Osteonecrosis: current perspectives on pathogenesis and treatment

Osteonecrosis as a complication of treating acute lymphoblastic leukemia in children: a report from the Children's Cancer Group

PURPOSE

To determine the incidence, risk factors, and morbidity for osteonecrosis (ON) in children with acute lymphoblastic leukemia (ALL) treated with intensive chemotherapy including multiple, prolonged courses of corticosteroid.

PATIENTS AND METHODS

The occurrence of symptomatic ON was investigated retrospectively in 1, 409 children ages 1 to 20 years old receiving therapy for high-risk ALL on Children's Cancer Group (CCG) protocol CCG-1882.

RESULTS

ON was diagnosed in 111 patients (9.3% +/- 0.9%, 3-year life-table incidence). The incidence was higher for older children (> or = 10 years: 14.2% +/- 1.3% v < 10 years: 0.9% +/- 0.4%; P: <.0001), especially females 10 to 15 years old and males 16 to 20 years old (19.2% +/- 2.3% and 20.7% +/- 4.7%, respectively). In patients 10 to 20 years old, the incidence of ON was higher for females versus males (17.4% +/- 2.1% v 11.7% +/- 1.6%, respectively; P: =.03) and for patients randomized to receive two 21-day dexamethasone courses versus one course (23.2% +/- 4.8% v 16.4% +/- 4.3%, respectively; P: =.27). Among ethnic groups, whites had the highest incidence and blacks the lowest, with other groups intermediate (16.7% +/- 1.4% v 3.3% +/- 2.3% v 6.7% +/- 2.2%, respectively; P: =.003). There was no difference in event-free survival in patients with or without ON. ON was diagnosed within 3 years of starting ALL therapy in all but one patient, involved weight-bearing joint(s) in 94% of patients, and was multifocal in 74% of patients. Symptoms of pain and/or immobility were chronic in 84% of patients, with 24% having undergone an orthopedic procedure and an additional 15% considered candidates for surgery in the future.

CONCLUSION

Children ages 10 to 20 years who receive intensive ALL therapy, including multiple courses of corticosteroid, are at significant risk for developing ON.

Osteonecrosis in HIV: a case-control study

BACKGROUND

Osteonecrosis (avascular necrosis) has been infrequently reported in HIV-infected patients. It is not known whether HIV itself is an independent risk factor for osteonecrosis.

METHODS

We identified 25 patients with osteonecrosis from 1984 to 1999 from a large county teaching hospital and two large practices in Dallas County that specialize in HIV-disease related therapy. A retrospective chart review was performed to evaluate potential risk factors for osteonecrosis. Each case was matched with two controls for HIV positive status and date of osteonecrosis diagnosis.

RESULTS

In the study, 22 of 25 (88%) case patients had at least one osteonecrosis risk factor compared with 24 of 50 (48%) controls, p =.003. The most common osteonecrosis risk factors were hyperlipidemia (32%), alcoholism (28%), pancreatitis (16%), corticosteroids (12%), and hypercoaguability (12%). Of the cases, 12% were idiopathic. Multiple joints were involved in 72% of cases. Four of the case patients compared with none of the controls received megesterol acetate before the diagnosis of osteonecrosis, p =.01. No significant differences were found between cases and controls with respect to liver function tests, testosterone levels, triglyceride levels, cholesterol levels, or CD4 cell counts. Saquinavir was independently associated with osteonecrosis, p <.05. However, no differences in overall use of protease inhibitors among cases and controls were noted: 79% versus 76%, respectively.

CONCLUSIONS

The increased incidence of osteonecrosis in HIV/AIDS may be due to an increased frequency of risk factors previously associated with osteonecrosis such as hyperlipidemia, corticosteroid use, alcohol abuse, and hypercoaguability. Use of protease inhibitors was not independently associated with osteonecrosis.

Osteonecrosis

Osteonecrosis (avascular necrosis, aseptic necrosis or subchondral avascular necrosis) is not a specific disease entity but the final common pathway of a number of conditions leading to bone death. The main predisposing factors (trauma, glucocorticosteroids, alcoholism and connective tissue disorders) should be carefully sought, but osteonecrosis can also be idiopathic in origin. Its most common localization is to the femoral head, followed by the humeral head, the knee and the small bones of the wrist and foot. New imaging techniques, especially magnetic resonance imaging, have improved the early diagnosis of osteonecrosis as radiographs may be normal in the initial stages. The outcome for the patient is influenced by many factors, the size and localization of the bone necrosis being of primary importance. Early intervention (both surgical and non-surgical) has definitively improved the outcome, but still nearly 50% of cases of femoral head osteonecrosis necessitate arthroplasty. In this chapter, we shall concentrate on patients at high risk of osteonecrosis, on evidence-based diagnosis, especially in the early stages, and on evidence-based treatment suited to the staging system of osteonecrosis.

Dysbaric osteonecrosis: a reassessment and hypothesis

Dysbaric osteonecrosis is associated with exposure to large ambient pressure changes, and comprises necrotic lesions in the fatty marrow-containing shafts of the long bones, and the ball and socket joints (hips and shoulders). The fundamental causes are still in question and the illness remains a significant health hazard. Radiological and pathological features of both dysbaric and non-dysbaric osteonecrosis are indistinguishable and both are characterized by intramedullary venous stasis, ischemia and necrosis of bone. It has been generally accepted that gas bubbles (probably by initiating intramedullary venous stasis) are the prime cause of dysbaric osteonecrosis, as well as being responsible for Type 1 Decompression Sickness or 'the bends'. Importantly, however, not all series have found a correlation between dysbaric osteonecrosis and 'the bends'. Thus even though it is likely that gas bubbles remain the prime cause of dysbaric osteonecrosis, workers have proposed that in some cases there is another etiological factor which may exaggerate the pathologic effects of gas bubbles, making the bone more susceptible to necrosis. It is proposed that rapid compression by impeding venous drainage from bone initiates intramedullary venous stasis. In the presence of intramedullary gas bubbles, this may progress to thrombosis, ischemia and bone necrosis. The review offers an explanation for total sparing of the knee joint in dysbaric osteonecrosis, and sole involvement of the hip and shoulder (in terms of sub-articular lesions and subsequent joint collapse). In addition to continued observance of proper decompression procedures, a slower rate of compression may further reduce the incidence of dysbaric osteonecrosis. Bone death or osteonecrosis is a concept which Hippocrates put forward in antiquity (1), but it was not until 1794 that James Russell of Edinburgh wrote the first modern-day descriptions. In these cases infection was the predominant etiology (1,2). In 1888 Konig described necrosis of the adult femoral head without infection (3) (aseptic necrosis of bone) and in the same year Twynam reported a case of osteonecrosis in a caisson worker (4) in which there was still a significant infective component. In 1911 Bornstein and Plate, followed later and independently by Bassoe in 1913, presented radiological confirmation of aseptic necrosis of bone in compressed air workers (5). The first report of aseptic necrosis in an underwater diver subsequently appeared in 1936 (6). The condition of aseptic necrosis of bone in association with exposure to raised ambient pressure (previously referred to as caisson disease, pressure-induced osteoarthropathy (7), 'bone rot' (8) and other synonyms (6)) is now generally known as dysbaric osteonecrosis (6). Despite detailed examination of this problem by many authorities, dysbaric osteonecrosis still remains a significant occupational hazard with serious medico-legal consequences (5-13). This suggests that preventative measures are being based upon an incomplete understanding of the pathophysiology of the disease, and that other etiological factors are perhaps being overlooked.

Transforming growth factor-beta1 modulates the expression of vascular endothelial growth factor by osteoblasts

Angiogenesis is essential to both normal and pathological bone physiology. Vascular endothelial growth factor (VEGF) has been implicated in angiogenesis, whereas transforming growth factor-beta1 (TGF-beta1) modulates bone differentiation, matrix formation, and cytokine expression. The purpose of this study was to investigate the relationship between TGF-beta1 and VEGF expression in osteoblasts and osteoblast-like cells. Northern blot analysis revealed an early peak of VEGF mRNA (6-fold at 3 h) in fetal rat calvarial cells and MC3T3-E1 osteoblast-like cells after stimulation with TGF-beta1 (2.5 ng/ml). The stability of VEGF mRNA in MC3T3-E1 cells was not increased after TGF-beta1 treatment. Actinomycin D inhibited the TGF-beta1-induced peak in VEGF mRNA, whereas cycloheximide did not. Blockade of TGF-beta1 signal transduction via a dominant-negative receptor II adenovirus significantly decreased TGF-beta1 induction of VEGF mRNA. Additionally, TGF-beta1 induced a dose-dependent increase in VEGF protein expression by MC3T3-E1 cells (P < 0.01). Dexamethasone similarly inhibited VEGF protein expression. Both TGF-beta1 mRNA and VEGF mRNA were concurrently present in rat membranous bone, and both followed similar patterns of expression during rat mandibular fracture healing (mRNA and protein). In summary, TGF-beta1-induced VEGF expression by osteoblasts and osteoblast-like cells is a dose-dependent event that may be intimately related to bone development and fracture healing.

Microvascular features and ossification process in the femoral head of growing rats

In the epiphysis of long bones, different patterns of development of ossification processes have been described in different species. The development of the vascularisation of the femoral head has not yet been fully clarified, although its role in the ossification process is obvious. Our aim was to investigate ossification and vascular proliferation and their relationship, in growing rat femoral heads. Male Wistar rats aged approximately 1, 5 and 8 wk and 4, 8 and 12 mo were used. Light microscopy frontal sections and vascular corrosion casts observed by scanning electron microscopy were employed. In the rat proximal femoral epiphysis, ossification develops from the medullary circulation of the diaphysis, quickly extending to the neck and the base of the head. Hypertrophic chondrocytes occupy the epiphyseal cartilage, and a physeal plate with regular cell columns is present. Starting from about the end of the third month one or more points of fibrovascular outgrowth, above the physeal line, can be observed in each sample. They are often placed centrally or, sometimes, peripherally. The fibrovascular outgrowths penetrate deeply into the cartilage and extend laterally. At age 8 mo, large fibro-osseous peduncles connect the epiphysis to the diaphyseal tissue. At 12 mo, the entire epiphysis appears calcified with an almost total absence of residual cartilage islands. This situation differs in man and in other mammals due both to differing thickness of the cartilage and to the presence of more extensive sources of blood vessels other than the diaphyseal microcirculation, as supplied by the teres ligament and Hunter's circle. In young rats, subchondral vessels and the synovial fluid could play a role in feeding the ossifying cartilage. Later, a loss of resistance of the physis due to marked degeneration of the cell columns, and extensive chondrocyte hypertrophy permit fibrovascular penetration starting from diaphyseal vessels rather than neighbouring vascular territories, such as those of the periosteum and capsule.

Medicolegal issues: headache

This article addresses headache-related topics in which medicolegal issues have occurred or in which they are likely to occur. Where possible, an actual case has been presented. Most sections of this article are divided into three parts: principle of care, case history, and discussion and recommendations. When appropriate, American Academy of Neurology guidelines have been noted.

Ischemic osteonecrosis under fixed partial denture pontics: radiographicand microscopic features in 38 patients with chronic pain

STATEMENT OF PROBLEM

Previous studies have identified focal areas of alveolar tenderness, elevated mucosal temperature, radiographic abnormality, and increased radioisotope uptake or "hot spots" within the quadrant of pain in most patients with chronic, idiopathic facial pain (phantom pain, atypical facial neuralgia, and atypical facial pain).

PURPOSE

This retrospective investigation radiographically and microscopically evaluated intramedullary bone in a certain subset of patients with histories of endodontics, extraction, and fixed partial denture placement in an area of "idiopathic" pain.

MATERIAL AND METHODS

Patients from 12 of the United States were identified through tissue samples, histories, and radiographs submitted to a national biopsy service. Imaging tests, coagulation tests, and microscopic features were reviewed. Of 38 consecutive idiopathic facial pain patients, 32 were women.

RESULTS

Approximately 90% of subpontic bone demonstrated either ischemic osteonecrosis (68%), chronic osteomyelitis (21%), or a combination (11%). More than 84% of the patients had abnormal radiographic changes in subpontic bone, and 5 of 9 (56%) patients who underwent radioisotope bone scan revealed hot spots in the region. Of the 14 patients who had laboratory testing for coagulation disorders, 71% were positive for thrombophilia, hypofibrinolysis, or both (normal: 2% to 7%). Ten pain-free patients with abnormal subpontic bone on radiographs were also reviewed.

CONCLUSIONS

Intraosseous ischemia and chronic inflammation were suggested as a pathoetiologic mechanism for at least some patients with atypical facial pain. These conditions were also offered as an explanation for poor healing of extraction sockets and positive radioisotope scans.

The use of perioperative corticosteroids in craniomaxillofacial surgery

A literature search could not identify a study on the prevalence of the use of perioperative corticosteroids by surgeons performing craniomaxillofacial surgery. To gather this information, we conducted a survey of North American members of the American Society of Maxillofacial Surgeons classified as "active" in the society's roster. The first 90 members in forward and reverse alphabetical order who were capable of receiving a fax transmission were faxed our survey. Sixty surgeons responded, for a response rate of 66.7 percent. Twenty-eight (46.7 percent) reported using short-term, high-dose, perioperative corticosteroids to control postsurgical inflammation. Surgeons performing facial aesthetic surgery alone or in addition to craniomaxillofacial surgery were more likely to be using steroids (Fisher's exact test, p = 0.038). A variety of steroid drugs and regimens were cited by steroid users. The most common reason for using steroids was to decrease edema. Thirty-two (53.3 percent) responders reported that they were not using steroids. The most common reason for not using them was a lack of literature to support their effectiveness. All responders were asked to report any complications encountered with the use of steroids. The majority (78.3 percent) reported no complications. The most common complication encountered was euphoria (13.3 percent). No one reported the occurrence of avascular necrosis of the hip or humerus with the use of steroids. Based on a literature review, an analysis of the steroid regimens and complications reported revealed that steroid use was generally safe. Nevertheless, in addition to the traditional steroid contraindications, consideration should be given to withholding steroids in patients with any of the known risk factors for avascular necrosis, in patients who are or recently have been on nonsteroidal anti-inflammatory drugs, and in aspirin-sensitive asthmatics. These patients may be at increased risk for serious adverse effects with the use of steroids. More research is required to objectively measure the effect of steroids on edema and, if beneficial, to determine the optimal drug regimen.

Avascular osteonecrosis in patients treated for Hodgkin's disease

The aim of this study is to assess the risk of avascular osteonecrosis (AVN) of the femoral head in patients treated for Hodgkin's disease (HD), in relation to the type of treatment they have received. For this purpose, a cohort of 1391 patients treated for HD at University of Rome between 1972 and 1996 was divided into 2 groups according to their initial treatment. The first group contained 784 patients treated, at the onset of HD, either with chemotherapy (CT) containing steroids, combined in some cases with subdiaphragmatic radiotherapy (RT), or with subdiaphragmatic RT combined with CT without steroids. The second group was made up of 607 patients who had received, initially, supradiaphragmatic RT alone or supradiaphragmatic RT combined with CT without steroids. For the purpose of this study, only the 784 patients belonging to the first group were observed for the appearance of AVN, which occurred in 9 cases. The period of time which elapsed between the end of treatment and the radiological evidence of AVN ranged from 23 to 97 months, with an average of 35 months. Because the number of cases of AVN was so small, the pathogenesis of this complication could not be identified.

Exogenous estrogen may exacerbate thrombophilia, impair bone healing and contribute to development of chronic facial pain

A 32 year old white female, in apparently good health, failed to respond to conservative wound care for alveolar osteitis after a routine mandibular first molar extraction. Curettage and biopsy of necrotic alveolar bone from the #30 socket escalated her pain such that hospitalization was necessary for pain management with intravenous morphine. Twelve months prior to admission she had been placed on exogenous estrogen (Premarin, 0.625 mg/day) after a partial oophorectomy. While hospitalized, she was found to have resistance to activated protein C (APCR). Premarin was discontinued. After discharge, weekly changes of an antibiotic impregnated dressing allowed for progressive regeneration of bone and epithelium with gradual reduction in her pain. She was found to be heterozygous for the mutant Factor V Leiden, a heritable factor for increased tendency to form thrombi, so-called thrombophilia. We speculate that the exogenous estrogen administration exacerbated the thrombophilia associated with the Factor V Leiden mutation by compounding the patient's resistance to activated protein C thereby contributing to her development of osteonecrosis and severe alveolar neuralgia.

Avascular necrosis of bilateral knees secondary to corticosteroid enemas

Avascular necrosis (AVN) is a devastating adverse effect of corticosteroid therapy rarely reported in the setting of inflammatory bowel disease. We describe a 48-year-old woman with 6 weeks of progressive bilateral knee pain resulting in the inability to ambulate. Her symptoms developed suddenly, 9 months after treatment with hydrocortisone enemas for ulcerative proctitis. On physical examination, the patient had knee tenderness, decreased range of motion, and flexion contractures. Magnetic resonance imaging showed multiple bony infarcts in bilateral distal femora and proximal tibias, consistent with advanced AVN. Initial therapy included pain management, serial casting, gentle flexibility and strengthening, and limited mobility training. The rehabilitation efforts led to functional improvement. Ultimately, bilateral total knee arthroplasties were recommended to treat her advanced AVN. This is the first reported case of AVN secondary to hydrocortisone enemas. We review the literature and discuss the pathophysiology and management of corticosteroid-induced AVN.

Is avascular necrosis of the femoral head the result of inhibition of angiogenesis?

An hypothesis is offered here that the pathogenesis of avascular necrosis (AVN) of the femoral head is based on the inhibition of angiogenesis. Well-established facts supporting this hypothesis are: 1, the lesion of AVN is vascular obliteration often leading to infarction; 2, glucocorticoids, which are a risk factor for AVN, are inhibitors of angiogenesis; 3, interferons, which are now being used in the treatment of multiple sclerosis, hepatitis, leukemias, and hemangiomas are inhibitors of angiogenesis, and other endogenously produced cytokines are also inhibitors; 4, constituents of cartilage are inhibitors of angiogenesis, explaining the subchondral location of AVN; 5, angiography of the femoral head indicates the need for continual renewal of its blood supply, shows the inhibition of revascularization by steroids, and suggests that the stress of weight bearing makes the femoral head particularly vulnerable. This hypothesis has implications for the therapeutic use of inhibitors of angiogenesis.

Osteonecrosis of the Humeral Head

Current understanding of osteonecrosis of the humeral head is largely based on previous studies of the femoral head. Similarities between the two sites are numerous, but the shoulder has many unique characteristics. The anatomy of the glenohumeral joint, motion at the scapulothoracic joint, the rich vascular supply of the surrounding soft tissues, and the accommodations for the different forces (shear, compression) exerted across the glenohumeral joint all allow the shoulder to tolerate a greater amount of deformity. A number of pathologic agents can cause bone death by disrupting the blood supply, among them corticosteroid use, trauma, dysbarism, hemoglobinopathies, and various systemic diseases that disrupt the vascular system, such as Gaucher's disease and systemic lupus erythematosus. Management is similar to that of femoral osteonecrosis; the earlier stages respond well to nonoperative approaches, and the more advanced stages require surgical intervention. Hemiarthroplasty and total shoulder arthroplasty have produced good outcomes. Surgical intervention with core decompression, vascular flaps, and arthroscopic debridement have also shown promise, but further studies are necessary to define their optimal use.

Total hip arthroplasty for avascular necrosis and degenerative osteoarthritis of the hip

Although several studies of various treatment modalities have been reported during the past decade, osteonecrosis of the femoral head remains a difficult therapeutic problem. Total hip replacement which is reserved for patients showing collapse of the femoral head, usually shows poorer results in patients with osteonecrosis compared with those with osteoarthritis. Uncemented total hip arthroplasty was performed on 29 patients with avascular necrosis of the femoral head and 29 patients with degenerative osteoarthritis. After a mean followup of 7.6 years and 7.1 years for the two groups of patients, only one failure was observed in one patient with osteonecrosis. Clinical evaluation after cementless total hip arthroplasty in both groups of patients revealed improvement in all parameters. Postoperatively, pain improved from 1.4 to 5.1, walking ability from 3.4 to 5.3, and range of motion from 4.5 to 5.5 in patients with osteonecrosis, and pain improved from 1.2 to 5.3, walking ability from 3.2 to 5.4, and range of motion from 3.1 to 4.7 in patients with osteoarthritis. Thigh pain was observed postoperatively in only two and three patients treated for osteonecrosis and osteoarthritis, respectively. The present results using cementless arthroplasty seem to be somewhat better than those reported for cemented arthroplasty in patients suffering from osteonecrosis. The clinical and radiographic findings after noncemented arthroplasty in patients with osteonecrosis of the femoral head and in patients with degenerative arthritis of the hip were similar in the two groups.

Patient-related risk factors for early revision of total hip replacements. A population register-based case-control study of 674 revised hips

In this population register-based, matched case-control study, we assessed patient-related factors and early risk of revision after total hip replacement (THR). Information was obtained via a mall survey among patients reported to the Norwegian Arthroplasty Register during the period 1987-1993. The study included 674 revised hips, as cases, and 1,343 hips with a primary operation only, as controls. Completed questionnaires were received from 81% of the 2,017 individual cases and controls. We identified a set of patient-related factors associated with poor THR prognosis. Increasing weight was a risk factor among male patients older than 67 years who were more than 1.77 m tall (p = 0.01). Smoking had no overall effect, but former heavy smokers had an increased risk of 2.8 compared to never-smokers. Alcohol intake was associated with an increased risk of dislocation. Revision due to infection was commoner among patients taking anti-diabetic drugs (OR = 14) than among patients taking no medication. An increased overall revision risk was found among patients using systemic steroids (OR = 2.8) or local pulmonary steroids (OR = 6.0). The risk also increased in male patients performing regular exercise before the primary operation (OR = 2.6), and in female patients of working-age doing heavy work (OR = 1.9).

Polyostotic osteonecrosis in a patient with celiac disease

OBJECTIVE

To emphasize the role of history and physical examination in the clinical evaluation of hypocalcemia and to describe a patient with celiac sprue and multiple osteonecrosis, a previously unrecognized association.

METHODS

A case report is presented of a 39-year-old man with mild hypocalcemia, diarrhea, and arthralgias, and the appropriate clinical and laboratory assessment for these complaints is outlined.

RESULTS

Secondary hyperparathyroidism, celiac sprue, and extensive osteonecrosis were detected by hematologic and radiologic studies. The hematologic variables normalized after institution of a gluten-free diet and calcium supplementation.

CONCLUSION

This is the first report of celiac sprue and osteonecrosis in one patient. A possible causal relationship due to secondary hyperparathyroidism is suggested, and alternative explanations are discussed.

Incidence and possible aetiological factors in the development of pelvic insufficiency fractures following radical radiotherapy

Five patients out of a total of 183 treated with radical radiotherapy for carcinoma of cervix at The Royal Marsden Hospital from 1991 to 1994 inclusive have developed severe pelvic fractures. Two patients had rheumatoid arthritis, one of whom died as a result of the radiation induced damage. This patient developed radiological evidence of radionecrosis within 1 month of completing radiotherapy. There are very few reports in the literature of such a rapid onset. We suggest that the presence of a connective tissue disorder in a patient with other risk factors such as steroid use, old age and osteopenia should alert the clinician to the risk of radionecrosis following radical irradiation.

Inducible osteonecrosis in a rabbit serum sickness model: deposition of immune complexes in bone marrow

We established inducible osteonecrosis in a rabbit serum sickness model. Osteonecrosis with marrow necrosis could be induced by the intravenous injection of horse serum in two doses separated in time by a period of three weeks. In this model, osteonecrosis could be successfully produced in rabbit femoral metaphysis. The incidence of marrow necrosis was 45% (9 of 20 rabbits) and trabecular necrosis occurred in 6 of 20 rabbits (30%) at 7 days after the second injection of the horse serum. In bone marrow of the femoral metaphysis, extravasation of erythrocytes and the formation of micro-thrombi in arterioles were often observed in an early stage of the present model and both findings correlate well each other (p = 0.0001). Immune complexes could be demonstrated using immunohistochemistry in bone marrow of the femoral metaphysis as well as in glomeruli of the kidney. Extravasation of erythrocytes in bone marrow of the femoral metaphysis was observed in 8 of 12 (67%) cases with immune complex deposition in the sinusoidal space of the femoral metaphysis and in 12 of 21 (57%) cases with immune complex deposition in glomeruli of the kidney. Immune complex deposition both in the sinusoidal space of femoral bone marrow (p = 0.0385) and in glomeruli of the kidney (p = 0.0209) closely related to extravasation of erythrocytes and microthrombi in arterioles in the early stage of this model. Early microcirculatory injury (extravasation of erythrocytes and microthrombi in arterioles) adjacent to osteonecrosis could be induced by immune complex deposition in femoral bone marrow and might be predictable characteristics for the inducible osteonecrosis in the present serum sickness model. The important findings in this study were that early microcirculatory injury was closely related to the deposition of immune complexes in femoral bone marrow, and that early microcirculatory injury associated with immune complex deposition was located close to osteonecrotic regions.

The pathophysiology of alveolar osteonecrosis of the jaw: anticardiolipin antibodies, thrombophilia, and hypofibrinolysis

We studied 55 patients (50 women, 5 men) with severe facial pain and biopsy-proven neuralgia-inducing cavitational osteonecrosis (NICO) of the alveolar bone of the jaws. Our aim was to assess the pathophysiologic contributions to NICO of anticardiolipin antibodies (aCLA), thrombophilia (increased tendency to intravascular thrombi), and hypofibrinolysis (reduced ability to lyse thrombi). Of the 55 patients, 43 (78%) had one or more tests positive for thrombophilia or hypofibrinolysis (or both), and only 12 (22%) were normal. Eighteen of 55 (33%) patients had high aCLA (> 2 SD above mean value for control subjects); immunoglobulin G (IgG) (p = 0.01) and immunoglobulin A (IgA)(p = 0.001) levels were higher in patients than in controls. The distribution of elevated aCLA immunoglobulin classes among patients was as follows: IgG alone, 5 (9%); IgA alone, 7 (13%); and IgM alone, 3 (5%). Three patients (5%) had high levels of both IgG and IgA aCLA. Other defects of the thrombotic or fibrinolytic systems in the 55 patients included high lipoprotein(a) in 36% (vs 20% in control subjects (p = 0.03)), low stimulated tissue plasminogen activator activity (tPA-Fx) in 22% (vs 7% in control subjects (p = 0.08)), high plasminogen activator inhibitor activity (PAI-Fx) in 18% (vs 8% in control subjects (p = 0.03)), resistance to activated protein C in 16% (vs 0% in control subjects (p = 0.007)), low antigenic protein C in 4+ (vs 0% in control subjects (p > 0.2)), and low antigenic protein S in 4% (vs 0% in control subjects (p > 0.2)). Anticardiolipin antibodies and other defects of the thrombotic and fibrinolytic systems appear to be common, potentially reversible pathogenetic risk factors associated with osteonecrosis of the jaw.

Thrombophilia, hypofibrinolysis, and alveolar osteonecrosis of the jaws

OBJECTIVES

Our specific aim in 49 patients (42 women, 7 men) with osteonecrosis of the jaw was to determine whether thrombophilia (increased tendency to intravascular thrombosis) or hypofibrinolysis (reduced ability to lyse thrombi) were associated with this regional avascular necrosis.

STUDY DESIGN

Determinants of thrombosis and fibrinolysis were compared in healthy controls and in 42 women and 7 men who had biopsy-proven idiopathic osteonecrosis of the jaw with severe chronic jaw or facial pain syndromes and failure to respond to conventional medical and dental treatments.

RESULTS

Of the 49 patients, 35 (71%) had thrombophilia or hypofibrinolysis and only 14 were normal. Thrombophilia as a sole coagulation defect was found in 10 patients, 7 with resistance to activated protein C and 3 with low protein C (deficiency of an antithrombotic protein). Hypofibrinolysis with low stimulated tissue plasminogen activator activity and high lipoprotein (a) (an atherogenic, hypofibrinolytic lipoprotein) were found as sole coagulation defects in seven and eight patients, respectively. Ten patients had mixed defects; 7 of these 10 had thrombophilia with resistance to activated protein C. Sinusoidal dilatation was a constant feature in maxillary and mandibular bone biopsies, suggesting venous occlusion with intramedullary hypertension. Marrow fibrosis and occasional fibrin plugs were additional microscopic features believed to impair venous drainage and to contribute to ischemic necrosis of the alveolar bone.

CONCLUSIONS

Primary thrombophilia and hypofibrinolysis appear to be common, heritable, pathophysiologic risk factors for idiopathic osteonecrosis of the jaws. These coagulation defects may also contribute to alveolar neuralgia, atypical odontalgia and facial neuralgia, idiopathic trigeminal neuralgia, and to treatment failures so often encountered in patients with alveolar osteonecrosis and disabling chronic facial and jawbone pain syndromes.

Magnetic resonance imaging of the femoral head to detect avascular necrosis in active rheumatoid arthritis treated with methylprednisolone pulse therapy

Efficacious management of patients with avascular necrosis of bone (AVN) necessitates the identification of patients with a high risk of collapse of the femoral head. In this prospective study we imaged both hips of 10 patients with active rheumatoid arthritis, who were treated with methylprednisolone pulse therapy. MRI and conventional radiography were performed before MP-pulse therapy and 6 and 12 months thereafter. Two patients showed unilateral changes, compatible with AVN. One patient became symptomatic and revealed characteristic radiographic abnormalities. The other patient remained asymptomatic and the MRI appearance returned to normal after 6 months.

Local anesthetic effects in the presence of chronic osteomyelitis (necrosis) of the mandible: implications for localizing the etiologic sites of referred trigeminal pain

The aims of this study were: (1) to demonstrate how reproducible variations in incomplete anesthesia of the inferior alveolar nerve can be used as a guide to locate the etiologic sites of referred trigeminal pain emanating from the mandible; (2) to describe the salient histopathologic features of a lowgrade, nonsuppurative osteomyelitis seen in this patient population. Forty-six patients with idiopathic facial pain were subjected to a specific protocol of local anesthetic injections to sequentially block branches of the mandibular nerve to determine the effects on his/her pain. If this significantly reduced or altered the pain on three separate appointments, then exploratory surgery was conducted near identified zones of unanesthetized gingiva. Blocking (92%), bridging (4%), and divergence (4%) were observed patterns of anesthetic resistance of the mucogingival tissues used to categorize the incomplete anesthesia. A 100% correlation was found between the identified zones of unanesthetized gingiva and the discovery of intramedullary pathology. Medullary fibrosis with ischemic and degenerative changes in the cancellous bone were common findings, along with chronic inflammatory cell infiltrates and clusters of lymphocytes. It is concluded that Ratner's method of diagnostic anesthesia be implemented when searching for occult pain producing pathology of the jaws.