Subchondral insufficiency fractures of the femoral head

The aim of this study was to increase awareness of, and to show the variable clinical and radiological features of, subchondral insufficiency fractures of the femoral head. The clinical and radiological findings in 7 patients with subchondral insufficiency fractures of the femoral head were reviewed retrospectively. The diagnosis was confirmed histologically in 4 patients. Radiographs were performed in all patients, MRI in 5 and scintigraphy in 4 patients. Radiographs showed varying degrees of femoral head collapse in 4 patients. In the remaining 3 patients radiographs showed a normal femoral head, regional osteoporosis and focal sclerosis, respectively. Magnetic resonance imaging showed a low-signal band on T1- and T2-weighted images in the subchondral bone adjacent or parallel to the articular surface associated with bone marrow oedema. Scintigraphy showed increased uptake in the femoral head. Insufficiency fractures of the femoral head are easily overlooked or confused with avascular necrosis and, when there is significant joint destruction, osteoarthritis. Unsuspected insufficiency fracture of the femoral head can lead to significant and rapid loss of bone stock in osteoporotic patients waiting for arthroplasty for osteoarthritis. Increased awareness of this condition will hopefully lead to earlier diagnosis and a successful outcome of conservative treatment.

Spontaneous resolution of lumbar vertebral eosinophilic granuloma

Eosinophilic granuloma (EG) is a rare disease but is more common in adults than children. It's often self-limiting. Spinal involvement is rare. It is the localized and most benign form of Langerhans' cell histiocytosis (previously known as histiocytosis X), characterised by lytic lesions in one or more bones. Spontaneous resolution of vertebral body lesions is very rare. In this case, the patient had one EG in a cervical vertebra and a similar lesion in a lumbar vertebra. This case is important because it featured a symptomatic lesion in the cervical spine accompanied by an asymptomatic lesion in a lumbar vertebra. We treated the cervical lesion by surgical fusion and followed the lumbar lesion up conservatively, with the patient in a corset. After 8 years of follow-up, control MRI showed that the lumbar lesion had spontaneously resolved.

Metastatic burst fracture risk prediction using biomechanically based equations

Clinical guidelines are a useful adjunct to select patients with spinal metastases for prophylactic intervention. The objective of this study is to determine the ability of biomechanically based models to accurately predict metastatic burst fracture risk. Ninety-two vertebrae with osteolytic spinal metastases were examined retrospectively. Vertebrae were categorized as burst fractured, wedge fractured, or intact and analyzed using three predictive models: vertebral bulge (maximum radial displacement under load), vertebral axial displacement (maximum axial displacement under load), and a volumetric estimate of tumor size. The load-bearing capacity parameter (tumor volume, bone mineral density, disc quality, pedicle involvement) was determined from computed tomography while the load-bearing requirement parameter (pressure load, loading rate) was determined using computed tomography and patient records (retrieved for 37 patients [52%]). Fracture prediction was optimized using the vertebral bulge model considering only load-bearing capacity with a specificity, sensitivity, and confidence interval of 1 to yield a clear threshold for burst fracture risk. Fracture prediction in the other two models, vertebral axial displacement considering only load-bearing capacity and tumor size, also was strong with receiver-operator curve values of 0.992 and 0.988, respectively. The predictive power of these models can provide useful clinical information for prophylactic decision-making.

Fracture risk in monoclonal gammopathy of undetermined significance

To assess fractures in monoclonal gammopathy of undetermined significance (MGUS), the precursor of multiple myeloma, we followed 488 Olmsted County, MN, residents with MGUS in a retrospective cohort study. There was a 2.7-fold increase in the risk of axial fractures but no increase in limb fractures. The pathophysiologic basis for the increased axial fractures should be determined.

INTRODUCTION

Multiple myeloma is often preceded by monoclonal gammopathy of undetermined significance (MGUS). Fractures are common in myeloma as a result of lytic bone lesions, generalized bone loss, and elevated bone turnover from excessive cytokine production. Whether fractures are also increased in MGUS is unknown.

MATERIALS AND METHODS

In a population-based retrospective cohort study, 488 Olmsted County, MN, residents with MGUS first diagnosed in 1960-1994 (52% men; mean age, 71.4 +/- 12.8 years) were followed for 3901 person-years; follow-up was censored at progression to myeloma. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models.

RESULTS AND CONCLUSIONS

Altogether, 200 patients experienced 385 fractures. Compared with expected rates in the community, statistically significant increases were seen for fractures at most axial sites, for example, vertebrae (SIR, 6.3; 95% CI, 5.2-7.5). There was a slight increase in hip (SIR, 1.6; 95% CI, 1.2-2.2) but not distal forearm fractures (SIR, 0.8; 95% CI, 0.4-1.5). The relative risk (SIR) of any axial fracture was 2.7 (95% CI, 2.3-3.1) compared with only 1.1 (95% CI, 0.9-1.4) for all limb fractures combined. In a multivariate analysis, the independent predictors of any subsequent fracture were age (hazard ratio [HR] per 10-year increase, 1.4; 95% CI, 1.2-1.6) and corticosteroid use (HR, 1.8; 95% CI, 1.2-2.6); greater weight at diagnosis (HR per 10 kg, 0.8; 95% CI, 0.8-0.9), and IgG monoclonal protein (HR, 0.7; 95% CI, 0.5-0.97) were protective. Baseline monoclonal protein level, a determinant of myeloma progression, did not predict fracture risk. Thus, the risk of axial, but not peripheral, fractures is increased among MGUS patients even before progression to myeloma. The pathophysiologic basis for this should be determined because elevated bone turnover, for example, might be treatable.

Quantitative assessment of diffusion abnormalities in benign and malignant vertebral compression fractures by line scan diffusion-weighted imaging

OBJECTIVE

Acute vertebral collapse is common, and it is sometimes difficult to determine whether the cause is benign or malignant. Recently, diffusion-weighted imaging has been reported to be useful for differentiating the two types. The purpose of this study was to evaluate diffusion abnormalities quantitatively in benign and malignant compression fractures using line scan diffusion-weighted imaging. SUBJECTS AND METHODS. Line scan diffusion-weighted imaging was prospectively performed in 17 patients with 20 acute vertebral compression fractures caused by osteoporosis or trauma, in 12 patients with 16 vertebral compression fractures caused by malignant tumors, and in 35 patients with 47 metastatic vertebrae without collapse. Images were obtained at b values of 5 and 1,000 sec/mm(2). The apparent diffusion coefficient (ADC) was measured in vertebral compression fractures and metastatic vertebrae without collapse.

RESULTS

The ADC (mean +/- SD) was 1.21 +/- 0.17 x 10(-3) mm(2)/sec in benign compression fractures, 0.92 +/- 0.20 x 10(-3) mm(2)/sec in malignant compression fractures, and 0.83 +/- 0.17 x 10(-3) mm(2)/sec in metastatic vertebral lesions without collapse. The ADC was significantly higher in benign compression fractures than in malignant compression fractures (p < 0.01), although the two types showed considerable overlap.

CONCLUSION

Although the quantitative assessment of vertebral diffusion provides additional information concerning compressed vertebrae, the benign and malignant compression fracture ADC values overlap considerably. Therefore, even a quantitative vertebral diffusion assessment may not always permit a clear distinction between benign and malignant compression fractures.

Insufficiency fractures of the sternum

Insufficiency fractures occur within weakened bones that are unable to withstand the stress of every day normal activities. The spine, pelvis, and lower long-bone extremities are common sites of insufficiency fractures. Spontaneous sternal insufficiency fracture (SIF) has rarely been reported in elderly patients. To recognise a sternal insufficiency fracture is important in selecting the adequate diagnostic procedures.

Atypical Pott's disease: localized infection of the thoracic spine due to Mycobacterium avium-intracellulare in a patient without human immunodeficiency virus infection

Mycobacterium avium-intracellulare (MAI) rarely causes disease of the spine in healthy individuals. We describe an elderly woman who had isolated skeletal involvement with MAI, mimicking Pott's disease. She responded well to surgical excision of the inflamed tissue and antibiotic therapy. Osteomyelitis due to MAI must be differentiated from that due to Mycobacterium tuberculosis because the treatment regimens are different.

[Diffusion-weighted imaging of acute vertebral compression: Differential diagnosis of benign versus malignant pathologic fractures]

PURPOSE

Our purpose was to assess the value of diffusion-weighted steady-state free precession (SSFP) sequence for differentiating between benign and pathologic compression fractures.

MATERIALS AND METHODS

Forty-nine patients with 63 acute vertebral compression fractures caused by osteoporosis (n = 23), trauma (n = 7), malignancy (n = 30), infection (n = 3) were examined with a diffusion-weighted SSFP sequence (diffusion gradient strength; 23 mT/m, diffusion pulse length 5 ms), T1-weighted turbo spin-echo sequence, and short-inversion-time (TI 150 ms) T2-weighted turbo inversion recovery sequence. The signal intensity characteristics were analyzed qualitatively and quantitatively for all sequences. Statistical analysis was performed with the Student's t test.

RESULTS

In diffusion-weighted MR imaging, benign osteoporotic and traumatic fractures were hypo- to isointense to adjacent normal vertebral bodies. Pathologic and infectious compression fractures were hyperintense to normal vertebral bodies. Pathologic vertebral fractures had positive bone marrow contrast ratios at diffusion-weighted imaging, whereas non infectious benign vertebral fractures had negative values (p < 0.001). The difference in bone marrow contrast ratios for benign and pathologic compression fractures at T1-weighted TSE and T2-weighted turbo IR was not significant (p > 0.01).

CONCLUSION

Diffusion-weighted SSFP sequence provides unique information that significantly impacts the accuracy of radiologic diagnosis. Diffusion-weighted SSFP sequence may allow the differentiation of acute benign osteoporotic fractures from malignant compression fractures. Acute benign osteoporotic or traumatic fractures show hypointense or isointense signal on diffusion-weighted sequences that reflects persistent free water proton mobility. Malignant compression fractures show hyperintensity compared with normal surrounding bone marrow probably due to altered water proton mobility within the neoplasm.

Intravertebral clefts in osteoporotic vertebral compression fractures

OBJECTIVE

To describe the characteristics, radiographic appearance, and significance of intravertebral clefts in vertebral compression fractures (VCFs) of patients with osteoporosis presenting for vertebroplasty.

METHODS

This was a prospective radiographic study of 50 consecutive patients with 82 VCFs who underwent vertebroplasty at a tertiary referral center. Patients underwent imaging preoperatively with standing lateral and supine cross-table lateral radiographs and magnetic resonance imaging (MRI). Standing lateral radiographs were also obtained postoperatively. Clefts were defined at the time of vertebroplasty as confluent reservoirs for polymethylmethacrylate (PMMA). Postoperatively, all images were reexamined for the presence and characterization of intravertebral clefts.

RESULTS

Twenty-four of 50 patients (48%) had clefted VCFs, and 30 of 82 VCFs (37%) contained clefts. Clefted VCFs were severe, dynamically mobile, and occurred primarily in the thoracolumbar junction. Clefts were detectable by standing lateral radiography in 14%, by supine cross-table radiography in 64%, and by MRI in 96% of fractured vertebrae. Clefts occurred primarily in the anterosuperior portion of the vertebral body, and cleft margins appeared increasingly sclerotic in persistently mobile VCFs. PMMA fill patterns of clefted and unclefted VCFs were distinct.

CONCLUSION

Intravertebral clefts occur frequently in osteoporotic VCFs of patients who present for vertebroplasty. The radiographic characteristics of clefts evolve over time and can be indistinguishable from Kümmell's disease in severe, persistently mobile, clefted osteoporotic VCFs.

Insufficiency fracture of the femoral neck during osteoporosis treatment: a case report

Acase of insufficiency fracture of the femoral neck that occurred during treatment for osteoporosis is reported. A 77-year-old woman (height 150 cm, body weight 43 kg) with osteoporosis associated with high bone turnover was treated with oral cyclical etidronate (400 mg/day for 2 weeks every 3 months). Three months after the treatment was started the patient experienced pain in the right hip joint while walking despite no evidence of trauma. Although radiographs were normal, weight-bearing was not possible because of pain. T2-weighted magnetic resonance (MR) imaging was used to detect a fracture line localized on the inferior aspect of the femoral neck. Because on bone marker measurement bone resorption was increased and bone formation was decreased from baseline, treatment was switched to oral alendronate (5 mg/day, daily). Pain resolved 3 weeks after the fracture was evident, and free gait was possible during the following 3 weeks. Follow-up radiographs, obtained 3 and 6 months after the fracture was evident, showed bony sclerosis on the aspect in which the fracture line was observed on the T2-weighted MR image. The dissociation (imbalance) of bone formation and resorption was also alleviated. A possibility of increased bone fragility should be kept in mind when oral cyclical etidronate is applied to elderly Japanese, small-physique women with osteoporosis at a daily dose of 400 mg (higher dose).

Burst fracture in the metastatically involved spine: development, validation, and parametric analysis of a three-dimensional poroelastic finite-element model

STUDY DESIGN

A finite-element study and in vitro experimental validation was performed for a parametric investigation of features that contribute to burst fracture risk in the metastatically involved spine.

OBJECTIVES

To develop and validate a three-dimensional poroelastic model of a metastatically compromised vertebral segment, to evaluate the effect of lytic lesions on vertebral strains and pressures, and to determine the influence of loading and motion segment status (bone density, pedicle involvement, disc degeneration, and tumor size) on the relative risk of burst fracture initiation.

SUMMARY OF BACKGROUND DATA

Finite-element analysis has been used successfully to predict failure loads and fracture patterns for bone. Although models for vertebra affected with tumors have been presented, these have not been thoroughly validated experimentally. Consequently, their predictive capabilities remain uncertain.

METHODS

A three-dimensional poroelastic finite-element model of the first lumbar vertebra and adjacent intervertebral discs, including a tumor of variable size, was developed. To validate the model, 12 cadaver spinal motion segments were tested in axial compression, in intact condition, and with simulated osteolytic defects. Features of the validated model were parametrically varied to investigate the effects of tumor size, trabecular bone density, pedicle involvement, applied loads, loading rates, and disc degeneration using outcome variables of vertebral bulge and vertebral axial deformation.

RESULTS

Consistent trends between the experimental data and model predictions were observed. Overall, the model results suggest that tumor size contributes most toward the risk of initiating burst fracture, followed by the applied load magnitude and bone density.

CONCLUSIONS

The parametric analysis suggests that the principal factors affecting the initiation of burst fracture in metastatically affected vertebrae are tumor size, magnitude of spinal loading, and bone density. Consequently, patient-specific measures of these factors should be factored into decisions regarding clinical prophylaxis. Pedicle involvement or disc degeneration was less important according to the outcome measures in this study.

Vanishing bone disease in a five year old: report of a case and review of the literature

Vanishing bone disease is a rare condition of unknown aetiology. It can affect almost any bone, including those of the maxillofacial region. It is most commonly seen in the second and third decades of life. To the author's knowledge, this is the second case reported in the maxillofacial region of a child within the first decade of life, and the first who survived.

Fine-needle aspiration biopsy of solid aneurysmal bone cyst in the humerus

We report the fine-needle aspiration biopsy (FNAB) cytology findings of a solid aneurysmal bone cyst in the left humerus of a 69-yr-old woman. Radiographically, the lesion showed an extensive, relatively well-defined osteolysis in the diaphysis, with a pathologic fracture. FNAB smears of the lesion consisted of benign, mononuclear cells and numerous osteoclast-like multinucleated giant cells. Some clusters of the mononuclear cells were closely associated with dense, homogeneous, extracellular, matrix material. To our knowledge, the FNAB features of solid ABC of the long bones have not been described previously in the English-language literature. The cytologic features are indistinguishable from those of giant cell tumors of bone and brown tumors of hyperparathyroidism.

Percutaneous vertebroplasty and kyphoplasty for painful vertebral body fractures in cancer patients

OBJECT

The current North American experience with minimally invasive vertebro- and kyphoplasty is largely limited to the treatment of benign osteoporotic compression fractures. The objective of this study was to assess the safety and efficacy of these procedures for painful vertebral body (VB) fractures in cancer patients.

METHODS

The authors reviewed a consecutive group of cancer patients (21 with myeloma and 35 with other primary malignancies) undergoing vertebro- and kyphoplasty at their institution. Ninety-seven (65 vertebro- and 32 kyphoplasty) procedures were performed in 56 patients during 58 treatment sessions. The mean patient age was 62 years (+/- 13 years [standard deviation]) and the median duration of symptoms was 3.2 months. All patients suffered intractable spinal pain secondary to VB fractures. Patients noted marked or complete pain relief after 49 procedures (84%), and no change after five procedures (9%); early postoperative Visual Analog Scale (VAS) pain scores were unavailable in four patients (7%). No patient was worse after treatment. Reductions in VAS pain scores remained significant up to 1 year (p = 0.02, Wilcoxon signed-rank test). Analgesic consumption was reduced at 1 month (p = 0.03, Wilcoxon signed-rank test). Median follow-up length was 4.5 months (range 1 day-19.7 months). Asymptomatic cement leakage occurred during vertebroplasty at six (9.2%) of 65 levels; no cement extravasation was seen during kyphoplasty. There were no deaths or complications related to the procedures. The mean percentage of restored VB height by kyphoplasty was 42 +/- 21%.

CONCLUSIONS

Percutaneous vertebro- and kyphoplasty provided significant pain relief in a high percentage of patients, and this appeared durable over time. The absence of cement leakage-related complications may reflect the use of 1) high-viscosity cement; 2) kyphoplasty in selected cases; and 3) relatively small volume injection. Precise indications for these techniques are evolving; however, they are safe and feasible in well-selected patients with refractory spinal pain due to myeloma bone disease or metastases.

Elevation of IL-6 in ATL patient with a pathological fracture

Hypercalcemia and osteolytic bone lesion are important complications in the prognosis of patients with adult T cell leukemia/lymphoma (ATL). We report a 61-year-old Japanese woman who died of ATL and had multiple osteolytic lesions and pathological fractures of her extremities. Highly increased serum levels of Interleukin-6 (IL-6) and a parathyroid hormone-related protein (PTHrP) together with a high level of serum calcium observed at the time of fractures suggested their contribution to the formation of the bone lesions.

[Pathological fractures of the knee]

The authors present the methods and results of treatment of 20 epiphyseal and low-metaphysis pathological knee fractures treated at the Department of Orthopedics of the Lublin University of Medical Sciences between 1962-1999. The average age was 39 years. Malignant tumours (2 lymphomas, 1 plasmocytoma, 1 hemangiopericitoma, 2 adenocarcinoma metastases) and benign lesions (10 giant cell tumours, 3 solitary bone cysts, 1 intraosseous extension of pigmented villonodular synovitis) causes 18 femur fractures and 2 tibia fractures. The fractures caused by lymphomas in 2 patients and plasmocytoma in 1 patients were treated with either a plaster cast or skeletal traction and healed within 16 weeks. Tumour resection and reconstruction with Rush rods, Kuntscher nail, plate and methylmetacrylate were performed in 2 cases. In 1 case with hemangiopericytoma hip exarticulation was performed. In 5 cases pain relief and weight bearing capacity of the limb was not achieved because of neoplasm recurrences; 5 deaths occurred within 6 months to 7 years after femur fracture because of pulmonary metastases. Benign bone lesions were treated by curettage of pathological tissues, burring bony walls of the lesions and filling the cavities with bone grafts or methylmetacrylate (1 case). Displaced fragments were reduced whenever possible. Limbs were immobilised in plaster casts. The follow-up period for patients with benign lesions was 8 years. All fractures healed. Arthritis with persistent pain and knee contracture was noted in 1 patient who underwent surgery 3 times for giant cell tumour recurrences, complicated by infection and varus deformity.

[Does dynamic contrast-enhanced MRI enable recognition of development of vertebral fractures in multiple myeloma?]

PURPOSE

To compare the value of MRI sequences with dynamic MRI measurements (d-MRT) for the assessment of risk of lumbar vertebral fractures in patients with multiple myeloma.

MATERIAL AND METHODS

In 10 patients with multiple myeloma a sagittal T 1 -, T 2 -weighted spin-echo and an inversion-recovery sequence were performed. For dynamic measurements a fast gradient-echo sequence (turbo fast low angle shot 2 D) with machine-controlled Gd-DTPA administration was used. The presence of bone marrow abnormalities was determined and additionally the value of the highest signal increase (amplitude Alpha) was calculated for each of the 50 vertebral bodies. The subsequent development of vertebral fractures was assessed by MRI at a mean time interval of 6.2 months after the initial d-MRI. The pattern of marrow involvement and the amplitudes of the vertebral bodies that collapsed in the observation period were statistically compared with those of the vertebral bodies that did not collapse.

RESULTS

During the follow-up period newly or progressive fractures occurred in 6 of 10 patients (7 of 50 vertebral bodies). The degree of pathological signal changes that preceded fractures was not significantly different (p > 0.05) from that of the other contemporary lesions identified in vertebral bodies that did not collapse in follow-up. In contrast, the amplitude of vertebrae that collapsed (A: 33.1 +/- 8.2) was significantly higher (p < 0.0001) than the amplitude of vertebrae that did not collapse (A: 16.7 +/- 4.2). The amplitude was a reliable predictor of vertebrae that collapsed in all cases.

CONCLUSION

In contrast to the analysis of marrow lesions detected with non-dynamic MRI, this study suggests that the perfusion-parameter amplitude in dynamic contrast-enhanced MRI is a potentially relevant value to predict the risk of vertebral fractures in patients with multiple myeloma.

Successful limb salvage of pathological fracture of the distal tibia caused by cancer metastasis

Pathological fractures of the distal tibia as a result of cancer metastases are rare. In particular, the management of intraarticular fractures of the distal tibia has not been established. In this article, we present a case of pathological intraarticular fracture with an extensive bone defect of the distal tibia that was successfully treated by limb salvage with a locked intramedullary nail and pirarubicin-impregnated methylmethacrylate. A 52-year-old patient with duodenal cancer presented with a painful swelling in the left crus. The condition was diagnosed as an impending pathological fracture of the tibia because of cancer metastasis. During radiation therapy, an actual pathological fracture of the distal tibia occurred due to an accident. Limb-salvage surgery was performed by removing the metastatic lesion, followed by using a locked intramedullary nail. Three distal and seven proximal locking screws were inserted into the tarsal bones and the remaining tibia. About 10 cm of bone defect was reconstructed by pirarubicin-impregnated methylmethacrylate. Consequently, good stability was achieved. One month later the patient could walk without any aid. Postoperative functional score was 77% according to the Musculoskeletal Tumor Society criteria. There was no recurrence; however, the patient died of lung metastases 4 months after the limb-salvage surgery.

Delayed posttraumatic vertebral collapse with intravertebral vacuum cleft

OBJECTIVE

To discuss the case of a 79-year-old man who had a delayed posttraumatic vertebral collapse and an intravertebral vacuum cleft. The patient had been on long-term corticosteroid therapy. A discussion of Kummell's disease and the controversy surrounding the etiology of the condition is also presented.

CLINICAL FEATURES

Six weeks before coming to the clinic, the patient remembered twisting, hearing a pop, and having severe low back pain. Two weeks after the incident, while hospitalized for bacterial cellulitis, he underwent lumbar spine radiography. The radiographs showed degenerative changes and remote (healed) compression fractures but did not demonstrate any deformity of L2. Four weeks later, he sought care for persistent low back pain. Radiographs revealed marked compression of the L2 vertebral body with an intravertebral vacuum phenomenon.

INTERVENTION AND OUTCOME

The patient was referred to his geriatrician for evaluation as a candidate for vertebroplasty or other stabilization procedures. He required a moderately high dose (60 mg) of prednisone daily to combat the symptoms of myasthenia gravis; therefore, the prognosis appears unfavorable for this patient.

CONCLUSION

Clinical research is needed to determine the definitive etiology and pathophysiology of Kummell's disease. This case demonstrates that the intravertebral vacuum is a dynamic entity, subject to changes in size and shape. Previous case reports have suggested that Kummell's disease only presents as a linear, horizontal cleft. This disease needs further investigation to determine the true correlation between radiographic signs and the underlying pathophysiology.