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Natural history of avascular necrosis of the femoral head in systemic lupus erythematosus
~
J Orthop Sci (1997) 2:10-15
Journalof
thopaedic Science TheJapaneseOrthopaedicAssociation
Natural history of avascular necrosis of the femoral head in systemic lupus erythematosus MASAAKI USUI, HAJIME INOUE, SHIGEHUMIYUKIHIRO, and NOBUHIRO ABE Department of Orthopaedic Surgery, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama 700, Japan
Abstract: Clinical and radiographic studies were performed on 228 hips of 145 patients with avascular necrosis of the femoral head (ANFH). The patients were divided into three groups: group A consisted of 33 patients with systemic lupus erythematosus (SLE) who had been treated with systemic corticosteroids (59 hips); group B consisted of 41 patients with a history of corticosteroid treatment, excluding patients with SLE (69 hips); and group C consisted of 71 patients with no history of corticosteroid use (100 hips). Of the 228 hips, 80 hips at an early stage of the necrosis, but not showing collapse, were selected and classified by the criteria of the Japanese Investigation Committee (JIC) to define the natural history of the disease. In the SLE patients (group A), there was a predisposition to bilateral involvement and multiple sites of bone necrosis. Eighty percent of the femoral heads followed at an early stage had collapsed at the end of the follow-up, the incidence of collapse in group A being higher than that in the other groups. The collapses in group A were predominantly types 1C, 2, and 3B according to the JIC criteria. The incidence of collapse was significantly lower in type 1A and type 3A than in the other types. The classification proposed by the JIC, in terms of types with regard to size and location of the necrotic area on antero-posterior radiographs, was very useful for evaluation of the risk of collapse as well as for selecting appropriate treatment modalities, either conservative or surgical, during the early stages of ANFH.
the past four decades. 6 As the life expectancy of these patients has increased, bone necrosis, particularly of the femoral head, is now a major complication that may produce marked functional impairment. Osteonecrosis was first described in SLE by Dubois and Cozen in 1960. 3 Numerous reports have since indicated a prevalence ranging from 7% to 16%. 1,s,z7 In the course of avascular necrosis of the femoral head (ANFH), collapse of the femoral head usually results in incongruity of the hip joint, leading to secondary osteoarthrosis. In some patients, the disease is static or progresses very slowly. 9,t~,12If we could predict the natural course in an individual patient, in particular, the susceptibility to femoral collapse, it would be easier to select the appropriate treatment. The goals of this study were to make clear the clinical features of A N F H in patients with SLE compared with these features in non-SLE patients, particularly in terms of the natural history. In this study, we adopted the criteria of the Japanese Investigation Committee (JIC) (under the auspices of the Ministry of Health and Welfare) for the radiographic classification of A N F H in an attempt to determine susceptibility to collapse and to provide a functional prognosis. 11
Key words: necrosis, femoral head, systemic lupus erythematosus, natural history
Patients and methods
Introduction
The prognosis of patients with systemic lupus erythematosus (SLE) has improved considerably over
Offprint requests to: M. Usui Received for publication on April 12, 1996; accepted on Aug. 1, 1996
From 1972 to 1992, 228 hips in 145 patients with A N F H were examined at Okayama University Hospital. The patients were divided into three groups according to etiology. Group A consisted of 33 SLE patients with A N F H (4 men, 29 women; 59 hips), all of whom had had corticosteroid therapy. Group B consisted of 41 patients (16 men, 25 women; 69 hips) who had A N F H secondary to corticosteroid administration for diseases other than SLE, and group C consisted 71 of A N F H patients who had no history of corticosteroid administration (39 men, 32 women; 100 hips). In group A and group B patients,
M. Usui et al.: AVN of the femoral head in SLE
11
either corticosteroid had been administered for at least 1 year, or if the duration of corticosteroid administration was less than 1 year, the maximum dose of corticosteroids had been more than 30rag/day of prednisolone. Table 1 shows the underlying diseases in Group B patients, who had connective tissue diseases other than SLE, and other conditions. The average age of onset of ANFH was 31.3 years (20-64 years) in group A, 46.7 years (16-69 years) in group B, and 52.2 years (19-86 years) in group C. In group A, ANFH had developed within a mean of 4 years and 10 months after the appearance of SLE and within a mean of 3 years and 2 months after the beginning of the steroid therapy. Eighteen patients had received high-dose steroid therapy (more than 30mg/day of prednisolone). In group B, ANFH had developed within a mean of 5 years after the appearance of the underlying disease and within a mean of 4 years and 3 months after the beginning of the steroid therapy. In addition to ANFH, multiple sites of involvement were frequent in group A. In 8 patients in group A, 10 humeral heads, 10 femoral condyles, and 1 talus were affected with avascular necrosis. Three patients in group B had multiple sites of osteonecrosis; however, in group C, there were no patients with multiple sites of osteonecrosis. Of the 228 hips in the 145 patients with ANFH, 80 hips, at an early stage of ANFH, but not showing collapse, were selected and followed to determine their natural history. The radiographic stage of ANFH was assessed by the criteria of Ficat, 4 and only patients with ANFH in Ficat's stage 2 were examined, because in stages 3 and 4, irreversible destruction of the joint had already occurred. A series of radiographs were evaluated to determine the incidence of femoral collapse. The follow-up period ranged from 2 to 10 years (mean, 4 years and 6 months). Twenty-eight hips in group A, 24 hips in group B, and 28 hips in group C were studied. The survival rate of the hips was analyzed by the Kaplan-Meier method, the end point being defined as the time at which the collapse of
Table 1. Underlying disease in group B
No. of patients Connective tissue disease (other than systemic lupus erythematosus) Blood disease Liver disease Renal transplantation Nephrosis Skin disease Subacute myelo-optico-neuropathy Other
8 7 5 5 4 4 3 5
the femoral heads had progressed more than 2ram. Statistical analysis of differences among the groups was made by the generalized Wilcoxon test and differences were considered significant if the P value was less than 0.05. Using the criteria of the JIC, we classified the femoral heads in stage 2 into six distinct types according to the size and location of the necrotic area on the anteroposterior radiographs (Fig. 1). Type 1 femoral head necrosis, which is characterized by the presence of a line of demarcation, is further divided into three subtypes, 1A, 1B, and 1C, according to the relationship of the necrotic area to the weightbearing surface; that is, the outer end of the line of demarcation is located at the medial one-third of the weight-bearing surface in type 1A, the middle one-third in type 1B, and the lateral one-third or more in type 1C. Type 2 shows early flattening of the weight-bearing surface and there is no line of demarcation. In type 3, there are cystic lesions, and these lesions are divided into subtypes according to location. In type 3A, the cystic lesion is located anteriorly or medially, far from the weight-bearing surface. Type 3B is characterized by a cystic lesion under the lateral weight-bearing surface. According to these criteria, the hips in stage 2 were classified into six different types and the incidence of collapse of the femoral head was determined.
Results
The type of necrosis and the incidence of collapse in each group are shown in Table 2. Type 1C and type 2 were the most frequently seen in all groups. In group A, 86% of the femoral heads collapsed. Only two hips of type 3A did not collapse and remained at stage 2. In group B, 79% of the femoral heads collapsed; all femoral heads of type 1C and type 2 collapsed. In group C, 75% of the femoral heads collapsed. The femoral heads of type 1A and type 3A had good prognoses (i.e., no collapse). Overall, 80% of the femoral heads collapsed. These collapses were predominantly in type 1C, type 2, and type 3B. There was no apparent relation between the dose of corticosteroid and the type or the incidence of collapse. Kaplan-Meier analysis showed that, in group A, 80% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 86% of them have collapsed. In group B, the analysis showed that 76% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 79% of them have collapsed. In group C, the analysis showed that 70% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 75% of them have collapsed (Fig. 2). The
J ,
/J j
f9
M.
s
Type 1-B
Type ]-A
Type 1-C
Type 2
Type 3- B
Type 3-A
Fig, 1. Classification of avascular necrosis of the femoral head in Ficat's stage 24proposed by the Japanese Investigation Committee ~1 according to size and location of necrotic area
(%)
100
GroupA ] GroupB............../ P
T~ 50 _~
Gr~
~~
~
I
0
I
I
2
I
I
a
I
i
4 6 follow-up
!
8
I
,,|
10 (y.)
Fig. 2. Survival rate of the femoral heads in stage 2 analyzed by the KaplanMeier method
Table 2. Progression of collapse in stage 2 Group A
Group B
Group C
Total
Number of heads
Number collapsed
Number of heads
Number collapsed
Number of heads
Number collapsed
Number of heads
Number collapsed
1A 1B 1C 2 3A 3B
0 4 9 11 2 2
0 (0%) 3 (75%) 8 (89%) 11 (100%) 0 (0%) 2 (100%)
1 3 8 9 3 0
0 (0%) 2 (67%) 8 (100%) 9 (100%) 0 (0%) 0 (0%)
1 1
0 (0%) 1 (100%)
10 5 3
10 (100%) 1 (2o%) 2 (67%)
2 8 25 30 10 5
0 (0%) 6 (75%) 23 (92%) 30 (100%) 1 (10%) 4 (80%)
Total
28
24 (86%)
24
28
21 (75%)
80
64 (80%)
Type
19 (79%)
8
7(88%)
M. Usui et al.: AVN of the femoral head in SLE difference between groups A and C was significant. Eventually, as stated above, 80% of the femoral heads collapsed. Replacement surgery was carried out for 28 femoral heads.
13 within 2 years and bilateral total hip arthroplasty was performed (Fig. 3b). In this patient, osteonecrosis was also seen in the right humeral head and left talus. Case 2
Case reports Case 1
A woman was diagnosed with SLE at the age of 33 years and corticosteroid therapy was begun 4 years later. The maximum dose of corticosteroids was 30mg/day of prednisolone and the maintenance dose was 5mg/day. At age 39 years, she developed pain in the bilateral hips and visited our clinic. The initial radiograph showed type 2 femoral head necrosis of the right hip and type 1C in the left hip (Fig. 3a). The femoral heads collapsed
A woman developed SLE at the age of 21 years and corticosteroid therapy was begun immediately and continued. The maximum dose of corticosteroids was 10mg/day of prednisolone and the maintenance dose was 5 mg/day. At age 24 years, she developed pain in the bilateral hips and visited our clinic. The initial radiograph showed type 1A femoral necrosis in the right hip and type 1B in the left hip (Fig. 4a). Seven years later, the necrotic area of the right femoral head had become smaller and the left femoral head showed no collapse on periodic observation (Fig. 4b).
b Fig. 3a,b. Radiographs of case 1. a Initial radiograph showed type 2 femoral head necrosis in the right hip and type 1C in the left hip. b Two years later, both femoral heads had completely collapsed
b Fig. 4a,b. Radiographs of case 2. a Initial radiograph showed type 1A necrosis of the femoral head in the right hip and type 1B in the left hip. b Seven years later, the right femoral head was repaired and the left femoral head showed no collapse
14
Discussion
M. Usui et al.: AVN of the femoral head in SLE Only 1 of 12 hips that were types 1A and 3A at stage 2 at the entry of the patients into the study had collapsed at the final examination (mean follow-up period, 5 years and i month). As collapse was rare in these two types of necrosis, we suggest that surgical intervention should be avoided in these patients; the best form of management is periodic observation. However, we found this type of good prognosis in only 15% of the ANFH patients. As all heads showing type 2 necrosis collapsed very rapidly, and the area of necrosis was usually large with poor reparative response, it would seem very difficult to treat these patients without replacement surgery of some sort. With femoral heads of type 1C necrosis, we feel that the collapse will progress if the management is not appropriate; our treatment of choice is Sugioka's transtrochanteric rotational osteotomy16to preserve the femoral head. In this procedure, the intact surface of the head on lateral view is introduced into the weightbearing portion and femoral collapse is prevented (Fig.
ANFH is reported to occur quite frequently in patients with SLE who receive high-dose corticosteroid therapy. 1,3,8,17In recent years, the prognosis for patients with SLE has improved considerably, and consequently, ANFH has become a major complication that may produce marked functional impairment in these patients. ANFH in SLE patients is characterized by bilateral involvement and a predilection for the young female. 5,~4 In our study, the average age of onset of ANFH, when the patients first developed pain in their hips, was 31.3 years, and about 80% of the patients showed bilateral involvement. Multiple sites of osteonecrosis were seen in 24% of these patients with SLE. As ANFH commonly involves the young adult, and as the results of hip replacement surgery have been poor in these patients, joint-preserving operations such as core decompression or osteotomy are preferable. 2,4,7,13,16Early detection and assessment of the prognosis of ANFH are very important in selecting the appropriate management. While there have been previous descriptions of the natural history of ANFH, 9,12 precise classifications and accurate determination of prognosis have been lacking. We found the classification system proposed by the JIC to be very useful for evaluating the risk of collapse? ~ This classification can enable accurate prediction of the fate of the femoral head, allowing the selection of appropriate treatment.
SLE patients with ANFH showed a greater susceptibility to femoral collapse than that shown in the other groups; this may be related to the high-dose corticosteroid therapy or to vasculitis caused by SLE. 1,8 However, the location and size of the area of necrosis was very closely related to the overall outcome for the hip. Sugano et a135 reported the prognosis of ANFH in SLE patients assessed by magnetic resonance imaging
Fig. 5a-c. Sugioka's transtrochanteric rotational osteotomy.16 a Type 1C necrosis in a 26-year-old man with systemic lupus erythematosus, b Smooth articular surface was introduced to
the weight-bearing portion by Sugioka's transtrochanteric rotational osteotomy, c Two years after the osteotomy, collapse had not occurred
5a-c).
a,b
M. Usui et al.: AVN of the femoral head in SLE
(MRI). They showed the importance of the early detection of A N F H and of subsequent treatment to prevent collapse of the femoral head. More recently, Mont and Hungerford 1~ proposed a new classification of A N F H according to MRI and scintiscan findings, and their recommendations for treatment, such as core decompression, osteotomy or total hip replacement, can be used as a general guide. However, these treatment modalities basically depend on the radiographic findings. Although the radiographic classification proposed by the JIC was based on the anteroposterior radiograph only, the validity and usefulness of the classification has been confirmed in this study.
Conclusion
1. In SLE patients, bilateral involvement, multiple bone necrosis, and predilection for young female patients were apparent. 2. The incidence of femoral collapse was higher in SLE patients than in non-SLE patients. 3. The classification proposed by the Japanese Investigation Committee was very useful for evaluating the risk of femoral collapse, as well as for selecting an appropriate treatment modality, either conservative or surgical, during the early stages of ANFH.
References l. Abeles M, Urman JD, Rothfield NF. Aseptic necrosis of bone in systemic lupus erythematosus: Relationship to corticosteroid therapy. Arch Intern Med 1978;138:750-4. 2. Dorr LD, Kane TJO, Conaty JP. Long-term results of cemented total hip arthrop/asty in patients 45 years old or younger. A 16year follow-up study. J Arthroplasty 1994;9:453-6.
15 3. Dubois EL, Cozen L. Avascular (aseptic) bone necrosis associated with systemic lupus erythematosus. JAMA 1960:174:966-71. 4. Ficat RP. Treatment of avascular necrosis of the femoral head. In: Hungerford DS, editor. The hip. St. Louis: CV Mosby, 1983:27995. 5. Griffiths ID, Maini RN, Scott JT. Clinical and radiological features of osteonecrosis in systemic lupus erythematosus. Ann Rheum Dis 1979;38:413-22. 6. Hahn BH. Management of systemic lupus erytematosus. In: Kelley WN, Harris ED, Ruddy S, Sledge CB, editors. Textbook of rheumatology, vol.2. 4th ed. Philadelphia: WB Saunders, 1993: 1043-56. 7. Hungerford DS, Zizic TM. Alcoholism-associated ischemic necrosis of the femoral head. Early diagnosis and treatment. Clin Orthop 1978;130:144-53. 8. Kalla AA, Learmonth ID, Klemp P. Early treatment of avascular necrosis in systemic lupus erythematosus. Ann Rheum Dis 1986;45:649-52. 9. Merle d'Aubigne' R, Postel M, Mazabraud A, et al. Idiopatic necrosis of the femoral head in adult. J Bone Joint Surg Br 1965;47:612-33. 10. Mont MA, Hungerford DS. Current concepts review. Non-traumatic avascular necrosis of the femoral head. J Bone Joint Surg Am 1995;77:459-74. 11. Ohzono K, Saito M, Takaoka K, et al. Natural history of nontraumatic avascular necrosis of the femoral head. J Bone Joint Surg Br 1991;73:68-72. 12. Patterson RJ, Bickel WH, Dahlin DC. Idiopathic avascular necrosis of the head of the femur. A study of 52 cases. J Bone Joint Surg Am 1964;64:267-82. 13. Saito S, Ohzono K, Ono K. Joint-preserving operation for idiopathic avascular necrosis of the femoral head. J Bone Joint Surg Br 1988;70:78-84. 14. Smith FE, Sweet DE, Brunner CM, et al. Avascular necrosis in SLE. An apparent predilection for young patients. Ann Rheum Dis 1976;35:227-32. 15. Sugano N, Ohzono K, Masuhara K, et al. Prognostication of osteonecrosis of the femoral head in patients with systemic lupus erythematosus by magnetic resonance imaging. Clin Orthop 1994;305:190-9. 16. Sugioka Y, Katsuki I, Hotokebuchi T. Transtrochanteric rotational osteotomy of the femoral head for the treatment of osteonecrosis. Follow-up statistics. Clin Orthop 1982;169:115-26. 17. Zizic TM, Hungerford DS, Stevens HB. Ischemic bone necrosis in systemic lupus erythematosus. 1. The early diagnosis of ischemic necrosis of bone. Medicine 1980;59:134-42.
J Orthop Sci (1997) 2:10-15
Journalof
thopaedic Science TheJapaneseOrthopaedicAssociation
Natural history of avascular necrosis of the femoral head in systemic lupus erythematosus MASAAKI USUI, HAJIME INOUE, SHIGEHUMIYUKIHIRO, and NOBUHIRO ABE Department of Orthopaedic Surgery, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama 700, Japan
Abstract: Clinical and radiographic studies were performed on 228 hips of 145 patients with avascular necrosis of the femoral head (ANFH). The patients were divided into three groups: group A consisted of 33 patients with systemic lupus erythematosus (SLE) who had been treated with systemic corticosteroids (59 hips); group B consisted of 41 patients with a history of corticosteroid treatment, excluding patients with SLE (69 hips); and group C consisted of 71 patients with no history of corticosteroid use (100 hips). Of the 228 hips, 80 hips at an early stage of the necrosis, but not showing collapse, were selected and classified by the criteria of the Japanese Investigation Committee (JIC) to define the natural history of the disease. In the SLE patients (group A), there was a predisposition to bilateral involvement and multiple sites of bone necrosis. Eighty percent of the femoral heads followed at an early stage had collapsed at the end of the follow-up, the incidence of collapse in group A being higher than that in the other groups. The collapses in group A were predominantly types 1C, 2, and 3B according to the JIC criteria. The incidence of collapse was significantly lower in type 1A and type 3A than in the other types. The classification proposed by the JIC, in terms of types with regard to size and location of the necrotic area on antero-posterior radiographs, was very useful for evaluation of the risk of collapse as well as for selecting appropriate treatment modalities, either conservative or surgical, during the early stages of ANFH.
the past four decades. 6 As the life expectancy of these patients has increased, bone necrosis, particularly of the femoral head, is now a major complication that may produce marked functional impairment. Osteonecrosis was first described in SLE by Dubois and Cozen in 1960. 3 Numerous reports have since indicated a prevalence ranging from 7% to 16%. 1,s,z7 In the course of avascular necrosis of the femoral head (ANFH), collapse of the femoral head usually results in incongruity of the hip joint, leading to secondary osteoarthrosis. In some patients, the disease is static or progresses very slowly. 9,t~,12If we could predict the natural course in an individual patient, in particular, the susceptibility to femoral collapse, it would be easier to select the appropriate treatment. The goals of this study were to make clear the clinical features of A N F H in patients with SLE compared with these features in non-SLE patients, particularly in terms of the natural history. In this study, we adopted the criteria of the Japanese Investigation Committee (JIC) (under the auspices of the Ministry of Health and Welfare) for the radiographic classification of A N F H in an attempt to determine susceptibility to collapse and to provide a functional prognosis. 11
Key words: necrosis, femoral head, systemic lupus erythematosus, natural history
Patients and methods
Introduction
The prognosis of patients with systemic lupus erythematosus (SLE) has improved considerably over
Offprint requests to: M. Usui Received for publication on April 12, 1996; accepted on Aug. 1, 1996
From 1972 to 1992, 228 hips in 145 patients with A N F H were examined at Okayama University Hospital. The patients were divided into three groups according to etiology. Group A consisted of 33 SLE patients with A N F H (4 men, 29 women; 59 hips), all of whom had had corticosteroid therapy. Group B consisted of 41 patients (16 men, 25 women; 69 hips) who had A N F H secondary to corticosteroid administration for diseases other than SLE, and group C consisted 71 of A N F H patients who had no history of corticosteroid administration (39 men, 32 women; 100 hips). In group A and group B patients,
M. Usui et al.: AVN of the femoral head in SLE
11
either corticosteroid had been administered for at least 1 year, or if the duration of corticosteroid administration was less than 1 year, the maximum dose of corticosteroids had been more than 30rag/day of prednisolone. Table 1 shows the underlying diseases in Group B patients, who had connective tissue diseases other than SLE, and other conditions. The average age of onset of ANFH was 31.3 years (20-64 years) in group A, 46.7 years (16-69 years) in group B, and 52.2 years (19-86 years) in group C. In group A, ANFH had developed within a mean of 4 years and 10 months after the appearance of SLE and within a mean of 3 years and 2 months after the beginning of the steroid therapy. Eighteen patients had received high-dose steroid therapy (more than 30mg/day of prednisolone). In group B, ANFH had developed within a mean of 5 years after the appearance of the underlying disease and within a mean of 4 years and 3 months after the beginning of the steroid therapy. In addition to ANFH, multiple sites of involvement were frequent in group A. In 8 patients in group A, 10 humeral heads, 10 femoral condyles, and 1 talus were affected with avascular necrosis. Three patients in group B had multiple sites of osteonecrosis; however, in group C, there were no patients with multiple sites of osteonecrosis. Of the 228 hips in the 145 patients with ANFH, 80 hips, at an early stage of ANFH, but not showing collapse, were selected and followed to determine their natural history. The radiographic stage of ANFH was assessed by the criteria of Ficat, 4 and only patients with ANFH in Ficat's stage 2 were examined, because in stages 3 and 4, irreversible destruction of the joint had already occurred. A series of radiographs were evaluated to determine the incidence of femoral collapse. The follow-up period ranged from 2 to 10 years (mean, 4 years and 6 months). Twenty-eight hips in group A, 24 hips in group B, and 28 hips in group C were studied. The survival rate of the hips was analyzed by the Kaplan-Meier method, the end point being defined as the time at which the collapse of
Table 1. Underlying disease in group B
No. of patients Connective tissue disease (other than systemic lupus erythematosus) Blood disease Liver disease Renal transplantation Nephrosis Skin disease Subacute myelo-optico-neuropathy Other
8 7 5 5 4 4 3 5
the femoral heads had progressed more than 2ram. Statistical analysis of differences among the groups was made by the generalized Wilcoxon test and differences were considered significant if the P value was less than 0.05. Using the criteria of the JIC, we classified the femoral heads in stage 2 into six distinct types according to the size and location of the necrotic area on the anteroposterior radiographs (Fig. 1). Type 1 femoral head necrosis, which is characterized by the presence of a line of demarcation, is further divided into three subtypes, 1A, 1B, and 1C, according to the relationship of the necrotic area to the weightbearing surface; that is, the outer end of the line of demarcation is located at the medial one-third of the weight-bearing surface in type 1A, the middle one-third in type 1B, and the lateral one-third or more in type 1C. Type 2 shows early flattening of the weight-bearing surface and there is no line of demarcation. In type 3, there are cystic lesions, and these lesions are divided into subtypes according to location. In type 3A, the cystic lesion is located anteriorly or medially, far from the weight-bearing surface. Type 3B is characterized by a cystic lesion under the lateral weight-bearing surface. According to these criteria, the hips in stage 2 were classified into six different types and the incidence of collapse of the femoral head was determined.
Results
The type of necrosis and the incidence of collapse in each group are shown in Table 2. Type 1C and type 2 were the most frequently seen in all groups. In group A, 86% of the femoral heads collapsed. Only two hips of type 3A did not collapse and remained at stage 2. In group B, 79% of the femoral heads collapsed; all femoral heads of type 1C and type 2 collapsed. In group C, 75% of the femoral heads collapsed. The femoral heads of type 1A and type 3A had good prognoses (i.e., no collapse). Overall, 80% of the femoral heads collapsed. These collapses were predominantly in type 1C, type 2, and type 3B. There was no apparent relation between the dose of corticosteroid and the type or the incidence of collapse. Kaplan-Meier analysis showed that, in group A, 80% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 86% of them have collapsed. In group B, the analysis showed that 76% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 79% of them have collapsed. In group C, the analysis showed that 70% of the femoral heads in stage 2 will have collapsed within 3 years; subsequently, 75% of them have collapsed (Fig. 2). The
J ,
/J j
f9
M.
s
Type 1-B
Type ]-A
Type 1-C
Type 2
Type 3- B
Type 3-A
Fig, 1. Classification of avascular necrosis of the femoral head in Ficat's stage 24proposed by the Japanese Investigation Committee ~1 according to size and location of necrotic area
(%)
100
GroupA ] GroupB............../ P
T~ 50 _~
Gr~
~~
~
I
0
I
I
2
I
I
a
I
i
4 6 follow-up
!
8
I
,,|
10 (y.)
Fig. 2. Survival rate of the femoral heads in stage 2 analyzed by the KaplanMeier method
Table 2. Progression of collapse in stage 2 Group A
Group B
Group C
Total
Number of heads
Number collapsed
Number of heads
Number collapsed
Number of heads
Number collapsed
Number of heads
Number collapsed
1A 1B 1C 2 3A 3B
0 4 9 11 2 2
0 (0%) 3 (75%) 8 (89%) 11 (100%) 0 (0%) 2 (100%)
1 3 8 9 3 0
0 (0%) 2 (67%) 8 (100%) 9 (100%) 0 (0%) 0 (0%)
1 1
0 (0%) 1 (100%)
10 5 3
10 (100%) 1 (2o%) 2 (67%)
2 8 25 30 10 5
0 (0%) 6 (75%) 23 (92%) 30 (100%) 1 (10%) 4 (80%)
Total
28
24 (86%)
24
28
21 (75%)
80
64 (80%)
Type
19 (79%)
8
7(88%)
M. Usui et al.: AVN of the femoral head in SLE difference between groups A and C was significant. Eventually, as stated above, 80% of the femoral heads collapsed. Replacement surgery was carried out for 28 femoral heads.
13 within 2 years and bilateral total hip arthroplasty was performed (Fig. 3b). In this patient, osteonecrosis was also seen in the right humeral head and left talus. Case 2
Case reports Case 1
A woman was diagnosed with SLE at the age of 33 years and corticosteroid therapy was begun 4 years later. The maximum dose of corticosteroids was 30mg/day of prednisolone and the maintenance dose was 5mg/day. At age 39 years, she developed pain in the bilateral hips and visited our clinic. The initial radiograph showed type 2 femoral head necrosis of the right hip and type 1C in the left hip (Fig. 3a). The femoral heads collapsed
A woman developed SLE at the age of 21 years and corticosteroid therapy was begun immediately and continued. The maximum dose of corticosteroids was 10mg/day of prednisolone and the maintenance dose was 5 mg/day. At age 24 years, she developed pain in the bilateral hips and visited our clinic. The initial radiograph showed type 1A femoral necrosis in the right hip and type 1B in the left hip (Fig. 4a). Seven years later, the necrotic area of the right femoral head had become smaller and the left femoral head showed no collapse on periodic observation (Fig. 4b).
b Fig. 3a,b. Radiographs of case 1. a Initial radiograph showed type 2 femoral head necrosis in the right hip and type 1C in the left hip. b Two years later, both femoral heads had completely collapsed
b Fig. 4a,b. Radiographs of case 2. a Initial radiograph showed type 1A necrosis of the femoral head in the right hip and type 1B in the left hip. b Seven years later, the right femoral head was repaired and the left femoral head showed no collapse
14
Discussion
M. Usui et al.: AVN of the femoral head in SLE Only 1 of 12 hips that were types 1A and 3A at stage 2 at the entry of the patients into the study had collapsed at the final examination (mean follow-up period, 5 years and i month). As collapse was rare in these two types of necrosis, we suggest that surgical intervention should be avoided in these patients; the best form of management is periodic observation. However, we found this type of good prognosis in only 15% of the ANFH patients. As all heads showing type 2 necrosis collapsed very rapidly, and the area of necrosis was usually large with poor reparative response, it would seem very difficult to treat these patients without replacement surgery of some sort. With femoral heads of type 1C necrosis, we feel that the collapse will progress if the management is not appropriate; our treatment of choice is Sugioka's transtrochanteric rotational osteotomy16to preserve the femoral head. In this procedure, the intact surface of the head on lateral view is introduced into the weightbearing portion and femoral collapse is prevented (Fig.
ANFH is reported to occur quite frequently in patients with SLE who receive high-dose corticosteroid therapy. 1,3,8,17In recent years, the prognosis for patients with SLE has improved considerably, and consequently, ANFH has become a major complication that may produce marked functional impairment in these patients. ANFH in SLE patients is characterized by bilateral involvement and a predilection for the young female. 5,~4 In our study, the average age of onset of ANFH, when the patients first developed pain in their hips, was 31.3 years, and about 80% of the patients showed bilateral involvement. Multiple sites of osteonecrosis were seen in 24% of these patients with SLE. As ANFH commonly involves the young adult, and as the results of hip replacement surgery have been poor in these patients, joint-preserving operations such as core decompression or osteotomy are preferable. 2,4,7,13,16Early detection and assessment of the prognosis of ANFH are very important in selecting the appropriate management. While there have been previous descriptions of the natural history of ANFH, 9,12 precise classifications and accurate determination of prognosis have been lacking. We found the classification system proposed by the JIC to be very useful for evaluating the risk of collapse? ~ This classification can enable accurate prediction of the fate of the femoral head, allowing the selection of appropriate treatment.
SLE patients with ANFH showed a greater susceptibility to femoral collapse than that shown in the other groups; this may be related to the high-dose corticosteroid therapy or to vasculitis caused by SLE. 1,8 However, the location and size of the area of necrosis was very closely related to the overall outcome for the hip. Sugano et a135 reported the prognosis of ANFH in SLE patients assessed by magnetic resonance imaging
Fig. 5a-c. Sugioka's transtrochanteric rotational osteotomy.16 a Type 1C necrosis in a 26-year-old man with systemic lupus erythematosus, b Smooth articular surface was introduced to
the weight-bearing portion by Sugioka's transtrochanteric rotational osteotomy, c Two years after the osteotomy, collapse had not occurred
5a-c).
a,b
M. Usui et al.: AVN of the femoral head in SLE
(MRI). They showed the importance of the early detection of A N F H and of subsequent treatment to prevent collapse of the femoral head. More recently, Mont and Hungerford 1~ proposed a new classification of A N F H according to MRI and scintiscan findings, and their recommendations for treatment, such as core decompression, osteotomy or total hip replacement, can be used as a general guide. However, these treatment modalities basically depend on the radiographic findings. Although the radiographic classification proposed by the JIC was based on the anteroposterior radiograph only, the validity and usefulness of the classification has been confirmed in this study.
Conclusion
1. In SLE patients, bilateral involvement, multiple bone necrosis, and predilection for young female patients were apparent. 2. The incidence of femoral collapse was higher in SLE patients than in non-SLE patients. 3. The classification proposed by the Japanese Investigation Committee was very useful for evaluating the risk of femoral collapse, as well as for selecting an appropriate treatment modality, either conservative or surgical, during the early stages of ANFH.
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