Introduction. Debridement, antibiotics irrigation and implant retention (DAIR) is a common management strategy for hip and knee prosthetic joint infections (PJI). However, failure rates remain high, which has led to the development of predictive tools to help determine success. These tools include KLIC and CRIME80 for acute-postoperative (AP) and acute haematogenous (AH) PJI respectively. We investigated whether these tools were applicable to a Waikato cohort. Method. We performed a retrospective cohort study that evaluated patients who underwent DAIR between January 2010 and June 2020 at Waikato Hospital. Pre-operative KLIC and CRIME80 scores were calculated and compared to success of operation. Failure was defined as: (i) need for further surgery, (ii) need for suppressive antibiotics, (iii) death due to the infection. Logistic regression models were used to calculate the area under the curve (AUC). Results. 117 eligible patients underwent DAIR, 53 in the AP cohort and 64 in the AH cohort. Failure rate at 2 years post-op was 43% in the AP cohort and 59% in the AH cohort. In the AP cohort a KLIC score of <4 had a DAIR failure rate of 28.6%, while those who scored ³4 had a failure rate of 72.2% (p=0.002). In the AH cohort a CRIME80 score of <3 had a DAIR failure rate of 48% while those who scored ³3 had a 100% failure rate (p<0.001). Discussion. This study represents the first external validation of the KLIC and CRIME80 scores for predicting DAIR failure in an Australasian population. The results indicate that both KLIC and CRIME80 scoring tools are valuable aids for the clinician seeking to determine the optimal management strategy in patients with AP or AH PJI

Iliopsoas tendonitis occurs in up to 30% of patients after hip resurfacing arthroplasty (HRA) and is a common reason for revision. The primary purpose of this study was to validate our novel computational model for quantifying iliopsoas impingement in HRA patients using a case-controlled investigation. Secondary purpose was to compare these results with previously measured THA patients. We conducted a retrospective search in an experienced surgeon's database for HRA patients with iliopsoas tendonitis, confirmed via the active hip flexion test in supine, and control patients without iliopsoas tendonitis, resulting in two cohorts of 12 patients. The CT scans were segmented, landmarked, and used to simulate the iliopsoas impingement in supine and standing pelvic positions. Three discrete impingement values were output for each pelvic position, and the mean and maximum of these values were reported. Cup prominence was measured using a novel, nearest-neighbour algorithm. The mean cup prominence for the symptomatic cohort was 10.7mm and 5.1mm for the asymptomatic cohort (p << 0.01). The average standing mean impingement for the symptomatic cohort was 0.1mm and 0.0mm for the asymptomatic cohort (p << 0.01). The average standing maximum impingement for the symptomatic cohort was 0.2mm and 0.0mm for the asymptomatic cohort (p << 0.01). Impingement significantly predicted the probability of pain in logistic regression models and the simulation had a sensitivity of 92%, specificity of 91%, and an AUC ROC curve of 0.95. Using a case-controlled investigation, we demonstrated that our novel simulation could detect iliopsoas impingement and differentiate between the symptomatic and asymptomatic cohorts. Interestingly, the HRA patients demonstrated less impingement than the THA patients, despite greater cup prominence. In conclusion, this tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis

There is very limited literature describing the outcomes of management for proximal humerus fractures with more than 100% displacement of the head and shaft fragments as a separate entity. This study aimed to compare operative and non-operative management of the translated proximal humerus fracture. A prospective cohort study was performed including patients managed at a Level 1 trauma centre between January 2010 to December 2018. Patients with 2, 3 and 4-part fractures were included based on the degree of translation of the shaft fragment (≥100%), resulting in no cortical contact between the head and shaft fragments. Outcome measures were the Oxford Shoulder Score (OSS), EQ-5D-5L, and radiological outcomes. Complications recorded included further surgery, loss of position/fixation, and non-union/malunion. Linear and logistic regression models were used to compare management options. There were 108 patients with a proximal humerus fracture with ≥100% translation; 76 underwent operative management and 32 were managed non-operatively with sling immobilisation. The mean (SD) age in the operative group was 54.3 (±20.2) and in the non-operative group was 73.3 (±15.3) (p<0.001). There was no association between OSS and management options (mean 38.5(±9.5) operative vs mean 41.3 (±8.5) non-operative, p=0.48). Operative management was associated with improved health status outcomes; EQ-5D utility score adjusted mean difference 0.16 (95%CI 0.04-0.27, p=0.008); EQ-5D VAS adjusted mean difference 19.2 (95%CI 5.2-33.2, p=0.008). Operative management was further associated with a lower odds of non-union (adjusted OR 0.30, 95%CI 0.09-0.97, p=0.04), malunion (adjusted OR 0.14, 95%CI 0.04-0.51, p=0.003) and complications (adjusted OR 0.07, 95%CI 0.02-0.32, p=0.001). Translated proximal humerus fractures with ≥100% displacement demonstrate improved health status and radiological outcomes following surgical fixation. Patients with this injury should be considered for operative intervention

Approximately 20% of patients feel unsatisfied 12 months after primary total knee arthroplasty (TKA). Current predictive tools for TKA focus on the clinician as the intended user rather than the patient. The aim of this study is to develop a tool that can be used by patients without clinician assistance, to predict health-related quality of life (HRQoL) outcomes 12 months after total knee arthroplasty (TKA). All patients with primary TKAs for osteoarthritis between 2012 and 2019 at a tertiary institutional registry were analysed. The predictive outcome was improvement in Veterans-RAND 12 utility score at 12 months after surgery. Potential predictors included patient demographics, co-morbidities, and patient reported outcome scores at baseline. Logistic regression and three machine learning algorithms were used. Models were evaluated using both discrimination and calibration metrics. Predictive outcomes were categorised into deciles from 1 being the least likely to improve to 10 being the most likely to improve. 3703 eligible patients were included in the analysis. The logistic regression model performed the best in out-of-sample evaluation for both discrimination (AUC = 0.712) and calibration (gradient = 1.176, intercept = -0.116, Brier score = 0.201) metrics. Machine learning algorithms were not superior to logistic regression in any performance metric. Patients in the lowest decile (1) had a 29% probability for improvement and patients in the highest decile (10) had an 86% probability for improvement. Logistic regression outperformed machine learning algorithms in this study. The final model performed well enough with calibration metrics to accurately predict improvement after TKA using deciles. An ongoing randomised controlled trial (ACTRN12622000072718) is evaluating the effect of this tool on patient willingness for surgery. Full results of this trial are expected to be available by April 2023. A free-to-use online version of the tool is available at . smartchoice.org.au.

Aim. Smoking is known to impair wound healing and to increase the risk of peri-operative adverse events and is associated with orthopaedic infection and fracture non-union. Understanding the magnitude of the causal effect on orthopaedic infection recurrence may improve pre-operative patient counselling. Methods. Four prospectively-collected datasets including 1173 participants treated in European centres between 2003 and 2021, followed up to 12 months after surgery for clinically diagnosed orthopaedic infections, were included in logistic regression modelling with Inverse Probability of Treatment Weighting for current smoking status [1–3]. Host factors including age, gender and ASA score were included as potential confounding variables, interacting through surgical treatment as a collider variable in a pre-specified structural causal model informed by clinical experience. The definition of infection recurrence was identical and ascertained separately from baseline factors in three contributing cohorts. A subset of 669 participants with positive histology, microbiology or a sinus at the time of surgery, were analysed separately. Results. Participants were 64% male, with a median age of 60 years (range 18–95); 16% of participants experienced treatment failure by 12 months. 1171 of 1173 participants had current smoking status recorded. As expected for the European population, current smoking was less frequent in older participants (Table 1). There was no baseline association between Charlson score or ASA score and smoking status (p=0.9, p=1, Chi squared test). The estimated adjusted odds ratio for treatment failure at 12 months, resulting from current smoking at the time of surgery, was 1.37 for all participants (95% CI 0.75 to 2.50) and 1.53 for participants with recorded confirmatory criteria (95% CI 1.14 to 6.37). Conclusions. Smoking contributes to infection recurrence, particularly in people with unequivocal evidence of osteomyelitis or PJI. People awaiting surgery for orthopaedic infection should be supported to cease smoking, not only to reduce anaesthetic risk, but to improve treatment outcomes. Limitations of this study include unmeasured socioeconomic confounding and social desirability bias resulting in uncertainty in true smoking status, resulting in underestimated effect size

Simultaneous bilateral total hip arthroplasty (THA) in patients with bilateral hip osteoarthritis is gradually becoming attractive, as it requires a single anesthesia and hospitalization. However, there are concerns about the potential complications following this surgical option. The purpose of this study is to compare the short-term major and minor complications and assess the readmission rate, between patients treated with same-day bilateral THA and those with staged procedures within a year. We retrospectively reviewed the charts of all patients with bilateral hip osteoarthritis that underwent simultaneous or staged (within a year) bilateral total THA in our institution, between 2016-2020. Preoperative patient variables between the two groups were compared using the 2-sample t-test for continuous variables, the Fisher's exact test for binary variables, or the chi-square test for multiple categorical variables. Similarly, differences in the 30-day major and minor complications and readmission rates were assessed. A logistic regression model was also developed to identify potential risk factors. A total of 160 patients (mean age: 64.3 years, SD: ±11.7) that underwent bilateral THA was identified. Seventy-nine patients were treated with simultaneous and eighty-one patients with staged procedures. There were no differences in terms of preoperative laboratory values, gender, age, Body Mass Index (BMI), or American Society of Anesthesiologists Scores (ASA) (p>0.05) between the two groups. Patients in the simultaneous group were more likely to receive general anesthesia (43% vs 9.9%, p0.05). After controlling for potential confounders, the multivariable logistic regression analysis showed similar odds of having a major (odds ratio 0.29, 95% confidence interval [0.30-2.88], p=0.29) or minor (odds ratio 1.714, 95% confidence interval [0.66-4.46], p=0.27) complication after simultaneous compared to staged bilateral THA. No differences in emergency department visits or readmission for reasons related to the procedure were recorded (p>0.05). This study shows that similar complication and readmission rates are expected after simultaneous and staged THAs. Simultaneous bilateral THA is a safe and effective procedure, that should be sought actively and counselled by surgeons, for patients that present with radiologic and clinical bilateral hip disease

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

Prolonged length of stay (LOS) is a significant contributor to the variation in surgical health care costs and resource utilization after elective spine surgery. The primary goal of this study was to identify patient, surgical and institutional variables that influence LOS. The secondary objective is to examine variability in institutional practices among participating centers. This is a retrospective study of a prospectively multicentric followed cohort of patients enrolled in the CSORN between January 2015 and October 2020. A logistic regression model and bootstrapping method was used. A survey was sent to participating centers to assessed institutional level interventions in place to decrease LOS. Centers with LOS shorter than the median were compared to centers with LOS longer than the median. A total of 3734 patients were included (979 discectomies, 1102 laminectomies, 1653 fusions). The median LOS for discectomy, laminectomy and fusion were respectively 0.0 day (IQR 1.0), 1.0 day (IQR 2.0) and 4.0 days (IQR 2.0). Laminectomy group had the largest variability (SD=4.4, Range 0-133 days). For discectomy, predictors of LOS longer than 0 days were having less leg pain, higher ODI, symptoms duration over 2 years, open procedure, and AE (p< 0.05). Predictors of longer LOS than median of 1 day for laminectomy were increasing age, living alone, higher ODI, open procedures, longer operative time, and AEs (p< 0.05). For posterior instrumented fusion, predictors of longer LOS than median of 4 days were older age, living alone, more comorbidities, less back pain, higher ODI, using narcotics, longer operative time, open procedures, and AEs (p< 0.05). Ten centers (53%) had either ERAS or a standardized protocol aimed at reducing LOS. In this study stratifying individual patient and institutional level factors across Canada, several independent predictors were identified to enhance the understanding of LOS variability in common elective lumbar spine surgery. The current study provides an updated detailed analysis of the ongoing Canadian efforts in the implementation of multimodal ERAS care pathways. Future studies should explore multivariate analysis in institutional factors and the influence of preoperative patient education on LOS

To systematically review the literature regarding post-surgical treatment regimens on ankle fractures, specifically whether there is a benefit to early weightbearing or early mobilization (6 weeks form surgery). The PubMed, MEDLINE and Embase databases were searched from inception to May 24, 2020. All randomized controlled trials that analyzed the effects of early weightbearing and mobilization following an ankle surgery were included. The primary outcome measure was the Olerud Molander Ankle Score (OMAS). Secondary outcomes included return to work (RTW) and complications. Logistic regression models with random intercepts were used to pool complication data by protocol clustered by study. Twelve RCT's were included, with a total of 1177 patients (41.8 ± 8.4 years). In total, 413 patients underwent early weightbearing and early mobilization (35%), 338 patients underwent early weightbearing and delayed mobilization (29%), 287 patients underwent delayed weightbearing and early mobilization (24%), and 139 patients underwent delayed weightbearing and delayed mobilization (12%). In total, 81 patients had a complication (7%), including 53 wound complications (5%), 11 deep vein thromboses (1%), and 2 failures/nonunions (0%). Early ankle mobilization resulted in statistically significant increases in OMAS scores compared to delayed mobilization (3 studies [222 patients], 12.65; 95% CI, 7.07-18.22; P < 0.00001, I2 = 49%). No significant differences were found between early and delayed weightbearing at a minimum of one-year follow-up (3 studies [377 patients], 1.91; 95% CI, −0.73-4.55, P = 0.16, I2 = 0%). Patients treated with early weightbearing and early mobilization were at higher odds of facing any complication (OR 3.6, 95%CI 1.05-12.1, p=0.041) or wound complications (OR 4.9, 95%CI 1.3-18.8, p=0.022) compared to those with delayed weightbearing and delayed mobilization. Early mobilization following surgical treatment for an ankle fracture resulted in improved ankle function scores compared to delayed mobilization regimens. There were no significant differences between early and delayed weightbearing with respect to patient reported outcomes. Patients who were treated with early mobilization and early weightbearing had an increased odds of postoperative complications

Aim. Recurrence of bone and joint infection, despite appropriate therapy, is well recognised and stimulates ongoing interest in identifying host factors that predict infection recurrence. Clinical prediction models exist for those treated with DAIR, but to date no models with a low risk of bias predict orthopaedic infection recurrence for people with surgically excised infection and removed metalwork. The aims of this study were to construct and internally validate a risk prediction model for infection recurrence at 12 months, and to identify factors that predict recurrence. Predictive factors must be easy to check in pre-operative assessment and relevant across patient groups. Methods. Four prospectively collected datasets including 1173 participants treated in European centres between 2003 and 2021, followed up to 12 months after surgery for orthopaedic infections, were included in logistic regression modelling [1–3]. The definition of infection recurrence was identical and ascertained separately from baseline factors in three contributing cohorts. Eight predictive factors were investigated following a priori sample size calculation: age, gender, BMI, ASA score, the number of prior operations, immunosuppressive medication, glycosylated haemoglobin (HbA1c), and smoking. Missing data, including systematically missing predictors, were imputed using Multiple Imputation by Chained Equations. Weekly alcohol intake was not included in modelling due to low inter-observer reliability (mean reported intake 12 units per week, 95% CI for mean inter-rater error −16.0 to +15.4 units per week). Results. Participants were 64% male, with a median age of 60 years (range 18–95). 86% of participants had lower limb orthopaedic infections. 732 participants were treated for osteomyelitis, including FRI, and 432 for PJI. 16% of participants experienced treatment failure by 12 months. The full prediction model had moderate apparent discrimination: AUROC (C statistic) 0.67, Brier score 0.13, and reasonable apparent calibration. Of the predictors of interest, associations with failure were seen with prior operations at the same anatomical site (odds ratio for failure 1.51 for each additional prior surgery; 95% CI 1.02 to 2.22, p=0.06), and the current use of immunosuppressive medications (odds ratio for failure 2.94; 95% CI 0.89 to 9.77, p=0.08). Conclusions. This association between number of prior surgeries and treatment failure supports the urgent need to streamline referral pathways for people with orthopaedic infection to specialist multidisciplinary units

Clinically significant proximal junctional kyphosis (PJK) occurs in 20% of children treated with posterior distraction-based growth friendly surgery. In an effort to identify modifiable risk factors, it has been theorized biomechanically that low radius of curvature (ROC) implants (i.e., more curved rods) may increase post-operative thoracic kyphosis, and thus may pose a higher risk of developing PJK. We sought to test the hypothesis that EOS patients treated with low ROC (more curved rods) distraction-based treatment will have a greater risk of developing PJK as compared to those treated with high ROC (straighter) implants. This is a retrospective review of prospectively collected data obtained from a multi-centre EOS database on children treated with rib-based distraction with minimum 2-year follow-up. Variables of interest included: implant ROC at index (220 mm or 500 mm), patient age, pre-operative scoliosis, pre-operative kyphosis, and scoliosis etiology. In the literature, PJK has been defined as clinically significant if revision surgery with superior extension of the upper instrumented vertebrae was performed. In 148 scoliosis patients, there was a higher risk of clinically significant PJK with low ROC (more curved) rods (OR: 2.6 (95%CI 1.09-5.99), χ2 (1, n=148) = 4.8, p = 0.03). Patients had a mean pre-operative age of 5.3 years (4.6y 220 mm vs 6.2y 500 mm, p = 0.002). A logistic regression model was created with age as a confounding variable, but it was determined to be not significant (p = 0.6). Scoliosis etiologies included 52 neuromuscular, 52 congenital, 27 idiopathic, 17 syndromic with no significant differences in PJK risk between etiologies (p = 0.07). Overall, patients had pre-op scoliosis of 69° (67° 220mm vs 72° 500mm, p = 0.2), and kyphosis of 48° (45° 220mm vs 51° 500mm, p = 0.1). The change in thoracic kyphosis pre-operatively to final follow up (mean 4.0 ± 0.2 years) was higher in patients treated with 220 mm implants compared to 500 mm implants (220 mm: 7.5 ± 2.6° vs 500 mm: −4.0 ± 3.0°, p = 0.004). Use of low ROC (more curved) posterior distraction implants is associated with a significantly greater increase in thoracic kyphosis which likely led to a higher risk of developing clinically-significant PJK in EOS patients

Lower-extremity orthopaedic procedures may be performed under either regional or general anaesthesia, or a combination of both techniques. There is a growing body of evidence supporting the benefits of regional anaesthesia, with meta-analyses of randomised controlled trials and registry data suggesting decreases in deep surgical site infections, thromboembolic events, cardiopulmonary complications and length of stay associated with use of regional anaesthesia. In patients undergoing foot and ankle surgery specifically, there is evidence demonstrating decreased post-operative pain, nausea, vomiting, opioid use and unplanned hospital admission. This supports an increased role for the use in regional anaesthesia in patients undergoing foot and ankle surgery. However, the type of anaesthetic used is dependent on surgeon, patient, anaesthesiologist and institutional factors. The purpose of this study is to investigate pre-operative factors that predict the type of anaesthetic used in patients undergoing foot and ankle surgery. Data was collected prospectively on 888 patients undergoing foot or ankle surgery at a single institution. The primary method of anaesthesia for each procedure was recorded. Ten additional variables were recorded and analysed: age, BMI, gender, diabetes, ASA status, procedure length, procedure start time, elective vs. trauma procedure, primary vs. revision procedure and preoperative anticoagulation. Logistic regression modelling was performed to identify factors that independently predict the type of anaesthetic used. General anaesthetic was employed in 280 patients (32%), and regional anaesthesia was the primary anaesthetic type used in 608 (68%). Logistic regression modelling demonstrated that factors that independently predict use of general anaesthetic include younger age (p<0.0001; Odds Ratio 0.97/year), male sex (0.0033; 1.618), procedure start time (0.0319; 1.066/hour) and length of procedure (<0.0001; 1.520/hour). Patients who underwent general anaesthetic had a mean length of procedure of 108 +/− 77 minutes, whereas patients provided with regional anaesthesia had a mean length of procedure 83 +/− 64 minutes. With increasing evidence supporting the benefits of regional anaesthesia in patients undergoing lower extremity surgery, it is important to identify modifiable factors that contribute to patients receiving alternative treatments. Since later procedure start time was identified as an independent predictor of general anaesthetic use, there may be a role for identifying patients at increased risk of complications associated with general anaesthesia and scheduling earlier start times. Furthermore, while it is logical that extended length of procedure may be a contraindication to regional anaesthesia, the mean procedure time of 108 minutes in the general anaesthesia group indicates that many of these patients should still be considered candidates for regional anaesthesia

Aim. Whether laminar airflow (LAF) in the operating room (OR) is effective for decreasing periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant yet controversial issue. This study investigated the association between operating room ventilation systems and the risk of PJI in TJA patients. Method. We performed a retrospective observational study on consecutive patients undergoing primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) from January 2013-September 2017 in two surgical facilities within a single institution, with a minimum 1-year follow-up. All procedures were performed by five board-certified arthroplasty surgeons. The operating rooms at the facilities were equipped with LAF and turbulent ventilation systems, respectively. Patient characteristics were extracted from clinical records. PJI was defined according to Musculoskeletal Infection Society criteria within 1-year of the index arthroplasty. A multivariate logistic regression model was performed to explore the association between LAF and risk of 1-year PJI, and then a sensitivity analysis using propensity score matching (PSM) was performed to further validate the findings. Results. A total of 6,972 patients (2,797 TKA, 4,175 THA) were included. The incidence of PJI within 1 year for patients from the facility without laminar flow was similar at 0·4% to that of patients from the facility with laminar flow at 0·5%. In the multivariate logistic regression analysis, after all confounding factors were taken into account, the use of LAF was not significantly associated with reduction of the risk of PJI. After propensity score matching, there was no significant difference in the incidence of PJI within 1 year for patients between the two sites. Conclusions. The use of LAF in the operating room was not associated with a reduced incidence of PJI following primary TJA. With an appropriate perioperative protocol for infection prevention, LAF does not seem to play a protective role in PJI prevention

Purpose. Although total knee replacement (TKR) has a high reported success rate, the pain relief and functional improvement after surgery varies. We asked what is the prevalence of patients showing no clinically significant improvement 1-year after TKR, and what are the patient level factors that may predict this outcome. Method. We reviewed primary TKR registry data that were collected from two academic hospitals: the Toronto Western Hospital (TWH) and the Henderson Hospital(HH) in Ontario. Relevant covariates including demographic data, body mass index, and comorbidity were recorded. Knee joint pain and functional status were assessed at baseline and at 1-year follow-up with the Western Ontario McMaster University Osteoarthritis Index (WOMAC) and Oxford knee score (OKS) to measure the change using the minimal clinically important difference (MCID). Logistic regression modeling was used to identify the predictors of interest. Results. Overall, 11.7% (373/3177) of patients reported no clinically significant improvement 1-year after surgery. Logistic regression modeling showed that a greater patient age independently predicted no clinically significant improvement on the WOMAC scale 1-year after surgery (p=0.0003), while male gender independently predicted no clinically significant improvement on the OKS 1-year after surgery (p=0.008). Conclusion. Awareness of the prevalence of patients who may show no clinically significant improvement and factors that predict this outcome will help patients and surgeons to set realistic expectations of surgery

Elderly patients undergoing surgery for a hip fracture are at risk of thromboembolic events (TEV). The risk of TEV is now rare due to thromboprophylaxis. However, hip fracture treatment has evolved over the last decade. The risk of TEV may have been modified. The objective of this study was to determine the risk of symptomatic TEV following surgery for a hip fracture, in an elderly population. Retrospective cohort study of all patients > 65 years old undergoing surgery for a femoral neck or intertrochanteric hip fracture in two academic centers, between January 1st 2008 and January 1st 2019. The follow-up was fixed at 3 months. The cumulated risk of thromboembolic events was calculated using the Kaplan-Meier estimator and a predictive logistic regression model was used to determine risk factors. 3265 patients were eligible for analysis. The mean age was 83.3 ±8.1 years old and 75.6% of patients were female. The mortality was 7.55% (N=112) at 3 months. 98.53% of this cohort received thromboprophylaxis. The cumulated risk for a thromboembolic event was 3.55% at 1 month and 6.41% at 3 months (N=99). There were 9 fatal pulmonary embolisms. 89.19% thromboembolic events occurred within 20 days following surgery. Chronic obstructive pulmonary disease (odds ratio 1.909 [1.179–3.089]), renal failure (odds ratio 1.896 [1.172–3.066]) and the use of a bridge between different types of anticoagulant (odds ratio 2.793 [1.057–7.384]) were associated with TEV. The risk of bleeding was 5.67% at 1 month and 9.38% at 3 months (N=142). 77% of bleeding events were hematomas. The risk of thromboembolic events is higher than expected in a population treated for this condition. Most thromboembolic events occur shortly following surgery. The risk of bleeding is high and most of them are hematomas. Future research could focus on the management of thromboprophylaxis in elderly patients undergoing surgery for a hip fracture

The primary objectives of this study were to: 1) identify risk factors for subsequent surgery following initial treatment of proximal humerus fractures, stratified by initial treatment type; 2) generate risk prediction tools to predict subsequent shoulder surgery following initial treatment; and 3) internally validate the discriminative ability of each tool. We identified patients ≥ 50 years with a diagnosis of proximal humerus fracture from 2004 to 2015 using linkable health datasets in Ontario, Canada. We used procedural and fee codes within 30 days of the index fracture to classify patients into treatment groups: 1) surgical fixation; 2) shoulder replacement; and 3) conservative. We used intervention and diagnosis codes to identify all instances of complication-related subsequent shoulder surgery following initial treatment within two years post fracture. We developed logistic regression models for randomly selected two thirds of each treatment group to evaluate the association of patient, fracture, surgical, and hospital variables on the odds of subsequent shoulder surgery following initial treatment. We used regression coefficients to compute points associated with each of the variables within each category, and calculated the risk associated with each point total using the regression equation. We used the final third of each cohort to evaluate the discriminative ability of the developed risk tools (via the continuous point total and a dichotomous point cut-off value for “higher” vs. “lower” risk determined by Receiver Operating Curves) using c-statistics. We identified 20,897 patients with proximal humerus fractures that fit our inclusion criteria for analysis, 2,414 treated with fixation, 1,065 treated with replacement, and 17,418 treated conservatively. The proportions of patients who underwent subsequent shoulder surgery within two years were 13.8%, 5.1%, and 1.3%, for fixation, replacement, and conservative groups, respectively. Predictors of reoperation following fixation included the use of a bone graft, and fixation with a nail or wire vs. a plate. The only significant predictor of reoperation following replacement was poor bone quality. The only predictor of subsequent shoulder surgery following conservative treatment was more comorbidities while patients aged 70+, and those discharged home following initial presentation (vs. admitted or transferred to another facility) had lower odds of subsequent shoulder surgery. The risk tools developed were able to discriminate between patients who did or did not undergo subsequent shoulder surgery in the derivation cohorts with c-statistics of 0.75–0.88 (continuous point total), and 0.82–0.88 (dichotomous cut-off), and 0.53–0.78 (continuous point total) and 0.51–0.79 (dichotomous cut-off) in the validation cohorts. Our results present potential factors associated with subsequent shoulder surgery following initial treatment of proximal humerus fractures, stratified by treatment type. Our developed risk tools showed good to strong discriminative ability in both the derivation and validation cohorts for patients treated with fixation, and conservatively. This indicates that the tools may be useful for clinicians and researchers. Future research is required to develop risk tools that incorporate clinical variables such as functional demands

Malnutrition is an important consideration during the perioperative period and albumin is the most common laboratory surrogate for nutritional status. The purpose of this study is to identify if preoperative serum albumin measurements are predictive of infection following arthroscopic procedures. Patients undergoing knee, shoulder or hip arthroscopy between 2006–2016 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients with an arthroscopic current procedural terminology code and a preoperative serum albumin measurement were included. Patients with a history of prior infection, including a non-clean wound class, pre-existing wound infection or systemic sepsis were excluded. Independent t-tests where used to compare albumin values in patients with and without the occurrence of a postoperative infection. Pre-operative albumin levels were subsequently evaluated as predictors of infection with logistic regression models. There were 31,906 patients who met the inclusion criteria. The average age was 55.7 years (standard deviation (SD) 14.62) and average BMI was 31.7 (SD 7.21). The most prevalent comorbidities were hypertension (49.2%), diabetes (18.4%) and smoking history (16.9%). The average preoperative albumin was 4.18 (SD 0.42). There were 45 cases of superficial infection (0.14%), 10 cases of wound dehiscence (0.03%), 17 cases of deep infection (0.05%), 27 cases of septic arthritis or other organ space infection (0.08%) and 95 cases of any infection (0.30%). The preoperative albumin levels for patients who developed septic arthritis (mean difference (MD) 0.20, 95% CI, 0.038, 0.35, P = 0.015) or any infection (MD 0.14, 95% CI 0.05, 0.22, P = 0.002) were significantly lower than the normal population. Additionally, disseminated cancer, Hispanic race, inpatient status and smoking history were significant independent risk factors for infection, while female sex and increasing albumin were protective towards developing any infection. Rates of all infections were found to increase exponentially with decreasing albumin. The relative risk of infection with an albumin of 2 was 3.46 (95% CI, 2.74–4.38) when compared to a normal albumin of 4. For each albumin increase of 0.69, the odds of developing any infection decreases by a factor of 0.52. This study suggests that preoperative serum albumin is an independent predictor of septic arthritis and all infection following elective arthroscopic procedures. Although the effect of albumin on infection is modest, malnutrition may represent a modifiable risk factor with regard to preventing infection following arthroscopy

Aim. Infection is one of the worst complications following total joint arthroplasty, which is often associated with significant morbidity and increased medical costs. Although Gram–positive bacteria remains the most prevalent causative agents, an increase in prosthetic joint infections (PJI) due to gram-negative bacteria (GNB) has been reported. Additionally, the emergence of multidrug resistant resistance (MDR) in GNB impacts the therapeutic options and may increase the rate of treatment failure and drug toxicity adverse effects due the prescription of harmful and toxics antimicrobial schemes. The purpose of the present study was to describe the predisposing factors associated to PJI caused by MDR-GNB in a specialized orthopedic reference hospital in Brazil from 2014 through 2018. Method. Retrospective case-control analysis of patients treated for MDR-GNB PJI over a four-year period (2014–2018). Data were collected from medical, surgical and laboratory records. PJI were defined according the criteria of MSIS. MDR was defined as non-susceptibility to at least one agent in three or more antimicrobial categories. Patients with prosthetic infection with at least two positive tissue cultures for MDR-GNB were selected. Univariate and multivariate logistic regression models were used to determine the independent risk factors associated with MDR-GNB PJI. Controls: patients with PJI with at least two positive tissue culture for non MDR- GNB. Results. A total of 104 patients were selected, 59 patients in the MDR-GNB PJI group and 44 in the control. Patients with MDR-GNB PJI were elderly (mean age of 68.36), distribution among sex was similar (49.2% female and 50.8% male) and 72.3% had one or more comorbidities. Most frequently identified comorbidities were diabetes (10.2%), malnutrition (5.5%), hypertension (4.7 %) and obesity (3.9%). Hip replacement accounted for 91.5% of the cases and 59.3% were revision arthroplasty. The mean time between the placement of the prothesis and the onset of PJI signs and symptoms was 438 days. In the univariate regression, the significant risk factors for MDR-GNB PJI were revision arthroplasty, alcoholism, nonelective arthroplasty, prior antimicrobial use, presence of concomitant infection and blood transfusion. However, in the multivariate analysis, prior use of antimicrobials (OR 9.31, CI95% 3.02–28.64) and the nonelective arthroplasty (OR 6.29, CI95% 1.75–22.6) remained as independent risk factors for MDR-GNB PJI. Conclusions. Previous use of antimicrobial and nonelective arthroplasty are important risk factors for PJI by GNB MDR

Aim. Duration of perioperative antimicrobial prophylaxis (PAP) remains controversial in prevention of fracture-related infection (FRI) – with rates up to 30% - in open fracture (OF) management. Objectives were to investigate the impact of the PAP duration exclusively in or related to long bone OF trauma patients and the influence of augmented renal clearance (ARC), a known phenomenon in trauma patients, as PAP consists of predominantly renally eliminated antibiotics. Method. Trauma patients with operatively treated OF, admitted between January 2003 and January 2017 at the University Hospitals Leuven, were retrospectively evaluated. FRI was defined following the criteria of the consensus definition of FRI. A logistic regression model was conducted with FRI as outcome. Results were considered statistically significant when p< 0.05. Results. Forty (8%) from the 502 patients developed a FRI, with 20% FRIs in Gustilo-Anderson (GA) III OFs. Higher GA grade and polytrauma were independently associated with the occurrence of FRI. The heterogeneity in OF management, especially with regard to the applied PAP regimens and duration, was striking and consequently hampering the investigation on the impact of PAP duration. To overcome this issue, a subgroup analysis was performed in patients treated with the two PAP regimens as defined in the hospitals' guidelines – i.e. cefazolin, with metronidazole and tobramycine when extensive contamination was present -, revealing flap coverage and relative duration of augmented renal ARC as independently associated factors. Conclusions. For the first time, a definition based on diagnostic criteria was used to objectively include patients with a FRI. In order to support clinicians in establishing strategies to prevent FRI in long bone OFs, further prospective large randomized controlled trials with clearly predefined PAP regimens are needed to provide reliable recommendations regarding the impact of duration of PAP and ARC

Aim. Cutibacterium acnes is a significant cause of late-onset spinal implant infection (SII). In addition, usual preoperative prophylactic measures may be insufficient to prevent C. acnes operating site colonisation and infection, as demonstrated for prosthetic shoulder surgery. However, little information is available regarding risk factors for SII due to this microorganism. The aims of this study were to determine the characteristics of and risk factors for C. acnes SII. Method. we conducted a retrospective unmatched case-control study including all adult patients treated for mono and polymicrobial C. acnes SII during 2010–2015. Controls were randomly selected among patients diagnosed with SII due to other microorganisms during the same period. Results. Fifty-nine patients with C. acnes SII were compared with 59 controls. There was no difference in sex distribution (39% vs 53% men). Patients with C. acnes SII were younger (median age 42 vs. 65, p< 0.001), thinner (median body mass index (BMI) 21 vs. 25 kg/m. 2. , p< 0.001), and presented a better health status (ASA score≤ 2, 83% vs. 65%, p= 0.015; and presence of immunosuppression, 3% vs. 27%, p= 0.002). Patients with C. acnes SII were more likely to experience delayed/late infections (i.e. diagnosed >3 months post-instrumentation, 66% vs. 22%, p< 0.001) and to be instrumented for scoliosis (83% vs. 27%, p< 0.001) with an extended osteosynthesis (median number of fused vertebrae 12 vs. 5, p< 0.001). However, 20 C. acnes SII (34%) developed early (≤3 months) after instrumentation. The clinical presentation was significantly more indolent in the C. acnes group (presence of fever, 27% vs. 61%, p= 0.001; wound inflammation 39% vs. 61%, p< 0.001 and median C-reactive protein level 38 vs. 146 mg/L). Mixed C. acnes SII were diagnosed on 24 occasions (41%), 22 of which involving both C. acnes and staphylococcal strains. In the multivariate logistic regression model, factors independently associated with the development of SII involving C. acnes were age less than 65 (adjusted odds ratio [aOR] 7.13, 95% CI [2.44–24.4], p= 0.001), BMI< 22kg/m. 2. (aOR 3.71 [1.34–10.7], p= 0.012) and a number of fused vertebrae >10 (aOR 3.90 IC 95% [1.51–10.4], p= 0.005). Conclusions. There were significant differences between SII involving C. acnes and those involving other microorganisms. We identified a specific profile of patients at increased risk of developing C. acnes SII. These findings could contribute to improve both the prevention and treatment of such infections