Primary Total Hip Arthroplasty in Systemic Lupus Erythematosus M i c h a e l H. H u o , MD,-t- E d u a r d o A. Salvati, M D , * M i c h a e l G. B r o w n e , M D , * P a u l M . Pellicci, M D , * T h o m a s P. S c u l c o , M D , * a n d N o r m a n A. J o h a n s o n , M D t
Abstract: Systemic lupus erythematosus (SLE) is a chronic inflammatory disease
affecting primarily young women. Osteonecrosis of the femoral head produces significant morbidity in these patients. The clinical and radiographic results of 33 total hip arthroplasties (THA) in 25 patients were studied. The Hospital for Special Surgery hip rating was good or excellent in all surviving index primary hip arthroplasties at a median follow-up of 47 months. Overall survival probability was 94.6% at 5 years and 81.8% at 9 years using survivorship analysis. Perioperative morbidity was minimal. Total hip arthroplasty using contemporary techniques and current management protocols can provide reliable functional improvement in patients with osteonecrosis secondary to SLE. Key words: systemic lupus erythematosus, total hip arthroplasty, osteonecrosis, survivorship analysis, radiographic, prognosis.
Systemic lupus erythematosus (SLE) is a chronic, relapsing, multisystem, inflammatory disorder associated with immunologic abnormalilies. It affects predominantly w o m e n in their second and third decades (19). Its prevalence has been estimated to be 0.5-1.0 per 1,000 w o m e n in North America (4, I5). It was estimated that greater than I30~000 patients may have been affected with this disease in 1985 (13). While arthralgia is the most con~non orthopaedic manifestation, osteonecrosis is the most painful and disabling. The incidence of osteonecrosis has been estimated to be as high as 52% (2 I). Although osteonecrosis has been reported in m a n y sites, the femoral head is the most frequently affected site. The treatment alternatives for osteonecrosis involving the femoral head are multiple in the early stages, and include decompression, bone graft, and osteotomy.
In the late stages, after subchondral collapse has occurred, prosthetic arthroplasty is the procedure of choice in patients with disabling pain. There have been only two previous reported series of the clinical results of total hip arthroplasty in patients with SLE (7, 17). While the relief of pain was predictable, the complication rate and revision rate was significantly greater than that reported in patients with osteoarthritis (7). Both studies reported the results of reconstructions performed in the 1970s using relatively old surgical techniques and prosthetic implants, In addition, the mortality from disease progression was 25% within the first 5 years following surgery in one report (7). The long-term prognosis for patients with SLE has improved considerably (9, 18, 19), thus the durability of prosthetic fixation following hip arthroplasty is an important issue. The purpose of this study was to evaluate the clinical and radiographic results of primary prosthetic hip replacements in consecutive patients with SLE during a 7-year period in the 1980s, at The Hospital for Special Surgery. Our hypothesis was that improved understanding and medical management of SLE would reduce the
From *The Hospitalfor Special Surgery, New York, New York, the fDepartment of Orthopaedic Surgery, Georgetown University Hospital, Washington, D. C., and the ~Department of Orthopaedic Surgery, Temple University, Philadelphia, Pennsylvania.
Reprint requests: Edwardo A. Salvati, MD, Hip Service, The Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021.
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overall morbidity and mortality in these patients. Furthermore, a survivorship analysis was undertaken to evaluate and predict the long-term performance of prosthetic hip reconstruction using contemporary techniques.
as revision of one or both components. Furthermore, a separate analysis was performed including radiographic failures to assess more accurately the longterm survival of the index arthroplasty
Results Materials and Methods Between June 1981 and June 1988, 33 primary prosthetic hip arthroplasties were performed in 25 consecutive patients with SLE and osteonecrosis at The Hospital for Special Surgery. The Medical Records Department at our institution became fully computerized in 1981. Identification of these patients was accomplished by using the International Classification of Disease (ICD) codes. The hospital records and office notes were carefully reviewed to establish the diagnosis of SLE. Pathology reports were reviewed to confirm the diagnosis of osteonecrosis in the resected femoral heads. The operative records and in-patient charts were reviewed to identify perioperative complications. An attempt was made to contact all patients for a follow-up evaluation. Clinical assessment was performed using the Hospital for Special Surgery hip rating system. This 40-point scale assigns 10 points each for pain, walking, motion and muscle power, and function. A current set of radiographs of the hip joint was also obtained at follow-up in each patient. Radiolucency around the acetabular component was evaluated according to the zones of DeLee and Charnley (2). Position of the cup and reconstruction of the hip rotation center were assessed according to the criteria by Yoder et al. (20). Cup angle is the angle between the edge of the cup and the horizontal line connecting the two teardrops (teardrop line). Cup height is the vertical distance between the hip center of rotation and the teardrop line. Cup lateralization distance is the horizontal distance between the hip center of rotation and medial edge of the ipsilateral teardrop. Radiolucency of the femoral component was determined by the zones of Green (6). The status of the femoral component was evaluated according to the criteria by Harris and McGann (8). Definite loosening was defined as subsidence, fracture of the stem or cement mantle, or progressive radiolucency between cement and stem. Probable loosening was considered if global bone-cement radiolucency of less than 2 mm was present. Possible loosening was defined as bone-cement radiolucency in greater than 50% but less than 100% of the seven Gruen zones. Survivorship analysis was performed using the methods described by Dobbs (3). Failure was defined
Twenty-two patients with 30 hip arthroplasties in this group had a recent clinical and radiographic evaluation (90%). One patient was excluded because of insufficient follow-up (8 months), and she could not be located. One patient was last evaluated at 50 months following surgery and could not be contacted. One patient died from bacterial pneumonitis at 30 months. Therefore, only those patients with a recent clinical and radiographic evaluation were included for final data analysis. However, to assess the survivorship of these reconstructions fully, all hips were included in survivorship analysis. All patients were women. The median age at arthroplasty was 35 years (mean 37.6 years; range 2074 years). The median age at diagnosis of SLE was 26 years (mean, 27.8 years; range, 18-44 years). The median interval between diagnosis and arthroplasty was 7.2 years (mean, 9.5 years; range, 2-45 years). The average height was 163 cm (range, 154-181 cm), and the mean weight was 63.2 kg (range, 4 9 106 kg). Only one patient (1 hip) had a previous failed core decompression 1 year prior to the hip arthroplasty. No other patient had any previous surgery in the ipsilateral involved hip joint. All patients had received corticosteroid therapy prior to undergoing hip replacement. Eighteen patients (22 hips, 76% of the study group) were taking corticosteroid at the time of hip arthroplasty. The mean dose of prednisone was 15 mg per day (range, 0-60 rag/day). Fourteen patients (22 hips, 73% of the final group) were under corticosteroid therapy at final follow-up. The average dose of prednisone was 20 mg per day (range, 0-140 rag/day). Furthermore, four patients (7 hips) required an increase in their daily prednisone dose during the follow-up period. Four patients (5 hips) also received cytotoxic medication, including Cytoxan and Immuran. Medical problems were numerous in these patients. Thirteen patients (60%) were diagnosed with glomerulonephritis either with biopsy or by laboratory parameters. Pleural effusion and pericarditis were diagnosed in five patients (23%). Central nervous system involvement was present in four patients (18%). Eight patients required bilateral total hip replacements. Two additional patients were noted to have radiographic evidence of osteonecrosis involving the
THA in Lupus
contralateral hip, however, remained asymptomatic. Therefore, I0 patients (46%) had bilateral hip involvement. No patient was diagnosed with knee osteonecrosis. Only one patient had unilateral involvement of the proximal humerus with osteonecrosis. All resected femoral heads showed histologic evidence of osteonecrosis. Among the 30 hips that had a recent follow-up, there were 26 cemented and 3 cementless total hip replacements. In the cemented group, femoral components included i4 Charnleys, 7 Triads, 2 each of Osteonics and DF-80s, and 1 Harris Precoat. There were I4 metal-backed and 12 all-polyethylene cemented sockets. In the cementless group, femoral components included two Omnifit (Osteonics), and one Harris-Galante. All three cementless sockets were the Harris-Galante design. One additional patient had a cemented Osteonics bipolar reconstruction. All procedures were performed in a laminar-flow operating room using body-exhaust suits. The posterior approach was used in every case. Contemporary cementing technique, including distal plug, lavaging and brushing the canal, and pressurization, was used in all cemented cases. Perioperative prophylactic antibiotics were given routinely. The average operative time was 111 minutes (range, 7 5 180 minutes). Mean intraoperative blood loss was 310 ml (range, 100-700 ml), while the postoperative drainage averaged 318 ml (range, 150-750 ml). The average hospital stay was 13 days (range, 9-25 days). The median length of follow-up study was 47 months (mean, 52 months; range, 24-108 months). The mean preoperative Hospital for Special Surgery hip score was 15 (range, I 2 - 1 8 ) . The postoperative score averaged 33 (range, 25-38). Twenty-two of the surviving arthroplasties were rated excellent, and eight hips were rated good. One patient required revision of the acetabular polyethylene liner and trochanteric advancement for recurrent dislocation at 31 months following the initial reconstruction. One additional patient required revision of both components for aseptic loosening at 84 months following surgery. Both patients were rated excellent at the most recent follow-up one year following revision surgery. Recent radiographs were available for review in all 30 hips (Figs. 1, 2). The mean cup angle was 43 ° (range, 30°-56°). The mean cup height and offset were 23 mm (range, 13-32 ram) and 29 mm (range, 2 5 - 3 4 mm), respectively. These parameters were comparable to those outlined by Yoder and associates for proper reconstruction of the hip center (15). Two sockets showed evidence of global radiolu-
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Fig. 1. Preoperative radiograph showing osteonecrosis involving both hips in a 25-year-old woman.
cency. One of these demonstrated evidence of cup migration at 96 months. The other patient showed evidence of cup loosening at 32 months of followup. Both of these patients were rated excellent functionally. Only one femoral component demonstrated radiographic evidence of probable loosening at 66 months of follow-up. The patient was rated good clinically. No other femoral component showed radiographic evidence of loosening. Radiographic analysis of the three hips (2 patients) with cementless implants demonstrated no acetabular nor femoral radiolucency at a mean final followup of 28 months. All three femoral components showed mild cortical canceIlization of the proximal medial cortex. The clinical rating was excellent in all three hips at a mean follow-up of 28 months (range, 2 4 - 3 0 months). Survivorship analysis considering revision as fail-
Fig. 2. Follow-up radiograph at 108 months for the right
hip, and 96 months for the left hip. The clinical result was excellent for both.
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The Journal of Arthroplasty Vol. 7 No. 1 March 1992 100
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Fig. 3. Survivorship analysis indicating overall survival probability of 94.6% at 5 years and 81.8% at 9 years.
ures showed a cumulative survival probability of 94.6% at 5 years. This decreased to 81.3% at 9 years of follow-up. If survivorship analysis included radiographic failures (two sockets, radiographically loose but asymptomatic), the cumulative probability of survival for this series was 94.3% and 71.4% at 5 and 9 years, respectively. There were no clinical evidence of thromboembolic disease, no wound-healing complications, no deep infections, and no patient had an exacerbation of their SLE condition following surgery.
Discussion The systemic form of lupus erythematosus and the etiology of vasculitis were first described by Osler in 1895 (16). This immune-mediated chronic inflammatory disease has been widely studied since. Genetic, hormonal, and environmental factors have been implicated in the etiology in addition to the immune mechanisms (19). The medical management of the complications of SLE has improved significantly over the past three to four decades (9, 12, 18, 19). Osteonecrosis remains the most common and disabling orthopaedic complication. Osteonecrosis has been estimated to be present in 20% to 50% of the patients with SLE (9, 11, 19, 2i). The etiologic factors for osteonecrosis include corticosteroid use and the underlying vasculitis. However, the clinical course of SLE patients with osteonecrosis is unpredictable (5, I 1, 12). In a prospective clinical study, 86 patients were followed 6 years (9). There was no symptomatic hip osteonecrosis. No patient was followed with serial radiographs and the incidence of osteonecrosis could not be assessed. In another study, 8% of a large patient population with SLE (3i of 375 patients) were found to have symptomatic osteonecrosis involving one or more joints (11). The femoral head was involved in 80% of these
patients. Seventeen of the 30 patients (57%) had bilateral hip involvement. When these patients were again assessed 7 years later, 56% of those with contralateral hip involvement had gone on to prosthetic reconstruction (5). Treatment options for symptomatic osteonecrosis of the femoral head include protected weight bearing, core decompression, bone graft, femoral osteotomy, and prosthetic arthroplasty (1, 10, 14). Bilateral involvement (46% in the present series) usually precludes hip arthrodesis. The most predictable relief of pain and restoration of function is achieved with prosthetic hip reconstruction. However, the limited longevity of prosthetic fixation is cause for concern because of their young age and improved life expectancy. Prupas and colleagues reported the results of hip arthroplasty in six patients (11 hips) with SLE (17). All procedures were performed between 1973 and 1978. The follow-up ranged from 23 to 76 months, but no average was reported. The median age at arthroplasty was 36 years (range, 22-50 years). All patients were pain free and ambulating independently at final evaluation, but a hip rating scale was not used for follow-up evaluation. More recently, Hanssen and associates reported the results of 43 hip reconstructions in 31 patients with SLE performed between 1971 and 1982 (7). There were i4 bipolar hemiarthroplasties and 29 total hip replacements. Thirty-seven hips (86%) were followed more than 2 years. The median follow-up was 57 months (range, 9-151 months). Ninety-one percent of the patients with a total hip reconstruction were rated good or excellent, while only 50% of the bipolar patients were rated sarisfactory. They also reported a 15% delayed wound healing and 10% superficial infection rate. Twentyfive percent of their patients died from their systemic illness at a mean of 54 months follow-up. The present study included 32 total hip replacements and one bipolar hemiarthroplasty. Thirty hips (90%) had a recent clinical and radiographic followup, and were included for final analysis. The median follow-up was 47 months, which was l0 months shorter than that reported by Hanssen and associates. However, all hips in the final group were followed for at least 24 months. All procedures were performed between 1981 and 1988, nearly a decade after the previously reported series. There was only one death due to pneumonia (3%). The perioperative complications were minimal. All surviving hips were rated good or excellent using the Hospital for Special Surgery hip rating system at final follow-up. The prognosis for patients with SLE has progressively improved between 1955 and 1975 (18, I9).
T H A i n Lupus
The estimated survival in corficosteroid-treated patients was as high as 94% at 5 years and 82% at 10 years. These figures may have improved since then because of earlier diagnosis, aggressive treatment with corticosteroid and cytotoxic medications, and collaboration with cardiologists and nephrologists. In a recent study, Reveille and colleagues found the best survival probability in patients with onset of SLE after the age of 20 years (10-year survival probability > 90%), and prior to age 49 (18). The m e a n age at diagnosis of SLE in our patients was 28 years (median, 26 years). Only one patient was diagnosed before age 20, and none was diagnosed later than age 49. Since their survival probability has been greatly improved with newer treatment moda]ities, longevity of the hip reconstruction is of importance to ensure long-term satisfactory results. The overall probability of survival of the arthroplasty at 5 years was estimated to be 94.6%. Even if radiographic failures were included in survivorship analysis, the overall probability of survival was 94.3% at 5 years. This good clinical result could be in part attributed to the improved surgical and cementing technique, improved biomaterial and prosthetic design, and anesthetic and medical management during the perioperative and postoperative period. Although all patients in this series were independent community ambulators, their activity demand was not comparable to patients of similar age with osteonecrosis because of other causes or degenerative arthritis. This was because of the multisystem involvement of the lupus disease process. Furthermore, the average weight was 63.2 kg. Data from this study should not be used to predict the prognosis of total hip arthroplasty in all patients with osteonecrosis or young adults at large. All four revisions and radiographic failures were associated with acetabular componenl loosening. Only one femoral c o m p o n e n t required revision for aseptic loosening. The clinical and radiographic results of the three cementless prostheses were encouraging. Hybrid total hip reconstructions using cementless sockets and cemented femoral components may offer better long-term fixation in this patient population. Our data confirmed the hypothesis that overall morbidity and mortality in patients with SLE following hip arthroplasty was improved over the study period. We believe that the preoperative clinical disease status of our patients were comparable to those reported by other authors in the past. It is impossible to outline the specific measures that couM have accounted for this improvement in a retrospective anal-
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55
ysis. Better understanding of the pathophysiology of the disease, and more aggressive m a n a g e m e n t with corticosteroid and cytotoxic medications m a y have contributed significantly to the improved results. The other important issue that we intended to address was the durability of total hip reconstruction in this patient population, The functional outcome was good or excellent in all surviving index hip replacements at a mean follow-up time of 4.4 years. The two patients with radiographically loose sockets were rated excellent. The two patients w h o have undergone revision surgery were also rated excellent at final follow-up. The short-term performance of prosthetic hip arthroplasty using contemporary surgical techniques was quite encouraging in this study. It is, however, important to note the survivorship analysis showed a decline to 81.8% by 9 years. Longer follow-up period and greater n u m b e r of patients are required to more conclusively evaluate the long-term results of total hip arthroplasty in patients with SLE. Further improvement in prosthetic fixation, such as hydroxylapatite-coated implants, m a y be beneficial in the future.
References 1. Camp JF, Colwell CW: Core decompression of the femoral head for osteonecrosis. J Bone Joint Surg 68A:1313, 1986 2. DeLee JG, Charnley J: Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop 121:20, 1976. 3. Dobbs HS: Survivorship of total hip replacements. J Bone Joint Surg 62B:168, 1980. 4. Fessell W J: Systemic lupus erythematosus in the community. Arch Intern Med 134:1027, 1974 5. Gerber LH, Shulman B, Klippel JH: Natural history of radiographic articular osteonecrosis in systemic lupus erythematosus. Presented at the American Rheumatism Association Meeting, New Orleans, LA, June, 1986 6. Gruen TA, McNiece GM, Amstutz HC: Modes of failure of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop 141:17, 1979 7. Hanssen AD, Cabanela ME, Michet CJ: Hip arthroplasty in patients with systemic lupus erythematosus. J Bone Joint Surg 69A:807, 1987 8. Harris WH, McGann WA: Loosening of the femoral component after use of the medullary-plug cementing technique. J Bone Joint Surg 68A: 1064, 1986 9. Jonsson H, Nived O, Sturfelt G: Outcome in systemic lupus erythematosus: a prospective study of patients from a defined population. Medicine 68:141, 1989
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10. Kenzora JE: Treatment of idiopathic osteonecrosis: the current philosophy and rationale. Orthop Clin North Am 16:717, 1985 11. Klippel JH, Gerber LH, Pollack L, Decker JL: Avascular necrosis in systemic lupus erythematosus. Silent symmetric osteonecroses. Am J Med 67:83, 1979 12. Klippel JH: Systemic lupus erythematosus, treatmentrelated complications superimposed on chronic disease. JAMA 263:1812, 1990 13. Lawrence RC, Horchberg MC, Kelsey JL, et al: Estimates of the prevalence of selected arthritis and musculoskeletal diseases in the United States. J Rheumatol 16:427, 1989 14. Maistrelli G, Fusco U, Avai A, Bombelli R: Osteonecrosis of the hip treated by intertrochanteric osteotomy: a four to 15-year follow-up. J Bone Joint Surg 70B:761, 1988 15. Michet CJ, Jr, McKenna CH, Elveback LR, et al: Epidemiology of systemic lupus erythematosus and other connective tissue disease in Rochester, Minnesota, 1950 through 1979. Mayo Clin Proc 60:105, 1985
16. Osler W: On the visceral manifestations of the erythema group of skin disease. Am J Med Sci 110:629, 1895 17. Prupas HM, Patzakis M, Quismorio FP, Jr: Total hip arthroplasty for avascular necrosis of the femur in systemic lupus erythematosus. Clin Orthop 161:186, 1981 18. Reveille JD, Bartolucci A, Alarcon GS: Prognosis in systemic lupus erythematosus. Arthritis Rheum 33:37, 1990 19. Rothfield NF: Systemic lupus erythematosus, clinical aspects and treatment, p. 1022. In McCarthy DJ (ed): Arthritis and allied conditions. Lea and Febiger, Philadelphia, 1989 20. Yoder SA, Brand RA, Pedersen DR, O'Gorman TW: Total hip acetabular componet position affects component loosening rates. Clin Orthop 228:79, 1988 21. Zizic TM, Marcoux C, Hungerford DS, et al: Corticosteroid therapy associated with ischemic necrosis of bone in systemic lupus erythematosus. Am J Med 79:596, 1985
Abstract: Systemic lupus erythematosus (SLE) is a chronic inflammatory disease
affecting primarily young women. Osteonecrosis of the femoral head produces significant morbidity in these patients. The clinical and radiographic results of 33 total hip arthroplasties (THA) in 25 patients were studied. The Hospital for Special Surgery hip rating was good or excellent in all surviving index primary hip arthroplasties at a median follow-up of 47 months. Overall survival probability was 94.6% at 5 years and 81.8% at 9 years using survivorship analysis. Perioperative morbidity was minimal. Total hip arthroplasty using contemporary techniques and current management protocols can provide reliable functional improvement in patients with osteonecrosis secondary to SLE. Key words: systemic lupus erythematosus, total hip arthroplasty, osteonecrosis, survivorship analysis, radiographic, prognosis.
Systemic lupus erythematosus (SLE) is a chronic, relapsing, multisystem, inflammatory disorder associated with immunologic abnormalilies. It affects predominantly w o m e n in their second and third decades (19). Its prevalence has been estimated to be 0.5-1.0 per 1,000 w o m e n in North America (4, I5). It was estimated that greater than I30~000 patients may have been affected with this disease in 1985 (13). While arthralgia is the most con~non orthopaedic manifestation, osteonecrosis is the most painful and disabling. The incidence of osteonecrosis has been estimated to be as high as 52% (2 I). Although osteonecrosis has been reported in m a n y sites, the femoral head is the most frequently affected site. The treatment alternatives for osteonecrosis involving the femoral head are multiple in the early stages, and include decompression, bone graft, and osteotomy.
In the late stages, after subchondral collapse has occurred, prosthetic arthroplasty is the procedure of choice in patients with disabling pain. There have been only two previous reported series of the clinical results of total hip arthroplasty in patients with SLE (7, 17). While the relief of pain was predictable, the complication rate and revision rate was significantly greater than that reported in patients with osteoarthritis (7). Both studies reported the results of reconstructions performed in the 1970s using relatively old surgical techniques and prosthetic implants, In addition, the mortality from disease progression was 25% within the first 5 years following surgery in one report (7). The long-term prognosis for patients with SLE has improved considerably (9, 18, 19), thus the durability of prosthetic fixation following hip arthroplasty is an important issue. The purpose of this study was to evaluate the clinical and radiographic results of primary prosthetic hip replacements in consecutive patients with SLE during a 7-year period in the 1980s, at The Hospital for Special Surgery. Our hypothesis was that improved understanding and medical management of SLE would reduce the
From *The Hospitalfor Special Surgery, New York, New York, the fDepartment of Orthopaedic Surgery, Georgetown University Hospital, Washington, D. C., and the ~Department of Orthopaedic Surgery, Temple University, Philadelphia, Pennsylvania.
Reprint requests: Edwardo A. Salvati, MD, Hip Service, The Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021.
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The Journal of Arthroplasty Vol. 7 No. 1 March 1992
overall morbidity and mortality in these patients. Furthermore, a survivorship analysis was undertaken to evaluate and predict the long-term performance of prosthetic hip reconstruction using contemporary techniques.
as revision of one or both components. Furthermore, a separate analysis was performed including radiographic failures to assess more accurately the longterm survival of the index arthroplasty
Results Materials and Methods Between June 1981 and June 1988, 33 primary prosthetic hip arthroplasties were performed in 25 consecutive patients with SLE and osteonecrosis at The Hospital for Special Surgery. The Medical Records Department at our institution became fully computerized in 1981. Identification of these patients was accomplished by using the International Classification of Disease (ICD) codes. The hospital records and office notes were carefully reviewed to establish the diagnosis of SLE. Pathology reports were reviewed to confirm the diagnosis of osteonecrosis in the resected femoral heads. The operative records and in-patient charts were reviewed to identify perioperative complications. An attempt was made to contact all patients for a follow-up evaluation. Clinical assessment was performed using the Hospital for Special Surgery hip rating system. This 40-point scale assigns 10 points each for pain, walking, motion and muscle power, and function. A current set of radiographs of the hip joint was also obtained at follow-up in each patient. Radiolucency around the acetabular component was evaluated according to the zones of DeLee and Charnley (2). Position of the cup and reconstruction of the hip rotation center were assessed according to the criteria by Yoder et al. (20). Cup angle is the angle between the edge of the cup and the horizontal line connecting the two teardrops (teardrop line). Cup height is the vertical distance between the hip center of rotation and the teardrop line. Cup lateralization distance is the horizontal distance between the hip center of rotation and medial edge of the ipsilateral teardrop. Radiolucency of the femoral component was determined by the zones of Green (6). The status of the femoral component was evaluated according to the criteria by Harris and McGann (8). Definite loosening was defined as subsidence, fracture of the stem or cement mantle, or progressive radiolucency between cement and stem. Probable loosening was considered if global bone-cement radiolucency of less than 2 mm was present. Possible loosening was defined as bone-cement radiolucency in greater than 50% but less than 100% of the seven Gruen zones. Survivorship analysis was performed using the methods described by Dobbs (3). Failure was defined
Twenty-two patients with 30 hip arthroplasties in this group had a recent clinical and radiographic evaluation (90%). One patient was excluded because of insufficient follow-up (8 months), and she could not be located. One patient was last evaluated at 50 months following surgery and could not be contacted. One patient died from bacterial pneumonitis at 30 months. Therefore, only those patients with a recent clinical and radiographic evaluation were included for final data analysis. However, to assess the survivorship of these reconstructions fully, all hips were included in survivorship analysis. All patients were women. The median age at arthroplasty was 35 years (mean 37.6 years; range 2074 years). The median age at diagnosis of SLE was 26 years (mean, 27.8 years; range, 18-44 years). The median interval between diagnosis and arthroplasty was 7.2 years (mean, 9.5 years; range, 2-45 years). The average height was 163 cm (range, 154-181 cm), and the mean weight was 63.2 kg (range, 4 9 106 kg). Only one patient (1 hip) had a previous failed core decompression 1 year prior to the hip arthroplasty. No other patient had any previous surgery in the ipsilateral involved hip joint. All patients had received corticosteroid therapy prior to undergoing hip replacement. Eighteen patients (22 hips, 76% of the study group) were taking corticosteroid at the time of hip arthroplasty. The mean dose of prednisone was 15 mg per day (range, 0-60 rag/day). Fourteen patients (22 hips, 73% of the final group) were under corticosteroid therapy at final follow-up. The average dose of prednisone was 20 mg per day (range, 0-140 rag/day). Furthermore, four patients (7 hips) required an increase in their daily prednisone dose during the follow-up period. Four patients (5 hips) also received cytotoxic medication, including Cytoxan and Immuran. Medical problems were numerous in these patients. Thirteen patients (60%) were diagnosed with glomerulonephritis either with biopsy or by laboratory parameters. Pleural effusion and pericarditis were diagnosed in five patients (23%). Central nervous system involvement was present in four patients (18%). Eight patients required bilateral total hip replacements. Two additional patients were noted to have radiographic evidence of osteonecrosis involving the
THA in Lupus
contralateral hip, however, remained asymptomatic. Therefore, I0 patients (46%) had bilateral hip involvement. No patient was diagnosed with knee osteonecrosis. Only one patient had unilateral involvement of the proximal humerus with osteonecrosis. All resected femoral heads showed histologic evidence of osteonecrosis. Among the 30 hips that had a recent follow-up, there were 26 cemented and 3 cementless total hip replacements. In the cemented group, femoral components included i4 Charnleys, 7 Triads, 2 each of Osteonics and DF-80s, and 1 Harris Precoat. There were I4 metal-backed and 12 all-polyethylene cemented sockets. In the cementless group, femoral components included two Omnifit (Osteonics), and one Harris-Galante. All three cementless sockets were the Harris-Galante design. One additional patient had a cemented Osteonics bipolar reconstruction. All procedures were performed in a laminar-flow operating room using body-exhaust suits. The posterior approach was used in every case. Contemporary cementing technique, including distal plug, lavaging and brushing the canal, and pressurization, was used in all cemented cases. Perioperative prophylactic antibiotics were given routinely. The average operative time was 111 minutes (range, 7 5 180 minutes). Mean intraoperative blood loss was 310 ml (range, 100-700 ml), while the postoperative drainage averaged 318 ml (range, 150-750 ml). The average hospital stay was 13 days (range, 9-25 days). The median length of follow-up study was 47 months (mean, 52 months; range, 24-108 months). The mean preoperative Hospital for Special Surgery hip score was 15 (range, I 2 - 1 8 ) . The postoperative score averaged 33 (range, 25-38). Twenty-two of the surviving arthroplasties were rated excellent, and eight hips were rated good. One patient required revision of the acetabular polyethylene liner and trochanteric advancement for recurrent dislocation at 31 months following the initial reconstruction. One additional patient required revision of both components for aseptic loosening at 84 months following surgery. Both patients were rated excellent at the most recent follow-up one year following revision surgery. Recent radiographs were available for review in all 30 hips (Figs. 1, 2). The mean cup angle was 43 ° (range, 30°-56°). The mean cup height and offset were 23 mm (range, 13-32 ram) and 29 mm (range, 2 5 - 3 4 mm), respectively. These parameters were comparable to those outlined by Yoder and associates for proper reconstruction of the hip center (15). Two sockets showed evidence of global radiolu-
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Fig. 1. Preoperative radiograph showing osteonecrosis involving both hips in a 25-year-old woman.
cency. One of these demonstrated evidence of cup migration at 96 months. The other patient showed evidence of cup loosening at 32 months of followup. Both of these patients were rated excellent functionally. Only one femoral component demonstrated radiographic evidence of probable loosening at 66 months of follow-up. The patient was rated good clinically. No other femoral component showed radiographic evidence of loosening. Radiographic analysis of the three hips (2 patients) with cementless implants demonstrated no acetabular nor femoral radiolucency at a mean final followup of 28 months. All three femoral components showed mild cortical canceIlization of the proximal medial cortex. The clinical rating was excellent in all three hips at a mean follow-up of 28 months (range, 2 4 - 3 0 months). Survivorship analysis considering revision as fail-
Fig. 2. Follow-up radiograph at 108 months for the right
hip, and 96 months for the left hip. The clinical result was excellent for both.
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Surgery
Fig. 3. Survivorship analysis indicating overall survival probability of 94.6% at 5 years and 81.8% at 9 years.
ures showed a cumulative survival probability of 94.6% at 5 years. This decreased to 81.3% at 9 years of follow-up. If survivorship analysis included radiographic failures (two sockets, radiographically loose but asymptomatic), the cumulative probability of survival for this series was 94.3% and 71.4% at 5 and 9 years, respectively. There were no clinical evidence of thromboembolic disease, no wound-healing complications, no deep infections, and no patient had an exacerbation of their SLE condition following surgery.
Discussion The systemic form of lupus erythematosus and the etiology of vasculitis were first described by Osler in 1895 (16). This immune-mediated chronic inflammatory disease has been widely studied since. Genetic, hormonal, and environmental factors have been implicated in the etiology in addition to the immune mechanisms (19). The medical management of the complications of SLE has improved significantly over the past three to four decades (9, 12, 18, 19). Osteonecrosis remains the most common and disabling orthopaedic complication. Osteonecrosis has been estimated to be present in 20% to 50% of the patients with SLE (9, 11, 19, 2i). The etiologic factors for osteonecrosis include corticosteroid use and the underlying vasculitis. However, the clinical course of SLE patients with osteonecrosis is unpredictable (5, I 1, 12). In a prospective clinical study, 86 patients were followed 6 years (9). There was no symptomatic hip osteonecrosis. No patient was followed with serial radiographs and the incidence of osteonecrosis could not be assessed. In another study, 8% of a large patient population with SLE (3i of 375 patients) were found to have symptomatic osteonecrosis involving one or more joints (11). The femoral head was involved in 80% of these
patients. Seventeen of the 30 patients (57%) had bilateral hip involvement. When these patients were again assessed 7 years later, 56% of those with contralateral hip involvement had gone on to prosthetic reconstruction (5). Treatment options for symptomatic osteonecrosis of the femoral head include protected weight bearing, core decompression, bone graft, femoral osteotomy, and prosthetic arthroplasty (1, 10, 14). Bilateral involvement (46% in the present series) usually precludes hip arthrodesis. The most predictable relief of pain and restoration of function is achieved with prosthetic hip reconstruction. However, the limited longevity of prosthetic fixation is cause for concern because of their young age and improved life expectancy. Prupas and colleagues reported the results of hip arthroplasty in six patients (11 hips) with SLE (17). All procedures were performed between 1973 and 1978. The follow-up ranged from 23 to 76 months, but no average was reported. The median age at arthroplasty was 36 years (range, 22-50 years). All patients were pain free and ambulating independently at final evaluation, but a hip rating scale was not used for follow-up evaluation. More recently, Hanssen and associates reported the results of 43 hip reconstructions in 31 patients with SLE performed between 1971 and 1982 (7). There were i4 bipolar hemiarthroplasties and 29 total hip replacements. Thirty-seven hips (86%) were followed more than 2 years. The median follow-up was 57 months (range, 9-151 months). Ninety-one percent of the patients with a total hip reconstruction were rated good or excellent, while only 50% of the bipolar patients were rated sarisfactory. They also reported a 15% delayed wound healing and 10% superficial infection rate. Twentyfive percent of their patients died from their systemic illness at a mean of 54 months follow-up. The present study included 32 total hip replacements and one bipolar hemiarthroplasty. Thirty hips (90%) had a recent clinical and radiographic followup, and were included for final analysis. The median follow-up was 47 months, which was l0 months shorter than that reported by Hanssen and associates. However, all hips in the final group were followed for at least 24 months. All procedures were performed between 1981 and 1988, nearly a decade after the previously reported series. There was only one death due to pneumonia (3%). The perioperative complications were minimal. All surviving hips were rated good or excellent using the Hospital for Special Surgery hip rating system at final follow-up. The prognosis for patients with SLE has progressively improved between 1955 and 1975 (18, I9).
T H A i n Lupus
The estimated survival in corficosteroid-treated patients was as high as 94% at 5 years and 82% at 10 years. These figures may have improved since then because of earlier diagnosis, aggressive treatment with corticosteroid and cytotoxic medications, and collaboration with cardiologists and nephrologists. In a recent study, Reveille and colleagues found the best survival probability in patients with onset of SLE after the age of 20 years (10-year survival probability > 90%), and prior to age 49 (18). The m e a n age at diagnosis of SLE in our patients was 28 years (median, 26 years). Only one patient was diagnosed before age 20, and none was diagnosed later than age 49. Since their survival probability has been greatly improved with newer treatment moda]ities, longevity of the hip reconstruction is of importance to ensure long-term satisfactory results. The overall probability of survival of the arthroplasty at 5 years was estimated to be 94.6%. Even if radiographic failures were included in survivorship analysis, the overall probability of survival was 94.3% at 5 years. This good clinical result could be in part attributed to the improved surgical and cementing technique, improved biomaterial and prosthetic design, and anesthetic and medical management during the perioperative and postoperative period. Although all patients in this series were independent community ambulators, their activity demand was not comparable to patients of similar age with osteonecrosis because of other causes or degenerative arthritis. This was because of the multisystem involvement of the lupus disease process. Furthermore, the average weight was 63.2 kg. Data from this study should not be used to predict the prognosis of total hip arthroplasty in all patients with osteonecrosis or young adults at large. All four revisions and radiographic failures were associated with acetabular componenl loosening. Only one femoral c o m p o n e n t required revision for aseptic loosening. The clinical and radiographic results of the three cementless prostheses were encouraging. Hybrid total hip reconstructions using cementless sockets and cemented femoral components may offer better long-term fixation in this patient population. Our data confirmed the hypothesis that overall morbidity and mortality in patients with SLE following hip arthroplasty was improved over the study period. We believe that the preoperative clinical disease status of our patients were comparable to those reported by other authors in the past. It is impossible to outline the specific measures that couM have accounted for this improvement in a retrospective anal-
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ysis. Better understanding of the pathophysiology of the disease, and more aggressive m a n a g e m e n t with corticosteroid and cytotoxic medications m a y have contributed significantly to the improved results. The other important issue that we intended to address was the durability of total hip reconstruction in this patient population, The functional outcome was good or excellent in all surviving index hip replacements at a mean follow-up time of 4.4 years. The two patients with radiographically loose sockets were rated excellent. The two patients w h o have undergone revision surgery were also rated excellent at final follow-up. The short-term performance of prosthetic hip arthroplasty using contemporary surgical techniques was quite encouraging in this study. It is, however, important to note the survivorship analysis showed a decline to 81.8% by 9 years. Longer follow-up period and greater n u m b e r of patients are required to more conclusively evaluate the long-term results of total hip arthroplasty in patients with SLE. Further improvement in prosthetic fixation, such as hydroxylapatite-coated implants, m a y be beneficial in the future.
References 1. Camp JF, Colwell CW: Core decompression of the femoral head for osteonecrosis. J Bone Joint Surg 68A:1313, 1986 2. DeLee JG, Charnley J: Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop 121:20, 1976. 3. Dobbs HS: Survivorship of total hip replacements. J Bone Joint Surg 62B:168, 1980. 4. Fessell W J: Systemic lupus erythematosus in the community. Arch Intern Med 134:1027, 1974 5. Gerber LH, Shulman B, Klippel JH: Natural history of radiographic articular osteonecrosis in systemic lupus erythematosus. Presented at the American Rheumatism Association Meeting, New Orleans, LA, June, 1986 6. Gruen TA, McNiece GM, Amstutz HC: Modes of failure of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop 141:17, 1979 7. Hanssen AD, Cabanela ME, Michet CJ: Hip arthroplasty in patients with systemic lupus erythematosus. J Bone Joint Surg 69A:807, 1987 8. Harris WH, McGann WA: Loosening of the femoral component after use of the medullary-plug cementing technique. J Bone Joint Surg 68A: 1064, 1986 9. Jonsson H, Nived O, Sturfelt G: Outcome in systemic lupus erythematosus: a prospective study of patients from a defined population. Medicine 68:141, 1989
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10. Kenzora JE: Treatment of idiopathic osteonecrosis: the current philosophy and rationale. Orthop Clin North Am 16:717, 1985 11. Klippel JH, Gerber LH, Pollack L, Decker JL: Avascular necrosis in systemic lupus erythematosus. Silent symmetric osteonecroses. Am J Med 67:83, 1979 12. Klippel JH: Systemic lupus erythematosus, treatmentrelated complications superimposed on chronic disease. JAMA 263:1812, 1990 13. Lawrence RC, Horchberg MC, Kelsey JL, et al: Estimates of the prevalence of selected arthritis and musculoskeletal diseases in the United States. J Rheumatol 16:427, 1989 14. Maistrelli G, Fusco U, Avai A, Bombelli R: Osteonecrosis of the hip treated by intertrochanteric osteotomy: a four to 15-year follow-up. J Bone Joint Surg 70B:761, 1988 15. Michet CJ, Jr, McKenna CH, Elveback LR, et al: Epidemiology of systemic lupus erythematosus and other connective tissue disease in Rochester, Minnesota, 1950 through 1979. Mayo Clin Proc 60:105, 1985
16. Osler W: On the visceral manifestations of the erythema group of skin disease. Am J Med Sci 110:629, 1895 17. Prupas HM, Patzakis M, Quismorio FP, Jr: Total hip arthroplasty for avascular necrosis of the femur in systemic lupus erythematosus. Clin Orthop 161:186, 1981 18. Reveille JD, Bartolucci A, Alarcon GS: Prognosis in systemic lupus erythematosus. Arthritis Rheum 33:37, 1990 19. Rothfield NF: Systemic lupus erythematosus, clinical aspects and treatment, p. 1022. In McCarthy DJ (ed): Arthritis and allied conditions. Lea and Febiger, Philadelphia, 1989 20. Yoder SA, Brand RA, Pedersen DR, O'Gorman TW: Total hip acetabular componet position affects component loosening rates. Clin Orthop 228:79, 1988 21. Zizic TM, Marcoux C, Hungerford DS, et al: Corticosteroid therapy associated with ischemic necrosis of bone in systemic lupus erythematosus. Am J Med 79:596, 1985
