Bone scintigraphy for osteonecrosis of the knee in patients with non-traumatic osteonecrosis of the femoral head: comparison with magnetic resonance imaging

Treatment options for secondary osteonecrosis of the knee

Knee osteonecrosis is a debilitating progressive degenerative disease characterized by subchondral bone ischemia. It can lead to localized necrosis, tissue death, and progressive joint destruction. For this reason, it is essential to diagnose and treat this disease early to avoid subchondral collapse, chondral damage, and end-stage osteoarthritis, where the only solution is total knee arthroplasty. Three types of knee osteonecrosis have been documented in the literature: spontaneous or primitive, secondary, and post arthroscopy. Spontaneous osteonecrosis is the most common type studied in the literature. Secondary osteonecrosis of the knee is a rare disease and, unlike the spontaneous one, involves patients younger than 50 years. It presents a particular set of pathological, clinical, imaging, and progression features. The management of secondary osteonecrosis is determined by the stage of the disorder, the clinical manifestation, the size and location of the lesions, whether the involvement is unilateral or bilateral, the patient's age, level of activity, general health, and life expectancy. This review aims to present the recent evidence on treatment options for secondary osteonecrosis of the knee, including conservative treatment, joint preserving surgery, and knee replacement.

Evaluation of whole-body modalities for diagnosis of multifocal osteonecrosis-a pilot study

Background

This study aimed to investigate the ability of whole-body bone scintigraphy (WB-BS) in the detection of multifocal osteonecrosis (ON) compared to whole-body magnetic resonance imaging (WB-MRI) and to clarify the characteristics of patients with multifocal ON among those with ON of the femoral head (ONFH) using WB-MRI.

Methods

Forty-six patients who had symptomatic ONFH and underwent surgery in our hospital from April 2019 to October 2020 were included in the study. Data on patient demographics, including age, sex, body mass index (BMI), history of corticosteroid intake, alcohol abuse, smoking, and symptomatic joints, were collected from their medical records. All patients underwent WB-MRI and WB-BS before surgery.

Results

The agreement in the detection of ON by WB-MRI vs the uptake lesions by WB-BS in the hip joints was moderate (κ = 0.584), while that in other joints was low (κ < 0.40). Among the 152 joints with ON detected by WB-MRI, 92 joints (60.5%) were symptomatic, and 60 joints (39.5%) were asymptomatic. Twelve out of the 46 (26.0%) patients had multifocal (three or more distinct anatomical sites) ON. Nonetheless, while WB-BS detected symptomatic ON detected by WB-MRI as uptake lesions in 82.6% (76/92) of the joints, asymptomatic ON detected by WB-MRI was detected as uptake lesions in 21.7% (13/60) of the joints. All patients with multifocal ON had a history of steroid therapy, which was significantly higher than that in patients with oligofocal ON (P = 0.035). The patients with a hematologic disease had multifocal ON at a higher rate (P = 0.015).

Conclusions

It might be difficult for WB-BS to detect the asymptomatic ON detected by WB-MRI compared to symptomatic ON. Considering the cost, examination time, and radiation exposure, WB-MRI might be useful for evaluating multifocal ON. Larger longitudinal studies evaluating the benefits of WB-MRI for detecting the risk factors for multifocal ON are required.

Osteonecrosis of both knees in a woman with Crohn's disease

Osteonecrosis is a very rare complication of Crohn’s disease (CD). It is not clear if it is related to corticosteroid therapy or if it occurs as an extraintestinal manifestation of inflammatory bowel disease. We present the case of a patient with CD who presented with osteonecrosis of both knees. A 22 years old woman was diagnosed with CD in April 2012 (Montreal Classification A2L1 + L4B3p). She was started on prednisolone (40 mg/d), azathioprine (100 mg/d) and messalazine (3 g/d). In July 2012, due to active perianal disease, infliximab therapy was initiated. In September 2012, she had a pelvic abscess complicated by peritonitis and an ileal segmental resection and right hemicolectomy were performed. In December 2012 she was diagnosed with bilateral septic arthritis of both knees with walking impairment. She was treated with amoxicillin-clavulanic acid, started a physical rehabilitation program and progressively improved. However, then, bilateral knee pain exacerbated by movement developed. Magnetic resonance imaging showed multiple osseous medullary infarcts in the distal extremity of the femurs, proximal extremity of the tibiae and patellas and no signs of subchondral collapse, which is consistent with osteonecrosis. The patient recovered completely and maintains therapy with azathioprine and messalazine. A review of the literature is also done.

Fast sequences MR imaging at the investigation of painful skeletal sites in patients with hip osteonecrosis

BACKGROUND

Multiple osteonecrotic foci can be clinically silent when located in metaphyses and becomes painful when it affects juxta-articular areas. The purpose of this study was to assess the value of fast MR imaging to depict the underlying pathology in cases with skeletal pain other than the already diagnosed hip osteonecrosis.

METHODS/DESIGN

Between 2008 and 2013, 49 patients with already diagnosed hip osteonecrosis reported symptoms of deep skeletal pain in an anatomical site different from the affected hip joint. All patients after thorough history & clinical examination underwent evaluation with x-rays and a single fat suppressed sequence with MR Imaging applying either T2-w TSE or STIR-TSE at the painful site. False positive and false negative findings were recorded for the conventional x-rays and compared to MRI.

DISCUSSION

Forty four (89.8%) patients were positive for osteonecrotic lesions in this study and 76 symptomatic osteonecrosis lesions were revealed at 14 distinct anatomic sites. The agreement between the x-ray findings and the MR imaging regarding osteonecrosis was 46.9%. Plain x-rays showed 43.4% sensitivity, 100% specificity, 100% positive predictive value and 10.4% negative predictive value. Fast MR imaging with fat suppressed sequences is necessary and adequate as a single method for the investigation of painful skeletal sites in patients with already diagnosed hip osteonecrosis. It allows early diagnosis of the potentially debilitating multiple juxta-articular lesions and consequently their prompt management.

Medullary decompression of the radius as treatment for lameness in a horse

Increased intraosseous pressure (IOP) is a well-characterized source of pain in humans that can be successfully treated by medullary decompression. This report describes the clinical and diagnostic findings, treatment and successful outcome of a horse with a four week long, non-weight bearing lameness secondary to suspected traumatically-induced increased IOP in the left radius. Scintigraphic examination characterized by severe increase in radiopharmaceutical uptake within the affected radius aided in the initial localization of the source of lameness. Decompression of the affected radius was performed by drilling two 3.2 mm tracts through the lateral bone cortex into the medullary cavity. Intramedullary pressure in the radius was measured (37-39 mmHg). Dramatic clinical improvement was observed after surgical decompression of the affected bone and the horse showed full recovery and returned to previous exercise use by 12 months after treatment. Gradual decrease in radial radiopharmaceutical uptake was observed during the following year. Increased IOP should be considered as a cause of lameness in horses and scintigraphic examination may aid in its diagnosis. Medullary decompression may be a successful treatment in some cases.

Osteonecrosis of the femoral head extending into the femoral neck

Osteonecrosis of the femoral head (ONFH) is an ischemic disorder that can lead to femoral head collapse and secondary osteoarthritis. Although the condition is usually limited to the femoral head, we report a rare case of biopsy-proven ONFH extending into the femoral neck, which required hip replacement surgery. We emphasize the imaging features of this condition and briefly discuss its potential relevance.

Osteonecrosis in children after therapy for malignancy

OBJECTIVE

Osteonecrosis in the growing population of childhood cancer survivors results from disease and treatment. Imagers must be knowledgeable about patient groups at risk for its development, patterns of involvement and potential implications. This review will focus on implications of this potentially life-altering toxicity.

CONCLUSION

Childhood cancer survivors are at increased risk for developing osteonecrosis. Because osteonecrosis is often asymptomatic until late in the process, imaging is critical for its detection and characterization when interventions may be most effective to ameliorate its progression.

Spontaneous regression of steroid-related osteonecrosis of the knee

It is unknown whether lesions of steroid-related osteonecrosis of the knee increase or decrease in size during the course of the disease after diagnosis. We sought to determine whether steroid-related osteonecrosis of the knee would have spontaneous changes in size, and if so, the factors affecting the change. We performed baseline and followup (minimum of 1 year) magnetic resonance imaging scans on 30 knees of 17 patients. We then used image registration techniques to match two sets of images. Lesion size change was evaluated on all contiguous pairs of matched magnetic resonance images. Fourteen Stage 1 (preradiographic stage) knees in seven patients showed spontaneous incomplete regression without subsequent collapse. These patients had early steroid-related lesions detected within 3 years after starting steroid treatment and all showed bilateral and multifocal involvement; lesion regression occurred regardless of location. The initial size and location of the lesions and discontinuing steroid administration did not seem to affect regression. Regression can occur in some patients with early steroid-related osteonecrosis of the knee, and the time between initiation of steroid treatment and its diagnosis might be the most significant predictive factor.

Osteonecrosis in patients with systemic lupus erythematosus

This study was to describe the findings of osteonecrosis in patients with SLE at MR and scintigraphic imaging. Among 415 patients with SLE, 37 patients were diagnosed to have osteonecrosis. MR images and bone scintigraphs were analyzed for sites of involvement, signal intensity, bilaterality and multiplicity. MR imaging features of osteonecrosis in patients with SLE included isointense signal intensity relative to adjacent bone marrow, hypointense rim, marginal enhancement and unusual involvement of flat bones. Bilateral and multiple involvements were common.

Evaluation of femoral perfusion in a non-traumatic rabbit osteonecrosis model with T2*-weighted dynamic MRI

We evaluated femoral perfusion in a non-traumatic rabbit serum sickness osteonecrosis (ON) model, using serial repetitive T2*-weighted (T2*W) dynamic magnetic resonance imaging (MRI) and investigated prediction of ON occurrence in early stages, comparing T2*W dynamic MRI with non-enhanced (T2-, T1- and fat suppression T1-weighted) and contrast-enhanced MRI. Early microcirculatory injury or necrotic lesion was detected in 0% of femora (extravasation, 0/6) at 72 h, 33% (necrotic, 4/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using non-enhanced MRI, and in 67% of femora (extravasation, 4/6) at 72 h, 58% (necrotic, 7/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using contrast-enhanced MRI. In contrast, microcirculatory injury or necrotic lesion was detected in 83% of femora (extravasation, 5/6) at 72 h, 92% (necrotic, 11/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using T2*W dynamic MRI as no transient decrease or less marked transient decrease in signal intensity of regions of interest (ROIs), compared to normal femora, which showed a clear transient decrease in signal intensity of ROIs. These results indicate that T2*W dynamic MRI with optimal imaging parameters and a dose of contrast agent is the most sensitive of these three MRI methods and may be clinically useful for evaluating femoral perfusion in artery phase and predicting ON occurrence.

The 2001 revised criteria for diagnosis, classification, and staging of idiopathic osteonecrosis of the femoral head

The 2001 revised criteria for the diagnosis, classification, and staging of idiopathic osteonecrosis of the femoral head were proposed in June 2001, by the working group of the Specific Disease Investigation Committee under the auspices of the Japanese Ministry of Health, Labor and Welfare, to establish criteria for diagnosis and management of idiopathic osteonecrosis of the femoral head. Five criteria that showed high specificity were selected for diagnosis: collapse of the femoral head (including crescent sign) without joint-space narrowing or acetabular abnormality on x-ray images; demarcating sclerosis in the femoral head without joint-space narrowing or acetabular abnormality; "cold in hot" on bone scans; low-intensity band on T1-weighted MRI (bandlike pattern); and trabecular and marrow necrosis on histology. Idiopathic osteonecrosis of the femoral head is diagnosed if the patient fulfills two of these five criteria and does not have bone tumors or dysplasias. Necrotic lesions are classified into four types, based on their location on T1-weighted images or x-ray images. Type A lesions occupy the medial one-third or less of the weight-bearing portion. Type B lesions occupy the medial two-thirds or less of the weight-bearing portion. Type C1 lesions occupy more than the medial two-thirds of the weight-bearing portion but do not extend laterally to the acetabular edge. Type C2 lesions occupy more than the medial two-thirds of the weight-bearing portion and extend laterally to the acetabular edge. Staging is based on anteroposterior and lateral views of the femoral head on x-ray images. Stage 1 is defined as the period when there are no specific findings of osteonecrosis on x-ray images, although specific findings are observed on MRI, bone scintigram, or histology. Stage 2 is the period when demarcating sclerosis is observed without collapse of the femoral head. Stage 3 is the period when collapse of the femoral head, including crescent sign, is observed without joint-space narrowing. Mild osteophyte formation in the femoral head or acetabulum may be observed in stage 3. Stage 3 is divided into two substages. In stage 3A, collapse of the femoral head is less than 3 mm. In stage 3B, collapse of the femoral head is 3 mm or greater. Stage 4 is the period when osteoarthritic changes are observed.