Andrew Furey

Classification of osteoarthritis phenotypes by metabolomics analysis

Objectives To identify metabolic markers that can classify patients with osteoarthritis (OA) into subgroups. Design A case-only study design was utilised. Participants Patients were recruited from those who underwent total knee or hip replacement surgery due to primary OA between November 2011 and December 2013 in St. Clares Mercy Hospital and Health Science Centre General Hospital in St. Johns, capital of Newfoundland and Labrador (NL), Canada. 38 men and 42 women were included in the study. The mean age was 65.2±8.7 years. Outcome measures Synovial fluid samples were collected at the time of their joint surgeries. Metabolic profiling was performed on the synovial fluid samples by the targeted metabolomics approach, and various analytic methods were utilised to identify metabolic markers for classifying subgroups of patients with OA. Potential confounders such as age, sex, body mass index (BMI) and comorbidities were considered in the analysis. Results Two distinct patient groups, A and B, were clearly identified in the 80 patients with OA. Patients in group A had a significantly higher concentration on 37 of 39 acylcarnitines, but the free carnitine was significantly lower in their synovial fluids than in those of patients in group B. The latter group was further subdivided into two subgroups, that is, B1 and B2. The corresponding metabolites that contributed to the grouping were 86 metabolites including 75 glycerophospholipids (6 lysophosphatidylcholines, 69 phosphatidylcholines), 9 sphingolipids, 1 biogenic amine and 1 acylcarnitine. The grouping was not associated with any known confounders including age, sex, BMI and comorbidities. The possible biological processes involved in these clusters are carnitine, lipid and collagen metabolism, respectively. Conclusions The study demonstrated that OA consists of metabolically distinct subgroups. Identification of these distinct subgroups will help to unravel the pathogenesis and develop targeted therapies for OA.

Does Open Reduction and Internal Fixation versus Primary Arthrodesis Improve Patient Outcomes for Lisfranc Trauma? A Systematic Review and Meta-analysis.

BackgroundAlthough Lisfranc injuries are uncommon, representing approximately 0.2% of all fractures, they are complex and can result in persistent pain, degenerative arthritis, and loss of function. Both open reduction and internal fixation (ORIF) and primary fusion have been proposed as treatment options for these injuries, but debate remains as to which approach is better.Questions/purposesWe asked whether ORIF or primary fusion led to (1) fewer reoperations for hardware removal; (2) less frequent revision surgery; (3) higher patient outcome scores; and (4) more frequent anatomic reduction.MethodsA systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Three trials met the criteria for inclusion within the meta-analysis. Qualifying articles for the meta-analysis had data extracted independently by two authors (NS, AF). The quality of each study was assessed using the Center for Evidence Based Medicine’s evaluation strategy; data were extracted from articles rated as good and fair: two and one article, respectively.ResultsThe risk ratio for hardware removal was 0.23 (95% confidence interval [CI], 0.11–0.45; p < 0.001) indicating more hardware removal for ORIF than fusion. For other revision surgery, the risk ratio for ORIF was 0.36 (95% CI, 0.08–1.59; p = 0.18) favoring neither. Similarly, neither was favored using patient-reported outcomes; the standard mean difference was calculated to be 0.50 (95% CI, −2.13 to 3.12; p = 0.71). When considering the risk of nonanatomic alignment, neither was favored (risk ratio, 1.48; 95% CI, 0.34–6.38; p = 0.60).ConclusionsThe surgeon should consider the increased risk of hardware removal along with its associated morbidity and discuss this with the patient preoperatively when considering ORIF of Lisfranc injuries. Because no new trials have been performed since 2012, further randomized controlled trials will be needed improve our understanding of these interventions.Level of EvidenceLevel I, therapeutic study.

Preoperative Signing of the Incision Site in Orthopaedic Surgery in Canada

Wrong-site surgery is an often catastrophic yet preventable problem. Reports of wrong-site surgery have been on the rise in the United States every year since 19951,2. The number of reported cases has increased from sixteen in 1998 to fifty-eight at the time of writing in 2001. Eleven cases occurred in the month of November 2001 alone1,2. These increases are cause for grave concern. Wrong-site surgery is a concern for every surgical specialty. However, orthopaedic surgery has an inherently higher risk compared with other types of surgery. Orthopaedic surgeons frequently operate on extremities, and many diseases do not have ob-vious external abnormalities. Of the 126 reported cases of wrong-site surgery in the United States, 41% were orthopaedic-related procedures1,2. Operating on the correct site can be ensured through a strict series of checks and rechecks involving the surgeons, nurses, residents, and patients. In 1994, the Canadian Orthopaedic Association (COA) began an educational program intended to prevent such mistakes from occurring. Their recommendations included marking the incision site with a permanent marker prior to entering the operating room3. The rates of wrong-site surgery in orthopaedic procedures in Canada have been declining since 1987 ( Fig. 1 ). Since 1994, the number of cases has been reduced from thirteen cases per year to five cases per year in 20004. Most of the cases involved knee surgery, and, in all but one, the knee had not been marked4. Fig. 1: Graph showing the number of reported occurrences of wrong-site surgery per year in Canada. (Data provided by the Canadian Medical Protective Association.) The purpose of this study was to evaluate the impact that the campaign to promote preoperative signing of the incision site had on Canadian orthopaedic surgeons by …

Metabolomic analysis of human plasma reveals that arginine is depleted in knee osteoarthritis patients

OBJECTIVE To identify novel biomarker(s) for knee osteoarthritis (OA) using a metabolomics approach. METHOD We utilized a two-stage case-control study design. Plasma samples were collected from knee OA patients and healthy controls after 8-h fasting and metabolically profiled using a targeted metabolomics assay kit. Linear regression was used to identify novel metabolic markers for OA. Receiver operating characteristic (ROC) analysis was used to examine diagnostic values. Gene expression analysis was performed on human cartilage to explore the potential mechanism for the novel OA marker(s). RESULTS Sixty-four knee OA patients and 45 controls were included in the discovery stage and 72 knee OA patients and 76 age and sex matched controls were included in the validation stage. We identified and confirmed six metabolites that were significantly associated with knee OA, of which arginine was the most significant metabolite (P < 3.5 × 10(-13)) with knee OA patients having on average 69 μM lower than that in controls. ROC analysis showed that arginine had the greatest diagnostic value with area under the curve (AUC) of 0.984. The optimal cutoff of arginine concentration was 57 μM with 98.3% sensitivity and 89% specificity. The depletion of arginine in OA patients was most likely due to the over activity of arginine to ornithine pathway, leading to imbalance between cartilage repair and degradation. CONCLUSION Arginine is significantly depleted in refractory knee OA patients. Further studies within a longitudinal setting are required to examine whether arginine can predict early OA changes.

Relationship between blood plasma and synovial fluid metabolite concentrations in patients with osteoarthritis.

Objective. To investigate the relationship between plasma and synovial fluid (SF) metabolite concentrations in patients with osteoarthritis (OA). Methods. Blood plasma and SF samples were collected from patients with primary knee OA undergoing total knee arthroplasty. Metabolic profiling was performed by electrospray ionization tandem mass spectrometry using the AbsoluteIDQ kit. The profiling yielded 168 metabolite concentrations. Correlation analysis between SF and plasma metabolite concentrations was done on absolute concentrations as well as metabolite concentration ratios using Spearman’s rank correlation (ρ) method. Results. A total of 69 patients with knee OA were included, 30 men and 39 women, with an average age of 66 ± 8 years. For the absolute metabolite concentrations, the average ρ was 0.23 ± 0.13. Only 8 out of 168 metabolite concentrations had a ρ ≥ 0.45, with a p value ≤ 2.98 × 10−4, statistically significant after correcting multiple testing with the Bonferroni method. For the metabolite ratios (n = 28,056), the average ρ was 0.29 ± 0.20. There were 4018 metabolite ratios with a ρ ≥ 0.52 and a p value ≤ 1.78 × 10−6, significant after correcting multiple testing. Sex-separate analyses found no difference in ρ between men and women. Similarly, there was no difference in ρ between people younger and older than 65 years. Conclusion. Correlation between blood plasma and SF metabolite concentrations are modest. Metabolite ratios, which are considered proxies for enzymatic reaction rates and have higher correlations, should be considered when using blood plasma as a surrogate of SF in OA biomarker identification.

Use of Human Patient Simulation and Validation of the Team Situation Awareness Global Assessment Technique (TSAGAT): A Multidisciplinary Team Assessment Tool in Trauma Education

OBJECTIVE Situation awareness (SA) is a vital construct for decision making in intense, dynamic environments such as trauma resuscitation. Human patient simulation (HPS) allows for a safe environment where individuals can develop these skills. Trauma resuscitation is performed by multidisciplinary teams that are traditionally difficult to globally assess. Our objective was to create and validate a novel tool to measure SA in multidisciplinary trauma teams using a HPS--the Team Situation Awareness Global Assessment Technique (TSAGAT). SETTING Memorial University Simulation Centre. DESIGN/PARTICIPANTS Using HPS, 4 trauma teams completed 2 separate trauma scenarios. Student, junior resident, senior resident, and attending staff teams each had 3 members (trauma team leader, nurse, and airway manager). Individual SAGATs were developed by experts in each respective field and contained shared and complimentary knowledge questions. Teams were assessed with SAGAT in real time and with traditional checklists using video review. TSAGAT was calculated as the sum of individual SAGAT scores and was compared with the traditional checklist scores. RESULTS Shared, complimentary, and TSAGAT scores improved with increasing team experience. Differences between teams for TSAGAT and complimentary knowledge were statistically significant (p < 0.05). Mean checklist differences between teams also reached statistical significance (p < 0.05). TSAGAT scores correlated strongly with traditional checklist scores (Pearson correlation r = 0.996). Interrater reliability for the checklist tool was high (Pearson correlation r = 0.937). CONCLUSION TSAGAT is the first valid and reliable assessment tool incorporating SA and HPS for multidisciplinary team performance in trauma resuscitation. TSAGAT could compliment or improve on current assessment methods and curricula in trauma and critical care and provides a template for team assessment in other areas of surgical education.

Lysophosphatidylcholines to phosphatidylcholines ratio predicts advanced knee osteoarthritis

OBJECTIVE To identify novel biomarker(s) for predicting advanced knee OA. METHODS Study participants were derived from the Newfoundland Osteoarthritis Study and the Tasmania Older Adult Cohort Study. All knee OA cases were patients who underwent total knee replacement (TKR) due to primary OA. Metabolic profiling was performed on fasting plasma. Four thousand and eighteen plasma metabolite ratios that were highly correlated with that in SF in our previous study were generated as surrogates for joint metabolism. RESULTS The discovery cohort included 64 TKR cases and 45 controls and the replication cohorts included a cross-sectional cohort of 72 TKR cases and 76 controls and a longitudinal cohort of 158 subjects, of whom 36 underwent TKR during the 10-year follow-up period. We confirmed the previously reported association of the branched chain amino acids to histidine ratio with advanced knee OA (P = 9.3 × 10(-7)) and identified a novel metabolic marker-the lysophosphatidylcholines (lysoPCs) to phosphatidylcholines (PCs) ratio-that was associated with advanced knee OA (P = 1.5 × 10(-7)) after adjustment for age, sex and BMI. When the subjects of the longitudinal cohort were categorized into two groups based on the optimal cut-off of the ratio of 0.09, we found the subjects with the ratio ⩾0.09 were 2.3 times more likely to undergo TKR than those with the ratio <0.09 during the 10-year follow-up (95% CI: 1.2, 4.3, P = 0.02). CONCLUSION We identified the ratio of lysoPCs to PCs as a novel metabolic marker for predicting advanced knee OA. Further studies are required to examine whether this ratio can predict early OA change.

SMAD3 is associated with the total burden of radiographic osteoarthritis: the Chingford study.

Background A newly-described syndrome called Aneurysm-Osteoarthritis Syndrome (AOS) was recently reported. AOS presents with early onset osteoarthritis (OA) in multiple joints, together with aneurysms in major arteries, and is caused by rare mutations in SMAD3. Because of the similarity of AOS to idiopathic generalized OA (GOA), we hypothesized that SMAD3 is also associated with GOA and tested the hypothesis in a population-based cohort. Methods Study participants were derived from the Chingford study. Kellgren-Lawrence (KL) grades and the individual features of osteophytes and joint space narrowing (JSN) were scored from radiographs of hands, knees, hips, and lumbar spines. The total KL score, osteophyte score, and JSN score were calculated and used as indicators of the total burden of radiographic OA. Forty-one common SNPs within SMAD3 were genotyped using the Illumina HumanHap610Q array. Linear regression modelling was used to test the association between the total KL score, osteophyte score, and JSN score and each of the 41 SNPs, with adjustment for patient age and BMI. Permutation testing was used to control the false positive rate. Results A total of 609 individuals were included in the analysis. All were Caucasian females with a mean age of 60.9±5.8. We found that rs3825977, with a minor allele (T) frequency of 20%, in the last intron of SMAD3, was significantly associated with total KL score (β = 0.14, Ppermutation = 0.002). This association was stronger for the total JSN score (β = 0.19, Ppermutation = 0.002) than for total osteophyte score (β = 0.11, Ppermutation = 0.02). The T allele is associated with a 1.47-fold increased odds for people with 5 or more joints to be affected by radiographic OA (Ppermutation = 0.046). Conclusion We found that SMAD3 is significantly associated with the total burden of radiographic OA. Further studies are required to reveal the mechanism of the association.

Does early fixation of posterior wall acetabular fractures lead to increased blood loss

Objective Controversy exists regarding the ideal timing of acetabular fracture surgery. Surgery within the first 24 hours might put patients at risk for increased blood loss; however, early treatment might facilitate fracture reduction and patient mobilization. The purpose of this study was to determine whether early surgery for posterior wall acetabular fractures results in higher intraoperative blood loss. Design Retrospective review. Setting Level I academic trauma center. Methods A 1-year retrospective review of 49 consecutive posterior wall acetabular fractures from a single Level I trauma center. Outcome variables were analyzed with t tests, Pearson correlation coefficient, and multiple linear regression analysis. Intervention Surgery for posterior wall acetabular fractures. Main Outcome Measures Estimated blood loss (EBL), preoperative and postoperative hematocrit levels, and intraoperative and postoperative blood product requirements as a function of the timing of surgery. Results No difference in EBL was shown between the fractures fixed within 24 hours of injury (mean = 644 mL) and those fixed later (573 mL, P = 0.50). No difference was observed when analyzing timing of surgery as a continuous variable (P = 0.45) or other outcome variables. A post hoc power analysis demonstrated that our sample could detect a difference in EBL of 166 mL. Conclusions Our study suggests that posterior wall fractures might be a subset of acetabular fractures that can be treated immediately without increased risk of excessive blood loss. It should be emphasized that our findings should not be applied to other more complex types of fractures of the acetabulum. Level of Evidence Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Hyperglycemia-related advanced glycation end-products is associated with the altered phosphatidylcholine metabolism in osteoarthritis patients with diabetes

To test whether type 2 diabetic patients have an elevated level of advanced glycation end-products (AGEs) and responsible for altered phosphatidylcholine metabolism, which we recently found to be associated with osteoarthritis (OA) and diabetes mellitus (DM), synovial fluid (SF) and plasma samples were collected from OA patients with and without DM. Hyperglycemia-related AGEs including methylglyoxal (MG), free methylglyoxal-derived hydroimidazolone (MG-H1), and protein bound N-(Carboxymethyl)lysine (CML) and N-(Carboxyethyl)lysine (CEL) levels were measured in both SF and plasma samples using liquid chromatography coupled tandem mass spectrometry methodology. The correlation between these AGEs and phosphatidylcholine acyl-alkyl C34:3 (PC ae C34:3) and C36:3 (PC ae C36:3) were examined. Eighty four patients with knee OA, including 46 with DM and 38 without DM, were included in the study. There was no significant difference in plasma levels of MG, MG-H1, CML, and CEL between OA patients with and without DM. However, the levels of MG and MG-H1, but not CML and CEL in SF were significantly higher in OA patients with DM than in those without (all p ≤0.04). This association strengthened after adjustment for age, body mass index (BMI), sex and hexose level (p<0.02). Moreover, the levels of MG-H1 in SF was negatively and significantly correlated with PC ae C34:3 (ρ = -0.34; p = 0.02) and PC ae C36:3 (ρ = -0.39; P = 0.03) after the adjustment of age, BMI, sex and hexose level. Our data indicated that the production of non-protein bound AGEs was increased within the OA-affected joint of DM patients. This is associated with changes in phosphatidylcholine metabolism and might be responsible for the observed epidemiological association between OA and DM.