS NS NS NS NS NS NS

Abbreviations: SNSA,seronegativespondyloarthropathy;PA, protrusio acetabuli;NS, not significant.

tive nature of our study, the duration of hip symptoms should be regarded cautiously. On comparison of groups with or without PA, whether adults or children, no statistically significant differences were discerned. Although PA was found in a greater number of males, there were no significant differences between genders either for adults (8 of 38 men, or 21%, v 3 of 12 women, or 25%, with PA) or for children (7 of 20 boys, or 35%, v 1 of 5 girls, or 20%). The possible relationship of PA with prior corticosteroid intake was studied, and no significant intergroup differences were found. In contrast, some authors have reported a positive Table 5: Radiological Hip Features in A d u l t and Juvenile SNSA

Radiological Features Joint spacing narrowing Erosions Growth alterations Subluxation Ankylosis

Adult

Juvenile

(n = 50}

(n = 25)

P

24/50 (48%) 7/50 (14%)

17/25 (68%) 3/25 (12%)

NS NS

4/50 (8%) 1/50 (2%) 1/50 (2%)

7/25 (28%) 3/25 (12%) 0/25 (0%)

NS NS NS

Abbreviations: SNSA, seronegativespondyloarthropathy;NS, not significant.

correlation of PA with higher frequency of corticosteroid intake. 6 Prior indomethacin intake also was evaluated, but differences again lacked significance. Neuman and Ling 23 described a relationship between NSAIDs, particularly indomethacin, and acetabular bone destruction in patients with osteoarthritis, although this putative association has been questioned by Richards and Capell. 31 A stringently selected population was studied, as shown by the lengthy time of underlying disease duration, with considerable radiological hip damage and greater bilaterality. Our high PA frequency could be explained in two ways: (1) our center is a nationwide referral source; and (2) our selection criteria allowed inclusion only of patients with an anteroposterior radiograph of the hip joint, which points to probable hip disease. During the 2-year follow-up period, only one case of adult AS, with considerable radiological damage in addition to PA, required total hip replacement. PA also did not lead to worsening functional capacity in the remaining affected patients. The study of Dwosh et al reported that 8 of 97 cases (9%) required hip surgery, but there are no data regarding PA. 16 Last, acute iridocyclitis as evidence ofextraarticular compromise in SNSA was not an indicator of greater frequency or more severe PA.

PROTRUSIOIN SNSA

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Table 6: Functional Capacity in 75 Cases of S N S A According to Presence of PA Juvenile (n = 25}

Adult (n = 50) Functional Class

With PA (n = 11)

Without PA (n = 391

I II Ill IV

0111 (0%) 1/11 (9%) 9/11 (82%) 1111 (9%)

4/39 (10%) 19/39 (49%) 15/39 (38%) 1/39 (3%)

With PA (n = 8)

0/8 4/8 4/8 0/8

(0%) (50%) (50%) (0%)

Without PA (n = 17)

2/17 (12%) 12/17 (70%) 3/17 (18%) 0/17 (0%)

Abbreviations: SNSA,seronegativespondyloarthropathy,PA, protrusioacetabuli. NOTE.Differenceswerenonsignificantthroughout.

We conclude that in our population of SNSA patients with lengthy follow-up, the overall frequency of PA was 25% (19 of 75). Although greater in children (32%) than in adults (22%), the difference was not statistically significant. Differences also were negligible in PA frequency according to disease type within the SNSAi PA was observed with almost equal frequency in men and in women. The finding of PA failed

to correlate with greater duration of underlying disease, more severe clinical hip involvement, previous medication, or ocular compromise, either in adults or in children. Radiological damage in adults and children with SNSA was similar and did not differentiate those with or without PA. Therefore, the presence of PA should not be regarded per se as an indication for hip surgery or as a necesarily disabling impairment.

REFERENCES 1. Guyer PB, Dewbury KC: The hip joint in Paget's disease (Paget's "coxopathy"). Br J Radiol 51:574-578, 1978 2. Resnick D: Patterns of migration of the femoral head in osteoarthritis of the hip. AJR 124:62-74, 1975 3. Bible MW, Pinals RS, Palmieri GMA, et ah Protrusio acetabuli in osteoporosis and osteomalacia. Clin Exp Rheumatol 1:323-326, 1983 4. Martinez S, Apple JS, Barber C, et ah Protrusio acetabuli in sickle-cell anemia. Radiology 151:43-44, 1984 5. Gusis SE, Maldonado Cocco JA, Rose CD, et ah Protrusio acetabuli in adult rheumatoid arthritis. Clin Rheumatol 10:158-161, 1991 6. Hasting DE, Parker SM: Protrusio acetabuli in rheumatoid arthritis. Clin Orthop 143:62-74, 1975 7. Ansell BM, Unlu M: Hip involvement in juvenile chronic polyarthritis. Ann Rheum Dis 29:687-688, 1970 8. Jacqueline F, Boujout A, Canet L: Involvement of the hips in juvenile rheumatoid arthritis. Arthritis Rheum 4:500-5i3, 1961 9. Fridenberg ZB: Protrusio acetabuli in childhood. J Bone Joint Surg 45A:373-378, 1963 10. Edelstein G, Murphy WA: Protrusio acetabuli: Radiographic appearence in arthritis and other conditions. Arthritis Rheum 26:1511-1516, 1983 11. Fast A, Otremsky Y, Pollack D, et ah Protrusio acetabuli in Marfan's syndrome. Report of two patients. J Rheumatol 11:549-551, 1984 12. Wenger DR, Dikoff TS, Herring JA, et ah Protrusio acetabuli in Marfan's syndrome. Clin Orthop 147:134-138, 1980 13. Judet R, Judet J, Letournal E: Fractures of the

acetabulum: classification and surgical approaches for open reduction. Preliminary report. J Bone Joint Surg 46A:16151616, 1964 14. Hooper JC, Jones EN: Primary protrusion of the acetabulum. J Bone Joint Surg 53B:23-29, 1971 15. Shore A, Macauley D, Ansell BM: Idiopathic protrusio acetabuli in juveniles. Rheumatol Rehabi120:1-10, 1981 16. Dwosh IL, Resnick D, Becker MA: Hip involvement in ankylosing spondylitis. Arthritis Rheum 19:683-692, 1976 17. Otto AW: Pfannenbeckenmistalung infolge deformierender osteoarthritis in neve seltene beobachtungen zur anatomie, physiologye gehorig (2nd ed). Berlin, Germany, Rucker, 1824 18. Pomeranz MM: Intrapelvic protrusion of the acetabular (Otto pelvis). J Bone Joint Surg 14A:663-686, 1932 19. Wiberg G: Studies on dysplastic acetabula and congenital subluxation of the hip joint--With special reference to the complication of osteoarthritis. Acta Chir Scand 58:28, 1939 (suppl) 20. Alexander C: The aetiology of primary protrusio acetabuli. Br J Radio138:567-580, 1965 21. Armbuster TG, Guerra J, Resnick D, et ah The adult hip: An anatomic study. Part I. The bony landmarks. Radiology 128:1-10, 1978 22. Gusis SE, Babini JC, Garay SM, et ah Evaluation of the measurement methods for protrusio acetabuli in normal children. Skeletal Radiol 19:279-282, 1990 23. Neuman NM, Ling RS: Acetabular bone destruction related to nonsteroidal anti-inflammatory drugs. Lancet 2:11-13, 1985 24. Bennet PJ, Burch TA: New york symposium on

160

population studies in the rheumatic diseases. New diagnostic criteria. Bull Rheum Dis 17:453-458, 1967 25. Bennet RM: Psoriatic arthritis, in McCarty DJ (ed): Arthritis and Allied Conditions. Philadelphia, PA, Lea & Febiger, 1985 pp 850 26. Willkens RF, Arnett FC, Bitter T, et al: Reiter's syndrome. Evaluation of preliminary criteria for definite disease. Bull Rheum Dis 32:31-34, 1982 27. Swinscow TDV" The X2 tests. Br Med J 43-53, 1983

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28. Swinscow TDV: The t test. Br Med J 33-42, 1983 29. Steinbrocker O, Traeger Ch, Batterman RC: Therapeutic criteria in rheumatoid arthritis. JAMA 140:659-662, 1949 30. Gusis SE, Maldonado Cocco JA, Rivero E, et al: Protrusio acetabuli in juvenile rheumatoid arthritis. Clin Rheumatol (in press) 31. Richards I, Capell H: Nonsteroidal anti-inflammatory drugs and the acetabulum. Lancet 2:661, 1985