Distal Fibular Metastasis of Colorectal Carcinoma: A Case Report.

Case: A 62-year-old woman presenting with ankle pain was initially treated for a non-displaced fracture. Persistent pain despite months of conservative management for her presumed injury prompted repeat radiographs which demonstrated the progression of a lytic lesion and led to an orthopedic oncology referral. Following a complete work-up, including biopsy and staging, she was diagnosed with colorectal carcinoma metastatic to the distal fibula. Conclusion: Secondary tumors of the fibula are uncommon but an important diagnosis to consider for intractable lower extremity pain especially in patients with history of malignancy or lack of age-appropriate cancer screening.

How do US orthopaedic surgeons view placebo-controlled surgical trials? A pilot online survey study.

Randomised placebo-controlled trials (RPCTs) are the gold standard for evaluating novel treatments. However, this design is rarely used in the context of orthopaedic interventions where participants are assigned to a real or placebo surgery. The present study examines attitudes towards RPCTs for orthopaedic surgery among 687 orthopaedic surgeons across the USA. When presented with a vignette describing an RPCT for orthopaedic surgery, 52.3% of participants viewed it as 'completely' or 'mostly' unethical. Participants were also asked to rank-order the value of five different types of evidence supporting the efficacy of a surgery, ranging from RPCT to an anecdotal report. Responses regarding RPCTs were polarised with 26.4% viewing it as the least valuable (even less valuable than an anecdote) and 35.7 .% viewing it as the most valuable. Where equipoise exists, if we want to subject orthopaedic surgeries to the highest standard of evidence (RPCTs) before they are implemented in clinical practice, it will be necessary to educate physicians on the value and ethics of placebo surgery control conditions. Otherwise, invasive procedures may be performed without any benefits beyond possible placebo effects.

How orthopedic surgeons view open label placebo pills: Ethical and effective, but opposed to personal use.

OBJECTIVE: To examine attitudes of Open Label Placebos (OLP) among a national sample of US orthopedic surgeons. METHODS: Orthopedic surgeons across the US were invited to participate in a brief online cross-sectional survey; n = 687 participated. The survey included a short vignette of a surgeon using adjunctive OLPs in addition to opioids for postoperative pain management. Participants indicated how ethical and effective they thought OLPs would be in this context, and whether they would personally consider using OLPs. RESULTS: Nearly three-quarters (73.9%) of the surgeons considered OLPs ethical. In total, 55.4% and 48.8% of participants said that OLPs would "probably" or "definitely" be effective for Vicodin reduction and pain relief, respectively. However, only 19.2% of participants indicated they were personally willing to consider OLPs, and 59.6% were unwilling to do so. CONCLUSIONS: Generally, orthopedic surgeons perceive OLPs as both ethical and effective, but would not consider using them in their practice. Further research is needed to identify clinician barriers to OLP use.

Human osteoarthritis cartilage-derived stromal cells activate joint degeneration through TGF-beta lateral signaling.

Human osteoarthritis cartilage contains chondrocytes (OAC) and mesenchymal stromal cells (OA-MSC). Here, we found that TGF-ß had different effects on OA-MSC and OAC, and revealed its lateral signaling mechanism in OA. RNAseq analysis indicated that OA-MSC expressed the same level of Bone Morphogenetic Protein (BMP) Receptor-1A as OAC but only 1/12 of Transforming Growth Factor beta (TGF-ß) Receptor-1. While TGF-ß specifically activated SMAD2 in OAC, it also activated BMP signaling-associated SMAD1 in OA-MSC. While TGF-ß stimulated chondrogenesis in OAC, it induced hypertrophy, mineralization, and MMP-13 in OA-MSC. Inhibiting TGF-ßR1 suppressed MMP-13 in OA-MSC but stimulated it in OAC. In contrast, by specifically targeting BMPR1A/ACVR1 in both cell types, LDN193189 inhibits cartilage degeneration through suppressing hypertrophy and MMP-13 in a mouse osteoarthritis model. Thus, LDN193189, a drug under development to inhibit constitutive BMP signaling during heterotopic ossification, may be re-purposed for OA treatment.

Anti-miRNA Oligonucleotide Therapy for Chondrosarcoma.

Chondrosarcoma is a highly aggressive primary malignant bone tumor mostly occurring in adults. There are no effective systemic treatments, and patients with this disease have poor survival. miR-181a is an oncomiR that is overexpressed in high-grade chondrosarcoma and promotes tumor progression. Regulator of G-protein signaling 16 (RGS16) is a target of miR-181a. Inhibition of RGS16 expression by miR-181a enhances CXC chemokine receptor 4 signaling, which in turn increases MMP1 and VEGF expression, angiogenesis, and metastasis. Here, we report the results of systemic treatment with anti-miRNA oligonucleotides (AMO) directed against miR-181a utilizing a nanopiece delivery platform (NPs). NPs were combined with a molecular beacon or anti-miR-181a oligonucleotides and are shown to transfect chondrosarcoma cells in vitro and in vivo Intratumoral injection and systemic delivery had similar effects on miR-181a expression in nude mice bearing chondrosarcoma xenografts. Systemic delivery of NPs carrying anti-miR-181a also restored RGS16 expression, decreased expression of VEGF and MMP1, MMP activity, and tumor volume by 32% at day 38, and prolonged survival from 23% to 45%. In conclusion, these data support that systemic delivery of AMO shows promise for chondrosarcoma treatment.

Does CT-based Rigidity Analysis Influence Clinical Decision-making in Simulations of Metastatic Bone Disease?

BACKGROUND: There is a need to improve the prediction of fracture risk for patients with metastatic bone disease. CT-based rigidity analysis (CTRA) is a sensitive and specific method, yet its influence on clinical decision-making has never been quantified. QUESTIONS/PURPOSES: What is the influence of CTRA on providers' perceived risk of fracture? (2) What is the influence of CTRA on providers' treatment recommendations in simulated clinical scenarios of metastatic bone disease of the femur? (3) Does CTRA improve interobserver agreement regarding treatment recommendations? METHODS: We conducted a survey among 80 academic physicians (orthopaedic oncologists, musculoskeletal radiologists, and radiation oncologists) using simulated vignettes of femoral lesions presented as three separate scenarios: (1) no CTRA input (baseline); (2) CTRA input suggesting increased risk of fracture (CTRA+); and (3) CTRA input suggesting decreased risk of fracture (CTRA-). Participants were asked to rate the patient's risk of fracture on a scale of 0% to 100% and to provide a treatment recommendation. Overall response rate was 62.5% (50 of 80). RESULTS: When CTRA suggested an increased risk of fracture, physicians perceived the fracture risk to be slightly greater (37% ± 3% versus 42% ± 3%, p < 0.001; mean difference [95% confidence interval {CI}] = 5% [4.7%-5.2%]) and were more prone to recommend surgical stabilization (46% ± 9% versus 54% ± 9%, p < 0.001; mean difference [95% CI] = 9% [7.9-10.1]). When CTRA suggested a decreased risk of fracture, physicians perceived the risk to be slightly decreased (37% ± 25% versus 35% ± 25%, p = 0.04; mean difference [95% CI] = 2% [2.74%-2.26%]) and were less prone to recommend surgical stabilization (46% ± 9% versus 42% ± 9%, p < 0.03; mean difference [95% CI] = 4% [3.9-5.1]). The effect size of the influence of CTRA on physicians' perception of fracture risk and treatment planning varied with lesion severity and specialty of the responders. CTRA did not increase interobserver agreement regarding treatment recommendations when compared with the baseline scenario (κ = 0.41 versus κ = 0.43, respectively). CONCLUSIONS: Based on this survey study, CTRA had a small influence on perceived fracture risk and treatment recommendations and did not increase interobserver agreement. Further work is required to properly introduce this technique to physicians involved in the care of patients with metastatic lesions. Given the number of preclinical and clinical studies outlining the efficacy of this technique, better education through presentations at seminars/webinars and symposia will be the first step. This should be followed by clinical trials to establish CTRA-based clinical guidelines based on evidence-based medicine. Increased exposure of clinicians to CTRA, including its underlying methodology to study bone structural characteristics, may establish CTRA as a uniform guideline to assess fracture risk. LEVEL OF EVIDENCE: Level III, economic and decision analyses.

CT-based Structural Rigidity Analysis Is More Accurate Than Mirels Scoring for Fracture Prediction in Metastatic Femoral Lesions.

BACKGROUND: Controversy continues regarding the appropriate assessment of fracture risk in long bone lesions affected by disseminated malignancy. QUESTIONS/PURPOSES: The purpose of this ongoing Musculoskeletal Tumor Society-sponsored, multi-institutional prospective cross-sectional clinical study is to compare CT-based structural rigidity analysis (CTRA) with physician-derived Mirels scoring for predicting pathologic fracture in femoral bone lesions. We hypothesized CTRA would be superior to Mirels in predicting fracture risk within the first year based on (1) sensitivity, specificity, positive predictive value, and negative predictive value; (2) receiver operator characteristic (ROC) analysis; and (3) fracture prediction after controlling for potential confounding variables such as age and lesion size. METHODS: Consented patients with femoral metastatic lesions were assigned Mirels scores by the individual enrolling orthopaedic oncologist based on plain radiographs and then underwent CT scans of both femurs with a phantom of known density. The CTRA was then performed. Between 2004 and 2008, six study centers performed CTRA on 125 patients. The general indications for this test were femoral metastatic lesions potentially at risk of fracture. The enrolling physician was allowed the choice of prophylactic stabilization or nonsurgical treatment, and the local treating oncology team along with the patient made this decision. Of those 125 patients, 78 (62%) did not undergo prophylactic stabilization and had followup sufficient for inclusion, which was fracture through the lesion within 12 months of CTRA, death within 12 months of CTRA, or 12-month survival after CTRA without fracture, whereas 15 (12%) were lost to followup and could not be studied here. The mean patient age was 61 years (SD, 14 years). There were 46 women. Sixty-four of the lesions were located in the proximal femur, 13 were in the diaphysis, and four were distal. Osteolytic lesions prevailed (48 lesions) over mixed (31 lesions) and osteoblastic (15 lesions). The most common primary cancers were breast (25 lesions), lung (14 lesions), and myeloma (11 lesions). CTRA was compared with Mirels based on sensitivity/specificity analysis, ROC, and fracture prediction by multivariate analysis. For the CTRA, reduction greater than 35% in axial, bending, or torsional rigidities at the lesion was considered at risk for fracture, whereas a Mirels score of 9 or above, as suggested in the original manuscript, was used as the definition of impending fracture. RESULTS: CTRA provided higher sensitivity (100% versus 66.7%), specificity (60.6% versus 47.9%), positive predictive value (17.6% versus 9.8%), and negative predictive value (100% versus 94.4%) compared with the classic Mirels definition of impending fracture (≥ 9), although there was considerable overlap in the confidence intervals. ROC curve analysis found CTRA to be better than the Mirels score regardless of what Mirels score cutoff was used. After controlling for potential confounding variables including age, lesion size, and Mirels scores, multivariable logistic regression indicated that CTRA was a better predictor of fracture (likelihood ratio test = 10.49, p < 0.001). CONCLUSIONS: CT-based structural rigidity analysis is better than Mirels score in predicting femoral impending pathologic fracture. CTRA appears to provide a substantial advance in the accuracy of predicting pathological femur fracture over currently used clinical and radiographic criteria. LEVEL OF EVIDENCE: Level III, diagnostic study.

miR-181a Targets RGS16 to Promote Chondrosarcoma Growth, Angiogenesis, and Metastasis.

UNLABELLED: Chondrosarcoma is the most common primary malignant bone tumor in adults, has no effective systemic treatment, and patients with this disease have poor survival. Altered expression of microRNA (miR) is involved in tumorigenesis; however, its role in chondrosarcoma is undetermined. miR-181a is overexpressed in high-grade chondrosarcoma, is upregulated by hypoxia, and increases VEGF expression. Here, the purpose was to determine the mechanism of miR-181a regulation of VEGF, determine whether miR-181a overexpression promotes tumor progression, and to evaluate an antagomir-based approach for chondrosarcoma treatment. Therapeutic inhibition of miR-181a decreased expression of VEGF and MMP1 in vitro, and angiogenesis, MMP1 activity, tumor growth, and lung metastasis, all by more than 50%, in a xenograft mouse model. A target of miR-181a is a regulator of G-protein signaling 16 (RGS16), a negative regulator of CXC chemokine receptor 4 (CXCR4) signaling. CXCR4 signaling is increased in chondrosarcoma, its expression is also increased by hypoxia, and is associated with angiogenesis and metastasis; however, receptor blockade is only partially effective. RGS16 expression is restored after miR-181a inhibition and partially accounts for the antiangiogenic and antimetastatic effects of miR-181a inhibition. These data establish miR-181a as an oncomiR that promotes chondrosarcoma progression through a new mechanism involving enhancement of CXCR4 signaling by inhibition of RGS16. IMPLICATIONS: Targeting miR-181a can inhibit tumor angiogenesis, growth, and metastasis, thus suggesting the possibility of antagomir-based therapy in chondrosarcoma.

Treatment Planning and Fracture Prediction in Patients with Skeletal Metastasis with CT-Based Rigidity Analysis.

PURPOSE: Pathologic fractures could be prevented if reliable methods of fracture risk assessment were available. A multicenter prospective study was conducted to identify significant predictors of physicians' treatment plan for skeletal metastasis based on clinical fracture risk assessments and the proposed CT-based Rigidity Analysis (CTRA). EXPERIMENTAL DESIGN: Orthopedic oncologists selected a treatment plan for 124 patients with 149 metastatic lesions based on the Mirels method. Then, CTRA was performed, and the results were provided to the physicians, who were asked to reassess their treatment plan. The pre- and post-CTRA treatment plans were compared to identify cases in which the treatment plan was changed based on the CTRA report. Patients were followed for a 4-month period to establish the incidence of pathologic fractures. RESULTS: Pain, lesion type, and lesion size were significant predictors of the pre-CTRA plan. After providing the CTRA results, physicians changed their plan for 36 patients. CTRA results, pain, and primary source of metastasis were significant predictors of the post-CTRA plan. Follow-up of patients who did not undergo fixation resulted in 7 fractures; CTRA predicted these fractures with 100% sensitivity and 90% specificity, whereas the Mirels method was 71% sensitive and 50% specific. CONCLUSIONS: Lesion type and size and pain level influenced the physicians' plans for the management of metastatic lesions. Physicians' treatment plans and fracture risk predictions were significantly influenced by the availability of CTRA results. Due to its high sensitivity and specificity, CTRA could potentially be used as a screening method for pathologic fractures.

MicroRNA regulates vascular endothelial growth factor expression in chondrosarcoma cells.

BACKGROUND: Systemic treatments to prevent or treat chondrosarcoma metastasis are lacking and targeted therapy has yet to be developed. Hypoxia develops in tumors as they grow and hypoxia-related alterations in gene expression underlie some of the traits of cancer. One critical trait is the ability to induce sustained angiogenesis, which is usually related to expression of vascular endothelial growth factor (VEGF). A potential hypoxia-related mechanism resulting in altered gene expression involves microRNA. Little is known about microRNA expression in chondrosarcoma and its potential role in regulation of VEGF expression. QUESTIONS/PURPOSES: Our purposes were (1) to determine if there is hypoxia-regulated microRNA overexpressed in chondrosarcoma; (2) if that contributes to increased VEGF expression; and (3) can VEGF expression be inhibited with a specific antagomir? METHODS: MicroRNA expression was analyzed in two primary human chondrosarcomas and articular cartilage using array analysis and a cutoff of a fourfold difference in expression between tumor and normal tissue. The effects of hypoxia and hypoxia-inducible factor-1α (HIF-1α) transfection and silencing with siRNA on expression of candidate microRNAs were analyzed in chondrosarcoma cell line JJ. VEGF expression was measured with quantitative polymerase chain reaction and enzyme-linked immunosorbent assay after specific microRNA transfection and knockdown. RESULTS: miR-181a was identified by array analysis and confirmed with quantitative reverse transcription-polymerase chain reaction, which showed that miR-181a was overexpressed in both human chondrosarcomas (33- and 55-fold) and the JJ cell line (sixfold) compared with cartilage and chondrocytes, respectively. In vitro, hypoxia and HIF-1α transfection each further increased miR-181a expression twofold in JJ cells. miR-181a transfection of JJ cells doubled expression of VEGF mRNA and increased secreted VEGF protein by 46% in normoxia, an effect that could be either direct or indirect. Similar enhancement of VEGF expression by miR-181a was found during hypoxia. Transfection with the antagomir anti-miR-181a decreased VEGF protein by 27% in normoxia and 23% in hypoxia. CONCLUSIONS: miR-181a is a hypoxia-regulated microRNA that is overexpressed in chondrosarcoma and enhances VEGF expression, an effect that could be inhibited by anti-miR-181a. CLINICAL RELEVANCE: Systemic treatment options for chondrosarcoma are limited. Antiangiogenic strategies could potentially be effective in limiting tumor progression. One method of inhibiting VEGF expression and associated angiogenesis could be an antagomir-based therapy targeted at miR-181a or other oncogenic microRNAs, although methods of systemic delivery are still under development. The effectiveness of antagomirs also needs to be compared with other antiangiogenic modalities in preclinical models.

CXCR4-targeted therapy inhibits VEGF expression and chondrosarcoma angiogenesis and metastasis.

Chondrosarcoma is notable for its lack of response to conventional cytotoxic chemotherapy, propensity for developing lung metastases, and poor survival. Therefore, a better understanding of angiogenic and metastatic pathways is needed. Multiple pathways regulate angiogenesis and metastasis, including chemokines and their receptors. In this study, we investigated chemokine (C-X-C motif) receptor 4 (CXCR4) signaling in chondrosarcoma and tested the hypotheses that CXCR4 inhibition suppresses tumor angiogenesis and metastasis. CXCR4 expression, analyzed by real-time PCR and Western blot, was increased in human chondrosarcoma cell line JJ compared with normal chondrocytes and was further increased in JJ by hypoxia (2% O2), vascular endothelial growth factor A (VEGFA; 10 ng/mL), and in xenograft tumors in nude mice. The CXCR4 ligand CXCL12 (10 ng/mL) doubled secreted VEGFA, measured with ELISA, under hypoxic conditions and this conditioned media increased human umbilical vein endothelial cell tube formation. These effects were inhibited by CXCR4 siRNA or AMD3100 (5 µg/mL). In a xenograft mouse model, four weeks of AMD3100 treatment (1.25 mg/kg, intraperitoneally twice daily) inhibited tumor angiogenesis, tumor growth, and metastasis. VEGFA content in tumor extracts was decreased (7.19 ± 0.52 ng/mL control vs. 3.96 ± 0.66 treatment) and bioimaging of angiogenesis was decreased by 56%. Tumor volumes averaged 4.44 ± 0.68 cm(3) in control compared with 2.48 ± 0.61 cm(3) in the treatment group. The number of lung metastatic nodules was 23 ± 9 in control compared with 10 ± 6 in the treatment group (N = 8/group). Therefore, CXCR4-targeted therapy may be a treatment strategy for chondrosarcoma.

Locking buttons increase fatigue life of locking plates in a segmental bone defect model.

BACKGROUND: Durability of plate fixation is important in delayed union. Although locking plates result in stronger constructs, it is not known if locking affects the fatigue life of a plate. Two locking screws on either side of the nonunion could decrease working length and increase strain in the plate. However, the reinforcing effect of the locking head on the plate may compensate, so that it is unclear whether locking reduces fatigue life. QUESTIONS/PURPOSES: We determined whether locking screws, compression screws, and locking buttons reduce or increase the fatigue life of a plate. METHODS: We tested fatigue life of four constructs using an eight-hole locking plate in a segmental defect model: (1) all locking screws (Locked; n = 5); (2) all compression screws (Unlocked; n = 5); (3) six compression screws with two locking buttons in the central holes (Button; n = 6); and (4) six compression screws with two open central holes (Open; n = 6). RESULTS: The Button group had the longest fatigue life (1.3 million cycles). There was no difference between the Locked and Unlocked groups. All of the constructs failed by fracture of the plates through a screw hole adjacent to the defect. CONCLUSIONS: Locking screws did not improve fatigue life, however a locking button increased the fatigue life of a locking plate in a segmental bone defect model. CLINICAL RELEVANCE: Locking buttons in holes adjacent to a defect may improve durability, which is important when delayed union is a possibility.

Benign tumors of the spine.

Benign tumors in the spine include osteoid osteoma, osteoblastoma, aneurysmal bone cyst, osteochondroma, neurofibroma, giant cell tumor of bone, eosinophilic granuloma, and hemangioma. Although some are incidental findings, some cause local pain, radicular symptoms, neurologic compromise, spinal instability, and deformity. The evaluation of spinal tumors includes a thorough history and physical examination, imaging, sometimes laboratory evaluation, and biopsy when indicated. Appropriate treatment may be observational (eg, eosinophilic granuloma) or ablative (eg, osteoid osteoma, neurofibroma, hemangioma), but generally is surgical, depending on the level of pain, instability, neurologic compromise, and natural history of the lesion. Knowledge of the epidemiology, common presentation, imaging, and treatment of benign bone tumors is essential for successful management of these lesions.

CXCR4/SDF1 mediate hypoxia induced chondrosarcoma cell invasion through ERK signaling and increased MMP1 expression.

BACKGROUND: Chondrosarcoma is a disease that does not respond to conventional cytotoxic chemotherapy and expression of MMP1 is a marker for a poor prognosis. The mechanism of increased MMP1 expression in chondrosarcoma is not completely known. Our goal is to identify molecular pathways that could serve as therapeutic targets. Chondrosarcoma become hypoxic as they grow, are capable of eliciting an angiogenic response, and typically metastasize to the lungs. The present study determined the effect of hypoxia and specifically HIF-1a on expression of CXCR4 and MMP1 and their role in chondrosarcoma cell invasion. RESULTS: CXCR4 and its ligand, SDF1, are upregulated in primary chondrosarcoma tumors compared to normal articular cartilage, and CXCR4 was upregulated in chondrosarcoma cell line JJ compared to normal chondrocytes. Hypoxia and specifically HIF-1a increased CXCR4 and MMP1 expression in JJ cell line and chondrosarcoma invasion in vitro. The hypoxia mediated increase in MMP1 expression and chondrosarcoma invasion could be inhibited by siRNA directed at HIF-1a or CXCR4, the CXCR4 inhibitor AMD3100, as well as with ERK inhibitor U0126 and ERK siRNA. CONCLUSIONS: Chondrosarcoma cell invasion is increased by hypoxia induced expression of CXCR4 and MMP1 and is mediated by HIF-1a and ERK. Both invasion and MMP1 can be inhibited with CXCR4 blockade, suggesting that CXCR4/SDF1 signaling may be a therapeutic target for chondrosarcoma.

HDAC4 represses vascular endothelial growth factor expression in chondrosarcoma by modulating RUNX2 activity.

Chondrosarcoma is a primary bone tumor with a dismal prognosis; most patients with this disease develop fatal pulmonary metastases, suggesting the need for a better systemic treatment. Anti-angiogenesis treatment may be useful, because angiogenesis is critical for both tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is the most potent pro-angiogenic factor and is regulated by pathways related to the normal physiologic response to hypoxia and genetic alterations related to the malignant phenotype. Our prior work has shown that VEGF is overexpressed in high grade chondrosarcoma and chondrosarcoma cell lines. Working on the premise that developmental pathways giving a selective growth advantage are often recapitulated in tumors, we investigated the regulation of VEGF by HDAC4 and Runx2 in chondrosarcoma. We tested the hypothesis that there is dysregulation of HDAC4/Runx2/VEGF gene expression and that decreased HDAC4 expression accounts for at least some of the increased VEGF expression seen in chondrosarcoma. We show that reduced expression of HDAC4 in chondrosarcoma cells increases expression of Runx2 leading to increased expression of VEGF and in vitro angiogenesis. Thus, both hypoxia and dysregulated expression of a developmental pathway are causes of increased VEGF expression in chondrosarcoma.