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

The routine use of intraoperative vancomycin powder to prevent postoperative wound infections has not been borne out in the literature in the pediatric spine population. The goal of this study is to determine the impact of vancomycin powder on postoperative wound infection rates and determine its potential impact on microbiology. A retrospective analysis of the Harms Study Group database of 1269 adolescent idiopathic scoliosis patients was performed. Patients that underwent a posterior fusion from 2004-2018 were analyzed. A comparative analysis of postoperative infection rates was done between patients that received vancomycin powder to those who did not. Statistical significance was determined using Chi-squared test. Additionally, the microbiology of infected patients was examined. In total, 765 patients in the vancomycin group (VG) were compared to 504 patients in the non-vancomycin group (NVG). NVG had a significantly higher rate of deep wound infection (p<0.0001) and associated reoperation rate compared to VG (p<0.0001). Both groups were compared for age, gender, race, weight, surgical time, blood loss, number of levels instrumented, and preop curve magnitude. There were significant differences between the groups for race (p<0.0001); surgical time (p=0.0033), and blood loss (p=0.0021). In terms of microbiology, VG grew p.acnes (n=2), and serratia (n=1), whereas NVG grew p.acnes (n=1) and gram positive bacilli (n=1). The remaining cultures were negative. The use of intraoperative vancomycin powder in adolescent idiopathic scoliosis appears to contribute significantly to deep wound infection prevention and reduction of associated reoperations. Based on this study's limited culture data, Vancomycin does not seem to alter the microbiology of deep wound infections

Title. Longitudinal Intravital Imaging to Quantify the “Race for the Surface” Between Host Immune Cell and Bacteria for Orthopaedic Implants with S. aureus Colonization in a Murine Model. Aim. To assess S. aureus vs. host cell colonization of contaminated implants vis intravital multiphoton laser scanning microscopy (IV-MLSM) in a murine model. Method. All animal experiments were approved by IACUC. A flat stainless steel or titanium L-shaped pin was contaminated with 10. 5. CFU of a red fluorescent protein (RFP) expressing strain of USA300LAC, and surgically implanted through the femur of global GFP-transgenic mice. IV-MLSM was performed at 2, 4, and 6 hours post-op. Parallel cross-sectional CFU studies were performed to quantify the bacteria load on the implant at 2,4,6,12,18 and 24 hours. Results. 1) We developed a high-fidelity reproducible IV-MLSM system to quantify S. aureus and host cell colonization of a bone implant in the mouse femur. Proper placement of all implants were confirmed with in vivo X-rays, and ex vivo photos. We empirically derive the ROI during each imaging session by aggregating the imaged volume which ranges from (636.4um × 636.4um × 151um) = 0.625 +/- 0.014 mm. 3. of bone marrow in a global GFP-transgenic mouse. 2) IV-MLSM imaging acquisition of the “race for the surface”.In vitro MPLSM images of implants partially coated with USA300LAC (RFP-MRSA) were verified by SEM image. Results from IV-MLSM of RFP-MRSA and GFP. +. host cell colonization of the contaminated implants illustrated the mutually exclusive surface coating at 3hrs, which to our knowledge is the first demonstration of “the race for the surface” between bacteria and host cells via intravital microscopy. 3) Quantifying the “race for the surface” with CFU verification of S. aureus on the implant. 3D volumetric rendering of the GFP. +. voxels and RFP+ voxels within the ROI were generated in Imaris. The voxel numbers suggeste that the fight for the surface concludes ∼3hrs post-infection, and then transitions to an aggressive MRSA proliferation phase. The results of WT control demonstrate a significant increase in CFU by 12hrs post-op for both stainless steel (P<0.01) and titanium (P<0.01). Conclusions. We developed IV-MLSM to quantify the “Race for the Surface” between host cells and contaminating S. aureus in a murine femur implant model. This race is remarkably fast, as the implant surface is completely covered with 3hrs, peak bacterial growth on the implant occurs between 2 and 12 hours and is complete by 12hrs

Most patients treated at our clinical setting present during chronic osteomyelitis stage, which is anecdotally likely to be poly-microbial. Adults with poly-microbial infection have a predilection for gram-negative bacteria and anaerobes, a scenario that hypothetically leads to a higher morbidity of poly-microbial osteomyelitis following trauma. Our study looks into the epidemiology of poly-microbial osteomyelitis treated at our Tumour and Infection unit. Retrospective study of patients treated for osteomyelitis from 2016 to 2020. Records of eligible patients were retrieved for examination. Demographics such as age, sex and race were recorded. Clinical presentation, organisms cultured, including their anti-microbial sensitivities were documented. There were 63 participants in the study. 31 (49.21%) had mono-microbial osteomyelitis with 32 (50.79%) having poly-microbial osteomyelitis. Majority of the poly-microbial patients presented with a sinus (68.75%) mostly located in the tibia (50%). Multiple mixed pathogens (both gam-positive and gram-negative) were cultured in our patients and this comprised 71.21% of the total bacteria cultured. Staphylococcus Aureus was the commonest bacteria (30%) isolated, followed by Enterococcus faecalis (12%). The commonest gram-negative bacteriae cultured was Enterococcus cloacae (10%) followed by Acinetobacter baumannii (7%). Most enterobacteriacae species were sensitive to Ertapenem and Ceftazidime. A slightly higher incidence of poly-microbial osteomyelitis was found in our study than that reported in literature. Furthermore, our study demonstrated a wide variety of organisms found in poly-microbial osteomyelitis, with a large contribution made by gram-negative anaerobic rod-shaped bacteria

INTRODUCTION. Utilization of a patient management support system in our clinical pathway has been successfully demonstrated to both reduce the length of hospital stay after primary THA, as well as reducing the number of hospital readmissions. While successful in a general patient population, the ability of a patient management support system to reduce readmissions in subsets of high risk THA patients has not been evaluated. METHODS. We identified all primary THAs performed at a single institution between 2013 and 2015. Patient sex, age at the time of surgery, race, ASA grade, and 120-day readmissions were retrieved from the patient medical record. Similar to previous studies, the patient's home address was used as a proxy for socioeconomic status, with the estimated median income of a given patient being estimated as the median household income for patients of similar ethnicity living within their zip code as reported in the 2014 U.S. Census. A binary regression was used to determine if a model of patient factors (age, sex, race, socioeconomic status, and/or ASA grade) could accurately predict 120-day readmission after primary THA. Age and socioeconomic status were treated as a continuous variable and all other factors were categorical in nature, and the individual effects of each categorical factor on readmissions were also assessed. RESULTS. A sample of 889 primary THAs was identified using the above criteria, of which 754 (84.8%) were Caucasian and 124 (13.9%) were African Americans. Eleven patients (1.2%) either self-reported a different race or race was unknown. Due to the small number of patients in the other/unknown group, this subset was not included in our analysis. With the remaining sample of 878 THAs (475 females, 403 males; age 62.1 ± 13.0 years), a model containing age, sex, race, socioeconomic status, and ASA grade was unable to accurately predict the need for hospital readmission (R2 = 0.02). When assessed individually, the rates of hospital readmission did not differ by sex or race; however, those with ASA grades I or II had significantly lower readmission rates than patients with ASA grades III or IV (Table 1). DISCUSSION AND CONCLUSION. Despite a comprehensive program, the risk of readmission for patients with greater comorbidity burdens was double that of patients with low ASA grades

In addition to mechanical stresses, an inflammatory mediated association between obesity and knee osteoarthritis (OA) is increasingly being recognised. Adipokines, such as adiponectin and leptin, have been postulated as likely mediators. Clinical and epidemiological differences in OA by race have been reported. What contributes to these differences is not well understood. In this study, we examined the profile of adipokines in knee synovial fluid (SF) and the gene expression profile of the infra-patellar fat pad (IFP) by race among patients with end-stage knee OA scheduled for knee arthroplasty. Age, sex, weight and height (used to derive body mass index (BMI)) and race (White, Asian and Black) were elicited through self-report questionnaire prior to surgery. SF and IFP samples were collected at the time of surgery. Adipokines (adiponectin and leptin) were examined in the SF using MAGPIX Multiplex platform. IFP was profiled using Human Adipogenesis PCRArray and genes of interest were further validated via quantitative relative RT-PCR using Student's t-test. Overall differences in adiponectin and leptin concentrations were tested across race. Linear regression modeling was used to investigate the association between adiponectin and leptin concentrations (outcomes) and race (predictor; referent group: White), adjusting for age, sex and BMI. 67 patients (18 White, 33 Asian, 16 Black) were included. Mean SF adiponectin concentration was greatest in Whites (1175.05 ng/mL), followed by Blacks (868.53 ng/mL) and Asians (702.23 ng/mL) (p=0.034). The mean SF leptin concentration was highest in Blacks (44.88 ng/mL), followed by Whites (29.86 ng/mL) and Asians (20.18 ng/mL) (p=0.021). Regression analysis showed Asians had significantly lower adiponectin concentrations compared to Whites (p<0.05). However, leptin concentrations did not differ significantly by race after adjusting for covariates. Testing of the IFP, using the Adipogenesis PCRArray, showed significant higher expression of LEP gene (leptin, p=0.03) in Asians (n=4) compared to Whites (n=4). There appears to be important racial differences in the SF adiponectin profile among individuals with end-stage knee OA. Differential gene expression in the IFP across racial groups could be a potential contributory source for the noted SF variations. Further work to determine the source and function of adipokines in knee OA pathophysiology across racial groups is warranted

This study documents the gross and histologic structure of the infrapatellar plica, and fat pad, and adds to an earlier report to the COA. The important new findings are that the femoral attachment of the plica is an enthesis, and that the plica itself is.

This study seeks to demonstrate that the structure of the fat pad (FP) and infrapatellar plica (IPP) is that of an enthesis organ.

Twelve fresh frozen cadaver knees, each with an IPP, were dissected and the gross anatomic features recorded. The IPP and FP were harvested for study. Representative histologic sections were prepared on tissue fixed in 10% neutral buffered formalin, embedded in paraffin, cut at 4 microns on a rotatory microtome. Staining techniques included hematoxylin and eosin, Masson's trichrome, elastic stain and S100. Appropriate decalcification of sections of the femoral insertion of the IPP was performed. All sections were examined by light microscopy at low, medium and high power. IPP types included 8 separate, 1 split, 2 fenestrated, and one vertical septum. The origin of the IPP is a fibrous arc arising from the apex of the notch separate from the margin of the articular cartilage. This attachment site is the instant centreof rotation of the IPP and FP; they are thus not isometric. The central zone of the IPP consists of a mix of connective tissue types.

Representative sections taken of the femoral attachment of the IPP display a transition zone between dense fibrillar collagen of the IPP, then fibrocartilage and cortical bone similar to a ligament attachment site or enthesis. The central plica histology is composed predominantly of dense regular connective tissue with variable clear space between the collagen bundles, and is thus ligamentous. There is abundant elastase staining throughout, as well as crimping of the collagen suggesting capacity for stretch. S100 staining demonstrates nerves around and in the substance of the IPP. The central body shows lobulated collections of mature adipose tissue admixed with loose connective tissue, containing abundant small peripheral nerves and vessels (all showing crimping and redundancy), merging with the dense fibrous tissue of the IPP. The FP is highly innervated, deformable, and fibro-fatty. Its histology shows lobules of fat, separated by connective tissue septa, which merge with the synovial areolar membrane surrounding the FP.

The linked structures, IPP, central body, and FP occupy the anterior compartment, and function as an enthesis organ: the IPP tethers the FP via the central body and together they rotate around the femoral origin of the IPP. They are not isometric, and must stretch and relax with knee motion. The histology correlates with this requirement. The origin of the IPP is an enthesis, a new observation. Elastase staining, redundancy of vessels and nerves, crimping and redundancy of the dense connective tissue all reflect the requirement to deform. The fat pad merges with the central body, both highly innervated space fillers, tethered by the IPP, which is a non-isometric ligament, also containing nerves. The important clinical significance of these structures is that release of the IPP at the origin reuces or eliminates anterior knee pain in most.

Purpose

Anterior knee pain has been relieved by resection of the infrapatellar plica (IPP). The question is: How? The hypothesis is: the IPP acts as an intra-articular ligament, a mechanical link between the forces of knee motion, the fat pad (FP) and the distal femur, holding the FP captive through the arc of motion. Release of the IPP severs this link, allowing the highly innervated FP to move freely. This may allow any underlying pathologic process to heal.

Perioperative glucocorticoids have been used as a successful non-opioid analgesic adjunct for various orthopaedic procedures. Here we describe an ongoing randomized control trial assessing the efficacy of a post-operative methylprednisolone taper course on immediate post-operative pain and function following surgical distal radius fixation. We hypothesize that a post-operative methylprednisolone taper course following distal radius fracture fixation will lead to improved patient pain and function. This study is a randomized control trial (NCT03661645) of a group of patients treated surgically for distal radius fractures. Patients were randomly assigned at the time of surgery to receive intraoperative dexamethasone only or intraoperative dexamethasone followed by a 6-day oral methylprednisolone (Medrol) taper course. All patients received the same standardized perioperative pain management protocol. A pain journal was used to record visual analog pain scores (VAS-pain), VAS-nausea, and number of opioid tablets consumed during the first 7 post-operative days (POD). Patients were seen at 2-weeks, 6-weeks, and 12-weeks post-operatively for clinical evaluation and collection of patient reported outcomes (Disabilities of the Arm, Shoulder and Hand Score [qDASH]). Differences in categorical variables were assessed with χ2 or Fischer's exact tests. T-tests or Mann-Whitney-U tests were used to compare continuous data. Forty-three patients were enrolled from October 2018 to October 2019. 20 patients have been assigned to the control group and 23 patients have been assigned to the treatment group. There were no differences in age (p=0.7259), Body Mass Index (p=0.361), race (p=0.5605), smoking status (p=0.0844), or pre-operative narcotic use (p=0.2276) between cohorts. 83.7% (n=36) of patients were female and the median age was 56.9 years. No differences were seen in pre-operative qDASH (p=0.2359) or pre-operative PRWE (p=0.2329) between groups. In the 7 days following surgery, patients in the control group took an average of 16.3 (±12.02) opioid tablets, while those in the treatment group took an average of 8.71 (±7.61) tablets (p=0.0270). We see that significant difference in Opioid consumption is formed at postoperative day two between the two groups with patients in the control group taking. Patient pain scores decreased uniformly in both groups to post-operative day 7. Patient pain was not statistically from POD0 to POD2 (p=0.0662 to 0.2923). However, from POD4 to POD7 patients receiving the methylprednisolone taper course reported decreased pain (p=0.0021 to 0.0497). There was no difference in qDASH score improvement at 6 or 12 weeks. Additionally, no differences were seen for wrist motion improvement at 6 or 12 weeks. A methylprednisolone taper course shows promise in reducing acute pain in the immediate post-operative period following distal radius fixation. Furthermore, although no statistically significant reductions in post-operative opioid utilization were noted, current trends may become statistically significant as the study continues. No improvements were seen in wrist motion or qDASH and continued enrollment of patients in this clinical trial will further elucidate the role of methylprednisolone for these outcomes

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

INTRODUCTION

Immediate post-operative stability of a cementless hip design is one of the key factors for osseointegration and therefore long-term success [1]. This study compared the initial stability of a novel, shortened, hip stem to a predicate standard tapered wedge stem design with good, long-term, clinical history. The novel stem is a shortened, flat tapered wedge stem design with a shape that was based on a bone morphology study of 556 CT scans to better fit a wide array of bone types [2].

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

Introduction. Total knee arthroplasty is very successful although the clinical assessment and rated outcome does not always match the patients reported satisfaction. One reason for patient dissatisfaction is less than desired range of motion. Poor postoperative motion inhibits many functional activities and may create a perception of dysfunction. Early in the postoperative period when patients are having trouble regaining motion (usually 6–8 weeks), manipulation under anesthesia can be used to advance range of motion by manually lysing adhesions. Comorbidities have been used as predictors for outcome in total knee arthroplasty in population health studies. Likewise, predicting which patients are most susceptible to early postoperative stiffness/manipulation would be valuable for patient education and to predict outcome. Methods. Prospectively collected data was retrieved from the hospital's MARCQI database (Michigan Arthroplasty Collaborative Quality Initiative) for the years 2014–2018. There were 3098 primary total knees performed during the study period and 139 manipulations (4.44%). The registry specifically abstracts patients’ preoperative comorbidities, operative data, and 90-day postoperative complications. Results. There were 2118 Cruciate Retaining/Cruciate Stabilized knees (105 MUA), 801 Posterior Stabilized (33), and 41 Total Stabilized/Hinge (1), 2160 knees were cemented (91) and 799 uncemented (48). No differences were found between the manipulation and non-manipulation groups for gender, race, alcohol consumption, bleeding disorders, history of DVT or PE, Diabetes, or use of pre-op narcotics or anti-coagulents. Patients undergoing manipulation were younger (67.2 vs. 63.8, p= 0.00001), had a lower BMI (32.6 vs. 30.9 p= 0.0007), and were more likely to be non or former (quit) smokers. There were no differences noted for the constraint of the component (cr/ps), or whether the implants were cemented or uncemented (35% vs. 27%, p= 0.064). Conclusions. Understanding the risk for postoperative stiffness and the potential for manipulation is helpful in the preoperative period for patient education and outcome prediction. Assessing comorbidities and patient characteristics may help avoid the need for manipulations postoperatively. This patient cohort may be biased since the manipulations were not based on predetermined criteria. The cohort represents patients whose range of motion was poor enough to cause the surgeon to perform the procedure. The findings do however highlight a patient pool that was surprisingly at risk: younger, thinner, nonsmokers regardless the implant design or use of cement

Background. The advent of value-based conscientiousness and rapid-recovery discharge pathways presents surgeons, hospitals, and payers with the challenge of providing the same total hip arthroplasty episode of care in the safest and most economic fashion for the same fee, despite patient differences. Various predictive analytic techniques have been applied to medical risk models, such as sepsis risk scores, but none have been applied or validated to the elective primary total hip arthroplasty (THA) setting for key payment-based metrics. The objective of this study was to develop and validate a predictive machine learning model using preoperative patient demographics for length of stay (LOS) after primary THA as the first step in identifying a patient-specific payment model (PSPM). Methods. Using 229,945 patients undergoing primary THA for osteoarthritis from an administrative database between 2009– 16, we created a naïve Bayesian model to forecast LOS after primary THA using a 3:2 split in which 60% of the available patient data “built” the algorithm and the remaining 40% of patients were used for “testing.” This process was iterated five times for algorithm refinement, and model performance was determined using the area under the receiver operating characteristic curve (AUC), percent accuracy, and positive predictive value. LOS was either grouped as 1–5 days or greater than 5 days. Results. The machine learning model algorithm required age, race, gender, and two comorbidity scores (“risk of illness” and “risk of morbidity”) to demonstrate excellent validity, reliability, and responsiveness with an AUC of 0.87 after five iterations. Hospital stays of greater than 5 days for THA were most associated with increased risk of illness and risk of comorbidity scores during admission compared to 1–5 days of stay. Conclusions. Our machine learning model derived from administrative big data demonstrated excellent validity, reliability, and responsiveness after primary THA while accurately predicting LOS and identifying two comorbidity scores as key value-based metrics. Predictive data has the potential to engender a risk-based PSPM prior to primary THA and other elective orthopaedic procedures

Aims

This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures.

Aim. The aim of this study was to compare outcomes between patients with diabetic foot soft-tissue infection and osteomyelitis. Methods. Medical records of patients with diabetic foot infection involving either soft-tissue (STI) or bone (OM) were retrospectively reviewed. Diagnosis was determined by bone culture, bone histopathology or imaging with magnetic resonance imaging (MRI) or single-photon emission computed tomography (SPECT/CT). Patient outcomes were recorded up to 1 year after admission. Results. Out of 294 patients included in the study, 137 were diagnosed with STI and 157 had OM. No differences in age (p=.40), sex (p=.79), race (p=.83), body-mass index (p=.79) or type of diabetes (p=.77) were appreciated between groups. Frequency of comorbidities (neuropathy, chronic kidney disease, peripheral arterial disease) also did not differ except for increased prevalence of cardiac disease in patients with STI (86.9%) compared to those with OM (31.8%) (p<.00001) and decreased prevalence of retinopathy (24.8% vs. 35.7%) (p=.04). Patients with OM had greater C-reactive protein (p<.00001), erythrocyte sedimentation rate (p<.00001) and white blood cell count (p<.00001). Among 1-year outcomes, patients with OM more often underwent surgery (p<.00001), had lower limb amputations (p<.00001), became reinfected (p=.0007), were readmitted for the initial problem (p=.008), had longer time to healing (p=.03) and had longer hospital length of stay (p=.00002). However, no differences in 1-year mortality (p=1.000), overall 1-year readmission (p=.06) or healing within 1-year (p=.64) were appreciated. Conclusion. In our study, OM was associated with more aggressive treatment, reinfection and longer time to healing than STI. However, despite being associated with more aggressive care and readmissions, patients with diabetic foot OM has similar 1-year mortality and healing rates to those with diabetic foot STI

Background. Non-invasive hemoglobin measurement was introduced to potentially eliminate blood draws postoperatively. We compared the accuracy and effectiveness of a non-invasive hemoglobin measurement system with a traditional blood draw in patients undergoing total joint arthroplasty. Methods. After IRB approval, 100 consecutive patients undergoing primary total hip or knee arthroplasty had their hemoglobin level tested by both traditional blood draw and a non-invasive hemoglobin monitoring system. Results were analyzed for the entire group, further stratifying patients based on gender, race, surgery (THA versus TKA), and post-operative hemoglobin level. Finally, we compared financial implications and patient satisfaction with the device. Paired t-test with 0.05 conferring significance was used. Stratified analyses of the absolute difference between the two measures were assessed using Mann- Whitney test. To assess the level of agreement between the two measures, the concordance correlation coefficient (CCC) was calculated. Results. Mean blood-draw hemoglobin value on POD1 was 11.063 ± 1.39 g/dL and 11.192 ± 1.333 g/dL with the non-invasive device. For all patients, the mean absolute difference between the two methods was 0.13 g/dL (p = 0.30). The CCC between the two methods was 0.58, conferring a moderate to strongly positive linear relationship (Figure 1). Non-invasive measurement was preferred by 100% of patients with a mean VAS score of 0/10. Additionally, the cost savings with the non-invasive system was $16.50 per patient. Discussion. Overall, there was no significant difference between the hemoglobin level obtained by traditional laboratory methods versus the Masimo Radical-7 system on post-operative day #1 in patients who underwent total joint arthroplasty. In the minority of patients (19%) who had a hemoglobin level of less than 10 g/dL, the difference between the two methods was statistically significant. Additionally, 100% of patients preferred the Masimo device to a traditional blood draw and the Masimo device was substantially cheaper. While further investigation of non-invasive hemoglobin monitoring systems is necessary, particularly in patients with a post-operative hemoglobin of less than 10 g/dL, our study shows that the Masimo Radical-7 device provides an accurate, preferable, and less expensive alternative to a traditional blood draw after total joint replacement. Conclusion. Overall, the non-invasive hemoglobin monitoring system offered a similar hemoglobin reading to the standard lab-draw reading, while improving satisfaction and lowering cost. The system relies on adequate perfusion for measurement, and our study demonstrated that lower hemoglobin values may reduce finger-tip perfusion and affect the hemoglobin reading

Background. Inpatient dislocation after total hip arthroplasty (THA) is considered a non-reimbursable “never event” by the Centers for Medicare and Medicaid Services. There is extensive evidence that technical procedural factors affect dislocation risk, but less is known about the influence of non-technical factors. We evaluated inpatient dislocation trends following elective primary THA, and identified patient and hospital characteristics associated with the occurrence of dislocation. Methods. We used discharge records from the Nationwide Inpatient Sample (2002–2011). Temporal trends were assessed and multivariable logistic regression modeling was used to identify factors associated with dislocation. Results. The in-hospital dislocation rate increased from 0.025% in 2002 to 0.15% in 2011, despite a downward trend in length of stay (P<0.001). Patient characteristics associated with the occurrence of dislocation were black or Hispanic race/ethnicity, lower household income, and Medicaid insurance. Comorbidities associated with dislocation included hemiparesis/hemiplegia, drug use disorder, chronic renal failure, psychosis, and obesity. Dislocations were less likely to occur at teaching hospitals and in the South. Conclusion. The in-hospital dislocation rate following elective primary THA is increasing, in spite of shorter stays and surgical advances over time. Given the sociodemographic disparities in dislocation risk documented herein, interventions to address social determinants of health might do as much or more to reduce the occurrence of dislocation than technical improvements

INTRODUCTION. Early discharge after total joint arthroplasty has started to gain acceptance in select academic centers. The purpose of this study was to compare the risk of readmission of Medicare patients discharged one day after total knee arthroplasty (TKA), versus those discharged two or three days after surgery. Our hypothesis was that patients with length of stay (LOS) of one day would not have a higher risk of readmission in a community setting. METHODS. A hospital impatient database was queried for all unilateral, primary total knee replacements performed on patients 65 years or older from January 1, 2013 to December 31, 2014. A total of 1,117 patients discharged the day after TKA (reduced LOS) were compared with 947 patients discharged POD #2 or 3 (traditional LOS). All cases were performed at a community-based joint replacement center with rapid recovery protocols. Discharge timing and disposition were based on established functional benchmarks judged by physical therapy. The main outcome measure was all-cause 30-day readmissions. Multivariate logistic regression was used to calculate odds ratio for all cause 30-day readmission for reduced versus traditional LOS while controlling for age, gender, race, diabetes mellitus, ASA score (less than 3 versus 3 or greater), discharge disposition (home versus rehab). RESULTS. The 30-day readmission rate for the reduced LOS group was 1.2%, as compared to 3.4% readmission rate for the traditional LOS group (p=.001). In the regression model, the traditional LOS group had an increased risk of readmission (odds ratio 2.10, 95% CI 1.02–4.35, p=0.045) when controlling for confounding factors. DISCUSSION AND CONCLUSIONS. Medicare patients can be discharged safely the day after total knee arthroplasty with no increased risk of 30-day readmission in a community medical center

Aims

The purpose of this survey study was to examine the demographic and lifestyle factors of women currently in orthopaedic surgery.