Insulin Dependence Increases the Risk of Complications and Death in Total Joint Arthroplasty: A Systematic Review and Meta-(Regression) Analysis.

OBJECTIVES: To investigate the proportion of insulin-dependent diabetes mellitus (IDDM) patients among diabetic patients undergoing total joint arthroplasty (TJA) and whether insulin dependence is associated with postoperative complications. METHODS: A systematic literature search was performed in EMBASE, PubMed, Ovid, Medline, the Cochrane Library, Web of Science, the China Science and Technology Journal Database, and China National Knowledge Infrastructure from the inception dates to 10 September 2019. Observational studies reporting adverse events with IDDM following TJA were included. Primary outcomes were cardiovascular complications, pulmonary complications, kidney complications, wound complications, infection, and other complications within 30 days of surgery. Secondary outcomes were the proportion of IDDM patients among diabetic patients undergoing TJA and its time trend. RESULTS: A total of 19 studies involving 85,689 participants were included. Among patients undergoing TJA, 26% of diabetic patients had IDDM. Compared with non-insulin-dependent diabetes (NIDDM), the incidences of cardiac arrest (risk ratio [RR], 2.346; 95% confidence interval [CI], 1.553 to 3.546), renal failure (relative risk [RR], 2.758; 95% CI, 1.830 to 4.156), deep incisional surgical site infection (RR, 1.968; 95% CI, 1.107 to 3.533), wound dehiscence (RR, 2.209; 95% CI, 1.830 to 4.156), and death (RR, 2.292; 95% CI, 1.568 to 3.349) were all significantly increased in IDDM. A significant time trend was witnessed for the prevalence of IDDM (P = 0.014). There was no statistical significance for organ/space surgical site infection, thrombotic events (deep venous thrombosis/ pulmonary embolism), and revision rates. CONCLUSION: Insulin-dependent diabetes is an independent high-risk factor for increased adverse outcomes relative to NIDDM, suggesting that hierarchical and optimal blood glucose management may contribute to reducing the adverse complications after surgery for these patients. In addition, because the risk of sepsis, deep wound infection, organ/space surgical site infection, urinary tract infection, renal insufficiency, and renal failure significantly increase after TJA in IDDM patients, more active postoperative antimicrobial prophylaxis may be needed on the premise of protecting renal function.

What Is the Implant Survivorship and Functional Outcome After Total Humeral Replacement in Patients with Primary Bone Tumors?

BACKGROUND: Total humeral replacement is an option to reconstruct massive bone defects after resection of locally advanced bone tumors of the humerus. However, implant survivorship, potential risk factors for implant revision surgery, and functional results of total humeral replacement are poorly elucidated because of the rarity of the procedure. QUESTIONS/PURPOSES: We asked: (1) What is the revision-free implant and overall limb survivorship after total humerus replacement? (2) What factors are associated with implant revision surgery? (3) What is the functional outcome of the procedure as determined by the Musculoskeletal Tumor Society (MSTS) score and the American Shoulder and Elbow Surgeons (ASES) score? METHODS: Between August 1999 and December 2018, 666 patients underwent megaprosthetic reconstruction after resection of a primary malignant or locally aggressive/rarely metastasizing tumor of the long bones at our department. In all, 23% (154) of these patients had a primary tumor located in the humerus. During the study, we performed total humeral replacement in all patients with a locally advanced sarcoma, in patients with pathological fractures, in patients with skip metastases, or in patients with previous intralesional contaminating surgery, who would have no sufficient bone stock for a stable implant fixation for a single joint megaprosthetic replacement of the proximal or distal humerus. We performed no biological reconstructions or reconstructions with allograft-prosthetic composites. As a result, 5% (33 of 666) of patients underwent total humerus replacement. Six percent (2 of 33) of patients were excluded because they received a custom-made, three-dimensionally (3-D) printed hemiprosthesis, leaving 5% (31) of the initial 666 patients for inclusion in our retrospective analysis. Of these, 6% (2 of 31) had surgery more than 5 years ago, but they had not been seen in the last 5 years. Median (interquartile range) age at the time of surgery was 15 years (14 to 25 years), and indications for total humeral replacement were primary malignant bone tumors (n = 30) and a recurring, rarely metastasizing bone tumor (n = 1). All megaprosthetic reconstructions were performed with a single modular system. The implanted prostheses were silver-coated beginning in 2006, and beginning in 2010, a reverse proximal humerus component was used when appropriate. We analyzed endoprosthetic complications descriptively and assessed the functional outcome of all surviving patients who did not undergo secondary amputation using the 1993 MSTS score and the ASES score. The median (IQR) follow-up in all survivors was 75 months (50 to 122 months), with a minimum follow-up period of 25 months. We evaluated the following factors for possible association with implant revision surgery: age, BMI, reconstruction length, duration of surgery, extraarticular resection, pathological fracture, previous intralesional surgery, (neo-)adjuvant radio- and chemotherapy, and metastatic disease. RESULTS: The revision-free implant survivorship at 1 year was 77% (95% confidence interval 58% to 89%) and 74% (95% CI 55% to 86%) at 5 years. The overall limb survivorship was 93% (95% CI 75% to 98%) after 1 and after 5 years. We found revision-free survivorship to be lower in patients with extraarticular shoulder resection compared with intraarticular resections (50% [95% CI 21% to 74%] versus 89% [95% CI 64% to 97%]) after 5 years (subhazard ratios for extraarticular resections 4.4 [95% CI 1.2 to 16.5]; p = 0.03). With the number of patients available for our analysis, we could not detect a difference in revision-free survivorship at 5 years between patients who underwent postoperative radiotherapy (40% [95% CI 5% to 75%]) and patients who did not (81% [95% CI 60% to 92%]; p = 0.09). The median (IQR) MSTS score in 9 of 13 surviving patients after a median follow-up of 75 months (51 to 148 months) was 87% (67% to 92%), and the median ASES score was 83 (63 to 89) of 100 points, with higher scores representing better function. CONCLUSION: Total humeral replacement after resection of locally advanced bone tumors appears to be associated with a good functional outcome in patients who do not die of their tumors, which in our study was approximately one- third of those who were treated with a resection and total humerus prosthesis. However, the probability of early prosthetic revision surgery is high, especially in patients undergoing extraarticular resections, who should be counseled accordingly. Still, our results suggest that if the prosthesis survives the first year, further risk for revision appears to be low. Future studies should reexamine the effect of postoperative radiotherapy on implant survival in a larger cohort and evaluate whether the use of soft tissue coverage with plastic reconstructive surgery might decrease the risk of early revisions, especially in patients undergoing extraarticular resections. LEVEL OF EVIDENCE: Level III, therapeutic study.

Short-term mortality after primary and revision total joint arthroplasty: a single-center analysis of 103,560 patients.

INTRODUCTION: The demand for total joint arthroplasty (TJA) is increasing worldwide with excellent long-term results. In general, TJA provides several benefits to the patients but also causes possible complications. The aim of our study was to describe trends in mortality after TJA in a high-volume arthroplasty center, and to examine the potential risk factors. METHODS: From 1996 to 2018, a total of 103,560 patients (73,130 primary cases, 30,430 revision cases) underwent a TJA procedure in our institution. Anthropometric parameters, Charlson Comorbidity Index (CCI), pre- and postoperative hemoglobin (Hb), blood loss during surgery, postoperative complication (such as infection, deep vein thrombosis, pulmonary embolism, etc.) and cause of death from all patients who deceased during hospitalization were collected. The short-term mortality rate was analyzed between the primary and the revision groups. RESULTS: The short-term mortality rate within our investigated groups was low with 0.041% in primary THA, 0.299% in revision THA, 0.045% in primary TKA, 0.205% in revision TKA, 0.214% in TSA/RSA, 0.15 % in primary TAA and 0% after TEA. Significant differences were found for preoperative Hb-values in patients undergoing septic revision (10.7 g/dl) compared to patients undergoing aseptic revision (12.8 g/dl) or primary arthroplasty (13.6 g/dl) (p < 0.001). Furthermore, we found significant differences regarding CCI between the groups. The comparison between causes of death (COD) showed a significantly higher number for pulmonary embolisms in the aseptic groups, while septic shock was the leading COD in the septic group and myocardial infarction as COD was found significantly more often after primary TJA. CONCLUSION: This is the largest single-center study presenting the short-term mortality rate following TJA. Consequently, TJA is a safe procedure with a low short-term mortality rate. However, depending on the type of surgery, certain risk factors cannot be eliminated. In order to further reduce the mortality, procedures as such should continue to be performed at specialized centers under standardized conditions.

What Are the Frequency, Related Mortality, and Factors Associated with Bone Cement Implantation Syndrome in Arthroplasty Surgery?

BACKGROUND: Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, and the loss of consciousness during cemented arthroplasty; it may result in death. Its incidence has only been explored for hemiarthroplasty and THA after fracture or cancer. To our knowledge, there are no studies that comprehensively explore and compare the incidence of BCIS in other arthroplasty procedures. QUESTIONS/PURPOSES: (1) To report the incidence of BCIS in TKA, unicondylar knee arthroplasty, hip hemiarthroplasty, THA, shoulder arthroplasty, TKA, and revision THA and TKA; (2) to determine whether severe BCIS is associated with an increased risk of death within 30 days of surgery; and (3) to identify factors associated with the development of severe BCIS. METHODS: All patients undergoing cemented arthroplasty for any reason (TKA [11% cemented, 766 of 7293], unicondylar knee arthroplasty [100% cemented, 562 procedures], hip hemiarthroplasty for femur fractures [100% cemented, 969 procedures], THA [8% cemented, 683 of 8447], shoulder arthroplasty [84% cemented, 185 of 219], and revision arthroplasty of the hip and knee [36% cemented, 240 of 660]) between January 2008 and August 2019 were considered for inclusion in the current retrospective observational study. Fixation choice was dependent on surgeon preference (THA and TKA), prosthesis design (shoulder arthroplasty), or bone quality (revision arthroplasty). The following procedures were excluded because of insufficient data: < 1% (1 of 766) of TKAs, 1% (4 of 562) of unicondylar knee arthroplasties, 6% (54 of 969) of hip hemiarthroplasties, 1% (6 of 683) of THAs, 6% (12 of 185) of shoulder arthroplasties, and 14% (34 of 240) of revision procedures. This resulted in a final inclusion of 3294 procedures (765 TKAs [23%], 558 unicondylar knee arthroplasties [17%], 915 hip hemiarthroplasties [28%], 677 THA [21%], 173 shoulder arthroplasties [5%], and 206 revision arthroplasties [6%]), of which 28% (930 of 3294) had an emergent indication for surgery. Of the patients, 68% (2240 of 3294) were females, with a mean age of 75 ± 11 years. All anesthetic records were extracted from our hospital's database, and the severity of BCIS was retrospectively scored (Grade 0 [no BCIS], Grade 1 [O2% < 94% or fall in systolic blood pressure of 20% to 40%], Grade 2 [O2% < 88% or fall in systolic blood pressure of > 40%], and Grade 3 [cardiovascular collapse requiring CPR]). Procedures were dichotomized into no or moderate BCIS (Grades 0 and 1) and severe BCIS (Grades 2 and 3). The adjusted 30-day mortality of patients with severe BCIS was assessed with a multivariate Cox regression analysis. A multivariate logistic regression analysis was performed to identify factors associated with the development of severe BCIS. RESULTS: BCIS occurred in 26% (845 of 3294) of arthoplasty procedures. The incidence was 31% (282 of 915) in hip hemiarthroplasty, 28% (210 of 765) in TKA, 24% (165 of 677) in THA, 23% (47 of 206) in revision arthroplasty, 20% (113 of 558) in unicondylar knee arthroplasty, and 16% (28 of 173) in shoulder arthroplasty. Patients with severe BCIS were more likely (hazard ratio 3.46 [95% confidence interval 2.07 to 5.77]; p < 0.001) to die within 30 days of the index procedure than were patients with less severe or no BCIS. Factors independently associated with the development of severe BCIS were age older than 75 years (odds ratio 1.57 [95% CI 1.09 to 2.27]; p = 0.02), American Society of Anesthesiologists Class III or IV (OR 1.58 [95% CI 1.09 to 2.30]; p = 0.02), and renal impairment (OR 3.32 [95% CI 1.45 to 7.46]; p = 0.004). CONCLUSION: BCIS is common during cemented arthroplasty; severe BCIS is uncommon, but it is associated with an increased risk of death within 30 days of surgery. Medically complex patients undergoing hip hemiarthroplasty may be at particular risk. Patients at high risk for severe BCIS (renal impairment, ASA III/IV, and age older than 75 years) should be identified and preventive measures such as medullary lavage before cementation, femoral venting, and avoidance of excessive pressurization of implants should be taken to reduce the likelihood and consequences of BCIS. Because of the increased risk of periprosthetic fractures in uncemented hip stems, factors associated with the development of BCIS should be weighed against the risk factors for sustaining periprosthetic fractures (poor bone quality, female sex) to balance the risks of fixation method against those of BCIS for each patient. LEVEL OF EVIDENCE: Level III, therapeutic study.

What Is the Effect of Using a Competing-risks Estimator when Predicting Survivorship After Joint Arthroplasty: A Comparison of Approaches to Survivorship Estimation in a Large Registry.

BACKGROUND: There is increasing interest in the development of statistical models that can be used to estimate risk of adverse patient outcomes after joint arthroplasty. Competing risk approaches have been recommended to estimate risk of longer-term revision, which is often likely to be precluded by the competing risk of death. However, a common approach is to ignore the competing risk by treating death as a censoring event and using standard survival models such as Cox regression. It is well-known that this approach can overestimate the event risk for population-level estimates, but the impact on the estimation of a patient's individualized risk after joint arthroplasty has not been explored. QUESTIONS/PURPOSES: We performed this study to (1) determine whether using a competing risk or noncompeting risk method affects the accuracy of predictive models for joint arthroplasty revision and (2) determine the magnitude of difference that using a competing risks versus noncompeting risks approach will make to predicted risks for individual patients. METHODS: The predictive performance of a standard Cox model, with competing risks treated as censoring events, was compared with the performance of two competing risks approaches, the cause-specific Cox model and Fine-Gray model. Models were trained and tested using data pertaining to 531,304 TKAs and 274,618 THAs recorded in the Australian Orthopaedic Association National Joint Replacement Registry between January 1, 2003 and December 31, 2017. The registry is a large database with near-complete capture and follow-up of all hip and knee joint arthroplasty in Australia from 2003 onwards, making it an ideal setting for this study. The performance of the three modeling approaches was compared in two different prediction settings: prediction of the 10-year risk of all-cause revision after TKA and prediction of revision for periprosthetic fracture after THA. The calibration and discrimination of each approach were compared using the concordance index, integrated Brier scores, and calibration plots. Calibration of 10-year risk estimates was further assessed within subgroups of age by comparing the observed and predicted proportion of events. Estimated 10-year risks from each model were also compared in three hypothetical patients with different risk profiles to determine whether differences in population-level performance metrics would translate into a meaningful difference for individual patient predictions. RESULTS: The standard Cox and two competing risks models showed near-identical ability to distinguish between high-risk and low-risk patients (c-index 0.64 [95% CI, 0.64 to 0.64] for all three modeling approaches for TKAs and 0.66 [95% CI 0.66 to 0.66] for THA). All models performed similarly in patients younger than 75 years, but for patients aged 75 years and older, the standard Cox model overestimated the risk of revision more than the cause-specific Cox and Fine-Gray model did. These results were echoed when predictions were made for hypothetical individual patients. For patients with a low competing risk of mortality, the 10-year predicted risks from the standard Cox, cause-specific Cox, and Fine-Gray models were similar for TKAs and THAs. However, a larger difference was observed for hypothetical 89-year-old patients with increased mortality risk. In TKAs, the revision risk for an 89-year-old patient was so low that this difference was negligible (0.83% from the cause-specific Cox model versus 1.1% from the standard Cox model). However, for THAs, where older age is a risk factor for both death and revision for periprosthetic fracture, a larger difference was observed in the 10-year predicted risks for a hypothetical 89-year-old patient (3.4% from the cause-specific Cox model versus 5.2% from the standard Cox model). CONCLUSION: When developing models to predict longer-term revision of joint arthroplasty, failing to use a competing risks modeling approach will result in overestimating the revision risk for patients with a high risk of mortality during the surveillance period. However, even in an extreme instance, where both the frequency of the event of interest and the competing risk of death are high, the largest absolute difference in predicted 10-year risk for an individual patient was just 1.8%, which may not be of consequence to an individual. Despite these findings, when developing or using risk prediction models, researchers and clinicians should be aware of how competing risks were handled in the modeling process, particularly if the model is intended for use populations where the mortality risk is high. LEVEL OF EVIDENCE: Level III, therapeutic study.

Associations between comorbidity and quality of life outcomes after total joint replacement.

PURPOSE: We examined associations between self-reported and clinician-assessed comorbidity and quality of life (QOL) outcomes after hip and knee replacement. METHODS: This is a cross-sectional, questionnaire-based national survey. Participants aged 45 years or older (n = 409) were recruited from the New Zealand Joint Registry six months after a total hip (THR), total knee (TKR) or unicompartmental knee replacement (UKR). The main outcome QOL was measured using an 8-item short form of the World Health Organisation Quality of Life (WHOQOL-Bref) questionnaire six months following joint replacement surgery. The WHOQOL is a generic and non-health condition specific measure of QOL. RESULTS: Participants were on average 68 years of age, with more men (54%) than women (46%). Number of coexisting conditions and body mass index were correlated with age, pain and function scores, and QOL (p < 0.01), but not with each other. Linear regression analyses showed that comorbidities such as number of comorbid conditions and BMI had moderate associations with QOL outcomes. CONCLUSION: This study showed that general QOL outcomes following hip and knee joint replacement, while generally high, were associated with comorbidity burden and BMI. Future prospective research examining change in QOL before and following surgery would help to advance understandings of the various factors that contribute to patient satisfaction with their joint replacement.

Comparison of total joint arthroplasty outcomes between renal transplant patients and dialysis patients-a meta-analysis and systematic review.

OBJECTIVES: End-stage renal disease (ESRD) patients are at an increased risk of needing total joint arthroplasty (TJA); however, both dialysis and renal transplantation might be potential predictors of adverse TJA outcomes. For dialysis patients, the high risk of blood-borne infection and impaired muscular skeletal function are threats to implants' survival, while for renal transplant patients, immunosuppression therapy is also a concern. There is still no high-level evidence in the published literature that has determined the best timing of TJA for ESRD patients. METHODS: A literature search in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (up to November 2019) was performed to collect studies comparing TJA outcomes between renal transplant and dialysis patients. Two reviewers independently conducted literature screening and quality assessments with the Newcastle-Ottawa Scale (NOS). After the data were extracted, statistical analyses were performed. RESULTS: Compared with the dialysis group, a lower risk of mortality (RR = 0.56, Cl = [0.42, 0.73], P < 0.01, I2 = 49%) and revision (RR = 0.42, CI = [0.30, 0.59], P < 0.01, I2 = 43%) was detected in the renal transplant group. Different results of periprosthetic joint infection were shown in subgroups with different sample sizes. There was no significant difference in periprosthetic joint infection in the small-sample-size subgroup, while in the large-sample-size subgroup, renal transplant patients had significantly less risk (RR = 0.19, CI = [0.13, 0.23], P < 0.01, I2 = 0%). For dislocation, venous thromboembolic disease, and overall complications, there was no significant difference between the two groups. CONCLUSION: Total joint arthroplasty has better safety and outcomes in renal transplant patients than in dialysis patients. Therefore, delaying total joint arthroplasty in dialysis patients until renal transplantation has been performed would be a desirable option. The controversy among different studies might be partially accounted for that quite a few studies have a relatively small sample size to detect the difference between renal transplant patients and dialysis patients.

The Use of Aspirin for Prophylaxis Against Venous Thromboembolism Decreases Mortality Following Primary Total Joint Arthroplasty.

BACKGROUND: The use of aspirin as prophylaxis against venous thromboembolism (VTE) following total joint arthroplasty (TJA) has increased in popularity; however, the potential cardioprotective effects of aspirin when administered as VTE prophylaxis remain unknown. The present study investigated the influence of VTE prophylaxis, including aspirin, on mortality following TJA. METHODS: We retrospectively reviewed 31,133 patients who underwent primary TJA from 2000 to 2017. Patient demographics, body mass index, and comorbidities were obtained from an electronic chart query. Patients were allocated into 2 cohorts on the basis of the VTE prophylaxis administered: aspirin (25.9%, 8,061 patients) and non-aspirin (74.1%, 23,072 patients). Mortality was assessed with use of an institutional mortality database that is updated biannually. Univariate and multivariate regression analyses were performed. RESULTS: The overall mortality rate was 0.2% and 0.6% at 30 days and 1 year after TJA, respectively. The use of aspirin was independently associated with lower risk of death at both 30 days (odds ratio [OR], 0.39; p = 0.020) and 1 year (OR, 0.51; p = 0.004). Patients in the non-aspirin cohort showed 3 times the risk of death at 30 days compared with the aspirin cohort (0.3% compared with 0.1%; p = 0.004), and twice the risk of death at 1 year (0.7% compared with 0.3%; p < 0.001). At 1 year, the primary cause of death in the non-aspirin group was cardiac-related (46 of 23,072, 0.20%). In the aspirin group, the rate of cardiac-related death was almost 5 times lower (3 of 8,061, 0.04%; p = 0.005). Risk factors for mortality at 1 year included higher age (p < 0.001), male sex (p = 0.020), history of congestive heart failure (p = 0.003), cerebrovascular disease (p < 0.001), malignancy (p < 0.001), and history of prior myocardial infarction (p < 0.001). CONCLUSIONS: The present study demonstrates that the use of aspirin as prophylaxis against VTE following TJA may reduce the risk of mortality. Given the numerous options available and permitted by the current guidelines, orthopaedic surgeons should be aware of the potential added benefits of aspirin when selecting a VTE-prophylactic agent. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Patient relevant outcomes of unicompartmental versus total knee replacement: systematic review and meta-analysis.

OBJECTIVE: To present a clear and comprehensive summary of the published data on unicompartmental knee replacement (UKA) or total knee replacement (TKA), comparing domains of outcome that have been shown to be important to patients and clinicians to allow informed decision making. DESIGN: Systematic review using data from randomised controlled trials, nationwide databases or joint registries, and large cohort studies. DATA SOURCES: Medline, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Clinical Trials.gov, searched between 1 January 1997 and 31 December 2018. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies published in the past 20 years, comparing outcomes of primary UKA with TKA in adult patients. Studies were excluded if they involved fewer than 50 participants, or if translation into English was not available. RESULTS: 60 eligible studies were separated into three methodological groups: seven publications from six randomised controlled trials, 17 national joint registries and national database studies, and 36 cohort studies. Results for each domain of outcome varied depending on the level of data, and findings were not always significant. Analysis of the three groups of studies showed significantly shorter hospital stays after UKA than after TKA (-1.20 days (95% confidence interval -1.67 to -0.73), -1.43 (-1.53 to -1.33), and -1.73 (-2.30 to -1.16), respectively). There was no significant difference in pain, based on patient reported outcome measures (PROMs), but significantly better functional PROM scores for UKA than for TKA in both non-trial groups (mean difference -0.58 (-0.88 to -0.27) and -0.32 (-0.48 to -0.15), respectively). Regarding major complications, trials and cohort studies had non-significant results, but mortality after TKA was significantly higher in registry and large database studies (risk ratio 0.27 (0.16 to 0.45)), as were venous thromboembolic events (0.39 (0.27 to 0.57)) and major cardiac events (0.22 (0.06 to 0.86)). Early reoperation for any reason was higher after TKA than after UKA, but revision rates at five years remained higher for UKA in all three study groups (risk ratio 5.95 (1.29 to 27.59), 2.50 (1.77 to 3.54), and 3.13 (1.89 to 5.17), respectively). CONCLUSIONS: TKA and UKA are both viable options for the treatment of isolated unicompartmental osteoarthritis. By directly comparing the two treatments, this study demonstrates better results for UKA in several outcome domains. However, the risk of revision surgery was lower for TKA. This information should be available to patients as part of the shared decision making process in choosing treatment options. SYSTEMATIC REVIEW REGISTRATION: PROSPERO number CRD42018089972.

Risk of venous thromboembolism after endoprosthetic surgeries: lower versus upper extremity endoprosthetic surgeries.

Venous thromboembolism (VTE) is a potentially fatal disease. Important risk factors of a provoked VTE are trauma, surgery or immobilization. Especially, patients who undergo hip and knee replacements are at high risk for postoperative VTE. We aimed to compare in-hospital VTE burden and other outcomes after upper and lower extremity endoprosthetic surgeries in Germany. The nationwide German inpatient sample of the years 2005-2015 was used for data analysis. Patients who underwent endoprosthetic joint/bone replacements of the extremities (OPS codes 5-820, 5-822, 5-824 and 5-826) were further stratified in those operated on lower (OPS codes 5-820, 5-822 and 5-826) or upper extremity (OPS code 5-824) joints. Patients operated at upper and lower extremity were compared and lower extremity endoprosthetic surgery was investigated as a predictor for adverse outcomes. Overall, 4,134,088 hospitalized patients with extremity joint endoprosthetic surgeries (64.3% females, 54.0% aged > 70 years) were included in our analysis. Of these, 3,950,668 patients (95.6%) undergo lower and 183,420 (4.4%) upper extremity endoprosthetic joint surgery. VTE [RR 2.60 (95% CI 2.41-2.79), P < 0.001] and all-cause death [RR 1.68 (95% CI 1.58-1.77), P < 0.001] were more common in patients with lower extremity joint surgery. Risk for VTE events [OR 2.69 (2.50-2.90), P < 0.001] and in-hospital death [OR 1.65 (1.56-1.75), P < 0.001] were both higher in lower than in upper extremity joint surgeries independently of age, sex and comorbidities. Patients who undergo lower extremity endoprosthetic joint surgeries, bear a higher risk for VTE and in-hospital death compared to those with upper extremity endoprosthetic joint surgeries.

American Joint Replacement Registry Risk Calculator Does Not Predict 90-day Mortality in Veterans Undergoing Total Joint Replacement.

BACKGROUND: The American Joint Replacement Registry (AJRR) Total Joint Risk Calculator uses demographic and clinical parameters to provide risk estimates for 90-day mortality and 2-year periprosthetic joint infection (PJI). The tool is intended to help surgeons counsel their Medicare-eligible patients about their risk of death and PJI after total joint arthroplasty (TJA). However, for a predictive risk model to be useful, it must be accurate when applied to new patients; this has yet to be established for this calculator. QUESTIONS/PURPOSES: To produce accuracy metrics (ie, discrimination, calibration) for the AJRR mortality calculator using data from Medicare-eligible patients undergoing TJA in the Veterans Health Administration (VHA), the largest integrated healthcare system in the United States, where more than 10,000 TJAs are performed annually. METHODS: We used the AJRR calculator to predict risk of death within 90 days of surgery among 31,214 VHA patients older than 64 years of age who underwent primary TJA; data was drawn from the Veterans Affairs Surgical Quality Improvement Project (VASQIP) and VA Corporate Data Warehouse (CDW). We then used VHA mortality data to evaluate the extent to which the AJRR calculator estimates distinguished individuals who died compared with those who did not (C-statistic), and graphically depicted the relationship between estimated risk and observed mortality (calibration). As a secondary evaluation of the calculator, a sample of 39,300 patients younger than 65 years old was assigned to the youngest age group available to the user (65-69 years) as might be done in real-world practice. RESULTS: C-statistics for 90-day mortality for the older samples were 0.62 (95% CI, 0.60-0.64) and for the younger samples they were 0.46 (95% CI, 0.43-0.49), suggesting poor discrimination. Calibration analysis revealed poor correspondence between deciles of predicted risk and observed mortality rates. Poor discrimination and calibration mean that patients who died will frequently have a lower estimated risk of death than surviving patients. CONCLUSIONS: For Medicare-eligible patients receiving TJA in the VA, the AJRR risk calculator had a poor performance in the prediction of 90-day mortality. There are several possible reasons for the model's poor performance. Veterans Health Administration patients, 97% of whom were men, represent only a subset of the broader Medicare population. However, applying the calculator to a subset of the target population should not affect its accuracy. Other reasons for poor performance include a lack of an underlying statistical model in the calculator's implementation and simply the challenge of predicting rare events. External validation in a more representative sample of Medicare patients should be conducted to before assuming this tool is accurate for its intended use. LEVEL OF EVIDENCE: Level I, diagnostic study.

External Validation and Optimization of the SPRING Model for Prediction of Survival After Surgical Treatment of Bone Metastases of the Extremities.

BACKGROUND: Survival predictions before surgery for metastatic bone disease in the extremities (based on statistical models and data of previous patients) are important for choosing an implant that will function for the remainder of the patient's life. The 2008-SPRING model, presented in 2016, enables the clinician to predict expected survival before surgery for metastatic bone disease in the extremities. However, to maximize the model's accuracy, it is necessary to maintain and update the patient database to refit the prediction models achieving more accurate calibration. QUESTIONS/PURPOSES: The purposes of this study were (1) to refit the 2008-SPRING model for prediction of survival before surgery for metastatic bone disease in the extremities with a more modern cohort; and (2) to evaluate the performance of the refitted SPRING model in a population-based cohort of patients having surgery for metastatic bone disease in the extremities. METHODS: We produced the 2013-SPRING model by adding to the 2008-SPRING model (n = 130) a cohort of patients from a consecutive institutional database of patients who underwent surgery for bone metastases in the extremities with bone resection and reconstruction between 2009 and 2013 at a highly specialized surgical center in Denmark (n = 140). Currently the model is only available as the nomogram fully available in the current article, which is sufficient to use in daily clinical work, but we are working on making the tool available online. As such, the 2013-SPRING model was produced using a consecutive cohort of patients (n = 270) treated during an 11-year period (2003-2013) called the training cohort, all treated with bone resection and reconstruction. We externally validated the 2008-SPRING and the 2013-SPRING models in a prospective cohort (n = 164) of patients who underwent surgery for metastatic bone disease in the extremities from May 2014 to May 2016, called the validation cohort. The validation cohort was identified from a cross-section of the Danish population who were treated for metastatic lesions (using endoprostheses and internal fixation) in the extremities at five secondary surgical centers and one highly specialized surgical center. This cross-section is representative of the Danish population and no patients were treated outside the included centers as a result of public healthcare settings. The indications for surgery for training and the validation cohort were pathologic fracture, impending fracture, or intractable pain despite radiation. Exact date of death was known for all patients as a result of the Danish Civil Registration System and no loss to followup existed. In the training cohort, 150 patients (out of 270 [56%]) and in the validation cohort 97 patients (out of 164 [59%]) died of disease within 1 year postoperatively. The 2013 model did not differ from the 2008 model and included hemoglobin, complete fracture/impending fracture, visceral and multiple bone metastases, Karnofsky Performance Status, and the American Society of Anesthesiologists score and primary cancer. The models were evaluated by area under the receiver operating characteristic curve (AUC ROC) and Brier score (the lower the better). RESULTS: The 2013-SPRING model was successfully refitted with a cohort using more patients than the 2008-SPRING model. Comparison of performance in external validation between the 2008 and 2013-SPRING models showed the AUC ROC was increased by 3% (95% confidence interval [CI], 0%-5%; p = 0.027) and 2% (95% CI, 0%-4%; p = 0.013) at 3-month and 6-month survival predictions, respectively, but not at 12 months at 1% (95% CI, 0%-3%; p = 0.112). Brier score was improved by -0.018 (95% CI, -0.032 to -0.004; p = 0.011) for 3-month, -0.028 (95% CI, -0.043 to -0.0123; p < 0.001) for 6-month, and -0.014 (95% CI, -0.025 to -0.002; p = 0.017) for 12-month survival prediction. CONCLUSIONS: We improved the SPRING model's ability to predict survival after surgery for metastatic bone disease in the extremities. As such, the refitted 2013-SPRING model gives the surgeon a tool to assist in the decision-making of a surgical implant that will serve the patient for the remainder of their life. The 2013-SPRING model may provide increased quality of life for patients with bone metastasis because potential implant failures can be minimized by precise survival prediction preoperatively and the model is freely available and ready to use from the current article. LEVEL OF EVIDENCE: Level I, diagnostic study.

COST-UTILITY ANALYSIS OF PRIVATE CONTRACTING TO REDUCE PUBLIC WAITING TIMES FOR JOINT REPLACEMENT SURGERY.

OBJECTIVES: Earlier treatment of publicly funded patients may achieve health gains that justify the additional costs of reducing waiting times. This study reports on the cost-effectiveness of implementing a private contracting model to meet alternative maximum waiting time targets for publicly funded patients undergoing total knee replacement surgery in Australia. METHODS: A linked decision tree and cohort Markov model was developed and populated and validated using secondary data sources to represent the pathways, costs, and quality adjusted life-years (QALYs) gained of non-urgent patients with alternative waiting times for total knee replacement surgery to a maximum age of 100 years. RESULTS: Assuming public waiting times are reduced through the purchase of private services, additional QALYs are gained at an incremental cost of less than $40,000. Value could be increased if lower private prices could be negotiated. Results are also sensitive to the rate of deterioration in function while waiting for surgery and the impact of functional status at the time of surgery on postsurgery outcomes. CONCLUSIONS: More evidence on the value of expanded capacity or new models of care may inform new funding models to support such investments and reduced prices for new technologies, leading to more efficient and sustainable publicly funded healthcare systems.

Local Anesthetic Systemic Toxicity in Total Joint Arthroplasty: Incidence and Risk Factors in the United States From the National Inpatient Sample 1998-2013.

BACKGROUND: Local anesthetic systemic toxicity (LAST) is a rare and potentially devastating complication of regional anesthesia. Single-institution registries have reported a decreasing incidence, but these results have limited broad applicability. A recent study using a US database found a relatively high incidence of LAST. We used the National Inpatient Sample, a US database of inpatient admissions, to identify the national incidence and associated risk factors for LAST in total joint arthroplasties. METHODS: In this retrospective study, we studied patients undergoing hip, knee, or shoulder arthroplasty, from 1998 to 2013, with an adjunct peripheral nerve blockade. We used a multivariable logistic regression to identify patient conditions, hospital level variables, and procedure sites associated with LAST. RESULTS: A total of 710,327 discharges met inclusion criteria. The average adjusted incidence was 1.04 per 1000 peripheral nerve blocks, with decreasing trend over the 15-year study period (odds ratio [OR], 0.90; P = 0.002). Shoulder arthroplasty (OR, 4.35; P = 0.0001) compared with knee or hip arthroplasty and medium-size (OR, 3.34; P = 0.003) and large-size (OR, 2.40; P = 0.025) hospitals as compared with small hospitals were associated with increased odds of LAST. CONCLUSIONS: The incidence of LAST nationally in total joint arthroplasty with adjunct nerve blocks is similar to recent estimates from academic centers, with a small decreasing trend through the study period. Despite an overall low incidence rate, practitioners should continue to maintain vigilance for manifestations of LAST, especially as the use of regional anesthesia continues to increase.

Outcomes of shoulder arthroplasty in haematopoietic stem cell transplant patients.

BACKGROUND: With the growing population of patients undergoing haematopoietic stem cell transplants (HSCTs), the demand for shoulder arthroplasty (SA) in this population can be expected to increase. No studies in the literature have examined the outcomes of SA in HSCT patients. PATIENTS AND METHODS: A retrospective review of 11 SAs in 10 patients with previous HSCT was performed. We characterized the clinical outcomes, survivorship, and peri-operative complication rates in patients who underwent SA after receiving a HSCT. We also performed a subanalysis based on implant and transplant type. RESULTS: Seven of ten patients died with average two and five year post-operative patient survival rates of 70% +/- 14% and 47% +/- 17%, respectively. At average follow up of 4.2 years of the seven patients with two year followup, pain and range of motion improved with SA (p = 0.0625-0.2500). At final follow-up, five of seven shoulders were rated as satisfactory or excellent with modified Neer ratings. Two and five year survival rates free of re-operation were 100% +/- 0% and 67% +/- 27%, respectively. There were no other complications. No differences in outcomes were seen based on implant or transplant type besides RSA being associated with greater mortality risk (p = 0.0424, hazard ratio = 10.6). CONCLUSIONS: Patients with previous HSCT who undergo SA can expect to have good pain relief, range of motion improvement, subjective satisfaction, and low peri-operative complication rate with appropriate choice of implant. However, surgeons must inform patients about realistic post-operative outcomes given the high post-operative mortality rate. LEVEL OF EVIDENCE: Level IV, Prognosis.

Patients with Staged Bilateral Total Joint Arthroplasty in Registries: Immortal Time Bias and Methodological Options.

BACKGROUND: In arthroplasty data, patients with staged bilateral total joint arthroplasty (TJA) pose a problem in statistical analysis. Subgroup analysis, in which patients with unilateral and bilateral TJA are studied separately, is sometimes considered an appropriate solution to the problem; we aim to show that this is not true because of immortal time bias. METHODS: We reviewed patients who underwent staged (at any time) bilateral TJA. The logical fallacy leading to immortal time bias is explained through a simple artificial data example. The cumulative incidences of revision and death are computed by subgroup analysis and by landmark analysis based on hip replacement data from the Dutch Arthroplasty Register and on simulated data sets. RESULTS: For patients who underwent unilateral TJA, subgroup analysis can lead to an overestimate of the cumulative incidence of death and an underestimate of the cumulative incidence of revision. The reverse conclusion holds for patients who underwent staged bilateral TJA. Analysis of these patients can lead to an underestimate of the cumulative incidence of death and an overestimate of the cumulative incidence of revision. Immortal time bias can be prevented by using landmark analysis. CONCLUSIONS: When examining arthroplasty registry data, patients who underwent staged bilateral TJA should be analyzed with caution. An appropriate statistical method to address the research question should be selected.

Perioperative Complications in Patients With Sleep Apnea Undergoing Total Joint Arthroplasty.

BACKGROUND: This study aims to evaluate the effect of sleep apnea (SA) on perioperative complications after total joint arthroplasty (TJA) and whether the type of anesthesia influences these complications. METHODS: Using the ninth and tenth revisions of the International Classification of Diseases, coding systems, we queried our institutional TJA database from January 2005 to June 2016 to identify patients with SA who underwent TJA. These patients were matched in a 1:3 ratio based on age, gender, type of surgery, and comorbidities to patients who underwent TJA but were not coded for SA. Perioperative complications were identified using the same coding systems. Multivariate analysis was used to test if SA is an independent predictor of perioperative complications and if type of anesthesia can affect these complications. RESULTS: A total of 1246 patients with SA were matched to 3738 patients without SA. Pulmonary complications occurred more frequently in patients with SA (1.7% vs 0.6%; P < .001), confirmed using multivariate analysis (odds ratio = 2.91; 95% confidence interval, 1.58-5.36; P = .001). Use of general anesthesia increased risk of all but central nervous system complications and mortality (odds ratio = 15.88; 95% confidence interval, 3.93-64.07; P < .001) regardless of SA status compared with regional anesthesia. Rates of pulmonary and gastrointestinal complications, acute anemia, and mortality were lower in SA patients when regional anesthesia was used (P < .05). CONCLUSION: SA increases risk of postoperative pulmonary complications. The use of regional anesthesia may reduce risk of pulmonary complications and mortality in SA patients undergoing TJA.

Consensus on draft OMERACT core domains for clinical trials of Total Joint Replacement outcome by orthopaedic surgeons: a report from the International consensus on outcome measures in TJR trials (I-COMiTT) group.

BACKGROUND: There are no core outcome domain or measurement sets for Total Joint Replacement (TJR) clinical trials. Our objective was to achieve an International consensus by orthopaedic surgeons on the OMERACT core domain/area set for TJR clinical trials. METHODS: We conducted surveys of two orthopaedic surgeon cohorts, which included (1) the leadership of international orthopaedic societies and surgeons (IOS; cohort 1), and (2) the members of the American Academy of Orthopaedic Surgeons' Outcome Special Interest Group (AAOS-Outcome SIG), and/or the Outcome Research Interest Group of the Orthopaedic Research Society (ORS; cohort 2). Participants rated OMERACT-endorsed preliminary core area set for TJR clinical trials on a 1 to 9 scale, indicating 1-3 as domain of limited importance, 4-6 being important, but not critical, and 7-9 being critical. RESULTS: Eighteen survey participants from the IOS group and 69 participants from the AAOS-Outcome SIG/ORS groups completed the survey questionnaire. The median (interquartile range [IQR]) scores were seven or higher for all six proposed preliminary core areas/domains across both groups, IOS and AAOS-Outcome SIG/ORS, respectively: pain, 8 [8, 9] and 8 [7, 9]; function, 8 [8, 8] and 8 [7, 9]; patient satisfaction, 8 [7, 9] and 8 [7, 8]; revision surgery, 7 [6, 9] and 8 [6, 8]; adverse events, 7 [5, 8] and 7 [6, 9]; and death, 7 [7, 9] and 8 [5, 9]. Respective median scores were lower for two additional optional domains: patient participation, 6.5 [5, 7] and 6 [5, 8]; and cost, 6 [5, 7] and 6 [5, 7]. CONCLUSIONS: This study showed that two independent surveys dervied from three groups of orthopaedic surgeons with international representation endorsed a preliminary/draft OMERACT core domain/area set for Joint Replacement clinical trials.

Health Care Exceptionalism? Performance and Allocation in the US Health Care Sector.

The conventional wisdom for the healthcare sector is that idiosyncratic features leave little scope for market forces to allocate consumers to higher performance producers. However, we find robust evidence - across several different conditions and performance measures - that higher quality hospitals have higher market shares and grow more over time. The relationship between performance and allocation is stronger among patients who have greater scope for hospital choice, suggesting that patient demand plays an important role in allocation. Our findings suggest that healthcare may have more in common with "traditional" sectors subject to market forces than often assumed.