Osteosarcoma near joints: assessment and implications

Association of MRI findings with intra-articular tumour extension

Aims

Treatment of high-grade limb bone sarcoma that invades a joint requires en bloc extra-articular excision. MRI can demonstrate joint invasion but is frequently inconclusive, and its predictive value is unknown. We evaluated the diagnostic accuracy of direct and indirect radiological signs of intra-articular tumour extension and the performance characteristics of MRI findings of intra-articular tumour extension.

Methods

We performed a retrospective case-control study of patients who underwent extra-articular excision for sarcoma of the knee, hip, or shoulder from 1 June 2000 to 1 November 2020. Radiologists blinded to the pathology results evaluated preoperative MRI for three direct signs of joint invasion (capsular disruption, cortical breach, cartilage invasion) and indirect signs (e.g. joint effusion, synovial thickening). The discriminatory ability of MRI to detect intra-articular tumour extension was determined by receiver operating characteristic analysis.

Results

Overall, 49 patients underwent extra-articular excision. The area under the curve (AUC) ranged from 0.65 to 0.76 for direct signs of joint invasion, and was 0.83 for all three combined. In all, 26 patients had only one to two direct signs of invasion, representing an equivocal result. In these patients, the AUC was 0.63 for joint effusion and 0.85 for synovial thickening. When direct signs and synovial thickening were combined, the AUC was 0.89.

Conclusion

MRI provides excellent discrimination for determining intra-articular tumour extension when multiple direct signs of invasion are present. When MRI results are equivocal, assessment of synovial thickening increases MRI's discriminatory ability to predict intra-articular joint extension. These results should be interpreted in the context of the study's limitations. The inclusion of only extra-articular excisions enriched the sample for true positive cases. Direct signs likely varied with tumour histology and location. A larger, prospective study of periarticular bone sarcomas with spatial correlation of histological and radiological findings is needed to validate these results before their adoption in clinical practice.

Correlation between post-chemotherapy MRI and histopathology of malignant bone tumors treated with extra-articular resection

OBJECTIVE

Magnetic resonance imaging (MRI) remains the gold standard for diagnosing tumoral joint involvement; however, its interpretation remains uncertain due to the presence of perilesional edema that can lead to unjustified arthrectomy. The aim of the study is to identify precise MRI signs that are predictive of joint involvement.

MATERIALS AND METHODS

This retrospective multicenter study included 25 patients who underwent extra-articular resection for malignant bone tumor with suspected joint involvement at the shoulder, hip, or knee, between January 2004 and July 2023. Joint resection was indicated based on preoperative MRI examination. MRI signs of joint involvement were joint effusion, capsuloligamentous invasion, disruption of articular cartilage, and intra-articular tumor mass. We then compared histopathological "true" joint involvement of the resected specimen with its preoperative MRI diagnosis.

RESULTS

Extra-articular resection was performed in 9 shoulders, 4 hips, and 12 knees. Histological analysis confirmed wide resections for all patients. Based on histopathological analysis, extra-articular resection was unjustified in 40% (44%, 0%, and 50%, respectively). The most specific iconographic criteria were intra-capsular cortical breach and the presence of a tumor mass inside the joint. Articular cartilage disruption is often the most accurate sign.

CONCLUSION

Our results suggest that MRI has a poor ability to accurately diagnose joint involvement. To date, however, this is the best tool available. In addition to obvious signs of joint involvement, MRI analysis must be performed with a thorough understanding of capsular anatomy and its particularities for each joint so as not to miss other signs, such as intra-capsular cortical effraction.

Clinical Perspectives on Surgical Reconstruction of Eccentric Tumors at the Distal Femur with Unicondylar Resection

The distal femur is one of the most common sites for primary bone tumors. As the tumor progresses and bone destruction worsens, it can severely affect knee function and even pose a threat to life. In cases where only one condyle is affected and requires resection, preserving the healthy contralateral condyle can substantially enhance the biomechanics of the knee. Furthermore, preserving bone stock may enable future salvage procedures in the event of initial surgery failure, be it from fractures or osteoarthritis. Distal femoral unicondyle resection can offer better functional outcomes in select cases. However, it is essential to prioritize oncological safety with adequate margins over short-term knee function. Currently, the primary methods for reconstruction after the excision of a unicondylar tumor include allograft transplantation (bi- or uni-condylar) and prosthetic or allograft-prosthesis composite replacement (APC). However, there is currently some controversy regarding the optimal surgical reconstruction method, and a consensus within the academic community has yet to be reached. Moreover, due to the rarity of bone tumors, extensive clinical data from a single center is limited. Current studies are mainly retrospective and single-center, lacking sufficient cases and follow-up duration. This article reviews surgical reconstruction after solitary condylar excision in distal femoral tumors. It summarizes, compares, and analyzes mainstream reconstruction methods, exploring their technical details and clinical outcomes to highlight their potential in bone oncology.

En bloc resection and reconstruction using a talar prosthesis for malignant talar bone tumor: a surgical technique

En bloc resection is required for treatment of intermediate-grade talar tumors with extraosseous extension (Enneking stage 3) and malignant talar tumors without intra-articular invasion (Enneking stages IA and IIA). After resection, reconstruction options include tibiocalcaneal fusion, frozen autograft, and talar prosthesis; however, a talar prosthesis is preferable because it preserves ankle range of motion, does not cause leg length discrepancy, and is associated with good long-term outcomes. To the best of our knowledge, en bloc resection and reconstruction of a malignant talar tumor has not been previously reported in detail. We report a detailed surgical technique for en bloc resection of a malignant talar bone tumor using combined anterior and lateral approaches followed by reconstruction using a talar prosthesis.

Can conventional magnetic resonance imaging at presentation predict chemoresistance in osteosarcoma?

OBJECTIVES

Histological tumour necrosis is the current indicator for the response of osteosarcoma after neoadjuvant chemotherapy. Chemoresistant tumours require close monitoring and adjustment of treatment. Characteristics of tumours on baseline MRI may be able to predict response to chemotherapy. The aim is to identify which baseline MRI findings can help predict chemoresistant osteosarcoma.

METHODS

Baseline MRI before giving neoadjuvant chemotherapy of 95 patients during 2008-2021 was reviewed by 2 musculoskeletal radiologists. Histological necrosis from surgical specimens was the reference standard. MRIs were reviewed for tumour characteristics (tumour volume, maximum axial diameter, central necrosis, haemorrhage, fluid-fluid level), peritumoural bone and soft tissue oedema, and other parameters including intra-articular extension, epiphyseal involvement, neurovascular involvement, pathologic fracture, and skip metastasis. The cut-off thresholds were generated by receiver operating characteristic curves which then tested for diagnostic accuracy.

RESULTS

Two-third of patients were chemoresistance (histological necrosis <90%). Tumour volume >150 mL, maximum axial diameter >7.0 cm, area of necrosis >50%, presence of intra-articular extension, and peritumoural soft tissue oedema >6.5 cm significantly predicted chemoresistance, particularly when found in combination. Tumour volume >150 mL and maximum axial diameter >7.0 cm could be used as an independent predictor (multivariable analysis, P-value = .025, .045).

CONCLUSIONS

Findings on baseline MRI could help predicting chemoresistant osteosarcoma with tumour size being the strongest predictor.

ADVANCES IN KNOWLEDGE

Osteosarcomas with large size, large cross-sectional diameter, large area of necrosis, presence of intra-articular extension, and extensive peritumoural soft tissue oedema were most likely to have a poor response to neoadjuvant chemotherapy.

PET/MR of pediatric bone tumors: what the radiologist needs to know

Integrated 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) positron emission tomography (PET)/magnetic resonance (MR) imaging can provide "one stop" local tumor and whole-body staging in one session, thereby streamlining imaging evaluations and avoiding duplicate anesthesia in young children. 18F-FDG PET/MR scans have the benefit of lower radiation, superior soft tissue contrast, and increased patient convenience compared to 18F-FDG PET/computerized tomography scans. This article reviews the 18F-FDG PET/MR imaging technique, reporting requirements, and imaging characteristics of the most common pediatric bone tumors, including osteosarcoma, Ewing sarcoma, primary bone lymphoma, bone and bone marrow metastases, and Langerhans cell histiocytosis.

Reconstruction after Talar Tumor Resection: A Systematic Review

This systematic review investigated the functional outcomes and complications of reconstruction methods after talar tumor resection. A systematic search of PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases identified 156 studies, of which 20 (23 patients) were ultimately included. The mean Musculoskeletal Tumor Society scores in the groups reconstructed using tibiocalcaneal fusion (n = 17), frozen autograft (n = 1), and talar prosthesis (n = 5) were 77.6 (range 66-90), 70, and 90 (range 87-93), respectively. Regarding complications, sensory deficits were observed in one patient (6%) and venous thrombosis in two patients (12%) in the tibiocalcaneal fusion group, while osteoarthritis was observed in one patient (100%) in the frozen autograft group. No complications were observed in the talar prosthesis group. Reconstruction with talar prosthesis seems preferable to conventional tibiocalcaneal fusion after talar tumor resection because it offers better function and fewer complications. However, as this systematic review included only retrospective studies with a small number of patients, its results require re-evaluation in future randomized controlled trials with larger numbers of patients.

Diagnosis of joint invasion in patients with malignant bone tumors: value and reproducibility of direct and indirect signs on MR imaging

OBJECTIVES

To evaluate the performance and reproducibility of MR imaging features in the diagnosis of joint invasion (JI) by malignant bone tumors.

METHODS

MR images of patients with and without JI (n = 24 each), who underwent surgical resection at our institution, were read by three radiologists. Direct (intrasynovial tumor tissue (ITT), intraarticular destruction of cartilage/bone, invasion of capsular/ligamentous insertions) and indirect (tumor size, signal alterations of epiphyseal/transarticular bone (bone marrow replacement/edema-like), synovial contrast enhancement, joint effusion) signs of JI were assessed. Odds ratios, sensitivity, specificity, PPV, NPV, and reproducibilities (Cohen's and Fleiss' κ) were calculated for each feature. Moreover, the diagnostic performance of combinations of direct features was assessed.

RESULTS

Forty-eight patients (28.7 ± 21.4 years, 26 men) were evaluated. All readers reliably assessed the presence of JI (sensitivity = 92-100 %; specificity = 88-100%, respectively). Best predictors for JI were direct visualization of ITT (OR = 186-229, p < 0.001) and destruction of intraarticular bone (69-324, p < 0.001). Direct visualization of ITT was also highly reliable in assessing JI (sensitivity, specificity, PPV, NPV = 92-100 %), with excellent reproducibility (κ = 0.83). Epiphyseal bone marrow replacement and synovial contrast enhancement were the most sensitive indirect signs, but lacked specificity (29-54%). By combining direct signs with high specificity, sensitivity was increased (96 %) and specificity (100 %) was maintained.

CONCLUSION

JI by malignant bone tumors can reliably be assessed on preoperative MR images with high sensitivity, specificity, and reproducibility. Particularly direct visualization of ITT, destruction of intraarticular bone, and a combination of highly specific direct signs were valuable, while indirect signs were less predictive and specific.

KEY POINTS

• Direct visualization of intrasynovial tumor was the single most sensitive and specific (92-100%) MR imaging sign of joint invasion. • Indirect signs of joint invasion, such as joint effusion or synovial enhancement, were less sensitive and specific compared to direct signs. • A combination of the most specific direct signs of joint invasion showed best results with perfect specificity and PPV (both 100%) and excellent sensitivity and NPV (both 96 %).

Pediatric Osteosarcoma: Correlation of Imaging Findings with Histopathologic Features, Treatment, and Outcome

Osteosarcoma is the most common primary bone sarcoma in children. Imaging plays a pivotal role in diagnostic workup, surgical planning, and follow-up monitoring for possible disease relapse. Survival depends on multiple factors, including presence or absence of metastatic disease, chemotherapy response, and surgical margins. At diagnosis, radiography and anatomic MRI are used to characterize the primary site of disease, whereas chest CT and whole-body bone scintigraphy and/or PET are used to identify additional sites of disease. Treatment starts with neoadjuvant chemotherapy, followed by en bloc tumor resection and limb reconstruction, and finally, adjuvant chemotherapy. Preoperative planning requires precise tumor delineation, which traditionally has been based on high-spatial-resolution anatomic MRI to identify tumor margins (medullary and extraosseous), skip lesions, neurovascular involvement, and joint invasion. These findings direct the surgical approach and affect the options for reconstruction. For skeletally immature children, the risk of cumulative limb-length discrepancy and need for superior longevity of the reconstruction have led to the advent and preferential use of several pediatric-specific surgical techniques, including rotationplasty, joint preservation surgery, autograft or allograft reconstruction, and extendible endoprostheses. A better understanding of the clinically impactful imaging features can directly and positively influence patient care. Online supplemental material is available for this article. ^©RSNA, 2022.

Ferumoxytol magnetic resonance imaging detects joint and pleural infiltration of bone sarcomas in pediatric and young adult patients

BACKGROUND

The diagnosis of joint infiltration by a malignant bone tumor affects surgical management. The specificity of standard magnetic resonance imaging (MRI) for diagnosing joint infiltration is limited. During our MRI evaluations with ferumoxytol nanoparticles of pediatric and young adult patients with bone sarcomas, we observed a surprising marked T1 enhancement of joint and pleural effusions in some patients but not in others.

OBJECTIVE

To evaluate if nanoparticle extravasation differed between joints and pleura with and without tumor infiltration.

MATERIALS AND METHODS

We retrospectively identified 15 pediatric and young adult patients (mean age: 16±4 years) with bone sarcomas who underwent 18 MRI scans at 1 h (n=7) or 24 h (n=11) after intravenous ferumoxytol infusion. Twelve patients also received a gadolinium-enhanced MRI. We determined tumor invasion into the joint or pleural space based on histology (n=11) and imaging findings (n=4). We compared the signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) of the joint or pleural fluid for tumors with and without invasion using a Mann-Whitney U test.

RESULTS

MRI scans 24 h after intravenous ferumoxytol infusion demonstrated a positive T1 enhancement of the effusion in all joints and pleural spaces with tumor infiltration and no joint or pleural space without infiltration. Corresponding SNR (P=0.004) and CNR (P=0.004) values were significantly higher for joints and pleural spaces with tumor infiltration than without. By contrast, unenhanced MRI, gadolinium-enhanced MRI and 1-h post-contrast ferumoxytol MRI did not show any enhancement of the joint or pleural effusion, with or without tumor infiltration.

CONCLUSION

This pilot study suggests that 24-h post-contrast ferumoxytol MRI scans can noninvasively differentiate between joints with and without tumor infiltration.

Is magnetic resonance imaging reliable for assessing osteosarcoma of the knee joint in children?

INTRODUCTION

The study of tumor extension in knee osteosarcomas is an essential diagnostic tool that helps determine the surgical approach. Magnetic resonance imaging (MRI) is the key component in this decision-making process, but the interpretation of signals can be difficult because peritumoral edema and inflammation may be mistaken for the tumor.

HYPOTHESIS

There is a discrepancy between MRI and histopathology findings in the assessment of joint involvement in pediatric osteosarcomas of the knee.

MATERIALS AND METHODS

All children who underwent an extra-articular resection for an osteosarcoma of the knee between 2007 and 2016 were included. This was indicated if there was at least one of the following MRI signs: presence of articular effusion, involvement of either the peripheral capsuloligamentous structures, central pivot or patella, or lesion abutting the articular cartilage.

RESULTS

Nine patients were operated on with a mean age of 13±2.7 years. There were at least two of the described signs, mainly the involvement of the peripheral capsuloligamentous structures (78%) and central pivot (56%). The histopathology confirmed that the resection margins were healthy in all cases, but the indication for extra-articular resection could have been avoided in 89% of them.

DISCUSSION

MRI is the current gold standard for assessing tumor extension, but the signs contraindicating the transarticular approach remain poorly defined. Joint effusion detected by clinical or radiological assessment is the least reliable one. It seems that the tumor's proximity to the articular cartilage, as long as there is no loss of continuity in the latter, or its extension into the central pivot should no longer be considered as relevant signs. The involvement of the peripheral capsuloligamentous structure remains an indication criterion because oncologic resection is otherwise impossible, and the risk of false-negative histopathologic diagnoses is higher. Other MRI sequences could better assess the true extension into the joint space.

LEVEL OF EVIDENCE

IV, retrospective study.

Treatment of Osteosarcoma of the Talus With a 3D-Printed Talar Prosthesis

A 31-year-old male was diagnosed with osteoblastic osteosarcoma of the talus. Limb-salvage surgery for talar osteosarcoma was performed by replacing the intact talus with a 3D-printed talar prosthesis made from medical-grade titanium. The prosthesis had 3 tunnels for simulating the ligaments around the talus. At the last follow-up, the functional and clinical outcomes were excellent. Our patient achieved 93% restoration of the Musculoskeletal Tumor Society functional score as well as a Toronto Extremity Salvage Score of 93 points, and there was no local recurrence or distant metastasis. A 3D-printed talar prosthesis showed excellent functional and clinical outcomes for a patient with osteosarcoma of the talus. A 3D-printed implant is a feasible option for patients with osteosarcoma of the foot.

Osteosarcoma arising from acetabulum extended to femoral head through round ligament: a case report

A skip metastasis was defined as a solitary separate focus of osteosarcoma occurring synchronously with a primary osteosarcoma in the absence of anatomic extension. The progression of skip metastasis is considered less likely because the articular cartilage acts as a barrier, so there have been few reports on progression of the extremity bone tumor across a joint. In our case report, the acetabular osteosarcoma progressed to the femoral head through the ligament of the femoral head. From the findings of magnetic resonance imaging and resected specimen and tissue specimen, we considered that the tumor progressed between ligament and synovial tissue covering the ligament, and not passing through the inside of the ligament. This case suggested a possibility that the tumor might progress through the synovium around the ligament of femoral head in the cases of osteosarcoma arising from the proximal femur and acetabulum.

[The importance of radiology in bone sarcoma diagnostics : Initial and advanced diagnostics]

BACKGROUND

Reliable diagnostic assessment of malignant bone lesions remains a challenge in all the medical disciplines involved. The high incidence of benign (mainly pediatric) bone lesions needs to be distinguished from the rare malignant counterparts. If clinical presentation and patient history are unable to exclude a malignant tumour, adequate imaging of the affected region is necessary.

OBJECTIVES

This article focuses on giving implementable advice in dealing with problems and questions arising in the diagnostic process of treating patients with suspected or confirmed bone sarcoma. Also, follow-up recommendations from a radiological point of view are presented.

METHODS

Review and discussion of relevant literature against personal experiences in the medical imaging of patients with bone sarcomas.

RESULTS

Interpretation of projection radiographic images usually succeeds in assessing a bone tumour's dignity by evaluating periosteal reaction, the formation of a tumour matrix and consideration of the Lodwick classification. A current adaptation of the classic Lodwick classification incorporates diagnostic possibilities of more recent imaging techniques (magnetic resonance imaging (MRI), positron emission tomography (PET)) and is presented in this article. Plain radiographs are superseded by MRI as the primary imaging performed when depicting bone lesions with increasing frequency. The role of MRI in terms of primary diagnostics, staging, planning of biopsy tracts and tumour resections, evaluation of treatment response and follow-up are discussed. All diagnostic imaging techniques, including whole-body imaging methods, relevant in the diagnosis and therapy of bone sarcomas are presented in the sequence in which they appear during treatment.

CONCLUSIONS

Radiological imaging and expertise are important pillars in diagnosis and treatment of bone sarcomas. A variety of complementing imaging techniques provide a treatment-relevant basis significant for all medical disciplines involved.

The current status of MRI in the pre-operative assessment of intramedullary conventional appendicular osteosarcoma

Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majority of cases being conventional intra-medullary high-grade tumours affecting the appendicular skeleton. Treatment is typically with a combination of neo-adjuvant chemotherapy, tumour resection with limb reconstruction and post-operative chemotherapy. The current article reviews the role of magnetic resonance imaging (MRI) in the pre-operative assessment of high-grade central conventional osteosarcoma.

Velvet Antler compounds targeting major cell signaling pathways in osteosarcoma - a new insight into mediating the process of invasion and metastasis in OS

Velvet antler is the only renewable bone tissue of mammalian animals, which consists of a variety of growth factors, amino acids and polypeptides. But the mechanism of high-speed proliferation without carcinogenesis is still mystifying. The previous study of this work found that the velvet antler peptides (VAP) could not only inhibit the proliferation and migration of osteosarcoma cell lines MG-63 and U2OS, but also induced U2OS apoptosis and inhibited MG-63 epithelial-mesenchymal transition (EMT) through TGF-β and Notch pathways. These results lead us to conclude that VAP has the potential ability to mediate osteosarcoma cells by regulating related signaling pathways and growth factors. Therefore, finding a new appropriate inhibitor for OS is a valuable research direction, which will give patients a better chance to receive proper therapy. From an applied perspective, this review summarized the effects of velvet antler, genes, growth factors and research progress of relative pathways and genes of osteosarcoma, which are poised to help link regenerative molecular biology and regenerative medicine in osteosarcoma pathogenesis.

Is there still a role for osteoarticular allograft reconstruction in musculoskeletal tumour surgery? a long-term follow-up study of 38 patients and systematic review of the literature

AIMS

To assess complications and failure mechanisms of osteoarticular allograft reconstructions for primary bone tumours.

PATIENTS AND METHODS

We retrospectively evaluated 38 patients (28 men, 74%) who were treated at our institution with osteoarticular allograft reconstruction between 1989 and 2010. Median age was 19 years (interquartile range 14 to 32). Median follow-up was 19.5 years (95% confidence interval (CI) 13.0 to 26.1) when 26 patients (68%) were alive. In addition, we systematically searched the literature for clinical studies on osteoarticular allografts, finding 31 studies suitable for analysis. Results of papers that reported on one site exclusively were pooled for comparison.

RESULTS

A total of 20 patients (53%) experienced graft failure, including 15 due to mechanical complications (39%) and three (9%) due to infection. In the systematic review, 514 reconstructions were analysed (distal femur, n = 184, 36%; proximal tibia, n = 136, 26%; distal radius, n = 99, 19%; proximal humerus, n = 95, 18%). Overall rates of failure, fracture and infection were 27%, 20%, and 10% respectively. With the distal femur as the reference, fractures were more common in the humerus (odds ratio (OR) 4.1, 95% CI 2.2 to 7.7) and tibia (OR 2.2, 95% CI 1.3 to 4.4); infections occurred more often in the tibia (OR 2.2, 95% CI 1.3 to 4.4) and less often in the radius (OR 0.1, 95% CI 0.0 to 0.8).

CONCLUSION

Osteoarticular allograft reconstructions are associated with high rates of mechanical complications. Although comparative studies with alternative techniques are scarce, the risk of mechanical failure in our opinion does not justify routine employment of osteoarticular allografts for reconstruction of large joints after tumour resection. Cite this article: Bone Joint J 2017;99-B:522-30.

[The value of MRI in the diagnosis of joint involvement in malignant primitive tumors of the knee]

INTRODUCTION

Surgical treatment of malignant primitive tumors of bone needs a precise preoperative assessment of tumor local extension. Joint involvement (JI) represents the most important finding to determine, for the choice of surgical procedure (intra- or extra-articular resection).

OBJECTIVE

To determine the value of different MR signs for the diagnosis of joint involvement in malignant primitive tumors of the knee.

METHODS

Ten-year period retrospective study of 42 patients. Patients' clinical and imaging data have been studied. Two senior musculoskeletal radiologists have blindly and consensually reviewed imaging data. Histopathological data have been reviewed by an experimented pathologist. The results have been compared using several statistical methods to determine the global and detailed (sign by sign) diagnostic value and accuracy of MRI by reference to histopathology.

RESULTS

Some MR signs were performant in the diagnosis of joint involvement. The most sensitive were epiphyseal extension (Se: 100%), osteochondral extension (Se: 87.5%) and extension to the tibial spines (Se: 83.3%). The most specific MR signs were the presence of an intra-articular mass (Sp: 84.62%), extension to the intercondylar notch (Sp: 80.77%) and longitudinal axis≥120mm (Sp: 84.62%).

CONCLUSION

A rigorous and reproducible MR technique has to be used, the knee being explored in the transversal, sagittal and coronal planes. MR conclusion has to be clear and simple (intact, doubtful or involved joint). MR interpretation has to consider tumoral extension pathways. In doubtful cases, CT may help in this diagnosis by studying the bone cortex.

LEVEL OF EVIDENCE

IV.

Microwave ablation of malignant extremity bone tumors

Background

The current application of limb salvage process has some unsolved problems, such as prosthesis loosening, which severely limits the function of the preserved limbs. Innovative approaches are needed to further improve functional outcome.

Patients and methods

Instead of en-bloc resection of tumor-bearing bone, it is dissected from the surrounding normal tissues, followed by devitalizing the bone segment and the extra-cortical bulk by microwave induced hyperthermia in situ through the antenna array. From May 1999 to March 2012, 544 patients with malignant bone tumors of the extremities were treated by the novel method.

Results

The over 3-year survival rate was 59.1 % for high-grade malignancy, 88.7 % for low-grade malignancy. In the majority of the patients, cosmetic and useful limbs were preserved. Local recurrence rate was 9.8 % for the high grade malignancy (mainly occurred at the early stage of the research). The overall fracture rate was 2.6 %. Deep infection rate was 1.8 %. The complication rate is lower than the literature reports. After heat necrosis, the dead bone maintains both the osteoconduction and osteoinduction properties.

Conclusions

The application of microwave induced hyperthermia for treatment of malignant bone tumors, except the late diagnosed cases who’s tumor-bearing bone was destroyed too severe to do biological reconstruction, is an effective, simple, and inexpensive method. The oncological and functional results are encouraging.

Postoperative nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma

BACKGROUND

Metastasis is the most crucial prognostic factor in osteosarcoma. The goal of this study was to develop a new nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma after neoadjuvant chemotherapy and limb salvage surgery.

METHODS

We examined medical records of 91 patients who had undergone surgery between March 1994 and March 2007. A nomogram was developed using multivariate logistic regression. The nomogram was validated internally by bootstrapping-method (200 repetitions) and externally in independent validation set (n = 34). A Youden-derived cutoff value was assigned to the nomogram to predict dichotomous outcomes for metastasis.

RESULTS

The nomogram was built from four predictors of tumor site, serum alkaline phosphatase, intracapsular extension, and Huvos grade, and an additional clause that the cutoff value should be added to the total points in the cases of incomplete surgical resection. P-value of Hosmer and Lemshow Goodness-of-fit test of this model was 0.649. Area under receiver operating curve values of 0.83 (95% confidence interval [CI], 0.75 to 0.92) in the training set and 0.80 (95% CI, 0.63 to 0.96) in the validation set were obtained. The accuracy of dichotomous outcomes was 79.1% (95% CI, 0.69 to 0.86) and 82.4% (95% CI, 0.63 to 0.92) in the training and validation sets.

CONCLUSIONS

We have developed a new high-performance nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma after limb salvage surgery.

The healing process of intracorporeally and in situ devitalized distal femur by microwave in a dog model and its mechanical properties in vitro

Background

Limb-salvage surgery has been well recognized as a standard treatment and alternative to amputation for patients with malignant bone tumors. Various limb-sparing techniques have been developed including tumor prosthesis, allograft, autograft and graft-prosthesis composite. However, each of these methods has short- and long-term disadvantages such as nonunion, mechanical failures and poor limb function. The technique of intracorporeal devitalization of tumor-bearing bone segment in situ by microwave-induced hyperthermia after separating it from surrounding normal tissues with a safe margin is a promising limb-salvage method, which may avoid some shortcomings encountered by the above-mentioned conventional techniques. The purpose of this study is to assess the healing process and revitalization potential of the devitalized bone segment by this method in a dog model. In addition, the immediate effect of microwave on the biomechanical properties of bone tissue was also explored in an in vitro experiment.

Methods

We applied the microwave-induced hyperthermia to devitalize the distal femurs of dogs in situ. Using a monopole microwave antenna, we could produce a necrotic bone of nearly 20 mm in length in distal femur. Radiography, bone scintigraphy, microangiography, histology and functional evaluation were performed at 2 weeks and 1, 2, 3, 6, 9 and 12 months postoperatively to assess the healing process. In a biomechanical study, two kinds of bone specimens, 3 and 6 cm in length, were used for compression and three-point bending test respectively immediately after extracorporeally devitalized by microwave.

Findings

An in vivo study showed that intracorporeally and in situ devitalized bone segment by microwave had great revitalization potential. An in vitro study revealed that the initial mechanical strength of the extracorporeally devitalized bone specimen may not be affected by microwave.

Conclusion

Our results suggest that the intracorporeal microwave devitalization of tumor-bearing bone segment in situ may be a promising limb-salvage method.

Limb salvage surgery complimented by customised mega prostheses for malignant fibrous histiocytomas of bone

PURPOSE

To assess functional and oncological outcomes of patients with malignant fibrous histiocytomas of bone, after limb salvage surgery complimented by a customised prosthesis.

METHODS

Between May 1991 and December 2002, 15 men and 5 women (mean age, 42 years) with histologically proven malignant fibrous histiocytoma of bone underwent treatment involving limb salvage surgery complimented by a customised mega prosthesis. Most of the tumours were stage II according to the Enneking system, and located around the knee. Wide resection margins were achieved in 18 patients.

RESULTS

Following a mean follow-up of 58 months, 4 patients underwent amputation for local recurrence and 5 died of the disease. Two patients had prosthesis fractures; revision of the prosthesis was carried out in one. The functional result was excellent in 5 and good in 9 patients. The Kaplan-Meier 5-year survival rates of the patients treated without chemotherapy and with chemotherapy were 50% and 76%, respectively.

CONCLUSION

Limb salvage surgery with chemotherapy is a viable treatment option for patients with malignant fibrous histiocytoma of bone. It achieves higher survival rates than resection alone. Such therapy improves quality of life and provides a useful and functional limb.

Magnetic resonance imaging of bone tumors and joints

PURPOSE

In this invited review, the main subtypes of commoner bone tumors will be reviewed. Background and general concepts on pathology and surgery will be given with magnetic resonance imaging features of bone tumors. TEXT: The main malignant bone tumors being: osteogenic sarcoma, Ewings sarcoma, and chondrosarcoma are reviewed. Malignant intra-articular tumors are mentioned. The differential diagnoses including tumor mimickers are also reviewed.

CONCLUSION

Magnetic resonance imaging allows for basic anatomical review and characterization of tumor type for diagnosis, therapy monitoring, and preoperative planning. A team approach to tumor imaging and treatment is optimal.

High-grade intramedullary osteosarcoma of the talus: case report

This is a presentation of a rare malignant tumor that uncommonly affects the bones of the foot. The following case involves a malignancy which usually presents during childhood or adolescence presenting much later in life. Physicians treating the foot and ankle must include osteosarcoma in their list of differential diagnoses to exclude when vague symptoms involving deep pain and edema present. It is critical to prevent misdiagnosis and delayed treatment with this form of tumor.

A review of clinical and molecular prognostic factors in osteosarcoma

Traditional prognostic determinants in osteosarcoma have included demographics (age, sex), tumour size, site, stage, and the response to chemotherapy. Many of these are determined using varying techniques and units of measurement, which can make comparison between studies difficult. The absence of survival difference between limb sparing surgery and amputation has been repeatedly demonstrated in primary disease, and even in the setting of pathological fracture. On the other hand, there is still some controversy over the existence of increased local recurrence for limb-sparing surgery, and the implications of this. Commonly used prognostic determinants such as metastases, and response to chemotherapy enable a high degree of prognostic accuracy but usually at a late stage in the course of disease. Leading on from this, there is a need to uncover molecular pathways with specific influence over osteosarcoma progression to facilitate earlier treatment changes. Some important pathways are already being defined, for example the association of CXCR4 with metastases on presentation, the likelihood of doxorubicin resistance with positive P-glycoprotein, and the reduced survival prediction of over expressed survivin. It is anticipated that the future of osteosarcoma treatment will involve treatment tailored to the molecular profile of tumours at diagnosis, adjuvant therapy directed towards dysfunctional molecular pathways rather than the use of cytotoxics, and a more standardised approach to the measurement of clinical prognostic factors.

Anti-angiogenic therapy for osteosarcoma

Even in tumor centers using established protocols, the survival rate of patients with osteosarcoma has not improved significantly in recent years. Novel therapies are urgently needed as an adjunct to conventional treatment modalities, to reduce the dose and subsequent toxicity associated with current chemotherapy, improve local disease control, prevent development of metastases, and offer an alternative treatment for those tumors that are poorly responsive to chemotherapy. Anti-angiogenic therapy currently holds great potential in conjunction with conventional treatment modalities for osteosarcoma. Specifically, anti-angiogenic factors derived from cartilage, a natural barrier to osteosarcoma invasion, may have important therapeutic applications in osteosarcoma.