Aims. This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures. Methods. Using the National Surgical Quality Improvement Programme (NSQIP) database, patients who underwent common orthopaedic surgery procedures from 1 January to 31 December 2021 were extracted. Patient preoperative COVID-19 status, demographics, comorbidities, type of surgery, and postoperative complications were analyzed. Propensity score matching was conducted between COVID-19-positive and -negative patients. Multivariable regression was then performed to identify both patient and provider risk factors independently associated with the occurrence of 30-day postoperative adverse events. Results. Of 194,121 included patients, 740 (0.38%) were identified to be COVID-19-positive. Comparison of comorbidities demonstrated that COVID-19-positive patients had higher rates of diabetes, heart failure, and pulmonary disease. After propensity matching and controlling for all preoperative variables, multivariable analysis found that COVID-19-positive patients were at increased risk of several postoperative complications, including: any adverse event, major adverse event, minor adverse event, death, venous thromboembolism, and pneumonia. COVID-19-positive patients undergoing hip/knee arthroplasty and trauma surgery were at increased risk of 30-day adverse events. Conclusion. COVID-19-positive patients undergoing orthopaedic surgery had increased odds of many 30-day postoperative complications, with hip/knee arthroplasty and trauma surgery being the most high-risk procedures. These data reinforce prior literature demonstrating increased risk of venous thromboembolic events in the acute postoperative period. Clinicians caring for patients undergoing orthopaedic procedures should be mindful of these increased risks, and attempt to improve patient care during the ongoing global pandemic. Cite this article: Bone Jt Open 2023;4(9):704–712

Total knee and hip arthroplasty (TKA and THA) are two of the highest volume and resource intensive surgical procedures. Key drivers of the cost of surgical care are duration of surgery (DOS) and postoperative inpatient length of stay (LOS). The ability to predict TKA and THA DOS and LOS has substantial implications for hospital finances, scheduling and resource allocation. The goal of this study was to predict DOS and LOS for elective unilateral TKAs and THAs using machine learning models (MLMs) constructed on preoperative patient factors using a large North American database. The American College of Surgeons (ACS) National Surgical and Quality Improvement (NSQIP) database was queried for elective unilateral TKA and THA procedures from 2014-2019. The dataset was split into training, validation and testing based on year. Multiple conventional and deep MLMs such as linear, tree-based and multilayer perceptrons (MLPs) were constructed. The models with best performance on the validation set were evaluated on the testing set. Models were evaluated according to 1) mean squared error (MSE), 2) buffer accuracy (the number of times the predicted target was within a predesignated buffer of the actual target), and 3) classification accuracy (the number of times the correct class was predicted by the models). To ensure useful predictions, the results of the models were compared to a mean regressor. A total of 499,432 patients (TKA 302,490; THA 196,942) were included. The MLP models had the best MSEs and accuracy across both TKA and THA patients. During testing, the TKA MSEs for DOS and LOS were 0.893 and 0.688 while the THA MSEs for DOS and LOS were 0.895 and 0.691. The TKA DOS 30-minute buffer accuracy and ≤120 min, >120 min classification accuracy were 78.8% and 88.3%, while the TKA LOS 1-day buffer accuracy and ≤2 days, >2 days classification accuracy were 75.2% and 76.1%. The THA DOS 30-minute buffer accuracy and ≤120 min, >120 min classification accuracy were 81.6% and 91.4%, while the THA LOS 1-day buffer accuracy and ≤2 days, >2 days classification accuracy were 78.3% and 80.4%. All models across both TKA and THA patients were more accurate than the mean regressors for both DOS and LOS predictions across both buffer and classification accuracies. Conventional and deep MLMs have been effectively implemented to predict the DOS and LOS of elective unilateral TKA and THA patients based on preoperative patient factors using a large North American database with a high level of accuracy. Future work should include using operational factors to further refine these models and improve predictive accuracy. Results of this work will allow institutions to optimize their resource allocation, reduce costs and improve surgical scheduling. Acknowledgements:. The American College of Surgeons National Surgical Quality Improvement Program and the hospitals participating in the ACS NSQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors

Total hip arthroplasty (THA) is performed under general anesthesia (GA) or spinal anesthesia (SA). The first objective of this study was to determine which patient factors are associated with receiving SA versus GA. The second objective was to discern the effect of anesthesia type on short-term postoperative complications and readmission. The third objective was to elucidate factors that impact the effect of anesthesia type on outcome following arthroplasty. This retrospective cohort study included 108,905 patients (median age, 66 years; IQR 60-73 years; 56.0% females) who underwent primary THA for treatment of primary osteoarthritis in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database during the period of 2013-2018. Multivariable logistic regression analysis was performed to evaluate variables associated with anesthesia type and outcomes following arthroplasty. Anesthesia type administered during THA was significantly associated with race. Specifically, Black and Hispanic patients were less likely to receive SA compared to White patients (White: OR 1.00; Black: OR 0.73; 95% confidence interval [CI] 0.71-0.75; Hispanic: OR 0.81; CI, 0.75-0.88), while Asian patients were more likely to receive SA (OR 1.44, CI 1.31-1.59). Spinal anesthesia was associated with increased age (OR 1.01; CI 1.00-1.01). Patients with less frailty and lower comorbidity were more likely to receive SA based on the modified frailty index ([mFI-5]=0: OR 1.00; mFI-5=1: OR 0.90, CI 0.88-0.93; mFI-5=2 or greater: OR 0.86, CI 0.83-0.90) and American Society of Anesthesiologists (ASA) class (ASA=1: OR 1.00; ASA=2: OR 0.85, CI 0.79-0.91; ASA=3: OR 0.64, CI 0.59-0.69; ASA=4-5: OR 0.47; CI 0.41-0.53). With increased BMI, patients were less likely to be treated with SA (OR 0.99; CI 0.98-0.99). Patients treated with SA had less post-operative complications than GA (OR 0.74; CI 0.67-0.81) and a lower risk of readmission than GA (OR 0.88; CI 0.82-0.95) following THA. Race, age, BMI, and ASA class were found to affect the impact of anesthesia type on post-operative complications. Stratified analysis demonstrated that the reduced risk of complications following arthroplasty noted in patients treated with SA compared to GA was more pronounced in Black, Asian, and Hispanic patients compared to White patients. Furthermore, the positive effect of SA compared to GA was stronger in patients who had reduced age, elevated BMI, and lower ASA class. Among patients undergoing THA for management of primary osteoarthritis, factors including race, BMI, and frailty appear to have impacted the type of anesthesia received. Patients treated with SA had a significantly lower risk of readmission to hospital and adverse events within 30 days of surgery compared to those treated with GA. Furthermore, the positive effect on outcome afforded by SA was different between patients depending on race, age, BMI, and ASA class. These findings may help to guide selection of anesthesia type in subpopulations of patients undergoing primary THA

This study was designed to compare atypical hip fractures with a matched cohort of standard hip fractures to evaluate the difference in outcomes. Patients from the American College of Surgeons National Surgical Quality Improvement Program's (NSQIP) targeted hip fracture data file (containing a more comprehensive set of variables collected on 9,390 specially targeted hip fracture patients, including the differentiation of atypical from standard hip fractures) were merged with the standard 2016 NSQIP data file. Atypical hip fracture patients aged 18 years and older in 2016 were identified via the targeted hip fracture data file and matched to two standard hip fracture controls by age, sex, and fracture location. Patient demographics, length of hospital stay, 30-day mortality, major and minor complications, and other hip-specific variables were identified from the database. Binary outcomes were compared using the McNemar's test for paired groups, and continuous outcomes were compared using a paired t-test. Ninety-five atypical hip fractures were identified, and compared to 190 age, sex, and fracture location matched standard hip fracture controls. There was no statistical difference in body mass index (BMI), race, ASA score, smoking status, timing of fixation, or functional status between the two groups (P>0.05). Thirty-day mortality was significantly higher in the atypical hip fracture group (atypical 7.36%, standard 2.11% p. This is the first study, to our knowledge, that demonstrates an increase in the rate of mortality in atypical hip fractures. Comparing atypical hip fractures with a matched cohort of standard hip fractures revealed a significantly greater 30-day mortality rate with an odds ratio of 3.62 in atypical hip fractures (95% CI 1.03–12.68). Prospective, clinical studies are recommended to further investigate these findings

To describe the longitudinal trends in patients with obesity and Metabolic Syndrome (MetS) undergoing TKA and the associated impact on complications and lengths of hospital stay. We identified patients who underwent primary TKA between 2006 – 2017 within the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. We recorded patient demographics, length of stay (LOS), and 30-day major and minor complications. We labelled those with an obese Body Mass Index (BMI ≥ 30), hypertension, and diabetes as having MetS. We evaluated mean BMI, LOS, and 30-day complication rates in all patients, obese patients, and those with MetS from 2006-2017. We used multivariable regression to evaluate the trends in BMI, complications, and LOS over time in all patients and those with MetS, and the effect of BMI and MetS on complication rates and LOS, stratified by year. 270,846 patients underwent primary TKA at hospitals participating in the NSQIP database. 63.71% of patients were obese (n = 172,333), 15.21% were morbidly obese (n = 41,130), and 12.37% met criteria for MetS (n = 33,470). Mean BMI in TKA patients increased at a rate of 0.03 per year (0.02-0.05; p < 0 .0001). Despite this, the rate of adverse events in obese patients decreased: major complications by an odds ratio (OR) of 0.94 (0.93-0.96; p < 0 .0001) and minor complications by 0.94 (0.93-0.95; p < 0 .001). LOS also decreased over time at an average rate of −0.058 days per year (-0.059 to −0.057; p < 0 .0001). The proportion of patients with MetS did not increase, however similar improvements in major complications (OR 0.94 [0.91-0.97] p < 0 .0001), minor complications (OR 0.97 [0.94-1.00]; p < 0 .0330), and LOS (mean −0.055 [-0.056 to −0.054] p < 0 .0001) were found. In morbidly obese patients (BMI ≥ 40), there was a decreased proportion per year (OR 0.989 [0.98-0.994] p < 0 .0001). Factors specifically associated with major complications in obese patients included COPD (OR 1.75 [1.55-2.00] p < 0.0001) and diabetes (OR 1.10 [1.02-1.1] p = 0.017). Hypertension (OR 1.12 [1.03-1.21] p = 0.0079) was associated with minor complications. Similarly, in patients with MetS, major complications were associated with COPD (OR 1.72 [1.35-2.18] p < 0.0001). Neuraxial anesthesia was associated with a lower risk for major complications in the obese cohort (OR 0.87 [0.81-0.92] p < 0.0001). BMI ≥ 40 was associated with a greater risk for minor complications (OR 1.37 [1.26-1.50] p < 0.0001), major complications (1.11 [1.02-1.21] p = 0.015), and increased LOS (+0.08 days [0.07-0.09] p < 0.0001). Mean BMI in patients undergoing primary TKA increased from 2006 - 2017. MetS comorbidities such as diabetes and hypertension elevated the risk for complications in obese patients. COPD contributed to higher rates of major complications. The obesity-specific risk reduction with spinal anesthesia suggests an improved post-anesthetic clinical course in obese patients with pre-existing pulmonary pathology. Encouragingly, the overall rates of complications and LOS in patients with obesity and MetS exhibited a longitudinal decline. This finding may be related to the decreased proportion of patients with BMI ≥ 40 treated over the same period, possibly the result of quality improvement initiatives aimed at delaying high-risk surgery in morbidly obese patients until healthy weight loss is achieved. These findings may also reflect increased awareness and improved management of these patients and their elevated risk profiles

Delayed management of high energy femoral shaft fractures is associated with increased complication rates. It has been suggested that there is less urgency to stabilize lower energy femoral shaft fractures. The purpose of this study was to evaluate the effect of surgical delay on 30-day complications following fixation of lower energy femoral shaft fractures. Patients ≥ 18 years who underwent either plate or nail fixation of low energy (falls from standing or up to three steps' height) femoral shaft fractures from 2005 – 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) via procedural codes. Patients with pathologic fractures, fractures of the distal femur or femoral neck were excluded. Patients were categorized into early (< 2 4 hours) or delayed surgery (2–30 days) groups. Bivariate analyses were used to compare demographics and unadjusted rates of complications between groups. A multivariable logistic regression was used to compare the rate of major and minor complications between groups, while adjusting for relevant covariables. Head injury patients and polytrauma patients are not included in the NSQIP database. Of 2,716 lower energy femoral shaft fracture patients identified, 2,412 (89%) were treated within 1 day of hospital admission, while 304 (11.2%) were treated between 2 and 30 days post hospital admission. Patient age, American Society of Anesthesiologists (ASA) classification score, presence of diabetes, functional status, smoking status, and surgery type (nail vs. plate) were significantly different between groups (p After adjusting for all relevant covariables, delayed surgery significantly increased the odds of 30-day minor complications (p=0.02, OR = 1.48 95%CI 1.01–2.16), and 30-day mortality (p < 0 .001), OR = 1.31 (95%CI 1.03–2.14). The delay of surgical fixation of femoral shaft fractures appears to significantly increase patients' risk of minor adverse events as well as increase mortality. With only 89% of patients being treated in the 24 hour timeframe that constitutes best practice for treatment of femoral shaft fractures, there remains room for improvement. These results suggest that early treatment of all femoral shaft fractures, even those with a lower energy mechanism of injury, leads to improved outcomes

Resident involvement in the operating room is a vital component of their medical education. Conflicting and limited research exists regarding the effects of surgical resident participation on spine surgery patient outcomes. Our objective was to determine the effect of resident involvement on surgery duration, length of hospital stay and 30-day post-operative complication rates. This study was a multicenter retrospective analysis of the prospectively collected American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. All anterior cervical or posterior lumbar fusion surgery patients were identified. Patients who had missing trainee involvement information, surgery for cancer, preoperative infection or dirty wound classification, spine fractures, traumatic spinal cord injury, intradural surgery, thoracic surgery and emergency surgery were excluded. Propensity score for risk of any complication was calculated to account for baseline characteristic differences between the attending alone and trainee present group. Multivariate logistic regression was used to investigate the impact of resident involvement on surgery duration, length of hospital stay and 30 day post-operative complication rates. 1441 patients met the inclusion criteria: 1142 patients had surgeries with an attending physician alone and 299 patients had surgeries with trainee involvement. After adjusting using the calculated propensity score, the multivariate analysis demonstrated that there was no significant difference in any complication rates between surgeries involving trainees compared to surgeries with attending surgeons alone. Surgery times were found to be significantly longer for surgeries involving trainees. To further explore this relationship, separate analyses were performed for tertile of predicted surgery duration, cervical or lumbar surgery, instrumentation, inpatient or outpatient surgery. The effect of trainee involvement on increasing surgery time remained significant for medium predicted surgery duration, longer predicted surgery duration, cervical surgery, lumbar surgery, lumbar fusion surgery and inpatient surgery. There were no significant differences reported for any other factors. After adjusting for confounding, we demonstrated in a national database that resident involvement in surgeries did not increase complication rates, length of hospital stay or surgical duration of more routine surgical cases. We found that resident involvement in surgical cases that were generally more complexed resulted in increased surgery time. Further study is required to determine the relationship between surgery complexity and the effect of resident involvement on surgery duration

Increased operative time has been previously identified as a risk factor for complications following total joint arthroplasty. The purpose of this study was to evaluate the influence of surgical time on 30-day complications following Total Knee Arthroplasty (TKA) and to determine if there were specific time intervals associated with worse outcomes. The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was utilized to identify patients ≥18 years who underwent TKA between 2005 and 2016 using procedural codes. Patients with surgical durations >240 minutes were excluded. Patient demographics, operation length, and 30-day major and minor complication rates were captured. Multivariable logistic regression was used to determine if the rate of complications differed depending on length of operation, while adjusting for age, sex, American Society of Anaesthesiologists (ASA) class, functional status, smoking status, comorbidities, anesthesia type, and Body Mass Index (BMI). Multivariable linear regression was used to identify independent predictors of duration of surgery. A total of 213,921 TKA patients (average age 67 ± 10 years) were identified from the database. Within 30-days of the index procedure, 3,321 (1.55%) experienced a major complication, and 6,144 (2.86%) experienced a minor complication. Mean surgical duration was 92 minutes (range 20 – 240). Underweight, or overweight/obese BMI, male sex, hypertension, cancer, dependent functional status, epidural anaesthesia, and ASA class III and IV were determined to be independent predictors of prolonged operation length, while COPD, current smoking, spinal anesthesia, and older age predicted lower operation times. Operation lengths ≥ 90 minutes significantly increased the risk of both major and minor complications (P>0.01). Specifically, the rates of deep vein thrombosis (DVT), unplanned reintubation, surgical site infection (SSI), sepsis, and wound disruption were higher for patients whose operations lasted ≥ 90 minutes (p 0.05). With respect to specific complications, following covariate adjustment, operation lengths ≥ 90 minutes increased the risk of DVT, deep and superficial incisional SSI, and wound disruption, while operation lengths ≥ 120 minutes increased the risk of deep, non-incisional SSI, and sepsis (P < 0 .01). Surgical times of ≥90 minutes independently increase the 30-day risk of DVT, infection, and wound disruption following TKA after controlling for other variables that influence operation length. This study confirms the importance of surgical duration on early outcomes following TKA

Distal radius fractures are the most common adult fractures, yet there remains some uncertainty surrounding optimal treatment modalities. Recently, the rate of operative treatment of these injuries has been increasing, however, predictors of outcomes in patients treated surgically remain poorly understood. The purpose of this study was to evaluate independent predictors of 30-day readmission and complications following internal fixation of distal radius fractures. Patients ≥18 years who underwent surgical intervention for distal radius fractures between 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) using procedural codes. Patient demographics, as well as 30-day readmission, complication, and mortality rates were ascertained. Multivariable logistic regression was used to determine independent predictors of 30-day outcomes while adjusting for patient age, sex, American Society of Anaesthesiologists (ASA) class, functional status, smoking status, comorbidities, and Body Mass Index (BMI). A total of 10,051 patients were identified (average age 58 ±16). All patients received open reduction and internal fixation with no cases of external fixation identified in the data set. Included fractures were 37% extraarticular and 63% intraarticular. Within 30-days of initial fixation 143 (1.42%) patients were readmitted to the hospital, 71 patients experienced a complication, and 18 (0.18%) patients died. After adjusting for relevant covariables, current smoking increased the odds of readmission by 1.73 (95%Confidence interval [95%CI] 1.15 – 2.50), ASA class III/IV vs. I/II increased the odds of readmission by 2.74 (95%CI 1.85 – 4.06), and inpatient surgery vs. outpatient surgery increased the odds of readmission by 2.10 (95%CI 1.46 – 3.03). Current smoking also increased the odds of complications by 2.26 (95%CI 1.32 – 3.87), while ASA class III/IV increased it by 2.78 (95%CI 1.60 – 4.85), inpatient surgery increased it by 2.26 (95%CI 1.37 – 3.74), and dependent functional status increased it by 2.55 (1.16 – 5.64). In conclusion, patients with severe systemic disease, current smokers and patients undergoing inpatient surgery are at risk for 30-day readmissions and complications following operative treatment of distal radius fractures. In addition, patients with dependent functional statuses are more likely to experience a complication within 30-days

The objective of this paper is to demonstrate the difference in post-operative complication rates between Computer-assisted surgery (CAS) and conventional techniques in spine surgery. Several studies have shown that the accuracy of pedicle screw placement significantly improves with use of CAS. Yet, few studies have compared the incidence of post-operative complications between CAS and conventional techniques. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent posterior lumbar fusion from 2011 to 2013. Multivariate analysis was conducted to demonstrate the difference in post-operative complication rates between CAS and conventional techniques in spine surgery. Out of 15,222 patients, 14,382 (95.1%) were operated with conventional techniques and 740 (4.90%) were operated with CAS. Multivariate analysis showed that patients in the CAS group had less odds to experience adverse events post-operatively (OR 0.57, P <0.001). This paper examined the complications in lumbar spinal surgery with or without the use of CAS. These results suggest that CAS may provide a safer technique for implant placement in lumbar fusion surgeries

Recent studies have described safe outcomes for short-stays in the hospital after total shoulder arthroplasty. The purpose of this study is to identify pre-operative and operative risk factors for hospital admissions exceeding 24 hours. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried from 2006 to 2016 for the current procedural terminology (CPT) billing code related to total shoulder arthroplasty. Patients were then grouped as either having a length of stay (LOS) equal to or less than 24 hours or greater than 24 hours. Patients admitted to the hospital prior to the day of surgery were excluded. Patient demographics, co-morbidities, and operative time were then analyzed as risk factors for a hospital stay exceeding 24 hours. Pre-operative co-morbidities included body mass index (BMI), diabetes, smoking, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hypertension, dialysis, chronic steroid or immunosuppressant use, bleeding disorders, and American Society of Anesthesiologists (ASA) Classification. Univariate and multivariate analyses were then performed to identify risk factors associated with 30-day readmission. 14,339 patients met inclusion criteria and 6,507 (45.3%) had a hospital LOS less than or equal to 24 hours. The mean length of hospitalization was 1.95 ± 1.88 days, the average age was 69 ± 9.7 years old, and 56.9% of the patients were female. Following a risk adjusted multivariate analysis, increasing age (odds ratio [OR], 1.03, 95% confidence interval [CI], 1.02–1.03), ASA classification (OR, 1.50, 95% CI, 1.41–1.60), diabetes (OR, 1.69, 95% CI, 1.43–1.99), COPD (OR, 1.35, 95% CI, 1.16–1.57), CHF (OR, 2.67, 95% CI, 1.34–5.33), dialysis (OR, 2.47, 95% CI, 1.28, 4.77), history of a bleeding disorder (OR, 1.50, 95% CI, 1.20–1.88), or increasing operative time (OR, 1.01, 95% CI, 1.01–1.01) were identified as independent risk factors for hospital lengths of stay exceeding 24 hours. Male gender was identified as a protective factor for prolonged hospitalization (OR, 0.50, 95% CI, 0.46–0.53). This study identifies patient demographics, co-morbidities, and operative-relative risk factors that are associated with increased risk for a prolonged hospitalization following total shoulder arthroplasty. Female gender, increasing age, ASA classification, operative time, or a history of diabetes, COPD, CHF, or history of a bleeding disorder are risk factors hospitalizations exceeding 24 hours

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

This study was designed to compare length of hospital stay, and 30-day major and minor complications between patients undergoing total knee arthroplasty (TKA) with general anesthesia, to those undergoing TKA with spinal or epidural anesthesia with or without regional nerve blocks. Patients 18 years and older undergoing TKA between the years of 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP). Patient demographics, anesthesia type, length of operation and hospital stay, as well as 30-day major and minor complications were collected from the database. Patients with “primary anesthesia technique” codes for either spinal or epidural anesthesia along with “other anesthesia technique” codes for regional anesthesia were assumed to have been given a regional nerve block. Chi square tests, and analysis of variance were utilized to evaluate unadjusted differences in demographics and outcomes between anesthesia types. Multivariable regression was utilized to compare outcomes (length of stay and complications) between anesthesia types, while adjusting for age, American Society of Anesthesiologist (ASA) class, comorbidities, sex, steroid/immunosuppressant use, body mass index (BMI), diabetes, length of operation and smoking status. A total of 214,665 TKA patients were identified (average age 67 ± 10 years). Of these, 257 (0.12%) underwent epidural anesthesia with a nerve block (EB), while 2,318 (1.08%) underwent epidural anesthesia with no block (E), 14,468 (1.08%) underwent spinal anesthesia with a block (SB), and 85,243 (39.7%) underwent spinal anesthesia with no block (S), and 112,377 (52.4%) underwent general anesthesia (G). The unadjusted length of stay (LOS) was significantly longer in the E group (3.67 ± 5 days) compared to the G group (3.1 ± 3.9 days), while the unadjusted LOS was significantly shorter in the EB group (2.6 ± 1.2), and both SB and S groups (2.6 ± 3 and 2.9 ± 3, respectively), compared to the G group p < 0 .001. Following covariable adjustment, anesthesia type remained an independent predictor of length of stay. Compared to the G group, patients in the E group stayed 0.56 days longer (95% Confidence interval [95%CI] 0.42 – 0.71 days), while patients in the SB were discharged 0.28 days (95%CI 0.21 – 0.35 days) earlier, and those in the S group were discharged 0.06 days earlier (95%CI 0.02–0.09), (p < 0 .0001). While the unadjusted rates of major complications were not significantly different between groups, the unadjusted rates of minor complications were higher in the E, EB, and G groups compared to the S and SB groups. Following covariable adjustment, there were no differences between groups in the risk of minor complications. In conclusion, these data indicate that anesthesia type following TKA is associated with length of hospital stay, but not with 30-day complications. After adjusting for relevant covariables, patients who received epidural anesthesia without a nerve block for TKA were discharged later, while patients who received spinal anesthesia, both with and without a nerve block for TKA were discharged earlier, compared to patients who received general anesthesia for TKA

Background. Standard preoperative protocols in total joint arthroplasty utilize the International Normalized Ratio (INR) to determine patient coagulation profiles. However, the relevance of preoperative INR values in joint arthroplasty remains controversial. Acceptable INR cutoff values for joint replacement are inconsistent, and are often based on studies of primary arthroplasty, or even non-orthopedic procedures. This analysis examined the relationship between preoperative INR values and post-operative outcomes in revision total hip arthroplasty (rTHA). Optimal cutoff INR values correlated with specific outcomes were subsequently determined. Methods. The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) was retrospectively queried for revision total hip arthroplasty procedures performed between 2006 and 2017. Patients with a preoperative INR collected no later than 1 day prior to surgery were further stratified for analysis. INR values which correlated with specific outcomes were determined using receiver operating characteristics (ROC) curves for each outcome of interest. The optimal cutoff INR value for each outcome was then obtained using univariate and multivariate models which determined INR values that maximized both sensitivity and specificity. Results. There were a total of 11,393 patients who underwent a revision total hip arthroplasty from 2006–2017 recorded in NSQIP. Of the 2,012 patients who met inclusion and exclusion criteria, 858 had an INR < 1.0, 931 had an INR > 1.0 to 1.25, 175 had an INR > 1.25 to 1.5, and 48 patients had an INR > 1.5. Patients with progressively higher INR values had a significantly different risk of mortality within 30 days (p=0.005), bleeding requiring transfusion (p< 0.001), sepsis (p=0.002), stroke (p<0.001), failure to wean from ventilator within 48 hours (p=0.001), readmission (p=0.01), and hospital length of stay (p< 0.001). Similar results were obtained when utilizing optimal INR cutoff values. When correcting for other factors, the following poor outcomes were significantly associated with the respective INR cutoff values (Estimate, 95% CI, p value): LOS (1.67, 1.34–2.08, p <0.001), bleeding requiring transfusion (1.65, 1.30–2.09, p<0.001), sepsis (2.15, 1.11–4.17, p 0.02), and any infection (1.82, 1.01–3.29, p 0.04). Conclusions. INR values >1.65, >1.67, >1.82, and >2.15 were correlated with increased transfusion requirements, LOS, any infection, and sepsis respectively. Therefore, even subtherapeutic elevations in INR may predict poor outcomes following revision total joint replacement. Surgeons and perioperative medical specialists should consider more stringent INR goals when optimizing patients prior to revision arthroplasty. Level of Evidence. Prognostic Level IV. For any figures or tables, please contact authors directly

Previous studies have indicated that prolonged surgical time may lead to higher rates of infection following total hip arthroplasty (THA). The purpose of this study was to evaluate the influence of surgical time on 30-day complications following THA and to determine if there was a time interval associated with worse outcomes. Patients ≥18 years who underwent THA between 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database using procedural codes. Patients with surgical durations >240 minutes were excluded. Patient demographics, operation length, and 30-day major and minor complications were ascertained. Multivariable regression was used to determine if the rate of complications differed depending on length of operation, while adjusting for relevant covariables, and to identify independent predictors of operation length. Covariables of interest included age, sex, American Society of Anaesthesiologists (ASA) class, smoking status, functional status, comorbidities, anesthesia type, and Body Mass Index (BMI). A total of 131,361 THA patients (average age 65 ±12 years) were identified from the database. Of these, 2,177 (1.64%) experienced a major complication, and 3,504 (2.64%) experienced a minor complication within 30-days of the initial procedure. Average operation length was 91.9 minutes (range 20 – 240 minutes). Independent predictors of prolonged operation length included overweight/obese BMI, male sex, cancer, dependent functional status, epidural anaesthetic, lower pre-operative hematocrit, and ASA class II, III or IV vs. I Alternatively, older age, current smoking, and spinal anaesthetic were associated with shorter surgical durations. Unadjusted rates of both major and minor complications were significantly higher for patients whose operation lengths were ≥ 120 minutes (P>0.001). Specifically, patients whose operations lasted ≥ 120 minutes had higher rates of septic shock, sepsis, pulmonary embolism (PE), deep vein thrombosis (DVT), urinary tract infection (UTI), renal insufficiency, surgical site infection(SSI) and wound disruption. After covariable adjustment, surgical durations of 90–119 minutes increased the risk of minor complications by 1.2 (95%Confidence interval [95%CI] 1.1–1.3), while surgical durations of 120–179 minutes increased the risk of major complications by 1.4 (95%CI 1.3 – 1.6), and minor complications by 1.4 (95%CI 1.2 – 1.5), and surgical durations ≥180 minutes increased the risk of major complications by 2.1 (95%CI 1.8 – 2.6), and minor complications by 1.9 (95%CI 1.6 – 2.3). There was no difference in the overall risk of complications for operation times lasting 20 – 39, 40 – 59, or 60 – 89 minutes (P>0.05). In terms of specific complications, operation length ≥90 minutes was determined to be an independent risk factor for deep and superficial incisional SSI, as well as wound disruption, while operation length ≥ 120 minutes was an independent risk factor for sepsis, UTI, and deep, non-incisional SSI and operation length ≥ 180 minutes was an independent risk factor for PE, DVT, and cardiac arrest (p < 0 .05). These data indicate that prolonged surgical durations may be an independent predictor of major and minor complications following THA. This suggests that quality improvements could be made to improve operating room efficiency and surgical times and therefore postoperative outcomes

Over 300,000 total hip arthroplasties (THA) are performed annually in the USA. Surgical Site Infections (SSI) are one of the most common complications and are associated with increased morbidity, mortality and cost. Risk factors for SSI include obesity, diabetes and smoking, but few studies have reported on the predictive value of pre-operative blood markers for SSI. The purpose of this study was to create a clinical prediction model for acute SSI (classified as either superficial, deep and overall) within 30 days of THA based on commonly ordered pre-operative lab markers and using data from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. All adult patients undergoing an elective unilateral THA for osteoarthritis from 2011–2016 were identified from the NSQIP database using Current Procedural Terminology (CPT) codes. Patients with active or chronic, local or systemic infection/sepsis or disseminated cancer were excluded. Multivariate logistic regression was used to determine coefficients, with manual stepwise reduction. Receiver Operating Characteristic (ROC) curves were also graphed. The SSI prediction model included the following covariates: body mass index (BMI) and sex, comorbidities such as congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), smoking, current/previous steroid use, as well as pre-operative blood markers, albumin, alkaline phosphate, blood urea nitrogen (BUN), creatinine, hematocrit, international normalized ratio (INR), platelets, prothrombin time (PT), sodium and white blood cell (WBC) levels. Since the data met logistic assumption requirements, bootstrap estimation was used to measure internal validity. The area under the ROC curve for final derivations along with McFadden's R-squared were utilized to compare prediction models. A total of 130,619 patients were included with the median age of patients at time of THA was 67 years (mean=66.6+11.6 years) with 44.8% (n=58,757) being male. A total of 1,561 (1.20%) patients had a superficial or deep SSI (overall SSI). Of all SSI, 45.1% (n=704) had a deep SSI and 55.4% (n=865) had a superficial SSI. The incidence of SSI occurring annually decreased from 1.44% in 2011 to 1.16% in 2016. Area under the ROC curve for the SSI prediction model was 0.79 and 0.78 for deep and superficial SSI, respectively and 0.71 for overall SSI. CHF had the largest effect size (Odds Ratio(OR)=2.88, 95% Confidence Interval (95%CI): 1.56 – 5.32) for overall SSI risk. Albumin (OR=0.44, 95% CI: 0.37 – 0.52, OR=0.31, 95% CI: 0.25 – 0.39, OR=0.48, 95% CI: 0.41 – 0.58) and sodium (OR=0.95, 95% CI: 0.93 – 0.97, OR=0.94, 95% CI: 0.91 – 0.97, OR=0.95, 95% CI: 0.93 – 0.98) levels were consistently significant in all clinical prediction models for superficial, deep and overall SSI, respectively. In terms of pre-operative blood markers, hypoalbuminemia and hyponatremia are both significant risk factors for superficial, deep and overall SSI. In this large NSQIP database study, we were able to create an SSI prediction model and identify risk factors for predicting acute superficial, deep and overall SSI after THA. To our knowledge, this is the first clinical model whereby pre-operative hyponatremia (in addition to hypoalbuminemia) levels have been predictive of SSI after THA. Although the model remains without external validation, it is a vital starting point for developing a risk prediction model for SSI and can help physicians mitigate risk factors for acute SSI post THA

Total knee arthroplasty (TKA) is the most commonly performed elective orthopaedic procedure. With an increasingly aging population, the number of TKAs performed is expected to be ∼2,900 per 100,000 by 2050. Surgical Site Infections (SSI) after TKA can have significant morbidity and mortality. The purpose of this study was to construct a risk prediction model for acute SSI (classified as either superficial, deep and overall) within 30 days of a TKA based on commonly ordered pre-operative blood markers and using audited administrative data from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. All adult patients undergoing an elective unilateral TKA for osteoarthritis from 2011–2016 were identified from the NSQIP database using Current Procedural Terminology (CPT) codes. Patients with active or chronic, local or systemic infection/sepsis or disseminated cancer were excluded. Multivariate logistic regression was conducted to estimate coefficients, with manual stepwise reduction to construct models. Bootstrap estimation was administered to measure internal validity. The SSI prediction model included the following co-variates: body mass index (BMI) and sex, comorbidities such as congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), smoking, current/previous steroid use, as well as pre-operative blood markers, albumin, alkaline phosphatase, blood urea nitrogen (BUN), creatinine, hematocrit, international normalized ratio (INR), platelets, prothrombin time (PT), sodium and white blood cell (WBC) levels. To compare clinical models, areas under the receiver operating characteristic (ROC) curves and McFadden's R-squared values were reported. The total number of patients undergoing TKA were 210,524 with a median age of 67 years (mean age of 66.6 + 9.6 years) and the majority being females (61.9%, N=130,314). A total of 1,674 patients (0.8%) had a SSI within 30 days of the index TKA, of which N=546 patients (33.2%) had a deep SSI and N=1,128 patients (67.4%) had a superficial SSI. The annual incidence rate of overall SSI decreased from 1.60% in 2011 to 0.68% in 2016. The final risk prediction model for SSI contained, smoking (OR=1.69, 95% CI: 1.31 – 2.18), previous/current steroid use (OR=1.66, 95% CI: 1.23 – 2.23), as well as the pre-operative lab markers, albumin (OR=0.46, 95% CI: 0.37 – 0.56), blood urea nitrogen (BUN, OR=1.01, 95% CI: 1 – 1.02), international normalized ratio (INR, OR=1.22, 95% CI:1.05 – 1.41), and sodium levels (OR=0.94, 95% CI: 0.91 – 0.98;). Area under the ROC curve for the final model of overall SSI was 0.64. Models for deep and superficial SSI had ROC areas of 0.68 and 0.63, respectively. Albumin (OR=0.46, 95% CI: 0.37 – 0.56, OR=0.33, 95% CI: 0.27 – 0.40, OR=0.75, 95% CI: 0.59 – 0.95) and sodium levels (OR=0.94, 95% CI: 0.91 – 0.98, OR=0.96, 95% CI: 0.93 – 0.99, OR=0.97, 95% CI: 0.96 – 0.99) levels were consistently significant in all prediction models for superficial, deep and overall SSI, respectively. Overall, hypoalbuminemia and hyponatremia are both significant risk factors for superficial, deep and overall SSI. To our knowledge, this is the first prediction model for acute SSI post TKA whereby hyponatremia (and hypoalbuminemia) are predictive of SSI. This prediction model can help fill an important gap for predicting risk factors for SSI after TKA and can help physicians better optimize patients prior to TKA

Hemorrhage and transfusion requirements in spine surgery are common. This is especially true for thoracic and lumbar fusion surgeries. The purpose of this papersi to determine predictive factors for transfusion and their effect on short-term post-operative outcomes for thoracic and lumbar fusions. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent lumbar or thoracic fusion surgery from 2010 to 2013. Univariate and multivariate regression analysis was used to determine predictive factors and post-operative complications associated with transfusion. A total of 14,249 patients were included in this study; 13,586 had lumbar fusion and 663 had thoracic fusion surgery. The prevalence of transfusion was 35% for thoracic fusion and 17.5% for lumbar fusion. The multivariate analysis showed that age between 50–60 (OR 1.38, CI: 1.23–1.54), age between 61–70 (OR 1.65, CI: 1.40–1.95), dyspnea (OR 1.11, CI: 1.02–1.23), hypertension (OR 1.14, CI: 1.02–1.27), ASA class (OR 1.73, 1.18–1.45), pre-operative blood transfusion (OR 1.91, CI: 1.04–3.49), and extended surgical time (OR 4.51, CI: 4.09–4.98) were predictors of blood transfusion requirements for lumbar fusion. While only pre-operative BUN (OR 1.04, CI: 1.01–1.06) and extended surgical time (OR 4.70, CI: 3.12–6.96) were predictors of transfusion for thoracic fusion. In contrast, higher pre-operative hematocrit was protective against transfusion. Patients transfused who underwent lumbar fusion had an increased risk to develop superficial wound infection, deep wound infection, venous thromboembolism, myocardial infarction and had longer length of hospital stay. Patients transfused who underwent thoracic fusion were more likely to have venous thromboembolism and extended length of hospital stay. However, mortality was not associated with blood transfusion. This study used a large database to characterise the incidence, predictors and post-operative complications associated with blood transfusion in thoracic and lumbar fusion surgeries. Pre- and post-operative planning for patients deemed to be at high-risk of requiring blood transfusion should be considered to reduce post-operative complication in this population

Cervical spine fusion have gained interest in the literature since these procedures are now ever more frequently being performed in an outpatient setting with few complications and acceptable results. The purpose of this study was to assess the rate of blood transfusion after cervical fusion surgery, and its effect, if any on complication rates. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent cervical fusion surgery from 2010 to 2013. Univariate and multivariate regression analysis was used to determine post-operative complications associated with transfusion and cervical fusion. We identified 11,588 patients who had cervical spine fusion between 2010 and 2013. The overall rate of transfusion was found to be 1.47%. All transfused patients were found to have increased risk of: venous thromboembolism (TBE) (OR 3.19, CI: 1.16–8.77), myocardial infarction (MI) (OR 9.12, CI: 2.53–32.8), increased length of stay (LOS) (OR 28.03, CI: 14.28–55.01) and mortality (OR 4.14, CI: 1.44–11.93). Single level fusion had increased risk of: TBE (OR 3.37, CI: 1.01–11.33), MI (OR 10.5, CI: 1.88–59.89), and LOS (OR 14.79, CI: 8.2–26.67). Multilevel fusion had increased risk of: TBE (OR 5.64, CI: 1.15–27.6), surgical site infection (OR 16.29, CI: 3.34–79.49), MI (OR 10.84, CI: 2.01–58.55), LOS (OR 26.56, CI: 11.8–59.78) and mortality (OR 10.24, CI: 2.45–42.71). ACDF surgery had an increased risk of: TBE (OR 4.87, CI: 1.04–22.82), surgical site infection (OR 9.73, CI: 2.14–44.1), MI (OR 9.88, CI: 1.87–52.2), LOS (OR 28.34, CI: 13.79–58.21) and mortality (OR 6.3, CI: 1.76–22.48). Posterior fusion surgery had increased risk of: MI (OR 10.45, CI: 1.42–77.12) and LOS (OR 4.42, CI: 2.68–7.29). Our results demonstrate that although cervical fusions can be done as outpatient procedures special precautions and investigations should be done for patients who receive transfusion after cervical fusion surgery. These patients are demonstrated to have higher rate of MI, DVT, wound infection and mortality when compared to those who do not receive transfusion

Computer assisted surgery (CAS) has gained popularity in orthopaedics for both total knee (TKA) and total hip arthroplasty (THA) in the past decades as a stereotactic device that provides the surgeon with real-time feedback on implant position based on electromagnetic or infrared based instruments. The purpose of this study was to assess the effect of CAS on 30-day complication rates following THA and TKA. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify all patients that underwent THA and TKA from 2011 to 2013, as well as any complication they had within 30-days of their surgery. Univariate and multivariate regression analysis was used to compare the post-operative complications in patients whose surgery involved the use of CAS with those by conventional surgical techniques. We identified 104,550 patients who had THA (42,275 patients) and TKA (62,275 patients) procedures in the database between 2011 and 2013. Computer Assisted Surgery was used in 1,120 THA and 2,173 TKA procedures. There were higher overall adverse events (OR 1.40, CI: 1.22–1.59) in the Conventional group when compared to CAS for TKA. The rate of overall minor events (OR 1.38, CI: 1.21–1.58) and requirements for blood transfusion (OR 1.44, CI: 1.25–1.67) were higher in the Conventional group compared to the CAS group for TKA. However, rate of re-operation was significantly higher in the CAS group for TKA (OR 1.60, CI: 1.15–2.25). The results also showed higher overall adverse events (OR 2.61, CI: 2.09–3.26) in the Conventional group when compared to CAS for THA. The rate of overall minor events (OR 2.72, CI: 2.16–3.42) and requirements for blood transfusion (OR 3.27, CI: 2.52–4.25) was higher in the Conventional group whereas superficial wound infections (OR 0.46, CI: 0.46–0.81) were shown to be higher in the CAS group. The result also showed slightly longer operative times in CAS for both THA and TKA. This study analysed a large patient database involving multiple institutions and surgeons and found that, overall, the use off CAS in primary total hip and total knee arthroplasty reduced the number of adverse events in the first 30-days postoperatively, compared to conventional surgical techniques. However, CAS was associated with an increased number of reoperations, superficial infections and operating time. The clinical benefits and disadvantages of CAS should be considered by arthroplasty surgeons when determining the potential benefit-cost ratio of this technology