Osteonecrosis during the treatment of childhood acute lymphoblastic leukemia: a prospective MRI study

Femoral head osteonecrosis in pediatric and young adult patients with leukemia or lymphoma

PURPOSE

Osteonecrosis of the capital femoral epiphysis is a significant late toxicity of treatment for childhood leukemia and lymphoma. We determined clinical and imaging risk factors predicting clinical joint outcomes of femoral head osteonecrosis in pediatric patients with leukemia or lymphoma.

PATIENTS AND METHODS

We reviewed retrospectively medical records and magnetic resonance imaging scans of 80 patients with osteonecrosis of the capital femoral epiphysis. Logistic regression was used to examine relationships between risk factors and outcomes of joint surface collapse and arthroplasty. We used Kaplan-Meier survival curves to display the time to joint surface collapse and arthroplasty based on selected predictors.

RESULTS

Median time between primary diagnosis and diagnosis of osteonecrosis of the hip was 1.7 years (range, 0.1 to 17.5 years). Twenty-three patients (29%) underwent arthroplasty in 36 hips at a mean of 1.3 years (range, 0.5 to 8.6 years) after diagnosis of osteonecrosis. Median age at time of first arthroplasty was 20.1 years (range, 15.1 to 35.4 years). Joint outcome of osteonecrosis was predicted solely by lesion size at diagnosis of osteonecrosis. The worst prognosis was associated with lesions occupying more than 30% of the femoral head volume; 80% of hips with these lesions collapsed within 2 years of diagnosis and 50% required arthroplasty.

CONCLUSION

Lesion size of osteonecrosis is the best predictor of clinical joint outcome of hip osteonecrosis in survivors of pediatric hematologic malignancy. Lesions occupying more than 30% of the femoral head have high likelihood of joint deterioration necessitating arthroplasty at a young age.

The incidence and natural history of osteonecrosis in HIV-infected adults

BACKGROUND

Osteonecrosis is increasingly recognized as a debilitating complication of human immunodeficiency virus (HIV) infection, but the natural history has not been well described. We previously documented a high prevalence (4.4%) of magnetic resonance imaging (MRI)-documented osteonecrosis of the hip in a cohort of 339 asymptomatic HIV-infected patients. The present study was designed to determine the incidence of newly diagnosed osteonecrosis in this cohort and to describe the natural history of osteonecrosis in HIV-infected patients.

METHODS

Asymptomatic HIV-infected patients with a previous hip MRI negative for osteonecrosis underwent follow-up MRI. Patients with asymptomatic or symptomatic osteonecrosis were enrolled in a natural history study, which included serial MRIs and a physiotherapy follow-up.

RESULTS

Two hundred thirty-nine patients underwent a second MRI a median of 23 months after the initial MRI. Osteonecrosis of the femoral head was diagnosed in 3 patients (incidence, 0.65 cases per 100 person-years). During the period of January 1999 through April 2006, symptomatic hip osteonecrosis developed in 13 clinic patients (incidence, 0.26 cases per 100 person-years). Among 22 patients enrolled with symptomatic hip osteonecrosis, 18 had bilateral involvement of the femoral heads, and 7 had osteonecrosis involving other bones. Two (11%) of 18 asymptomatic patients and 13 (59%) of 22 symptomatic patients underwent total hip replacement. The percentage of involvement of the weight-bearing surface of the femoral head and the rate of progression to total hip replacement was significantly greater (P<.001) in symptomatic patients than in asymptomatic patients.

CONCLUSIONS

HIV-infected patients are at approximately 100-fold greater risk of developing osteonecrosis than the general population. Disease progression is slower in asymptomatic patients than in symptomatic patients. Given the high frequency of total hip replacement in symptomatic patients, studies to assess preventive and treatment strategies are essential.

Severe acute respiratory syndrome in children

BACKGROUND

Severe acute respiratory syndrome (SARS) is a febrile, respiratory tract illness caused by infection with the newly identified SARS-associated coronavirus. A notable feature of the 2003 global SARS outbreak was the relative paucity of cases reported among children. We reviewed the epidemiologic and clinical features of SARS in children and discuss implications of these findings for diagnosis, treatment and prevention of SARS.

METHODS

We performed a literature search to identify reports of pediatric (younger than 18 years of age) patients meeting the World Health Organization case definitions for SARS and abstracted relevant clinical and epidemiologic information.

RESULTS

We identified 6 case series reporting 135 pediatric SARS patients (80 laboratory-confirmed, 27 probable and 28 suspect) from Canada, Hong Kong, Taiwan and Singapore. Among laboratory-confirmed and probable SARS cases, the most common symptoms included fever (98%), cough (60%) and nausea or vomiting (41%); 97% had radiographic abnormalities. The clinical presentation of SARS in patients older than 12 years of age was similar to that in adults. However, patients 12 years of age or younger had milder disease and were less likely than older children to be admitted to an intensive care unit, receive supplemental oxygen or be treated with methylprednisolone. No deaths were reported among children or adolescents with SARS, and at 6 months after illness only mild residual changes were reported in exercise tolerance and pulmonary function. There is only 1 published report of transmission of SARS virus from a pediatric patient.

CONCLUSIONS

Children and adolescents are susceptible to SARS-associated coronavirus infection, although the clinical course and outcome are more favorable in children younger than 12 years of age compared with adolescents and adults. Transmission of SARS from pediatric patients appears to be uncommon but is possible.

Incidence of skeletal complications during treatment of childhood acute lymphoblastic leukemia: comparison of fracture risk with the General Practice Research Database

BACKGROUND

Skeletal complications during or after treatment of acute lymphoblastic leukemia (ALL) have been frequently reported and can cause substantial morbidity, yet their incidence is not well established. The present study assessed the incidence of fractures, osteonecrosis (ON), and bone pain during ALL treatment and compared the fracture incidence with age- and sex-specific reference data from the UK General Practice Research Database (GPRD).

PROCEDURE

Medical records of 122 ALL patients diagnosed at our institution from 1992 to 2004 were reviewed for information on fractures, ON, bone pain, and their anatomical location, risk group, phase of antileukemic therapy, and time since diagnosis. Evaluation of skeletal complications was followed up until July 2005 or the patient's death. Thirteen children were excluded as they were transferred to other institutions shortly after diagnosis.

RESULTS

Skeletal complications occurred at a 5-year incidence of 32.7%. The 5-year incidence of fractures, ON, and isolated bone pain was 13.5%, 12.1%, and 12.3%, respectively. The relative rate of fractures adjusted for age and sex was 2.03 (95% confidence interval 1.15-3.57) compared to the GPRD, with greatest rates in children <5 years. Thirty ON occurred in 10 patients with a 15 times greater incidence in children >10 years than in those <5 years. Nearly all skeletal complications occurred during maintenance therapy at a median of 14.92 months (range 0.0-53.8) after diagnosis and in weight-bearing bones.

CONCLUSIONS

The doubled fracture rate and the high incidence of skeletal complications during the first years after diagnosis suggest the developing skeleton is very vulnerable in this period. Adolescents develop more ON whereas younger children may be more prone to fractures. Serious "immediate effects" of chemotherapy on bone appear of great concern and should entail preventative studies in this group of patients.

Osteonecrosis in children and adolescents with cancer - an adverse effect of systemic therapy

Osteonecrosis (ON) is recognised increasingly as a complication of the treatment of cancer in children and adolescents. It is especially prevalent among survivors of acute lymphoblastic leukaemia and non-Hodgkin lymphoma, in whom as many as 1/3 may be affected, likely reflecting the cumulative exposure to glucocorticosteroid therapy. The pathogenesis is complex and includes suppression of bone formation, expansion of the intra-medullary lipocyte compartment and a direct effect on nutrient arteries. Children > or =10 years of age are at particular risk and the disorder is substantially more common in Whites than in Blacks. Genetic predispositions have been identified. ON is often multi-articular and bilateral, affecting weight-bearing joints predominantly. Surgical management options are of concern in young growing subjects, although injection of autologous marrow into affected sites offers promising results. Other novel approaches include the use of anti-resorptive drugs and strategies for prevention, such as with lipid-lowering agents, are being explored.

MRI of Knee Osteonecrosis in Children with Leukemia and Lymphoma: Part 2, Clinical and Imaging Patterns

OBJECTIVE

This aim of this study was to explore the relationship between MRI findings and clinical symptoms of knee osteonecrosis in children and to determine the significance of this relationship. Such information is important for early diagnosis of this frequent complication and for choosing an appropriate treatment strategy.

MATERIALS AND METHODS

Osteonecrotic lesion size and location were determined in a retrospective analysis of MR images of the knee obtained in our institution during the past 10 years. Association between MRI findings and clinical symptoms expressed by the knee scores was tested for a subgroup of our patient population who had clinical evaluation of the knees in the orthopedic clinic within 6 weeks of their MRI studies.

RESULTS

In 80% of patients, osteonecrosis was bilateral. Lesions were distributed as follows: femur and tibia, 66% of the knees; femur alone, 26%; and tibia alone, 8%. Clinical symptoms of knee osteonecrosis were associated with lesions involving the articular surface of the distal femur, large lesions, and involvement of any part of the tibia. MR images showed milder osteonecrosis in patients who were less than 10 years old at the time of primary diagnosis.

CONCLUSION

Osteonecrosis affecting the knees of children treated for leukemia and lymphoma is mostly asymptomatic. Children who are 10 years old or older have signs of more advanced osteonecrosis. Clinical symptoms often lag MRI presentation and may develop late in the course of the disease. Routine MRI evaluation is recommended for timely diagnosis of treatment-induced osteonecrosis.

MRI of Knee Osteonecrosis in Children with Leukemia and Lymphoma: Part 1, Observer Agreement

OBJECTIVE

The aim of this study was to determine whether a new MRI-based staging system for osteonecrosis of the knee in pediatric patients could be used with an acceptable level of intra- and interobserver agreement.

MATERIALS AND METHODS

We conducted a retrospective analysis of MRI studies of the knee performed in a single institution between April 1994 and July 2003. Knee osteonecrosis was identified in 168 children with a primary diagnosis of hematologic malignancy. This substantial number prompted us to design a staging system for use with pediatric patients. To assess interobserver reliability of two primary observers in using the system, they reviewed and interpreted the same 36 imaging studies of randomly chosen patients. For the assessment of intraobserver reproducibility, each observer rereviewed 16 studies. A senior observer coded potential causes of disagreement between the primary observers.

RESULTS

Interobserver agreement was substantial: the kappa value was 0.66 (95% confidence interval [CI], 0.58-0.75) in locations where the observers had to record only the presence or absence of a lesion, and the weighted kappa value was 0.65 (95% CI, 0.59-0.72) in locations where they had to classify the extent of involvement. The presence of marrow edema, punctate foci of altered signal, and mottled marrow changes was associated with a higher level of disagreement between the primary observers.

CONCLUSION

Our proposed classification system, developed specifically for use with MRI, was used with substantial intra- and interobserver agreement. We think its use can contribute to a standardized approach to the interpretation of MRI findings in pediatric osteonecrosis of the knee.

Osteonecrosis: a treatment related toxicity in childhood acute lymphoblastic leukemia (ALL)--experiences from trial ALL-BFM 95

BACKGROUND

Osteonecrosis (ON) as a complication during treatment of acute lymphoblastic leukemia (ALL) has gained rising attention over the past decade. Corticosteroids, representing an essential element of antileukemic therapy, are known to induce ON, which in turn may cause significant morbidity. Due to spontaneous reporting of affected patients with ON, a group-wide evaluation was performed to determine incidence, risk factors, and morbidity for ON.

PROCEDURE

Patients were identified via spontaneous reporting to the study center and via questionnaire, addressing all 64 participating centers. We retrospectively analyzed 1,951 patients below 18 years of age who were treated according to trial ALL-BFM 95 between 01.01.1996 and 30.06.2000.

RESULTS

Thirty-one patients (14 male, 17 female) affected by ON were identified. The overall 5-year cumulative incidence for ON is 1.8%. The incidence for patients <10 years is 0.2%, whereas for patients >/=10 years it is 8.9% (P = 0.00) and 16.7% (P = 0.003) for patients >/=15 years. The majority (n = 20) showed ON in two or more joints, and the joints most commonly affected were knees (14 patients, 24 affected knees) and hips (11 patients, 20 affected joints). Thirteen out of 31 patients had to undergo surgery in the course of their disease.

CONCLUSIONS

Symptomatic ON is a rare event in patients treated with BFM-type chemotherapy with an overall 5-year cumulative incidence of 1.8%. The age group >/=10 years, and particularly adolescents >/=15 years have a significantly higher risk of developing ON.

Osteonecrosis in children with severe acute respiratory syndrome

Osteonecrosis is a debilitating bone disease affecting adults who have recovered from severe acute respiratory syndrome in Hong Kong and China, but there are no data on its prevalence in children. We report 5 children with magnetic resonance imaging evidence of osteonecrosis. In view of the high prevalence and asymptomatic presentation of osteonecrosis, we suggest magnetic resonance imaging screening for osteonecrosis in children with severe acute respiratory syndrome.

Zoledronic acid treatment results in retention of femoral head structure after traumatic osteonecrosis in young Wistar rats

Osteonecrosis (ON) of the femoral head in childhood can lead to loss of femoral head architecture and subsequent deformity. When femoral head ON was surgically induced in 24 rats, zoledronic acid treatment and prophylaxis improved sphericity and maintenance of architecture at 6 weeks. This preliminary experiment supports the use of bisphosphonates in childhood ON.

INTRODUCTION

We hypothesized that the bisphosphonate zoledronic acid could preserve femoral head structure while allowing bone repair.

MATERIALS AND METHODS

Osteonecrosis (ON) was surgically induced in the right femoral head of 24 female Wistar rats. The rats were randomized into three treatment groups and dosed subcutaneously with saline, zoledronic acid (0.1 mg/kg) at 1 and 4 weeks postoperation (ZA post), or zoledronic acid (0.1 mg/kg) given 2 weeks preoperation and at 1 and 4 weeks postoperation (ZA pre-post). After death at 6 weeks postoperation, undecalcified specimens were analyzed by DXA and standardized histomorphometric analysis.

RESULTS

Seventy-one percent of saline-operated femoral heads were aspherical (Mose score > 1), whereas only 13% and 0% of operated heads in the ZA-treated groups were aspherical (p < 0.05). DXA-measured bone mineral density in saline-treated femoral heads was reduced by 34% and 43% compared with the ZA-treated groups (p < 0.01). Histomorphometry showed decreases of 12% and 17% in bone volume (BV/TV) in saline groups compared with ZA post and ZA pre-post (p < 0.05), and a decrease in trabecular number (Tb.N) of 18% and 14% (p < 0.05), respectively. Bone formation rate (BFR) was increased by 56% in saline-treated operated heads over ZA post and was 4.8 times increased over the ZA pre-post group (p < 0.05). The differences in BV/TV and Tb.N in treated groups must therefore be caused by a reduction in bone turnover. Observational histology confirmed the retention of necrotic architecture in treated groups.

CONCLUSIONS

Zoledronic acid treatment and prophylaxis preserved femoral head architecture after traumatic ON in this rat model at 6 weeks. These data indicate that, by conserving femoral head architecture, bone repair may occur in conjunction with improved femoral head shape.

Pathogenesis and natural history of osteonecrosis

BACKGROUND AND OBJECTIVES

Osteonecrosis (avascular necrosis) is a relatively common disorder seen by both rheumatologists and orthopedic surgeons. The vast majority of cases are secondary to trauma. However, for non-traumatic cases, there often remains a diagnostic challenge in defining the cause of bone death. The goal of this article is to review data extensively in the medical literature with respect to the pathogenesis of osteonecrosis, its natural history, and treatment.

METHODS

A review of 524 studies on osteonecrosis was performed, of which 213 were selected and cited.

RESULTS

Non-traumatic osteonecrosis has been associated with corticosteroid usage, alcoholism, infections, hyperbaric events, storage disorders, marrow infiltrating diseases, coagulation defects, and some autoimmune diseases. However, a large number of idiopathic cases of osteonecrosis have been described without an obvious etiologic factor. Although corticosteroids can produce osteonecrosis, careful history is always warranted to identify other risk factors. The pathogenesis of non-traumatic osteonecrosis appears to involve vascular compromise, bone and cell death, or defective bone repair as the primary event. Our understanding of the pathogenesis of osteonecrosis is now much better defined and skeletal scintigraphy and magnetic resonance imaging have enhanced diagnosis greatly. Early detection is important because the prognosis depends on the stage and location of the lesion, although the treatment of femoral head osteonecrosis remains primarily a surgical one.

CONCLUSIONS

Osteonecrosis has been associated with a wide range of conditions. Many theories have been proposed to decipher the mechanism behind the development of osteonecrosis but none have been proven. Because osteonecrosis may affect patients with a variety of risk factors, it is important that caregivers have a heightened index of suspicion. Early detection may affect prognosis because prognosis is dependent on the stage and location of the disease. In particular, the disease should be suspected in patients with a history of steroid usage, especially in conjunction with other illnesses that predispose the patient to osteonecrosis.

RELEVANCE

A better understanding of the pathophysiology, diagnosis and treatment of osteonecrosis will help the physician determine which patients are at risk for osteonecrosis, facilitating early diagnosis and better treatment options.

Bony morbidity in children treated for acute lymphoblastic leukemia

PURPOSE

Corticosteroids are widely used in the treatment of acute lymphoblastic leukemia (ALL). To determine the frequency of corticosteroid-associated bony morbidity in children with ALL, we retrospectively evaluated the incidence of fractures and osteonecrosis (ON) on two consecutive pediatric ALL protocols.

PATIENTS AND METHODS

One hundred seventy-six consecutive children were treated for ALL between 1987 and 1995 at the Dana-Farber Cancer Institute and Children's Hospital. Prednisone was used as the corticosteroid during postremission therapy from 1987 to 1991, and dexamethasone was used from 1991 to 1995. Medical records for all patients were reviewed to assess the occurrence of fractures and ON.

RESULTS

With a median follow-up of 7.6 years, the 5-year cumulative incidence (CI) +/- SE of any bony morbidity for the 176 patients was 30% +/- 4%, with a 5-year CI of fractures of 28% +/- 3% and of ON of 7% +/- 2%. With multivariate analysis, independent predictors of bony morbidity included age 9 to 18 years at diagnosis (P <.01), male sex (P <.01), and treatment with dexamethasone (P =.01). Dexamethasone was associated with a higher risk of fractures (5-year CI, 36% +/- 5% v 20% +/- 4% with prednisone; P =.04), but not ON (P =.40). The 5-year event-free survival for the 176 patients was 79% +/- 3%.

CONCLUSION

Children treated for ALL had a high incidence of fractures and ON. Older children, boys, and patients receiving dexamethasone were at increased risk for the development of bony morbidity. Future studies should attempt to minimize corticosteroid-associated bony morbidity without compromising clinical efficacy.

Magnetic resonance imaging detection of avascular necrosis of the bone in children receiving intensive prednisone therapy for acute lymphoblastic leukemia or non-Hodgkin lymphoma

The purpose of this study was to determine the frequency with which magnetic resonance (MR) imaging detects avascular necrosis of the bone (AVNB) in children with acute lymphoblastic leukemia (ALL) or advanced-stage non-Hodgkin lymphoma (NHL) who receive prednisone during remission induction, reinduction, and maintenance chemotherapy; to assess the clinical significance of these findings; and to identify factors predictive of AVNB. We prospectively obtained MR imaging of the hips and knees of 116 children who had completed at least 1 year of treatment for ALL or advanced-stage NHL on identical prednisone-containing regimens between December 1991 and October 1994. MR imaging findings of AVNB were compared with clinical outcomes, and the effect of therapeutic and patient factors on the frequency of AVNB was analyzed. The MR imaging findings of 17 of the 116 participating patients were consistent with AVNB. The most common clinical manifestation was joint pain (11 patients). Only one patient had progressive joint deterioration that necessitated surgical replacement. Only age 10 years or more at the time of the primary diagnosis was significantly associated with the development of AVNB (P = 0.004). MR imaging showed changes consistent with AVNB in approximately 15% of this patient population. However, most patients in this study who had MR imaging signs of AVNB did not experience progressive joint destruction, even with continued prednisone therapy. Therefore, the clinical usefulness of MR imaging as a screening tool for AVNB in this set of patients remains uncertain.

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.

Long term survivors of childhood leukemia

Changes in therapy, primarily intensification, for childhood leukemias have significantly improved cure rates during the past 30 years. The increasing number of survivors has led to a heightened appreciation of the late complications of treatment caused by both radiation and chemotherapy. Important late effects include decreased growth, poor school performance, altered cardiac function, infertility, and second malignant neoplasms. The long term outcome of children and adolescents suffering from the most recently recognized acute complication of treatment, avascular necrosis of weight-bearing bones, is still not known. These, and all patients treated on clinical trials, should be followed throughout their lives. Many of the complications of treatment are often not realized until years after the completion of therapy; some have been found to be related to dose intensity, emphasizing the importance of clinical trials that examine reduction of therapy for diseases with excellent cure rates. A successful example of this strategy is the elimination or reduction of radiation dose for the prevention of central nervous system acute lymphocytic leukemia. This has resulted in fewer long term central nervous system complications without a decrease in survival rates. As knowledge of late effects increases, design of future trials will need to focus on striking a balance between cure and long term toxicity.

Acute lymphoblastic leukemia in children

As the overall long-term event-free survival rate in children with acute lymphoblastic leukemia approaches 80%, emphasis is being placed on risk-directed therapy so that patients are neither overtreated nor undertreated. It has become apparent that a risk assignment system based on primary genetic abnormalities is inadequate by itself. For example, leukemias with the MLL-AF4 or BCR-ABL fusion gene are, in fact, heterogeneous diseases. Many require allogeneic hematopoietic stem-cell transplantation; some, if the patient is of favorable age and has a low presenting leukocyte count, can be cured with chemotherapy alone. Measurement of early responses to therapy and extent of minimal residual disease can greatly improve the accuracy of risk assessment. Consideration of the variable effects of therapy on the prognostic significance of specific genetic abnormalities is also important. Therefore, TEL-AML1 fusion confers a favorable prognosis in some protocols of chemotherapy but not in others. Studies to identify genetic polymorphisms with pharmacokinetic and pharmacodynamic significance promise to guide further refinement of treatment strategies. This will allow maximization of anticancer effects without induction of unacceptable toxicity in individual patients.