Monoclonal Antibodies for Targeted Fluorescence-Guided Surgery: A Review of Applicability across Multiple Solid Tumors

This study aims to review the status of the clinical use of monoclonal antibodies (mAbs) that have completed or are in ongoing clinical trials for targeted fluorescence-guided surgery (T-FGS) for the intraoperative identification of the tumor margins of extra-hematological solid tumors. For each of them, the targeted antigen, the mAb generic/commercial name and format, and clinical indications are presented, together with utility, doses, and the timing of administration. Based on the current scientific evidence in humans, the top three mAbs that could be prepared in a GMP-compliant bank ready to be delivered for surgical purposes are proposed to speed up the translation to the operating room and produce a few readily available "off-the-shelf" injectable fluorescent probes for safer and more effective solid tumor resection.

Layer-by-Layer Coatings of Collagen-Hyaluronic acid Loaded with an Antibacterial Manuka Honey Bioactive Compound to Fight Metallic Implant Infections

Implant-associated severe infections can result in catastrophic implant failures; thus, advanced antibacterial coatings are needed to combat infections. This study focuses on harnessing nature-inspired self-assembly of extracellular matrix (ECM)-like coatings on Ti alloy with a combination of jellyfish-derived collagen (J-COLL) and hyaluronic acid (HA) using our customized automated hybrid layer-by-layer apparatus. To improve the anti-infection efficacy of coatings, we have incorporated a natural antibacterial agent methylglyoxal (MGO, a Manuka honey compound) in optimized multilayer coatings. The obtainment of MGO-loaded multilayer coatings was successfully assessed by profilometry, contact angle, attenuated total reflectance (ATR)-Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. In vitro degradation confirmed the controlled release activity of MGO with a range of concentrations from 0.90 to 2.38 mM up to 21 days. A bacterial cell culture study using Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) confirmed that the MGO incorporated within layers 7 and 9 had a favorable effect on preventing bacterial growth and colonization on their surfaces. An in vitro cytocompatibility study confirmed that MGO agents included in the layers did not affect or reduce the cellular functionalities of L929 fibroblasts. In addition, MGO-loaded layers with Immortalized Mesenchymal Stem Cells (Y201 TERT-hMSCs) were found to favor the growth and differentiation of Y201 cells and promote calcium nodule formation. Overall, these surface coatings are promising candidates for delivering antimicrobial activity with bone-inducing functions for future bone tissue engineering applications.

Synthesis and In Vitro Evaluation of a HER2-Specific ImmunoSCIFI Probe

Secondary Cerenkov-induced fluorescence imaging (SCIFI) is an emerging biomedical optical imaging modality that leverages Cerenkov luminescence, primarily generated by β-emitting radioisotopes, to excite fluorophores that offer near-infrared emissions with optimal tissue penetrance. Dual-functionalized immunoconjugates composed of an antibody, a near-infrared fluorophore, and a β-emitting radioisotope have potential utility as novel SCIFI constructs with high specificity for molecular biomarkers of disease. Here, we report the synthesis and characterization of [89Zr]Zr-DFO-trastuzumab-BOD665, a self-excitatory HER2-specific "immunoSCIFI" probe capable of yielding near-infrared fluorescence in situ without external excitation. The penetration depth of the SCIFI signal was measured in hemoglobin-infused optical tissue phantoms that indicated a 2.05-fold increase compared to 89Zr-generated Cerenkov luminescence. Additionally, the binding specificity of the immunoSCIFI probe for HER2 was evaluated in a cellular assay that showed significantly higher binding to SKBR3 (high HER2 expression) relative to MDA-MB-468 (low HER2) breast cancer cells based on measurements of total flux in the near-infrared region with external excitation blocked. Taken together, the results of this study indicate the potential utility of immunoSCIFI constructs for interrogation of molecular biomarkers of disease.

Fluorescence lifetime of injected indocyanine green as a universal marker of solid tumours in patients

The surgical resection of solid tumours can be enhanced by fluorescence-guided imaging. However, variable tumour uptake and incomplete clearance of fluorescent dyes reduces the accuracy of distinguishing tumour from normal tissue via conventional fluorescence intensity-based imaging. Here we show that, after systemic injection of the near-infrared dye indocyanine green in patients with various types of solid tumour, the fluorescence lifetime (FLT) of tumour tissue is longer than the FLT of non-cancerous tissue. This tumour-specific shift in FLT can be used to distinguish tumours from normal tissue with an accuracy of over 97% across tumour types, and can be visualized at the cellular level using microscopy and in larger specimens through wide-field imaging. Unlike fluorescence intensity, which depends on imaging-system parameters, tissue depth and the amount of dye taken up by tumours, FLT is a photophysical property that is largely independent of these factors. FLT imaging with indocyanine green may improve the accuracy of cancer surgeries.

What Is the Significance of Indeterminate Pulmonary Nodules in High-Grade Soft Tissue Sarcomas? A Retrospective Cohort Study

BACKGROUND

Sarcomas are rare, aggressive cancers which frequently metastasise to the lungs. Following diagnosis, patients typically undergo staging by means of a CT scan of their chest. This often identifies indeterminate pulmonary nodules (IPNs), but the significance of these in high-grade soft tissue sarcoma (STS) is unclear. Identifying whether these are benign or malignant is important for clinical decision making. This study analyses the clinical relevance of IPNs in high-grade STS.

METHODS

All patients treated at our centre for high-grade soft tissue sarcoma between 2010 and 2020 were identified from a prospective database. CT scans and their reports were reviewed, and survival data were collected from patient records.

RESULTS

389 suitable patients were identified; 34.4% had IPNs on their CT staging scan and 20.1% progressed into lung metastases. Progression was more likely with IPNs ≥ 5 mm in diameter (p = 0.006), multiple IPNs (p = 0.013) or bilateral IPNs (p = 0.022), as well as in patients with primaries ≥ 5 cm (p = 0.014), grade 3 primaries (p = 0.009) or primaries arising deep to the fascia (p = 0.041). The median time to progression was 143 days. IPNs at diagnosis were associated with an increased risk of developing lung metastases and decreased OS in patients with grade 3 STS (p = 0.0019 and p = 0.0016, respectively); this was not observed in grade 2 patients.

CONCLUSIONS

IPNs at diagnosis are associated with significantly worse OS in patients with grade 3 STS. It is crucial to consider the primary tumour as well as the IPNs when considering the risk of progression. Surveillance CT scans should be carried out within 6 months.

Membrane-type 1 matrix metalloproteinase as predictor of survival and candidate therapeutic target in Ewing sarcoma

BACKGROUND

Ewing sarcoma (ES) is the second most common primary bone malignancy, with an urgent need for new treatments. ES is associated with high rates of progression and relapse, driven by drug-resistant cells capable of migration, self-renewal and single-cell tumorigenesis, termed cancer stem-like cells (CSCs). Membrane-type 1 matrix metalloproteinase (MT1-MMP) is a membrane-bound proteolytic enzyme, which, via direct and indirect mechanisms, digests four of the main types of collagen. This can be hijacked in malignancy for invasion and metastasis, with high expression predicting decreased survival in multiple cancers. In this study, we have examined the hypothesis that MT1-MMP is expressed by ES cells and explored the relationship between expression and outcomes.

PROCEDURE

MT1-MMP expression in ES established cell lines, primary patient-derived cultures and daughter ES-CSCs was characterised by RNA sequencing, Western blotting, immunocytochemistry and flow cytometry. Immunohistochemistry was used to detect MT1-MMP in tumour biopsies, and the relationship between expression, event-free and overall survival examined.

RESULTS

MT1-MMP was detected at both RNA and protein levels in five of six established cell lines, all primary cultures (n = 25) and all daughter ES-CSCs (n = 7). Immunohistochemistry of treatment-naïve biopsy tissue demonstrated that high MT1-MMP expression predicted decreased event-free and overall survival (p = .017 and .036, respectively; n = 47); this was not significant in multivariate analysis.

CONCLUSIONS

MT1-MMP is expressed by ES cells, including ES-CSCs, making it a candidate therapeutic target. The level of MT1-MMP expression at diagnosis may be considered as a prognostic biomarker if validated by retrospective analysis of a larger cohort of clinical trial samples.

In situ excitation of BODIPY fluorophores by 89Zr-generated Cerenkov luminescence

Secondary Cerenkov-induced fluorescence imaging (SCIFI) is an emerging optical imaging technology that affords high signal-to-noise images by utilising radionuclide-generated Cerenkov luminescence to excite fluorescent probes. BODIPY dyes offer attractive properties for SCIFI, including high quantum yields and photochemical stability, yet their utility in this application in combination with clinically relevant β⁺-emitting radioisotopes remains largely unexplored. In this report, the fluorescence properties of three meso-substituted BODIPY analogues have been assessed in combination with the positron emitter zirconium-89. Most notably, SCIFI data acquired over 7 days shows the BODIPY scaffold remain largely inert to radiolysis, indicating the promising utility of this fluorophore class in SCIFI applications.

Synthesis and In Vivo Evaluation of a Site-specifically Labeled Radioimmunoconjugate for Dual-Modal (PET/NIRF) Imaging of MT1-MMP in Sarcomas

Bone sarcomas are devastating primary bone cancers that mostly affect children, young adults, and the elderly. These aggressive tumors are associated with poor survival, and surgery remains the mainstay of treatment. Surgical planning is increasingly informed by positron emission tomography (PET), and tumor margin identification during surgery is aided by near-infrared fluorescence (NIRF) imaging, yet these investigations are confounded by probes that lack specificity for sarcoma biomarkers. We report the development of a dual-modal (PET/NIRF) immunoconjugate ([⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW) that targets MT1-MMP, a matrix metalloproteinase overexpressed in high-grade sarcomas. [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW was synthesized via site-specific chemoenzymatic glycan modification, characterized, and isolated in high specific activity and radiochemical purity. Saturation binding and immunoreactivity assays indicated only minor perturbation of binding properties. A novel mouse model of dedifferentiated chondrosarcoma based on intrafemoral inoculation of HT1080 WT or KO cells (high and low MT1-MMP expression, respectively) was used to evaluate target binding and biodistribution. Fluorescence and Cerenkov luminescence images of [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW showed preferential uptake in HT1080 WT tumors. Ex vivo gamma counting revealed that uptake in MT1-MMP-positive tumors was significantly higher than that in control groups. Taken together, [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW is a promising dual-modal sarcoma imaging agent for pre-operative surgical planning and intraoperative surgical guidance.

The addition of a flange does not improve the pressure generated during cemented acetabular cup implantation

Flanged acetabular cups were developed with the rationale that, at insertion, they would increase the pressure of the cement and improve penetration of cement into the acetabular bone. Various studies have been inconclusive regarding their effectiveness. In this work, we aimed to eliminate all confounding factors and measure the pressures generated during acetabular pressurization and cup implantation using a simplified steel acetabulum, high precision pressure transducers, proper surgical techniques and two acetabular cups, identical apart from the addition of a flange to one. It was found that the flanged acetabular component did not significantly increase the pressure in the acetabulum and in some cases reduced the pressures generated when compared to an unflanged cup. The addition of a flange did not reduce the pressure differential between the pole and the rim of the acetabulum, nor did it have a significant effect on pressure lost over the cup implantation period. It was concluded that flanged acetabular cups provide no significant improvement in the pressures generated in the acetabulum during acetabular cup implantation. It is hypothesized that the flange may be seen as a design feature intended to slow the insertion of the cup into the cement, thus requiring the surgeon to apply a larger load in order to correctly position the acetabular cup; in this way larger pressure will be generated.

The effect of vitamin D supplementation on outcomes following total hip or knee arthroplasty surgery: a rapid systematic review of current evidence

Purpose

Vitamin D deficiency has been linked to poorer outcomes following hip (THR) and knee (TKR) replacement. We review the effect of peri-operative supplementation on clinical and patient-reported outcomes following THR/TKR.

Methods

This study was registered with PROSPERO (CRD42021238086). Searches of electronic databases were performed from inception to March 2021. All randomised, cohort, or case-controlled studies reported in English of adults undergoing THR/TKR where vitamin D supplementation was given peri-operatively and at least one outcome was reported were included. Studies reporting on vitamin D in relation to osteoporosis and hip fracture were excluded, as were conference abstracts and those involving preclinical models. Risks of bias were performed using the RoB-2 and ROBINS-I tools.

Results

Three studies comprising 413 TKR patients were identified; two were randomised controlled trials and one was a prospective cohort study. No studies meeting the inclusion criteria reported on the outcomes following THR. Supplementation was associated with a statistically significant reduction in the IL6:IL10 ratio at 24- and 48h following surgery, but no effect was noted on Western Ontario and McMaster Universities Osteoarthritis Index scores or the rates of falls. All studies were judged to be limited by bias, with heterogeneity in the supplementation dose and timing of administration, as well as the reported outcome measures used.

Discussion

Further adequately powered randomised-controlled trials using vitamin D supplementation and a specific clinically relevant or patient-reported outcome measure are required to assess if pre-operative vitamin D insufficiency is a modifiable risk factor to improve outcomes following THR/TKR.

Leiomyosarcoma in the extremities and trunk wall: systematic review and meta-analysis of the oncological outcomes

Background

Leiomyosarcomas are aggressive malignancies which can occur on the trunk and extremities whose pathogenesis is poorly understood. We aim to quantify the prognostic impact of various clinical and pathological markers on survival and recurrence of leiomyosarcomas.

Methods

We conducted a systematic review as per PRISMA protocol. Survival, local recurrence, and metastasis were the outcome measures. Data were extracted from the studies for the outcome variables; the resultant odds ratios (OR) and 95% confidence interval (CI) were used for the synthesis of a forest plot.

Results

Our search revealed thirteen studies comprising 1380 patients. Seven of these 13 publications were since 2012. Our analysis showed that tumor size larger than 5 cm adversely affected the outcome with an OR 3.39 (2.26–5.10, p < 0.01). Other factors which reduced the overall survival were positive margins of excision OR 2.12 (1.36–3.32, p < 0.01). A reduced risk of metastasis has strongly associated the use of radiotherapy with OR 10.84 (4.41–26.61, p < 0.01). Only a few studies analyzed the impact of factors on local recurrence.

Conclusions

Size larger than 5 cm and positive margins of excision are associated with poor overall survival. In comparison, the use of adjuvant radiotherapy was associated with a lower metastatic rate. There is a need for methodically high-quality studies with more uniform study design and reporting to evaluate the impact of various risk factors on local recurrence and metastases.

Level of evidence

Level 1 Prognostic

Matrix metalloproteinase-13 is fully activated by neutrophil elastase and inactivates its serpin inhibitor, alpha-1 antitrypsin: Implications for osteoarthritis

Matrix metalloproteinase-13 (MMP-13) is a uniquely important collagenase that promotes the irreversible destruction of cartilage collagen in osteoarthritis (OA). Collagenase activation is a key control point for cartilage breakdown to occur, yet our understanding of the proteinases involved in this process is limited. Neutrophil elastase (NE) is a well-described proteoglycan-degrading enzyme which is historically associated with inflammatory arthritis, but more recent evidence suggests a potential role in OA. In this study, we investigated the effect of neutrophil elastase on OA cartilage collagen destruction and collagenase activation. Neutrophil elastase induced significant collagen destruction from human OA cartilage ex vivo, in an MMP-dependent manner. In vitro, neutrophil elastase directly and robustly activated pro-MMP-13, and N-terminal sequencing identified cleavage close to the cysteine switch at 72 MKKPR, ultimately resulting in the fully active form with the neo-N terminus of 85 YNVFP. Mole-per-mole, activation was more potent than by MMP-3, a classical collagenase activator. Elastase was detectable in human OA synovial fluid and OA synovia which displayed histologically graded evidence of synovitis. Bioinformatic analyses demonstrated that, compared with other tissues, control cartilage exhibited remarkably high transcript levels of the major elastase inhibitor, (AAT) alpha-1 antitrypsin (gene name SERPINA1), but these were reduced in OA. AAT was located predominantly in superficial cartilage zones, and staining enhanced in regions of cartilage damage. Finally, active MMP-13 specifically inactivated AAT by removal of the serine proteinase cleavage/inhibition site. Taken together, this study identifies elastase as a novel activator of pro-MMP-13 that has relevance for cartilage collagen destruction in OA patients with synovitis.

Intraoperative Near-Infrared Fluorescence Guided Surgery Using Indocyanine Green (ICG) for the Resection of Sarcomas May Reduce the Positive Margin Rate: An Extended Case Series

BACKGROUND

Sarcomas are rare, aggressive cancers which can occur in any region of the body. Surgery is usually the cornerstone of curative treatment, with negative surgical margins associated with decreased local recurrence and improved overall survival. Indocyanine green (ICG) is a fluorescent dye which accumulates in sarcoma tissue and can be imaged intraoperatively using handheld near-infrared (NIR) cameras, theoretically helping guide the surgeon's resection margins.

METHODS

Patients operated on between 20 February 2019 and 20 October 2021 for intermediate to high grade sarcomas at our centres received either conventional surgery, or were administered ICG pre-operatively followed by intra-operative NIR fluorescence guidance during the procedure. Differences between the unexpected positive margin rates were compared.

RESULTS

115 suitable patients were identified, of which 39 received ICG + NIR fluorescence guided surgery, and 76 received conventional surgery. Of the patients given ICG, 37/39 tumours fluoresced, and surgeons felt the procedure was guided by the intra-operative images in 11 cases. Patients receiving ICG had a lower unexpected positive margin rate (5.1% vs. 25.0%, p = 0.01).

CONCLUSIONS

The use of NIR fluorescence cameras in combination with ICG may reduce the unexpected positive margin rate for high grade sarcomas. A prospective, multi-centre randomised control trial is now needed to validate these results.

Circulating tumour DNA is a promising biomarker for risk stratification of central chondrosarcoma with IDH1/2 and GNAS mutations

Chondrosarcoma (CS) is a rare tumour type and the most common primary malignant bone cancer in adults. The prognosis, currently based on tumour grade, imaging and anatomical location, is not reliable, and more objective biomarkers are required. We aimed to determine whether the level of circulating tumour DNA (ctDNA) in the blood of CS patients could be used to predict outcome. In this multi-institutional study, we recruited 145 patients with cartilaginous tumours, of which 41 were excluded. ctDNA levels were assessed in 83 of the remaining 104 patients, whose tumours harboured a hotspot mutation in IDH1/2 or GNAS. ctDNA was detected pre-operatively in 31/83 (37%) and in 12/31 (39%) patients postoperatively. We found that detection of ctDNA was more accurate than pathology for identification of high-grade tumours and was associated with a poor prognosis; ctDNA was never associated with CS grade 1/atypical cartilaginous tumours (ACT) in the long bones, in neoplasms sited in the small bones of the hands and feet or in tumours measuring less than 80 mm. Although the results are promising, they are based on a small number of patients, and therefore, introduction of this blood test into clinical practice as a complementary assay to current standard-of-care protocols would allow the assay to be assessed more stringently and developed for a more personalised approach for the treatment of patients with CS.

RNA sequencing and functional studies of patient-derived cells reveal that neurexin-1 and regulators of this pathway are associated with poor outcomes in Ewing sarcoma

Purpose

The development of biomarkers and molecularly targeted therapies for patients with Ewing sarcoma (ES) in order to minimise morbidity and improve outcome is urgently needed. Here, we set out to isolate and characterise patient-derived ES primary cell cultures and daughter cancer stem-like cells (CSCs) to identify biomarkers of high-risk disease and candidate therapeutic targets.

Methods

Thirty-two patient-derived primary cultures were established from treatment-naïve tumours and primary ES-CSCs isolated from these cultures using functional methods. By RNA-sequencing we analysed the transcriptome of ES patient-derived cells (n = 24) and ES-CSCs (n = 11) to identify the most abundant and differentially expressed genes (DEGs). Expression of the top DEG(s) in ES-CSCs compared to ES cells was validated at both RNA and protein levels. The functional and prognostic potential of the most significant gene (neurexin-1) was investigated using knock-down studies and immunohistochemistry of two independent tumour cohorts.

Results

ES-CSCs were isolated from all primary cell cultures, consistent with the premise that ES is a CSC driven cancer. Transcriptional profiling confirmed that these cells were of mesenchymal origin, revealed novel cell surface targets for therapy that regulate cell-extracellular matrix interactions and identified candidate drivers of progression and relapse. High expression of neurexin-1 and low levels of regulators of its activity, APBA1 and NLGN4X, were associated with poor event-free and overall survival rates. Knock-down of neurexin-1 decreased viable cell numbers and spheroid formation.

Conclusions

Genes that regulate extracellular interactions, including neurexin-1, are candidate therapeutic targets in ES. High levels of neurexin-1 at diagnosis are associated with poor outcome and identify patients with localised disease that will relapse. These patients could benefit from more intensive or novel treatment modalities. The prognostic significance of neurexin-1 should be validated independently.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-021-00619-8.

The importance of clear margins in myxofibrosarcoma: Improving local control by means of staged resection and reconstruction

INTRODUCTION

Myxofibrosarcomas are associated with a locally infiltrative growth pattern, making a clear-margin resection margin challenging. This leads to high local recurrence rates. While immediate wound closure and adjuvant radiotherapy has been proposed to mitigate incomplete excisions, we present our experience treating myxofibrosarcomas with staged excisions until clear margins are obtained, prior to reconstruction.

METHODS

All patients with myxofibrosarcomas treated with a curative intent at our centre between 2009 and 2019 were identified. Patient demographics, tumour characteristics, number of resections, method of reconstruction, adjuvant therapy, complications, local recurrence rates, length of hospital stay and overall survival were assessed.

RESULTS

97 consecutive eligible patients were identified. Forty-six (47%) had positive margins reported following a first resection. The median number of resections required to obtain clear margins was two and the median time from first excision to definitive wound closure was 15 days. Local recurrence rate for the whole cohort was 14%. Patients who had staged resection until clear margins were obtained had a significantly lower rate of local recurrence compared to those who had positive margins at time of reconstruction (p-value = 0.001). The estimated 5-year disease-specific survival for the whole cohort was 93%.

DISCUSSION

Obtaining clear margins in myxofibrosarcoma via staged resections was associated with lower local recurrence rates for patients who had an initial resection with positive margins. The outcomes of performing staged resections are equivalent to patients for whom a clear margin were obtained in the first instance.

What Proportion of Patients with Bone and Soft Tissue Tumors Contracted Coronavirus-19 and Died From Surgical Procedures During the Initial Period of the COVID-19 Pandemic? Results From the Multicenter British Orthopaedic Oncology Society Observational Study

BACKGROUND

Delivering uninterrupted cancer treatment to patients with musculoskeletal tumors has been essential during the rapidly evolving coronavirus 2019 (COVID-19) pandemic, as delays in management can be detrimental. Currently, the risk of contracting COVID-19 in hospitals when admitted for surgery and the susceptibility due to adjuvant therapies and associated mortality due to COVID-19 is unknown, but knowledge of these potential risks would help treating clinicians provide appropriate cancer care.

QUESTIONS/PURPOSES

(1) What is the risk of hospital-acquired COVID-19 in patients with musculoskeletal tumors admitted for surgery during the initial period of the pandemic? (2) What is the associated mortality in patients with musculoskeletal tumors who have contracted COVID-19? (3) Are patients with musculoskeletal tumors who have had neoadjuvant therapy (chemotherapy or radiation) preoperatively at an increased risk of contracting COVID-19? (4) Is a higher American Society of Anesthesiologists (ASA) grade in patients with musculoskeletal tumors associated with an increased risk of contracting COVID-19 when admitted to the hospital for surgery?

METHODS

This retrospective, observational study analyzed patients with musculoskeletal tumors who underwent surgery in one of eight specialist centers in the United Kingdom, which included the five designated cancer centers in England, one specialist soft tissue sarcoma center, and two centers from Scotland between March 12, 2020 and May 20, 2020. A total of 347 patients were included, with a median (range) age of 53 years (10 to 94); 60% (207 of 347) were men, and the median ASA grade was II (I to IV). These patients had a median hospital stay of 8 days (0 to 53). Eighteen percent (61 of 347) of patients had received neoadjuvant therapy (8% [27] chemotherapy, 8% [28] radiation, 2% [6] chemotherapy and radiation) preoperatively. The decision to undergo surgery was made in adherence with United Kingdom National Health Service and national orthopaedic oncology guidelines, but specific data with regard to the number of patients within each category are not known. Fifty-nine percent (204 of 347) were negative in PCR testing done 48 hours before the surgical procedure; the remaining 41% (143 of 347) were treated before preoperative PCR testing was made mandatory, but these patients were asymptomatic. All patients were followed for 30 days postoperatively, and none were lost to follow-up during that period. The primary outcome of the study was contracting COVID-19 in the hospital after admission. The secondary outcome was associated mortality after contracting COVID-19 within 30 days of the surgical procedure. In addition, we assessed whether there is any association between ASA grade or neoadjuvant treatment and the chances of contracting COVID-19 in the hospital. Electronic patient record system and simple descriptive statistics were used to analyze both outcomes.

RESULTS

Four percent (12 of 347) of patients contracted COVID-19 in the hospital, and 1% (4 of 347) of patients died because of COVID-19-related complications. Patients with musculoskeletal tumors who contracted COVID-19 had increased mortality compared with patients who were asymptomatic or tested negative (odds ratio 55.33 [95% CI 10.60 to 289.01]; p < 0.001).With the numbers we had, we could not show that adjuvant therapy had any association with contracting COVID-19 while in the hospital (OR 0.94 [95% CI 0.20 to 4.38]; p = 0.93). Increased ASA grade was associated with an increased likelihood of contracting COVID-19 (OR 58 [95% CI 5 to 626]; p < 0.001).

CONCLUSION

Our results show that surgeons must be mindful and inform patients that those with musculoskeletal tumors are at risk of contracting COVID-19 while admitted to the hospital and some may succumb to it. Hospital administrators and governmental agencies should be aware that operations on patients with lower ASA grade appear to have lower risk and should consider restructuring service delivery to ensure that procedures are performed in designated COVID-19-restricted sites. These measures may reduce the likelihood of patients contracting the virus in the hospital, although we cannot confirm a benefit from this study. Future studies should seek to identify factors influencing these outcomes and also compare surgical complications in those patients with and without COVID-19.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Co-localisation of intra-nuclear membrane type-1 matrix metalloproteinase and hypoxia inducible factor-2α in osteosarcoma and prostate carcinoma cells

Increased membrane type-1 matrix metalloproteinase (MT1-MMP) expression in osteosarcoma is predictive of poor prognosis and directs bone metastasis in prostate carcinoma. MT1-MMP subcellular localisation varies with oxygen tension, and, therefore, the aim of the present study was to assess protein interactions between MT1-MMP and the hypoxia inducible factors (HIF-1α and HIF-2α). MT1-MMP protein expression was investigated across a panel of cancer cell lines, including a positive and negative control. The hypoxia-induced alteration in subcellular location of MT1-MMP, HIF-1α and HIF-2α in the U2OS osteosarcoma cell line was assessed using subcellular fractionation. A proximity ligation assay was utilised to assess protein to protein interactions in the osteosarcoma U2OS and prostate carcinoma PC3 cell lines. U2OS and PC3 cells exhibited a significantly increased intra-nuclear interaction between MT1-MMP and HIF-2α in response to hypoxia. The role of this warrants further investigation as it may unveil novel opportunities to target MT1-MMP, which is of particular significance for osteosarcoma since current treatment options are limited.

Venous thromboembolism in orthopaedic oncology

AIMS

Malignancy and surgery are risk factors for venous thromboembolism (VTE). We undertook a systematic review of the literature concerning the prophylactic management of VTE in orthopaedic oncology patients.

METHODS

MEDLINE (PubMed), EMBASE (Ovid), Cochrane, and CINAHL databases were searched focusing on VTE, deep vein thrombosis (DVT), pulmonary embolism (PE), bleeding, or wound complication rates.

RESULTS

In all, 17 studies published from 1998 to 2018 met the inclusion criteria for the systematic review. The mean incidence of all VTE events in orthopaedic oncology patients was 10.7% (1.1% to 27.7%). The rate of PE was 2.4% (0.1% to 10.6%) while the rate of lethal PE was 0.6% (0.0% to 4.3%). The overall rate of DVT was 8.8% (1.1% to 22.3%) and the rate of symptomatic DVT was 2.9% (0.0% to 6.2%). From the studies that screened all patients prior to hospital discharge, the rate of asymptomatic DVT was 10.9% (2.0% to 20.2%). The most common risk factors identified for VTE were endoprosthetic replacements, hip and pelvic resections, presence of metastases, surgical procedures taking longer than three hours, and patients having chemotherapy. Mean incidence of VTE with and without chemical prophylaxis was 7.9% (1.1% to 21.8%) and 8.7% (2.0% to 23.4%; p = 0.11), respectively. No difference in the incidence of bleeding or wound complications between prophylaxis groups was reported.

CONCLUSION

Current evidence is limited to guide clinicians. It is our consensus opinion, based upon logic and deduction, that all patients be considered for both mechanical and chemical VTE prophylaxis, particularly in high-risk patients (pelvic or hip resections, prosthetic reconstruction, malignant diagnosis, presence of metastases, or surgical procedures longer than three hours). Additionally, the surgeon must determine, in each patient, if the risk of haemorrhage outweighs the risk of VTE. No individual pharmacological agent has been identified as being superior in the prevention of VTE events. Cite this article: Bone Joint J 2020;102-B(12)1743:-1751.

Cholesterol-rich naked mole-rat brain lipid membranes are susceptible to amyloid beta-induced damage in vitro

Naked mole-rats are extraordinarily long-lived rodents that offer unique opportunities to study the molecular origins of age-related neurodegenerative diseases. Remarkably, they do not accumulate amyloid plaques, even though their brains contain high concentrations of amyloid beta (Aβ) peptide from a young age. Therefore, they represent a particularly favourable organism to study the mechanisms of resistance against Aβ neurotoxicity. Here we examine the composition, phase behaviour, and Aβ interactions of naked mole-rat brain lipids. Relative to mouse, naked mole-rat brain lipids are rich in cholesterol and contain sphingomyelin in lower amounts and of shorter chain lengths. Proteins associated with the metabolism of ceramides, sphingomyelins and sphingosine-1-phosphate receptor 1 were also found to be decreased in naked mole-rat brain lysates. Correspondingly, we find that naked mole-rat brain lipid membranes exhibit a high degree of phase separation, with the liquid ordered phase extending to 80% of the supported lipid bilayer. These observations are consistent with the 'membrane pacemaker' hypothesis of ageing, according to which long-living species have lipid membranes particularly resistant to oxidative damage. We also found that exposure to Aβ disrupts naked mole-rat brain lipid membranes significantly, breaking the membrane into pieces while mouse brain derived lipids remain largely intact upon Aβ exposure.

Does vacuum mixing affect diameter shrinkage of a PMMA cement mantle during in vitro cemented acetabulum implantation?

Radiolucent lines on immediate postoperative cemented acetabular component radiographs between the PMMA bone cement mantle and bone are an indicator of an increased risk of early loosening. The cause of these lines has yet to be identified. Thermal and chemical necrosis, fluid interposition and cement shrinkage have all been suggested in the literature. The aim of the study reported here was to take an engineering approach - eliminating confounding variables present during surgery - to quantify the size of the interstice created by cement shrinkage when a 50 mm diameter flanged acetabular cup is implanted in a model acetabulum with a 52 mm hemispherical bore under controlled conditions using vacuum and non-vacuum mixed cement. Irrespective of the mixing method used, a significant interstice was created between the bone cement and the mock acetabulum. When the cement was mixed under vacuum the interstice created between the mock acetabulum and the cement mantle was 0.60 mm ± 0.09 mm; when the cement was mixed under non-vacuum conditions the interstice created was 0.39 mm ± 0.15 mm. Possible explanations for radiolucent lines are discussed.

Development of Natural-Based Bone Cement for a Controlled Doxorubicin-Drug Release

Osteosarcoma (OS) accounts for 60% of all global bone cancer diagnoses. Intravenous administration of Doxorubicin Hydrochloride (DOXO) is the current form of OS treatment, however, systemic delivery has been linked to the onset of DOXO induced cardiomyopathy. Biomaterials including calcium phosphate cements (CPCs) and nanoparticles (NPs) have been tested as localized drug delivery scaffolds for OS cells. However, the tumor microenvironment is critical in cancer progression, with mesenchymal stem cells (MSCs) thought to promote OS metastasis and drug resistance. The extent of MSC assisted survival of OS cells in response to DOXO delivered by CPCs is unknown. In this study, we aimed at investigating the effect of DOXO release from a new formulation of calcium phosphate-based bone cement on the viability of OS cells cocultured with hMSC in vitro. NPs made of PLGA were loaded with DOXO and incorporated in the formulated bone cement to achieve local drug release. The inclusion of PLGA-DOXO NPs into CPCs was also proven to increase the levels of cytotoxicity of U2OS cells in mono- and coculture after 24 and 72 h. Our results demonstrate that a more effective localized DOXO delivery can be achieved via the use of CPCs loaded with PLGA-DOXO NPs compared to CPCs loaded with DOXO, by an observed reduction in metabolic activity of U2OS cells in indirect coculture with hMSCs. The presence of hMSCs offer a degree of DOXO resistance in U2OS cells cultured on PLGA-DOXO NP bone cements. The consideration of the tumor microenvironment via the indirect inclusion of hMSCs in this study can act as a starting point for future direct coculture and in vivo investigations.

Role of routine blood tests for predicting clinical outcomes in osteosarcoma patients

BACKGROUND

This retrospective cohort study aimed to investigate whether simple routine blood tests at presentation (C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), alkaline phosphatase and albumin) predict survival in patients with osteosarcoma.

METHODS

Between January 1998 and February 2015, 134 patients with a histological diagnosis of osteosarcoma were treated in our unit. Of these, 79 patients with high-grade osteosarcomas were included in the study. Demographic and clinical data, and laboratory parameters obtained prior to biopsy (CRP, ESR, alkaline phosphatase and albumin levels), were obtained from patients' records.

RESULTS

There were 44 males and 35 females. Univariate analysis showed that high pre-biopsy CRP ( p = 0.004), raised pre-biopsy ESR ( p = 0.010), older age ( p < 0.001), poor tumour necrosis rates (≤90%, p = 0.023) and metastasis at presentation ( p < 0.001) were poor prognostic factors. Multivariate analysis showed pre-biopsy CRP and ESR levels to be independent predictors of overall survival ( p = 0.020 and p = 0.025, respectively). Kaplan-Meier survival was significantly lower in patients with elevated CRP ( p = 0.002) and ESR ( p = 0.003). Hypoalbuminaemia and elevated alkaline phosphatase levels did not correlate with overall survival.

CONCLUSION

Preoperative CRP and ESR levels may have value in building a prognostic model for patients presenting with osteosarcoma.

The material properties of naked mole-rat hyaluronan

Hyaluronan (HA) is a key component of the extracellular matrix. Given the fundamental role of HA in the cancer resistance of the naked mole-rat (NMR), we undertook to explore the structural and soft matter properties of this species-specific variant, a necessary step for its development as a biomaterial. We examined HA extracted from NMR brain, lung, and skin, as well as that isolated from the medium of immortalised cells. In common with mouse HA, NMR HA forms a range of assemblies corresponding to a wide distribution of molecular weights. However, unique to the NMR, are highly folded structures, whose characteristic morphology is dependent on the tissue type. Skin HA forms tightly packed assemblies that have spring-like mechanical properties in addition to a strong affinity for water. Brain HA forms three dimensional folded structures similar to the macroscopic appearance of the gyri and sulci of the human brain. Lung HA forms an impenetrable mesh of interwoven folds in a morphology that can only be described as resembling a snowman. Unlike HA that is commercially available, NMR HA readily forms robust gels without the need for chemical cross-linking. NMR HA gels sharply transition from viscoelastic to elastic like properties upon dehydration or repeated loading. In addition, NMR HA can form ordered thin films with an underlying semi-crystalline structure. Given the role of HA in maintaining hydration in the skin it is plausible that the folded structures contribute to both the elasticity and youthfulness of NMR skin. It is also possible that such densely folded materials could present a considerable barrier to cell invasion throughout the tissues, a useful characteristic for a biomaterial.

Surgical excision and not chemotherapy is the most powerful modality in treating synovial sarcoma: the UK's North East experience

BACKGROUND AND PURPOSE

We reviewed our experience of synovial sarcoma to identify factors predictive of local recurrence and overall survival, the impact of chemotherapy and outcomes after surgical excision alone.

MATERIALS AND METHODS

81 patients were treated between 1997 and 2014 of mean age 39 years (8-78). Tumours were in the extremity in 55 (67%). 9 patients presented with metastases and 10 with unresectable disease. Mean follow-up was 3.7 years (SD 3.8). Treatment groups were palliative, surgery only, surgery and radiotherapy, or surgery with chemotherapy (with or without radiotherapy).

RESULTS

Local recurrence-free survival (LRFS) was 73% at 5 years, and 68% at 10 and 15 years. In multivariate analysis, positive surgical margins were an independent predictor of LRFS. Overall survival (OS) was 50% at 5 years for all patients, and 62% at 5 years for those treated with curative intent. Larger tumour size and non-extremity locations were predictors of poorer OS. Patients who had chemotherapy did not have significantly better OS or LRS than others.

INTERPRETATION

These results show that where feasible, curative resection should not be delayed for chemotherapy. Treatment with surgery only can be associated with good outcomes in selected patients with smaller extremity tumours; although our series is small.

Macrophage proliferation distinguishes 2 subgroups of knee osteoarthritis patients

Osteoarthritis (OA) is a leading cause of disability, globally. Despite an emerging role for synovial inflammation in OA pathogenesis, attempts to target inflammation therapeutically have had limited success. A better understanding of the cellular and molecular processes occurring in the OA synovium is needed to develop novel therapeutics. We investigated macrophage phenotype and gene expression in synovial tissue of OA and inflammatory-arthritis (IA) patients. Compared with IA, OA synovial tissue contained higher but variable proportions of macrophages (P < 0.001). These macrophages exhibited an activated phenotype, expressing folate receptor-2 and CD86, and displayed high phagocytic capacity. RNA sequencing of synovial macrophages revealed 2 OA subgroups. Inflammatory-like OA (iOA) macrophages are closely aligned to IA macrophages and are characterized by a cell proliferation signature. In contrast, classical OA (cOA) macrophages display cartilage remodeling features. Supporting these findings, when compared with cOA, iOA synovial tissue contained higher proportions of macrophages (P < 0.01), expressing higher levels of the proliferation marker Ki67 (P < 0.01). These data provide new insight into the heterogeneity of OA synovial tissue and suggest distinct roles of macrophages in pathogenesis. Our findings could lead to the stratification of OA patients for suitable disease-modifying treatments and the identification of novel therapeutic targets.

Blood-borne biomarkers of osteosarcoma: A systematic review

Osteosarcoma is the most common type of primary malignant bone tumor in children and young adults. Development of clinically useful biomarkers has the potential to improve treatments. The aim of this review was to investigate the recent literature assessing the utility of biomarkers for osteosarcoma. A detailed literature search was performed, with hand searches for related research publications. The search was limited to publications in English between January 2007 and February 2017. Of 286 studies identified, 24 met the inclusion criteria. There is a wide range of osteosarcoma biomarkers identified which act as clinical prognostic factors in patient outcome.

Synovectomy during total knee arthroplasty: a pilot single-centre randomised controlled trial

Background

Total knee arthroplasty (TKA) is an effective procedure for late-stage osteoarthritis (OA) of the knee; however, up to 20% of patients remain dissatisfied. In some patients, this may be due to residual inflammation of the synovium. Our aim was to perform the first randomised controlled trial (RCT) of synovectomy during TKA for patients with macroscopically inflamed synovium. The main objectives were to assess recruitment rates, protocol adherence and outcomes relating to safety such as haemoglobin decrease and adverse events. We also collected data on patient-reported outcomes.

Methods

We performed a single-centre pilot RCT. Patients with a macroscopically inflamed synovium were randomised to receive synovectomy versus a control group that did not undergo synovectomy. We determined feasibility by measuring patient enrolment, completeness of follow-up, and safety via haemoglobin decrease and documentation of adverse events.

Results

We screened 360 patients with 260 deemed ineligible or could not be recruited. From the 100 eligible patients, 54 were enrolled and 40 progressed through to randomisation. All made it to the 12-month follow-up, indicating good protocol adherence. There were no major differences in adverse events or haemoglobin decrease demonstrating acceptable safety. Outcomes relating to satisfaction were reliably obtained.

Conclusions

Patients with macroscopically inflamed synovium of the knee who are due to undergo TKA can be reliably recruited to a randomised trial and synovectomy can be performed safely. A large number is needed to be screened to identify eligible participants, and therefore, a multi-centre trial would be required to assess whether routine synovectomy would improve outcomes in these patients.

Trial registration

ISRCTN, ISRCTN31010214. Registered 6 October 2016—retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s40814-018-0336-y) contains supplementary material, which is available to authorized users.

VASO (Vitamin D and Arthroplasty Surgery Outcomes) study - supplementation of vitamin D deficiency to improve outcomes after total hip or knee replacement: study protocol for a randomised controlled feasibility trial

BACKGROUND

Vitamin D deficiency has been linked to poor outcomes after total hip replacement (THR) or total knee replacement (TKR), including lower patient-reported outcome measures (PROMs), peri-prosthetic infection and longer hospital stay. We present a randomised feasibility trial protocol designed to prospectively investigate the influence of vitamin D testing, and subsequent supplementation for deficiency, prior to THR/TKR.

METHODS/DESIGN

One hundred adult patients undergoing primary THR/TKR for osteoarthritis at two NHS hospital trusts in North East England will be recruited. Exclusion criteria include lack of mental capacity, revision surgery, participants already taking vitamin D/calcium supplements, or a known contraindication to vitamin D treatment. Participants will be ineligible for the trial if they have an estimated glomerular filtration rate < 30 ml/minute. We will measure patients' vitamin D levels at baseline, and those identified as deficient (vitamin D < 50 nmol/L) will be randomised to receive either vitamin D supplementation or no supplementation prior to, and for 6 months following, surgery. Patients with a normal vitamin D level (≥50 nmol/L) will receive no supplementation. Vitamin D levels will be rechecked on the day of surgery and again at 6 months. Patients will also complete a lifestyle questionnaire, as well as the Oxford hip or knee and EQ-5D-3 L PROM questionnaires, at baseline and at 6 months following surgery. The aims are to determine the feasibility of the methodology and to gather data to inform the conduct of a future, larger trial to investigate if supplementation with vitamin D, in those who are deficient, prior to THR/TKR improves outcomes as measured by PROM scores.

DISCUSSION

Previous reports have measured vitamin D levels and correlated this to outcome, but we can find no randomised trial in which researchers investigated the effect of supplementation. The aim of this trial is to determine if vitamin D deficiency is a modifiable risk factor for poor outcome after THR/TKR.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN14533082 . Registered on 3 April 2017.

Temporary Single-Cell Coating for Bioprocessing with a Cationic Polymer

Temporary single-cell coating is a useful tool for cell processing, allowing manipulation of cells to prevent cell attachment and agglomeration, before re-establishing normal cell function. In this work, a speckled coating method using a known polycation [poly(l-lysine), PLL] is described to induce cell surface electrostatic charges on three different cell types, namely, two bone cancer cell lines and fibroblasts. The morphology of the PLL speckled coating on the cell surface, internalization and metabolization of the polymer, and prevention of cellular aggregations are reported. Polymer concentration was found to be the key parameter controlling both capsule morphology and cell health. This approach allows a temporary cell coating over the course of 1-2 h, with cells exhibiting phenotypically normal behavior after ingesting and metabolizing the polymer. The process offers a fast and efficient alternative to aid single-cell manipulation for bioprocessing applications. Preliminary work on the application of PLL speckled cell coating in enabling reliable bioprinting is also presented.

Long-term in vitro maintenance of clonal abundance and leukaemia-initiating potential in acute lymphoblastic leukaemia

Lack of suitable in vitro culture conditions for primary acute lymphoblastic leukaemia (ALL) cells severely impairs their experimental accessibility and the testing of new drugs on cell material reflecting clonal heterogeneity in patients. We show that Nestin-positive human mesenchymal stem cells (MSCs) support expansion of a range of biologically and clinically distinct patient-derived ALL samples. Adherent ALL cells showed an increased accumulation in the S phase of the cell cycle and diminished apoptosis when compared with cells in the suspension fraction. Moreover, surface expression of adhesion molecules CD34, CDH2 and CD10 increased several fold. Approximately 20% of the ALL cells were in G0 phase of the cell cycle, suggesting that MSCs may support quiescent ALL cells. Cellular barcoding demonstrated long-term preservation of clonal abundance. Expansion of ALL cells for >3 months compromised neither feeder dependence nor cancer initiating ability as judged by their engraftment potential in immunocompromised mice. Finally, we demonstrate the suitability of this co-culture approach for the investigation of drug combinations with luciferase-expressing primograft ALL cells. Taken together, we have developed a preclinical platform with patient-derived material that will facilitate the development of clinically effective combination therapies for ALL.

Hyaluronan in cancer - from the naked mole rat to nanoparticle therapy

Hyaluronan, a glycosaminoglycan, abundant in the tumour microenvironment, is a key player in many processes associated with cancer. Recently the cancer resistance of the naked mole rat has been attributed to the presence of an ultra-high molecular weight form of this molecule. The physical properties of this multifunctional biopolymer have been extensively studied in the context of synovial joints. However, relatively little has been reported with regard to the soft matter properties of hyaluronan in relation to cancer. In this review we examine the role of hyaluronan in cancer, paying particular attention to its mechanical interactions with malignant cells and its soft matter properties. In addition we discuss the use of hyaluronan based gels to study cancer invasion as well as nanoparticle based strategies for disease treatment.

Impact of Weekend Physiotherapy Service on the Cost Effectiveness of Elective Orthopaedic Hip and Knee Arthroplasty

We performed a prospective correlational study to evaluate the efficiency and cost effectiveness of weekend physiotherapy in accelerating rehabilitation, reducing hospital stay as well as hospital costs for joint arthroplasty patients in a busy Scottish district general hospital. Patients that underwent elective hip (470) and knee (321) arthroplasty were analysed over a 12 month period. A four month period with weekend physiotherapy provision was arranged to ascertain its effectiveness on the length of stay and the achievement of set physiotherapy milestones. Data collected included length of stay and progression in a defined set of physiotherapy milestones. The relationship between time to discharge, mobilisation with sticks, straight leg raise, 90º knee flexion and cost effectiveness of service were used to determine the correlation, and analysis of the interactions of these factors separately. Our Outcome data demonstrate a statistical significance for the time to mobilisation with two sticks for hip (p=0.0030) and knee (p= 0.0037) arthroplasty patients. There was a trend towards earlier discharge times for all patients receiving weekend physiotherapy, but this was not statistically significant. We conclude that the provision of a continuous programme of weekend physiotherapy for all arthroplasty patients has the potential benefit of a quicker rehabilitation that would results in a cost saving.

The orthopaedic research scene and strategies to improve it

Trauma and orthopaedics is the largest of the surgical specialties and yet attracts a disproportionately small fraction of available national and international funding for health research. With the burden of musculoskeletal disease increasing, high-quality research is required to improve the evidence base for orthopaedic practice. Using the current research landscape in the United Kingdom as an example, but also addressing the international perspective, we highlight the issues surrounding poor levels of research funding in trauma and orthopaedics and indicate avenues for improving the impact and success of surgical musculoskeletal research.

Characterization of the cartilage DNA methylome in knee and hip osteoarthritis

Objective

The aim of this study was to characterize the genome-wide DNA methylation profile of chondrocytes from knee and hip cartilage obtained from patients with osteoarthritis (OA) and hip cartilage obtained from patients with femoral neck fracture, providing the first comparison of DNA methylation between OA and non-OA hip cartilage, and between OA hip and OA knee cartilage.

Methods

The study was performed using the Illumina Infinium HumanMethylation450 BeadChip array, which allows the annotation of ∼480,000 CpG sites. Genome-wide methylation was assessed in chondrocyte DNA extracted from 23 hip OA patients, 73 knee OA patients, and 21 healthy hip control patients with femoral neck fracture.

Results

Analysis revealed that chondrocytes from the hip cartilage of OA patients and healthy controls have unique methylation profiles, with 5,322 differentially methylated loci (DMLs) identified between the 2 groups. In addition, a comparison between hip and knee OA chondrocytes revealed 5,547 DMLs between the 2 groups, including DMLs in several genes known to be involved in the pathogenesis of OA. Hip OA samples were found to cluster into 2 groups. A total of 15,239 DMLs were identified between the 2 clusters, with an enrichment of genes involved in inflammation and immunity. Similarly, we confirmed a previous report of knee OA samples that also clustered into 2 groups.

Conclusion

We demonstrated that global DNA methylation using a high-density array can be a powerful tool in the characterization of OA at the molecular level. Identification of pathways enriched in DMLs between OA and OA-free cartilage highlight potential etiologic mechanisms that are involved in the initiation and/or progression of the disease and that could be therapeutically targeted.

Pulmonary embolism following ankle fractures treated without an operation - an analysis using National Health Service data

The majority of ankle fractures are stable and can be treated without an operation, most commonly with cast immobilisation. Based on concerns regarding the risk of a venous thromboembolic event (VTE) while immobilised, there is currently debate as to whether these patients should receive VTE prophylaxis for the duration of treatment. Rates of pulmonary embolism (PE) in this patient group are unknown. This retrospective cohort study was designed to identify patients treated without an operation for ankle fracture and determine the occurrence of PE and inpatient mortality within 90 days of injury using the English National Health Service administrative databases. Logistic regression models were used to assess the influence of age, gender and Charlson co-morbidity score on these outcomes. We identified 14777 adult patients over a 54-month period (April 2007-September 2011) that met our linkage and inclusion criteria (isolated, unilateral closed ankle fracture that did not require hospitalisation). Mean age was 46.4 years (range 18-99) and the majority had a Charlson 0 score (97.7%). There were 32 (0.22%) PEs within 90 days of the fracture (including in one patient who subsequently died). After adjustment, Charlson score of ≥1 was associated with a greater risk of PE (Odds ratio = 11.97, p < 0.001) compared to Charlson 0. Risk for these patients was 2.08%. In total, fifteen patients (0.11%) died in hospital within 90 days. Pulmonary embolism is rare following ankle fractures treated without an operation. Patients with multiple co-morbidities are at a higher risk. Based on this evidence, an ankle fracture treated without an operation does not appear to be an indication for routine VTE prophylaxis.

Consultant and trainee attitudes towards supervision of operative procedures in the UK and Ireland

The e-logbook is used to monitor progression through training and to assess training within teaching units. We document consultant and trainee opinions with regards to supervision status, and to inform guidelines for trainees and trainers using the e-logbook. A questionnaire was sent to consultants and trainees in the UK and Ireland. Eight theatre scenarios were described and respondents were asked to state what they felt was the appropriate supervision status for the trainee. Significantly more consultants in the UK use the e-logbook than those based in Ireland (58.5%:14.5%). There were differences in consensus response to the scenarios between consultants and trainees, and between Irish and UK based surgeons. We have documented the opinions of consultants and trainees from across the UK and Ireland with regards to supervision status for trainees under certain theatre situations. This information should support formal guidelines for all users of the logbook.

Improving the peer review process in orthopaedic journals

The peer review process for the evaluation of manuscripts for publication needs to be better understood by the orthopaedic community. Improving the degree of transparency surrounding the review process and educating orthopaedic surgeons on how to improve their manuscripts for submission will help improve both the review procedure and resultant feedback, with an increase in the quality of the subsequent publications. This article seeks to clarify the peer review process and suggest simple ways in which the quality of submissions can be improved to maximise publication success. Cite this article: Bone Joint Res 2013;2:245-7.

Impact factors of orthopaedic journals between 2000 and 2010: trends and comparisons with other surgical specialties

PURPOSE

The impact factors (IF) of orthopaedic journals is an important component in determining the future of orthopaedic research funding. We aim to characterise the trend in journal IF over the last decade and draw comparisons with other surgical specialties.

METHODS

We conducted an analysis of impact factors from Journal Citation Reports between 2000 and 2010.

RESULTS

Between 2000 and 2010 the number of orthopaedic journals increased from 24 to 41, more than any other surgical specialty and the mean IF increased from 0.842 to 1.400. Journals printed in the English language had a significantly higher IF in the year 2010 (1.64 vs. 0.33, p = 0.01) than those printed in other languages. English language journals published in the US had significantly higher mean 2010 IF (1.932 vs. 1.243, p = 0.025) than those published in Europe, and this had changed compared with 2000 mean IF (0.978 Vs. 0.704, p = 0.360). Orthopaedics was ranked sixth out of 11 surgical subspecialties in 2000 but dropped to seventh out of 11 in 2010.

CONCLUSIONS

The quality of orthopaedic journals has significantly increased over the last decade and this has been accompanied by a rise in mean IF. It is important that orthopaedics continues to improve the quality of research, which may help orthopaedic researchers secure funding in the future.

Identification of the pathogenic pathways in osteoarthritic hip cartilage: commonality and discord between hip and knee OA

OBJECTIVE

To define for the first time the transcriptomes of normal and end-stage osteoarthritis (OA) hip cartilage.

MATERIALS AND METHODS

RNA was isolated from cartilage within 2h of joint replacement surgery. Gene expression was analyzed using Agilent GeneSpring GX 11 following hybridization to Illumina Human HT-12 V3 microarrays. Real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to validate the expression of six genes identified by microarray as differentially expressed. Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) were used to investigate enriched functions or canonical pathways amongst differentially expressed genes respectively.

RESULTS

In total we identified 998 differentially expressed genes (fold change ≥ ±1.5, P-value ≤ 0.01) between neck of femur fracture (NOF) (n = 10) and OA hip (n = 9) patient cartilage. These differentially expressed genes were enriched within 71 canonical pathways. A comparison between a comparable knee dataset(20) only identified 229 genes similarly differentially expressed although remarkably 34 canonical pathways overlapped between experiments.

CONCLUSIONS

This study is the first to report a comprehensive gene expression analysis of human hip OA cartilage compared to control (NOF) cartilage at the whole-genome level. Our differential gene expression dataset shows excellent correlation with similar defined studies using comparable tissue but reveals discord between hip and knee OA at the individual gene status but with commonality with regards the molecular pathways involved.

Of dogs and men: comparative biology as a tool for the discovery of novel biomarkers and drug development targets in osteosarcoma

The similarities between human and canine osteosarcoma with regard to histology, biological behavior and molecular genetic alterations suggest that the dog provides a supplementary model for the development and preclinical testing of novel therapeutics. Counter intuitively, careful examination of the differences between OS in the two species may also be rewarding in terms of increasing our understanding of the pathogenesis of this cancer. This review will discuss the arguments in favor of the "dog model" and outline how the evaluation of treatment strategies in dogs has indicated avenues for improvement of protocols for human patients.

A novel in vitro model to investigate behavior of articular chondrocytes in osteoarthritis

OBJECTIVE

To investigate in vivo simulation of the microenvironment in which osteoarthritis (OA) chondrocytes are cultured in vitro.

METHODS

Human articular chondrocytes were cultured under normoxic and hypoxic conditions. Cells were cultured on standard culture plastic or a porous polyHEMA surface that closely resembles the in vivo cartilage microarchitecture. Morphological changes to the cells were demonstrated by fluorescent staining with DAPI and vinculin. Proteoglycan and type II collagen protein levels were assessed using established techniques. Matrix metalloproteinase-1 (MMP-1) production was assessed by ELISA. The gene expression of type II collagen and SOX9 was measured using real-time polymerase chain reaction.

RESULTS

Cells grown on culture plastic were seen to be flat and hexagonal. Cells cultured on the porous polyHEMA surface exhibited morphology in keeping with the in vivo microenvironment. Glycosaminoglycan release in hypoxia was high from cells cultured on standard culture plastic. Transcriptional expression of type II collagen was upregulated in hypoxia and by culture on the polyHEMA surface. Transcriptional expression of SOX9 in hypoxia was upregulated compared to normoxia; no significant effect was seen by varying the culture surface. Translational expression of type II collagen was upregulated at 20% oxygen on the polyHEMA surface compared to culture plastic and this was related to MMP-1 expression.

CONCLUSION

Culture of chondrocytes in hypoxia and on a porous surface simulates the in vivo microenvironment and illustrates the molecular mechanisms of OA.