Adverse events after total knee arthroplasty: a national Medicare study

Complications, readmission rates, and in-hospital lengths-of-stay in octogenarian vs. non-octogenarians following total knee arthroplasty: An analysis of over 1.7 million patients

INTRODUCTION

Studies investigating complications between octogenarians and non-octogenarians undergoing primary total knee arthroplasty (TKA) are limited. Therefore, we investigated whether octogenarians are at greater odds of: (1) in-hospital lengths of stay (LOS) (2) readmission rates, (3) medical complications, and (4) hardware complications compared to non-octogenarians following TKA.

METHODS

A retrospective query of the PearlDiver database isolated 1,775,460 patients who underwent primary TKA from 2005 to 2014. Patients aged 80 and above represented the study cohort (n = 295,908) and patients 65 to 79 represented the control cohort (n = 1,479,552). Study group patients were matched to controls in a 1:5 ratio according to gender and medical comorbidities. Pearson's Chi Square and logistic regression were used to analyze the primary outcomes of the study which included 90-day medical complications, 90-day readmission rates, 2-year implant-related complications, and in-hospital LOS. A p-value less than 0.001 was statistically significant.

RESULTS

Octogenarians were found to have significantly higher incidence and odds of 90-day readmission rates (10.59 vs. 9.35%; OR: 1.15, p < 0.0001) and significantly longer in-hospital LOS (3.69 days ± 1.95 vs. 3.23 days ± 1.83, p < 0.0001) compared to controls. Octogenarians also had equal incidence and odds of developing any medical complication (1.26 vs. 1.26%; OR: 0.99, p = 0.99) and lower incidence and odds (1.67 vs. 1.93%; OR: 0.86, p < 0.001) of implant-related complications compared to controls.

CONCLUSION

Octogenarians undergoing primary TKA have similar odds of medical related complications and lower odds of implant-related complications compared to non-octogenarian patients, whereas readmission rates and in-hospital LOS are greater.

Risk factors of postoperative complications following total knee arthroplasty in Korea: A nationwide retrospective cohort study

BACKGROUND

The number of patients undergoing total knee arthroplasty (TKA) is gradually increasing and there is also increase in postoperative complications. The patient's demographic, socio-economic factors, hospital and clinical factors are all factors that can influence postoperative complications. The purpose of this study was to determine the risk factors associated with complications following TKA in a large national cohort.

METHODS

Among patients diagnosed with primary knee arthrosis, a total of 560,954 patients older than 50 years who underwent TKA from January 1, 2005 to December 31, 2018 were included in the study. The risk of postoperative complications (surgical site infection, sepsis, cardiovascular complications, respiratory complications, pulmonary embolism, stroke, acute renal failure, periprosthetic joint infection, and periprosthetic fracture) were assessed with eight independent variables: gender, age, place of residence, household income, hospital bed size, procedure type (unilateral or bilateral, primary or revision TKA), length of stay (LOS), use of transfusion. Multivariable Cox Proportional Hazard model analysis was used. The significant predictors for complications (P < .05) were as follows.

RESULTS

Surgical site infection: male, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Sepsis: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Cardiovascular complications: male, age, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Respiratory complications: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Pulmonary embolism: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Stroke: male, age, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Acute renal failure: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Periprosthetic joint infection: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Periprosthetic fracture: male, procedure type (bilateral, revision), LOS (≥35 days), transfusion.

CONCLUSION

In summary, male, procedure type (bilateral, revision), LOS (≥35 days), and use of transfusion were shown to be risk factors of postoperative complications following TKA.

Would high-dose corticosteroid addition to multimodal cocktail periarticular injection contribute to prolonged pain control and better recovery following total knee arthroplasty?: study protocol for a randomized controlled trial

BACKGROUND

Enhanced recovery following total knee arthroplasty (TKA) has been advocated to enhance postoperative recovery. Multimodal cocktail periarticular injection (MCPI) use for pain control in TKA has gained wide acceptance. MCPI-containing corticosteroids are believed to be an effective solution owing to their local anti-inflammatory effects and ability to reduce the local stress response postoperatively. However, there is conflicting evidence regarding its benefits. This trial aims to compare MCPI with a high dose of corticosteroid, normal dose of corticosteroid, and non-corticosteroid during TKA, to assess the effectiveness of MCPI containing corticosteroids in postoperative pain relief, functional improvement, rescue analgesia, and side effects and provide evidence that high-dose corticosteroids result in prolonged pain control and better recovery following TKA.

METHODS

This is a double-blinded, randomized, placebo-controlled study. A total of 234 patients scheduled for TKA will be recruited. During surgery, before wound closure, 80 ml of the cocktail analgesic will be injected into the muscle and joint capsule for local infiltration analgesia; the participants will be randomly assigned to three groups to receive a high dose of betamethasone MCPI (group H), normal dose of betamethasone MCPI (group N), and non-betamethasone MCPI (group C). The following indices will be recorded and analyzed: the strongest knee pain experienced during 90° flexion at 6 h, 24 h, 48 h, 72 h, 5 days, 14 days, and 30 days after surgery; 1 min walking ability; and circumference around the patella at 2, 5, 14, and 30 days after surgery; Knee Society knee score at 14 days and 30 days after surgery; C-reactive protein and blood sedimentation; blood sugar 2, 5, 14, and 30 days following surgery; rescue analgesic consumption; and adverse events. If any participant withdraws from the trial, an intention-to-treat analysis will be performed.

DISCUSSION

The results of this study will provide clinical evidence on the effectiveness of MCPI-containing corticosteroids in postoperative pain relief, functional improvement, rescue analgesia, and adverse events, as well as provide evidence on the efficacy of high-dose corticosteroids in prolonged pain control and better recovery following TKA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2000038671 . Registered on September 27, 2020.

Time Trends in Patient Characteristics and In-Hospital Adverse Events for Primary Total Knee Arthroplasty in the United States: 2010-2017

Background

Perioperative care for total knee arthroplasty (TKA) has improved over time. We present an analysis of inpatient safety after TKA.

Methods

14,057 primary TKAs captured by the Medicare Patient Safety Monitoring System between 2010 and 2017 were retrospectively reviewed. We calculated changes in demographics, comorbidities, and adverse events (AEs) over time. Risk factors for AEs were also assessed.

Results

Between 2010 and 2017, there was an increased prevalence of obesity (35.1% to 57.6%), tobacco smoking (12.5% to 17.8%), and renal disease (5.2% to 8.9%). There were reductions in coronary artery disease (17.3% to 13.4%) and chronic warfarin use (6.7% to 3.1%). Inpatient AEs decreased from 4.9% to 2.5%, (P < .01), primarily driven by reductions in anticoagulant-associated AEs, including major bleeding and hematomas (from 2.8% to 1.0%, P < .001), catheter-associated urinary tract infections (1.1% to 0.2%, P < .001), pressure ulcers (0.8% to 0.2%, P < .001), and venous thromboembolism (0.3% to 0.1%, P = .04). The adjusted annual decline in the risk of developing any in-hospital AE was 14% (95% confidence interval [CI] 10%-17%). Factors associated with developing an AE were advanced age (odds ratio [OR] = 1.01, 95% CI 1.00-1.01), male sex (OR = 1.21, 95% CI 1.02-1.44), coronary artery disease (OR = 1.35, 95% CI 1.07-1.70), heart failure (OR = 1.70, 95% CI 1.20-2.41), and renal disease (OR = 1.71, 95% CI 1.23-2.37).

Conclusions

Despite increasing prevalence of obesity, tobacco smoking, and renal disease, inpatient AEs after primary TKA have decreased over the past several years. This improvement is despite the increasing complexity of the inpatient TKA population over time.

A Single-Blinded Randomized Controlled Trial of Mesenchymal Stem Cell Therapy for the Treatment of Osteoarthritis of the Knee with Active Control

Background: Osteoarthritis is most prevalent in the knee and drives the growing incidence of total knee arthroplasty. There is a need to explore non-surgical treatment options to increase the portfolio of alternatives available. The study aimed to determine the clinical response to an autologous bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP) intra-articular injection compared to an active comparator. Methods: The study was a prospective, single-blinded, randomized controlled pilot study. Participants with diagnosed knee osteoarthritis were allocated to one of two treatment groups to receive a BMAC injection immediately followed by a PRP injection or a single injection of Gel-One® crosslinked hyaluronate (HA). Outcomes were assessed at 3, 6, and 12 months post-treatment. Results: Significant improvements were observed in both treatment groups for all Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales with the exception of the symptoms assessment at 12 months in the HA group. BMAC KOOS scores peaked at 12 months, while HA KOOS scores generally peaked at 6 months. The gap in mean scores at 12 months in favor of the BMAC group did not reach statistical significance. Secondary outcomes included a greater reduction in pain at 12 months in the BMAC group (-3.13 points; 95% CI: -3.96, -3.29) compared to the HA group (-1.56 points; 95% CI: -2.59, -0.53; p= 0.02) via the numeric pain rating scale. Conclusions: Results demonstrate that both treatment groups experienced clinically and statistically significant improvement across the KOOS subscales. While BMAC has shown promise in the treatment of knee OA, there is a need for multi-center investigations with larger sample sizes, an extended follow-up, and placebo-based control. ClinicalTrials.gov Identifier: NCT02958267.

Factors Associated with Knee Arthroplasty in a Knee Osteoarthritis Patient Cohort Treated with Intra-articular Injections of Hylan G-F 20

Hylan G-F 20 viscosupplementation can be used to treat knee osteoarthritis pain. This study evaluated time to knee arthroplasty (KA), KA risk factors, and health care resource utilization in patients aged ≥18 years with claims in the Optum Clinformatics Data Mart database (2006-2016) for knee osteoarthritis treated with at least one course of hylan G-F 20. Kaplan-Meier analysis estimated KA risk from osteoarthritis diagnosis and first hylan G-F 20 treatment. KA risk factors were determined using multivariate Cox regression. Among 62,033 patients treated with hylan G-F 20 and/or hylan G-F 20 single intra-articular injection, 60 to 64% did not undergo KA 8 years following first injection. KA risk factors from time of osteoarthritis diagnosis and first hylan G-F 20 treatment were similar: increased age, fewer comorbidities, fewer hylan G-F 20 treatments, female sex, and no ultrasound/fluoroscopy for injection guidance. Patients who underwent KA versus those who did not had more office visits and claims for opioids, nonsteroidal anti-inflammatory drugs, and physical therapy. Patients less likely to undergo KA were younger (<40 years), had more comorbidities, received more courses of hylan G-F 20, were males, or received ultrasound/fluoroscopic injection guidance. Patients who did not receive KA versus those who did used fewer health care resources.

Serious adverse events and 30-day hospital readmission rate following elective total knee arthroplasty: a systematic review and meta-analysis

Background

Elective total knee arthroplasty (TKA) is a common surgery which has evolved rapidly. However, there are no recent large systematic reviews of serious adverse event (SAE) rate and 30-day readmission rate (30-dRR) or an indication of whether surgical methods have improved.

Methods

To obtain a pooled estimate of SAE rate and 30-dRR following TKA, we searched Medline, Web of Science, Cochrane Library, and Google Scholar databases. Data were extracted by two authors following PRISMA guidelines. Eligibility criteria were defined prior to a comprehensive search. Studies were eligible if they were published in 2007 or later, described sequelae of TKA with patient N > 1000, and the SAE or 30-dRR rate could be calculated. SAEs included return to operating room, death or coma, venous thromboembolism (VTE), deep infection or sepsis, myocardial infarction, heart failure or cardiac arrest, stroke or cerebrovascular accident, or pneumonia.

Results

Of 248 references reviewed, 28 are included, involving 10,153,503 patients; this includes 9,483,387 patients with primary TKA (pTKA), and 670,116 patients with revision TKA (rTKA). For pTKA, the SAE rate was 5.7% (95% CI 4.4−7.2%, I² = 100%), and the 30-dRR was 4.8% (95% CI 4.3−5.4%, I² = 100%). For rTKA, the SAE rate was 8.5% (95% CI 8.3−8.7%, I² = 77%), while the 30-dRR was 7.2% (95% CI 6.4−8.0%, I² = 81%). Odds of 30-dRR following pTKA were about half that of rTKA (OR 0.57, 95% CI 0.53−0.62%, p < 0.001, I² = 45%). Of patients who received pTKA, the commonest SAEs were VTE (1.22%; 95% CI 0.83−1.70%) and genitourinary complications including renal insufficiency or renal failure (1.22%; 95% CI 0.83−1.67%). There has been significant improvement in SAE rate and 30-dRR since 2010 (χ² test < 0.001).

Conclusions

TKA procedures have a relatively low complication rate, and there has been a significant improvement in SAE rate and 30-dRR over the past decade.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02358-w.

Comparison of readmission and early revision rates as a quality metric in total knee arthroplasty using the Nationwide Readmission Database

Background

After release of the Comprehensive Care for Joint Replacement bundle, there has been increased emphasis on reducing readmission rates for total knee arthroplasty (TKA). The potential for a separate, clinically-relevant metric, TKA revision rates within a year following surgery, has not been fully explored. Based on this, we compared rates and payments for TKA readmission and revision procedures as metrics for improving quality and cost.

Methods

We utilized the 2013 Nationwide Readmission Database (NRD) to examine national readmission and revision rates, the reasons for revision procedures, and associated costs for elective TKA procedures. As data are not linked across years, we examined revision rates for TKA completed in the month of January by capturing revision procedures in the subsequent following 11-month period to approximate a 1-year revision rate. Diagnosis and procedure codes for revision procedures were collected. Average readmission and revision procedure costs were then calculated, and the cost distributed across the entire TKA population.

Results

We identified 20,851 patients having TKA surgery. The mean unadjusted 30- and 90-day TKA readmission rates were 3.4% and 5.8%, respectively. In contrast, the mean unadjusted 3-month and approximate 1-year reoperation rates were 1.0% and 1.6%, respectively. The most common cause for revision was periprosthetic joint infection, which accounting for 62% of all reported revision procedures. The mean payment for 90-day readmission was roughly half ($10,589±$11,084) of the mean inpatient payment for single reoperation procedure at 90 days ($20,222±$17,799). Importantly, nearly half (46%) of all 90-day readmissions were associated with a reoperation event within the first year.

Conclusions

Readmission following TKA is associated with a 1-year reoperation in approximately half of patients. These reoperations represent a significant patient burden and have a higher per episode cost. Early reoperation may represent a more clinically relevant target for quality improvement and cost containment.

Validity of patient-reported complications after total hip and knee arthroplasty

BACKGROUND

Evaluating the effectiveness of total hip arthroplasty (THA) and total knee arthroplasty (TKA) often relies on accurate patient reporting of postoperative complications. Despite this, there is little research regarding the accuracy of patient reports. We aimed to determine the accuracy of patient-reported significant complications after THA and TKA.

METHODS

Patients were recruited prior to undergoing primary hip or knee arthroplasty at 19 high-volume hospitals. After surgery, follow-up of patients via telephone interviews at 35, 90 and 365 days recorded surgical outcomes including readmission, reoperation and venous thromboembolism (VTE). Patient-reported complications were verified via medical record audits and liaison with surgeons, general practitioners or other health professionals. Surgical and demographic information and patient-reported and verified complications were entered into a database. Patient-reported and verified complications were compared for readmission, reoperation and VTE.

RESULTS

The sample included 150 of 1811 patients who reported a total of 242 significant complications. Of the 242 patient-reported complications, 224 (92.6%) were correct (true positive). The type of complication had variable levels of accuracy in patient reports. Readmission to hospital was accurately reported by 90.2% (129/143) of patients. Reoperation (including any manipulations under anaesthesia, joint washouts, reductions of dislocated joints and revisions) was accurately reported by 98.7% (75/76) of patients. VTE was accurately reported by 86.7% (20/23) of patients.

CONCLUSION

A high level of accuracy in patient-reported experience of complications was demonstrated following THA and TKA. Patient-reported complications may be reliably used for post-operative surveillance of joint replacement surgery.

Perioperative morbidity in total knee arthroplasty

Introduction

As the life expectancy and weight of patients are increasing, more old and obese patients are undergoing total knee arthroplasty (TKA). TKA may lead to several perioperative complications. These include anesthesia-related risks, exacerbation of comorbid medical issues and complications of surgical procedure. We have no studies reporting medical complications following TKA among our population. This study aimed to evaluate perioperative complications of TKA and to identify the related risk factors.

Methods

It was a monocentric retrospective including 410 observations in the local TKA registry. Data of patients operated for primary unilateral TKA during the period from January 2014 to December 2017 were reviewed. All patients had standardized protocols of anesthesia and post operative care for three days following surgery. Multivariate logistic regression was used to identify the predicting factors for complications.

Results

Incidence of perioperative complications was 37.1%. The most frequent were per operative hypotension (14.1%) and postoperative desaturation (21.7%, including pulmonary embolism in 2.4%). Multivariate logistic regression analysis identified: age ≥ 65 years (OR=1.9; p=0.006), respiratory diseases (OR=1.8; p=0.042) and general anesthesia (OR=2.8; p=0.009) as significant risk factors for any complications. Loss of autonomy (OR=4.8; p <0.001) and general anesthesia (OR=2.6; p=0.03) were significant risk factors for hypotension. Age ≥ 65 years (OR=2.6;p<0.001), female gender (OR=4.3;p=0.006) and respiratory diseases(OR=1.9;p=0.02) were associated with postoperative desaturation.

Conclusion

This study highlighted hemodynamic and respiratory complications as the most common early complications in TKA. Age ≥ 65years, general anesthesia and respiratory diseases were significant risk factors.

Predictors and Cost of Readmission in Total Knee Arthroplasty

BACKGROUND

The Comprehensive Care for Joint Replacement bundle was created to decrease total knee arthroplasty (TKA) cost. To help accomplish this, there is a focus on reducing TKA readmissions. However, there is a lack of national representative sample of all-payer hospital admissions to direct strategy, identify risk factors for readmission, and understand actual readmission cost.

METHODS

We used the Nationwide Readmission Database to examine national readmission rates, predictors of readmission, and associated readmission costs for elective TKA procedures. We fit a multivariable logistic regression model to examine factors associated with readmission. Then, we determined mean readmission costs and calculated the readmission cost when distributed across the entire TKA population.

RESULTS

We identified 224,465 patients having TKA across all states participating in the Nationwide Readmission Database. The mean unadjusted 30-day TKA readmission rate was 4%. The greatest predictors of readmission were congestive heart failure (odds ratio [OR] 2.51, 95% confidence interval [CI] 2.62-2.80), renal disease (OR 2.19, 95% CI 2.03-2.37), and length of stay greater than 4 days (OR 2.4, 95% CI 2.25-2.61). The overall median cost for each readmission was $6753 ± 175. Extrapolating the readmission cost for the entire TKA population resulted in the readmission cost being 2% of the overall 30-day procedure cost.

CONCLUSIONS

A major focus of the Comprehensive Care for Joint Replacement bundle is improving cost and quality by limiting readmission rates. TKA readmissions are low and comprise a small percentage of total TKA cost, suggesting that they may not be the optimal measure of quality care or a significant driver of overall cost.

Impact of comorbid conditions on outcomes of hip and knee replacement surgery: a systematic review and meta-analysis

OBJECTIVE

To systematically perform a meta-analysis of the association between different comorbid conditions on safety (short-term outcomes) and effectiveness (long-term outcomes) in patients undergoing hip and knee replacement surgery.

DESIGN

Systematic review and meta-analysis.

METHODS

Medline, Embase and CINAHL Plus were searched up to May 2017. We included all studies that reported data to allow the calculation of a pooled OR for the impact of 11 comorbid conditions on 10 outcomes (including surgical complications, readmissions, mortality, function, health-related quality of life, pain and revision surgery). The quality of included studies was assessed using a modified Newcastle-Ottawa Scale. Continuous outcomes were converted to ORs using the Hasselblad and Hedges approach. Results were combined using a random-effects meta-analysis.

OUTCOMES

The primary outcome was the adjusted OR for the impact of each 11 comorbid condition on each of the 10 outcomes compared with patients without the comorbid condition. Where the adjusted OR was not available the secondary outcome was the crude OR.

RESULTS

70 studies were included with 16 (23%) reporting on at least 100 000 patients and 9 (13%) were of high quality. We found that comorbidities increased the short-term risk of hospital readmissions (8 of 11 conditions) and mortality (8 of 11 conditions). The impact on surgical complications was inconsistent across comorbid conditions. In the long term, comorbid conditions increased the risk of revision surgery (6 of 11 conditions) and long-term mortality (7 of 11 conditions). The long-term impact on function, quality of life and pain varied across comorbid conditions.

CONCLUSIONS

This systematic review shows that comorbidities predominantly have an impact on the safety of hip and knee replacement surgery but little impact on its effectiveness. There is a need for high-quality studies also considering the severity of comorbid conditions.

Mortality After Total Knee Arthroplasty: A Systematic Review of Incidence, Temporal Trends, and Risk Factors

BACKGROUND

The capacity for total knee arthroplasty to improve pain, quality of life, and functional outcomes is widely recognized. Postoperative mortality is rare but of paramount importance, and needs to be accurately quantified and conveyed to patients in order to support decision-making prior to surgery. The purpose of this study was to determine a contemporary estimate of the risk of mortality following total knee arthroplasty, including the identification of temporal trends, common causes, and modifiable and nonmodifiable risk factors.

METHODS

We performed a systematic review with searches of MEDLINE, AMED, CAB Abstracts, and Embase. Studies in any language published from 2006 to 2016 reporting 30 or 90-day mortality following total knee arthroplasty were included, supplemented by contact with authors. Meta-analysis and meta-regression were performed for quantitative data.

RESULTS

Thirty-seven studies with mortality data from 15 different countries following over 1.75 million total knee arthroplasties formed the basis of this review. The pooled Poisson-normal random-effects meta-analysis estimates of 30 and 90-day mortality were 0.20% (95% confidence interval [CI], 0.17% to 0.24%) and 0.39% (95% CI, 0.32% to 0.49%). Both estimates have fallen over the 10-year study period (p < 0.001). Meta-regression using the median year of surgery as a moderator showed that 30 and 90-day mortality following total knee arthroplasty fell to 0.10% (95% CI, 0.07% to 0.14%) and 0.19% (95% CI, 0.15% to 0.23%), respectively, in 2015. The leading cause of death was cardiovascular disease.

CONCLUSIONS

There is an ongoing worldwide temporal decline in mortality following total knee arthroplasty. Improved patient selection and perioperative care and a healthy-population effect may account for this observation. Efforts to further reduce mortality should be targeted primarily at reducing cardiovascular events following total knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

One-year mortality and Periprosthetic infection rates after Total knee Arthroplasty in Cancer patients: a population-based cohort study

BACKGROUND

Knowledge on periprosthetic infection and mortality rate following total knee arthroplasty (TKA) is essential for justifying this treatment in patients with cancer; however, relevant data from population-based studies are lacking. Therefore, we examined 1-year periprosthetic infection, mortality, and 5-year relative survival rates in cancer patients who underwent TKA.

METHODS

This is a population-based cohort study based on analysis of the Taiwan National Health Insurance Research Database. We enrolled a total of 2294 cancer patients and 131,849 patients without cancer (control group) who underwent TKA between January 1, 1997, and December 31, 2011. All patients were followed until death, infection, withdrawal from the National Health Insurance, or December 31, 2012.

RESULTS

The periprosthetic knee joint infection rate in cancer patients (1.73%) was not significantly higher than that in the control group (1.87%). However, the 1-year mortality rate was significantly higher (p < 0.05) in the cancer group (4.10%) than in the control group (1.66%). The overall 5-year survival rate was 93.10% as compared with those without cancers.

CONCLUSION

Low periprosthetic knee joint infection rates and high 5-year relative survival rates indicate the feasibility of TKA in cancer patients. However, the surgeon should take into account a higher mortality rate in the first year following TKA.

Perioperative Outcomes and Complications in Patients With Heart Failure Following Total Knee Arthroplasty

BACKGROUND

Heart failure (HF) is a common comorbidity in the aging population and they will require major elective surgery. The purpose of this study is to determine if HF is a risk factor for adverse perioperative outcomes and short-term complications following total knee arthroplasty.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was utilized to identify all patients who underwent total knee arthroplasty for osteoarthritis from 2008 to 2014. Any diagnosis other than osteoarthritis was excluded. A total of 111,634 patients were identified and 251 of these patients had a preoperative diagnosis of HF. The main outcomes included operative time, lengths-of-stay, discharge disposition, return to operating room, readmission, and short-term complications, including death.

RESULTS

Patients with HF were found to have longer hospital stays (β = 0.59, 95% confidence interval [CI] 0.12-1.06) following total knee arthroplasty, and were more likely to return to the operating room (odds ratio 2.00, 95% CI 1.01-3.94) and be readmitted (OR 1.88, 95% CI 1.21-2.94). In addition, HF was found to be a risk factor for 1 or more complications (OR 1.41, 95% CI 1.05-1.90), wound dehiscence (OR 4.86, 95% CI 1.68-14.03), and myocardial infarction (OR 4.81, 95% CI 1.90-12.16) postoperatively.

CONCLUSION

Patients with HF are more likely to have a longer length-of-stay, return to the operating room, and be readmitted. Additionally, they have a higher risk for at least one postoperative complication, myocardial infarction, and wound dehiscence.

Benign heart murmurs as a predictor for complications following total joint arthroplasty

BACKGROUND

There is scant literature examining the predictive role of heart murmurs in the absence of suspected structural heart disease on complications of non-cardiac surgery. We hypothesize the detection of heart murmurs in the absence of structural heart disease will help identify patients at risk for complications following total joint arthroplasty (TJA) surgery.

METHOD

This was a prospective cohort of patients undergoing TJA over a twenty-month period. The study was performed at a single academic institution with four subspecialty surgeons. Patients undergoing primary TJA who were over eighteen years old, gave informed consent, and had adequate documentation were included in the study. Patients with a preoperative murmur or a newly discovered postoperative murmur were compared against patients with no murmur. Surgery-related complications, performance with physical therapy, and discharge to a non-home facility were measured in each group.

FINDINGS

345 (63%) eligible patients were included. 20 (5.8%) patients had a documented preoperative murmur and 36 (10.4%) patients had a new postoperative murmur. No patient had concern for major structural heart disease. Preoperative murmurs independently predicted development of acute kidney injury (OR 7.729, p < 0.001; RR 1.36). Preoperative murmurs also predicted likelihood to be discharged to a non-home facility (OR 2.97, p = 0.03; RR 1.87). New postoperative murmurs independently correlated with decreased performance with physical therapy (OR 0.466, p = 0.045; RR 0.664).

INTERPRETATION

Detection of heart murmurs both preoperatively and postoperatively is a low cost strategy to identify post-TJA surgical patients at risk for postoperative acute kidney injury, decreased physical performance, and discharge to non-home facilities. These patients may benefit from early fluid resuscitation and renally-dosed post-operative medications.

Reductions in Readmission Rates Are Associated With Modest Improvements in Patient-reported Health Gains Following Hip and Knee Replacement in England

Supplemental Digital Content is available in the text.

Background:

Although many hospital readmission reduction initiatives have been introduced globally, health care systems ultimately aim to improve patients’ health and well-being. We examined whether the hospitals that report greater success in reducing readmissions also see greater improvements in patient-reported outcomes.

Research Design:

We examined hospital groups (Trusts) that provided hip replacement or knee replacement surgery in England between April 2010 and February 2013. For each Trust, we calculated risk-adjusted 30-day readmission rates from administrative datasets. We also obtained changes in patient-reported health between presurgical assessment and 6-month follow-up, using general health EuroQuol five dimensions questionaire (EQ-5D) and EuroQuol visual analogue scales (EQ-VAS) and procedure-specific (Oxford Hip and Knee Scores) measures. Panel models were used to assess whether changes over time in risk-adjusted readmission rates were associated with changes over time in risk-adjusted health gains.

Results:

Each percentage point reduction in the risk-adjusted readmission rate for hip replacement was associated with an additional health gain of 0.004 for EQ-5D [95% confidence interval (CI), 0.002–0.006], 0.39 for EQ-VAS (95% CI, 0.26–0.52), and 0.32 for Oxford Hip Score (95% CI, 0.15–0.27). Corresponding figures for knee replacement were 0.003 for EQ-5D (95% CI, 0.001–0.004), 0.21 for EQ-VAS (95% CI, 0.12–0.30), and 0.14 in the Oxford Knee Score (95% CI, 0.09–0.20).

Conclusions:

Reductions in readmission rates were associated with modest improvements in patients’ sense of their health and well-being at the hospital group level. In particular, fears that efforts to reduce readmission rates have had unintended consequences for patients appear to be unfounded.

Factors Associated with Adverse Events in Inpatient Elective Spine, Knee, and Hip Orthopaedic Surgery

BACKGROUND

Orthopaedic procedures for degenerative musculoskeletal conditions (predominantly osteoarthritis and spinal stenosis) represent an increasing burden on the health-care system. These procedures are also associated with adverse event rates and related cost. The objective of this study was to identify risk factors for adverse events associated with orthopaedic surgeries as captured within a common clinical point-of-care system for documenting adverse events (Orthopaedic Surgical AdVerse Events Severity [OrthoSAVES] system).

METHODS

In-hospital adverse events were recorded at the point of care over a 2-year period for inpatient elective knee, hip, and spine orthopaedic procedures for degenerative musculoskeletal conditions. Multivariable logistic regression was employed to investigate the association between various factors (age, sex, surgical site, body mass index, surgical risk classification, operative duration, length of stay, and medical comorbidities) and the occurrence of adverse events.

RESULTS

The sample included 2,146 patients. The overall adverse event rate was 27% (571 of 2,146), and by surgical site, the rates were 29% (130 of 442) for spine; 27% (266 of 998) for knee; and 25% (175 of 706) for hip. The most common adverse events had a low severity grade, but spinal procedures demonstrated more adverse events with a severity grade of ≥3. Increasing age (odds ratio [OR] = 1.21, 95% confidence interval [CI] =1.05 to 1.41, per 15-year interval), male sex (OR = 1.43, 95% CI =1.16 to 1.77), increasing operative duration (OR = 1.13, 95% CI = 1.03 to 1.23, per 30-minute increase), length of stay (OR = 1.13, 95% CI = 1.10 to 1.17, per day), and undergoing revision surgery (OR = 2.23, 95% CI = 1.35 to 3.70) were independently associated with a greater likelihood of the occurrence of an adverse event. Spine surgery demonstrated decreased odds of an adverse event compared with knee surgery (OR = 0.38, 95% CI = 0.23 to 0.61) when operative duration and length of stay were taken into account.

CONCLUSIONS

On the basis of our adjusted analysis, we found increasing age, male sex, revision surgery, length of stay, and increasing operative duration to be common independent risk factors for an adverse event across the population studied. The first 3 risk factors are not modifiable. The association between increasing operative duration and the risk of an adverse event across all anatomical regions and surgical procedures is a unique finding. However, modification of procedural efficiency is multifactorial and warrants further investigation.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

All-Cause Versus Complication-Specific Readmission Following Total Knee Arthroplasty

BACKGROUND

Unplanned readmissions have become an important quality indicator, particularly for reimbursement; thus, accurate assessment of readmission frequency and risk factors for readmission is critical. The purpose of this study was to determine (1) the frequency of and (2) risk factors for readmissions for all causes or procedure-specific complications within 30 days after total knee arthroplasty (TKA) as well as (3) the association between hospital volume and readmission rate.

METHODS

The Statewide Planning and Research Cooperative System (SPARCS) database from the New York State Department of Health was used to identify 377,705 patients who had undergone primary TKA in the period from 1997 to 2014. Preoperative diagnoses, comorbidities, and postoperative complications were determined using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Readmission was defined as all-cause, due to complications considered by the Centers for Medicare & Medicaid Services (CMS) to be TKA-specific, or due to an expanded list of TKA-specific complications based on expert opinion. Multivariable logistic regression analysis was utilized to determine the independent predictors of readmission within 30 days after surgery.

RESULTS

There were 22,076 all-cause readmissions-a rate of 5.8%, with a median rate of 3.9% (interquartile range [Q1, Q3] = 1.1%, 7.2%]) among the hospitals-within 30 days after discharge. Of these, only 11% (0.7% of all TKAs) were due to complications considered to be TKA-related by the CMS whereas 31% (1.8% of all TKAs) were due to TKA-specific complications on the expanded list based on expert opinion. Risk factors for TKA-specific readmissions based on the expanded list of criteria included an age of >85 years (odds ratio [OR] = 1.32, 95% confidence interval [CI] = 1.15 to 1.52), male sex (OR = 1.41, 95% CI = 1.34 to 1.49), black race (OR = 1.24, 95% CI = 1.14 to 1.34), Medicaid coverage (OR = 1.40, 95% CI = 1.26 to 1.57), and comorbidities. Several comorbid conditions contributed to the all-cause but not the TKA-specific readmission risk. Very low hospital volume (<90 cases per year) was associated with a higher readmission risk.

CONCLUSIONS

The frequency of readmissions for TKA-specific complications was low relative to the frequency of all-cause readmissions. Reasons for hospital readmission are multifactorial and may not be amenable to simple interventions. Health-care-quality measurement of readmission rates should be calculated and risk-adjusted on the basis of procedure-specific criteria.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total Knee Arthroplasty for Knee Osteoarthritis: Support for a Foregone Conclusion?

Total knee arthroplasty (TKA) is generally accepted as the definitive treatment for advanced knee arthritis after patients fail nonoperative treatments; however, the safety and efficacy of TKA compared to continued nonoperative treatment has never been proven in high-quality, randomized controlled trials. Recently, a 2015 Danish study published a 12-month follow-up on a cohort of patients randomized to either a TKA or continued nonsurgical management for advanced knee osteoarthritis (OA). The authors reported significantly greater improvement in the TKA group in functional outcome scores such as the overall Knee Injury and Osteoarthritis Outcome Score (KOOS₄ score), the KOOS subscales, EQ-5D descriptive index, and timed get up-and-go and 20-m walk tests; however, patients in the TKA did suffer significantly more serious adverse events (SAE). The authors concluded that TKA combined with additional nonoperative care postoperatively is more efficacious than nonsurgical treatment alone in terms of improving pain, function, and quality of life at 12 months but is associated with more SAE. The purpose of this review is to identify the strengths and weaknesses of this trial, interpret its outcomes within the context of prior literature, and evaluate the validity of its conclusions.

Association between preoperative anaemia with length of hospital stay among patients undergoing primary total knee arthroplasty in Singapore: a single-centre retrospective study

OBJECTIVES

Studies in western healthcare settings suggest that preoperative anaemia is associated with poor outcomes after elective orthopaedic surgery. We investigated the prevalence of preoperative anaemia among patients with primary unilateral total knee arthroplasty (TKA) in Singapore and its association with length of hospital stay (LOS), perioperative blood transfusion and hospital readmission rates.

METHODS

Retrospective cohort study performed in a tertiary academic medical centre in Singapore, involving patients who underwent primary unilateral TKA between January 2013 and June 2014. Demographics, comorbidities, preoperative haemoglobin (Hb) level, LOS and 30-day readmission data were collected. Anaemia was classified according to WHO definition. Prolonged LOS was defined as more than 6 days, which corresponds to >75th centile LOS of the data.

RESULTS

We analysed 2394 patients. The prevalence of anaemia was 23.7%. 403 patients (16.8%) had mild anaemia and 164 patients (6.8%) had moderate to severe anaemia. Overall mean LOS was 5.4±4.8 days. Based on multivariate logistic regression, preoperative anaemia significantly increased LOS (mild anaemia, adjusted OR (aOR) 1.71, p<0.001; moderate/severe anaemia, aOR 2.29, p<0.001). Similar effects were seen when preoperative anaemia was defined by Hb level below 13 g/dL, regardless of gender. Transfusion proportionately increased prolonged LOS (1 unit: aOR 2.12, p=0.006; 2 or more units: aOR 6.71, p<0.001). Repeat operation during hospital stay, previous cerebrovascular accidents, general anaesthesia and age >70 years were associated with prolonged LOS. Our 30-day related readmission rate was 1.7% (42) cases.

CONCLUSION

Anaemia is common among patients undergoing elective TKA in Singapore and is independently associated with prolonged LOS and increased perioperative blood transfusion. We suggest measures to correct anaemia prior to surgery, including the use of non-gender-based Hb cut-off for establishing diagnosis.

Unplanned readmissions after primary total knee arthroplasty in Korean patients: Rate, causes, and risk factors

BACKGROUND

Unplanned hospital readmissions are indicators of the quality and performance of a health care system, but data on early readmission after primary total knee arthroplasty (TKA) in the Asian population are limited. The purpose of this study was to determine the causes, risk factors, and rate of unplanned readmission after primary TKA at a single institution in Korea.

METHODS

We analyzed all primary TKAs from 2004 to 2013 using the data from our institutional electronic database. A total of 4596 TKAs were performed on 3049 patients. All unplanned readmissions within 30 and 90days of discharge were identified, categorized into arthroplasty-related, medical, and other orthopedic causes.

RESULTS

The overall unplanned readmission rate was 1.9% (n=59) within 30days and 3.3% (n=101) within 90days, and both the 30 and 90day readmission rates remained stable over the entire study period. The majority of readmissions involved arthroplasty-related causes; the most common cause being wound problems, accounting for 22% (13/59) within 30days and 24% (24/101) within 90days. Age (P=0.029) and hypertension (P=0.021) were identified as risk factors for unplanned readmissions after TKA.

CONCLUSION

This study demonstrates that unplanned readmissions after TKA are not infrequent in Korean patients and has identified wound complication as the most frequent cause of unplanned readmissions. Optimized care systems should be established to minimize unplanned readmissions, particularly for patients with high risk factors.

A retrospective cohort study of adverse events in patients undergoing orthopaedic surgery

Background

This study’s objective was to identify adverse events following common orthopaedic procedures, and to estimate the incidence rates and risks of these events and their associations with age, sex, and comorbidities.

Methods

This retrospective cohort study manually reviewed and extracted electronic medical data on the incidence and predictors of adverse events that occurred within 90 days of the 50 most frequent orthopaedic surgeries at an academic hospital in 2010. We also extracted demographic data, baseline comorbidities, and duration of follow-up (≤90 days). Patients were scored on the Charlson Comorbidity Index (CCI) and the Functional Comorbidity Index (FCI). We estimated incidence rates and risks for all events and associations using regression methods. Prolonged pain 42-days post-surgery was treated as a separate outcome.

Results

We included 1,552 patients; average age was 53.4 years, and 51.7% were female. A total of 1,148 adverse events were identified in 729 patients. The incidence rate of all adverse events was 10 events per 1,000 person-days at risk; 47% of all patients experienced at least one adverse event within 90 days. The most frequent events were prolonged pain (31% of all adverse events) and persistent swelling (7%). We found positive associations between both comorbidity scores and the incidence rate and 90-day risk of all adverse events, excluding pain, adjusting for age and sex (neither of which was associated with adverse events); the association was stronger for the FCI than for the CCI. For total hip arthroplasty (THA) and total knee arthroplasty (TKA), the incidence rate of all adverse events, excluding pain, was positively associated with both comorbidity scores and age; the 90-day risk was positively associate with the FCI score and male sex. The prevalence of prolonged pain at 42 days was greater in patients with higher FCI scores; for THA and TKA only, pain prevalence was greater in those with higher FCI scores and in men.

Conclusions

Adverse events are frequent following common orthopaedic procedures. The incidence is greatest for patients with more functional comorbidities. For THA and TKA procedures, being male and being older are also associated with a greater incidence of adverse events.

Translating Comprehensive Conservative Care for Chronic Knee Pain Into a Digital Care Pathway: 12-Week and 6-Month Outcomes for the Hinge Health Program

Background

Chronic knee pain (CKP) affects a large number of adults, many of whom do not receive best-practice care and are at high risk for unnecessary surgery.

Objective

The aim of this study was to investigate the effect of the Hinge Health 12-week digital care program (DCP) for CKP on knee pain and function, with secondary outcomes of surgery interest and satisfaction, at 12 weeks and 6 months after starting the program.

Methods

Individuals with CKP were recruited onto the 12-week program, comprising sensor-guided physical exercises, weekly education, activity tracking, and psychosocial support such as personal coaching and cognitive behavioral therapy (CBT). We used a single-arm design with assessment of outcomes at baseline, 12 weeks, and 6 months after starting the program. We used a linear mixed effects model with Tukey contrasts to compare timepoints and report intention-to-treat statistics with last observation carried forward.

Results

The cohort consisted of 41 individuals (32 female, mean age 52 years, SD 9 years). Between baseline and week 12, participants reported clinically significant improvements in the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain and Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) function scales of 16 points (95% CI 12-21, P<.001) and 10 points (95% CI 6-14, P<.001), respectively. Significant reductions of 57% (mean difference 30, 95% CI 21-38, P<.001) and 51% (mean difference 25, 95% CI 16-33, P<.001) in visual analog scale (VAS) knee pain and stiffness, respectively, were observed at 12 weeks, as well as a 67% reduction in surgery interest (mean reduction 2.3 out of 10, 95% CI 1.5-3.1, P<.001). Average satisfaction at week 12 was 9.2 out of 10. Critically, all improvements were maintained at 6 months at similar or greater magnitude.

Conclusions

Participants on the Hinge Health DCP for CKP showed substantial clinical improvements that were maintained 6 months after enrolling in the program. This shows that DCPs carry strong potential to deliver evidence-based, cost-effective care to those suffering from CKP.

Complications after total knee replacement in patients with chronic obstructive pulmonary disease: A nationwide case-control study

The incidence and prevalence of chronic obstructive pulmonary disease (COPD) is associated with increasing age. Osteoarthritis is also a growing problem in the aging population, and total knee replacement (TKR) is a common surgical procedure for this population. An increasing number of COPD patients are receiving TKR, but few studies have examined the complications and outcomes after TKR in COPD patients. The purpose of this study was to investigate the complications, including mortality, wound infections, hospitalization readmission, pneumonia (PN), and cerebrovascular accidents (CVAs) in patients with COPD after receiving TKR.The National Health Insurance operated by the government is a nationwide health care program with universal coverage in Taiwan. It covers approximately 99% of the total Taiwanese population of 23 million people. In this case-control study, we analyzed the longitudinally linked National Health Insurance Research Database, which consists of a cohort of 1,000,000 randomly selected enrollees retrospectively followed from 1996 to 2010. This study analyzed patients who underwent TKR surgery between January 1, 2004 and December 31, 2009 by identifying the International Classification of Diseases, Ninth Revision, Clinical Modification code. We separated patients into COPD and non-COPD groups. Five study outcomes and complications were measured after TKR, including mortality for 1 and 3 years, wound infections for 1 and 2 years, hospitalization readmission for 30 and 90 days, PN for 30 and 90 days, and CVAs.A total of 3431 patients who underwent TKR surgery were identified, including 358 patients with COPD and 3073 patients without COPD. The COPD group had a higher percentage of 90-day PN (3.7% vs. 1.1%), 30-day readmission (7.0% vs. 4.0%), 30-day CVA (1.7% vs. 0.6%), 90-day CVA (3.9% vs. 2.1%), and 3-year mortality (3.9% vs. 2.1%) than the non-COPD group. COPD was associated with 90-day PN (adjusted hazard ratio[HR)] = 2.12, P = 0.030) after adjusting for sex, cardiovascular disease, and CVA occurrence.Patients with COPD had a higher risk of PN after TKR than patients without COPD, but no significant differences were found for CVAs and mortality.

Effect of Body Mass Index and Psychosocial Traits on Total Knee Replacement Costs in Patients with Osteoarthritis

Objective.

Clinical and psychosocial attributes are associated with clinical outcomes after total knee replacement (TKR) surgery in patients with osteoarthritis (OA), but their relationship with TKR-related costs is less clear. Our objective was to evaluate the effect of clinical and psychosocial attributes on TKR costs.

Methods.

We conducted a 6-month prospective cohort study of patients with knee OA who underwent TKR. We examined baseline demographic, clinical [body mass index (BMI) and comorbidities], and psychosocial attributes (social support, locus of control, coping, depression, anxiety, stress, and self-efficacy); baseline and 6-month OA clinical outcomes [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function]; and 6-month direct and indirect TKR-related costs. Multiple regression was performed to identify determinants of TKR-related costs.

Results.

We included 212 patients; 66% were women, 71% were white, and the mean age was 65.2 years. The mean baseline WOMAC pain score was 55 (SD 19) and WOMAC function score was 54 (SD 20). Mean total TKR-related costs were US$30,831 (SD $9893). Multivariate regression analyses showed that increasing BMI and anxiety levels and decreasing levels of positive social interactions were associated with increased costs. A lower cost scenario with a lower range of normal BMI (19.5), highest positive social interaction, and no anxiety predicted TKR costs to be $22,247. Predicted costs in obese patients (BMI 36) with lowest positive social interaction and highest anxiety were $58,447.

Conclusion.

Increased baseline BMI, anxiety, and poor social support lead to higher TKR-related costs in patients with knee OA. Preoperative interventions targeting these factors may reduce TKR-related costs, and therefore be cost-effective.

Age and Preoperative Knee Society Score Are Significant Predictors of Outcomes Among Asians Following Total Knee Arthroplasty

BACKGROUND

The ability to predict patients' functional outcomes will add value to preoperative counseling. The purpose of this study was to evaluate predictors of good outcomes following total knee arthroplasty (TKA) among Asian patients.

METHODS

Registry data from 2006 to 2010 were extracted. The Oxford Knee Score (OKS) and the Short Form (SF)-36 physical component summary (PCS) were used to evaluate outcomes. A "good outcome" was defined as an improvement in scores of greater than or equal to the minimal clinically important difference (MCID) in the primary analysis. The MCID for the OKS was 5, and the MCID for the PCS was 10. For the sensitivity analyses, a "good outcome" was defined as an OKS of <30 and a PCS score of >50. Clinical variables were used to develop a multiple logistic regression model for a good outcome following total knee arthroplasty at 5 years.

RESULTS

Follow-up data were available for 3,062 patients who underwent primary TKA (mean age of 66.4 years; 79.5% female). Eighty-five percent had a good outcome on the basis of the OKS and 83%, on the basis of the SF-36 PCS. Age and preoperative Knee Society score (KSS) were found to be significant predictors. When outcomes were assessed by the MCID, lesser age and lower (worse) preoperative KSS predicted a good outcome at 5 years. When outcomes were assessed by absolute criteria (postoperative scores measured against OKS and PCS thresholds), a higher (better) preoperative KSS predicted a good outcome at 5 years. Body mass index, preoperative flexion range, SF-36 mental component summary (MCS) score, mechanical alignment, sex, education level, ethnicity, operative side, number of comorbidities, type of anesthesia, and type of implant were found not to be significant predictors.

CONCLUSIONS

The majority of Asian patients with osteoarthritis had good outcomes according to the MCID criterion and benefitted from primary TKA. On the basis of our findings, we believe that older patients with a lower (worse) preoperative KSS can be informed that they have a high likelihood of improvement but a lower likelihood of achieving as good a functional outcome as those with better scores.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hospital-Based Acute Care After Total Hip and Knee Arthroplasty: Implications for Quality Measurement

BACKGROUND

Although hospital readmissions are being adopted as a quality measure after total hip or knee arthroplasty, they may fail accurately capture the patient's postdischarge experience.

METHODS

We studied 272,853 discharges from 517 hospitals to determine hospital emergency department (ED) visit and readmission rates.

RESULTS

The hospital-level, 30-day, risk-standardized ED visit (median = 5.6% [2.4%-13.7%]) and hospital readmission (5.0% [2.6%-9.2%]) rates were similar and varied widely. A hospital's risk-standardized ED visit rate did not correlate with its readmission rate (r = -0.03, P = .50). If ED visits were included in a broader "readmission" measure, 246 (47.6%) hospitals would change perceived performance groups.

CONCLUSION

Including ED visits in a broader, hospital-based, acute care measure may be warranted to better describe postdischarge health care utilization.

Hyaluronic Acid Injections Are Associated with Delay of Total Knee Replacement Surgery in Patients with Knee Osteoarthritis: Evidence from a Large U.S. Health Claims Database

BACKGROUND

The growing prevalence of osteoarthritis (OA) and the medical costs associated with total knee replacement (TKR) surgery for end-stage OA motivate a search for agents that can delay OA progression. We test a hypothesis that hyaluronic acid (HA) injection is associated with delay of TKR in a dose-dependent manner.

METHODS AND FINDINGS

We retrospectively evaluated records in an administrative claims database of ~79 million patients, to identify all patients with knee OA who received TKR during a 6-year period. Only patients with continuous plan enrollment from diagnosis until TKR were included, so that complete medical records were available. OA diagnosis was the index event and we evaluated time-to-TKR as a function of the number of HA injections. The database included 182,022 patients with knee OA who had TKR; 50,349 (27.7%) of these patients were classified as HA Users, receiving ≥1 courses of HA prior to TKR, while 131,673 patients (72.3%) were HA Non-users prior to TKR, receiving no HA. Cox proportional hazards modelling shows that TKR risk decreases as a function of the number of HA injection courses, if patient age, gender, and disease comorbidity are used as background covariates. Multiple HA injections are therefore associated with delay of TKR (all, P < 0.0001). Half of HA Non-users had a TKR by 114 days post-diagnosis of knee OA, whereas half of HA Users had a TKR by 484 days post-diagnosis (χ2 = 19,769; p < 0.0001). Patients who received no HA had a mean time-to-TKR of 0.7 years; with one course of HA, the mean time to TKR was 1.4 years (χ2 = 13,725; p < 0.0001); patients who received ≥5 courses delayed TKR by 3.6 years (χ2 = 19,935; p < 0.0001).

CONCLUSIONS

HA injection in patients with knee OA is associated with a dose-dependent increase in time-to-TKR.

The Impact of Risk Reduction Initiatives on Readmission: THA and TKA Readmission Rates

We assessed whether sequential incorporation of initiatives to decrease postoperative surgical complications were similarly effective in reducing 30-day readmission rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA). Readmission rates following TKA decreased substantially (5.6% vs. 3.0%, P<0.001), but readmissions following THA (4.0% vs. 3.4%, P=0.41) were not significantly reduced. The greatest impact of the multimodal treatment approach was a reduction of surgically related TKA complications. Advanced medical disease, facility discharge status, and Medicare or Medicaid coverage contributed to the highest risk for 30-day readmission after THA. Risk models defining expected readmission rates should account for these factors to avoid penalizing hospitals that provide higher proportional care to Centers for Medicaid and Medicare Services (CMS) beneficiaries.

Socioeconomically Disadvantaged CMS Beneficiaries Do Not Benefit From the Readmission Reduction Initiatives

We assessed the impact of minority and socioeconomic status on 30-day readmission rates after 3825 primary total hip arthroplasty (THA) and 3118 primary total knee arthroplasty (TKA) procedures. Minority patients had higher THA (7.4% vs 3.2%, P=0.001) and TKA (5.4% vs 3.7%, P<0.001) readmission rates. Low socioeconomic status was associated with higher THA (6.0% vs 3.1%, P<0.001) and TKA (6.3% vs 3.8%, P=0.02) readmission rates. Risk reduction initiatives were effective after TKA, but minority status and low socioeconomic status were still associated with higher 30-day readmission rates (4.6% vs 1.8%, P<0.01). Focused postoperative engagement for Centers for Medicare and Medicaid Services (CMS) beneficiaries less than 65 years of age may help reduce complications and 30-day readmissions.

Are there identifiable risk factors and causes associated with unplanned readmissions following total knee arthroplasty?

We conducted a retrospective review of 3218 primary total knee arthroplasties (TKA) performed over two years at an urban academic hospital network using clinical and administrative data. Increased length of stay (LOS) was associated with readmission (P < 0.001). Readmission was not associated with age (P = 0.100), gender (P = 0.608), body mass index (P = 0.329), or staged bilateral procedures (P = 0.420). The most common readmitting diagnoses were post-operative infection (22.5%), hematoma (10.1%), pulmonary embolus (7.9%) and deep vein thrombosis (5.6%). Of readmissions, 53.9% were for surgical reasons and 46.1% were for medical reasons. Certain interventions described in previous literature may be more successful in minimizing unplanned readmissions by focusing on patients with extended LOS, elevated infection risk and low socioeconomic status.

Mortality of elderly patients after two-stage reimplantation for total joint infection: a case-control study

The mortality of two-stage reimplantation for periprosthetic joint infection in patients over the age of 80 has not previously been studied. We retrospectively reviewed 134 elderly patients undergoing two-stage reimplantation at 90 days, 1 year and 5 years and compared them to a matched cohort who underwent single-stage aseptic total joint revision. There was no significant difference in preoperative comorbidities between groups. The mortality rates for the two-stage and aseptic groups were 39.9% and 34.1% respectively with an overall mortality rate of 36.7%. There was no significant difference in mortality at any time point (95% CI: 29.4, 43.1). Two-stage reimplantation does not significantly increase the mortality of patients over the age of 80 when compared to a matched cohort undergoing aseptic revision at our institution.

What are the economic consequences of unplanned readmissions after TKA?

BACKGROUND

In 2009, the Center for Medicare & Medicaid Services (CMS) began penalizing hospitals with high rates of 30-day readmissions after hospitalizations for certain conditions. This policy will expand to include TKA in 2015.

QUESTIONS/PURPOSES

What are the median profits and contribution margins of: (1) Medicare-reimbursed TKA, (2) 30-day TKA readmission, and (3) entire episode of care for readmitted TKA patients within 30 days compared to nonreadmitted patients? (4) Under new CMS guidelines, what financial penalty will the authors' institution face if its arthroplasty readmission rate exceeds the national average?

METHODS

A retrospective review of 3218 primary TKAs performed during 2 years at a large urban academic hospital network was conducted using administrative and financial data.

RESULTS

The median profit and contribution margins, respectively, were as follows: TKA episode, USD 5209 and USD 11,726; 30-day readmission, USD 608 and USD 3814; TKA visit with readmission, USD 2855 and USD 13,901; TKA visit without readmission, USD 5300 and USD 11,652. Readmission penalties could reach USD 6.21 million per year for the authors' institution.

DISCUSSION

If our results are generalizable, unplanned TKA readmissions lead to diminished total profit. Although associated with a positive contribution margin, this is likely to be a short-term phenomenon as the new CMS policy will result in readmissions coming at a steep cost to referral centers.

Hospital readmissions after primary shoulder arthroplasty

BACKGROUND

Although shoulder arthroplasty procedures are more frequently performed in the United States, there is insufficient information on outcome measures such as hospital readmission rates or factors for readmission after surgery.

METHODS

The State Inpatient Database from 7 different states was used to identify patients who underwent hemiarthroplasty, total shoulder arthroplasty (TSA), or reverse total shoulder arthroplasty (RTSA) from 2005 through 2010. The database was used to determine the 90-day readmission rate, causes of readmission, and risk factors for readmission. Multivariate modeling and a Cox proportional hazards model were used to measure factors and risk for readmission.

RESULTS

Included were 26,218 patients receiving shoulder arthroplasty, with an overall 90-day readmission rate of 7.3%. RTSA had the highest rate (11.2%), followed by hemiarthroplasty (8.2%) and TSA (6.0%; P < .001). Medical complications contributed to 82% of readmissions, and surgical complications contributed to 18%. Osteoarthritis was the most common medical diagnosis (11%), followed by deep venous thrombosis or pulmonary embolism (4.4%) and pneumonia (3.9%). Infection was the most common surgical cause of readmission (4.8%), followed by dislocation (4.6%). There was a stepwise increase in risk of readmission with increasing age. Patients with Medicaid insurance had more than a 50% greater risk of readmission than patients with Medicare. Procedures performed at medium-volume and high-volume hospitals showed lower risk of readmission than low-volume centers.

CONCLUSIONS

Patients undergoing RTSA had higher hospital readmission rates than those undergoing hemiarthroplasty or TSA, but most readmissions after shoulder arthroplasty were due to medical causes.

Differences in short-term complications between unicompartmental and total knee arthroplasty: a propensity score matched analysis

BACKGROUND

Knee arthroplasty has emerged as an effective treatment for end-stage gonarthrosis. Although total knee arthroplasty remains the gold standard, unicompartmental knee arthroplasty is an appropriate alternative for select patients. We sought to use a large, heterogeneous national database to identify differences in thirty-day complication rates between unicompartmental and total knee arthroplasty as well as to identify risk factors for complications.

METHODS

Patients in the ACS NSQIP (American College of Surgeons National Surgical Quality Improvement Program) database who had undergone total or unicompartmental knee arthroplasty from 2005 to 2011 were identified. CPT (Current Procedural Terminology) codes were used to select cases of elective primary knee arthroplasty. Statistical models employing univariate and multivariate logistic regression identified risk factors associated with the thirty-day incidence of morbidity and mortality after total and unicompartmental knee arthroplasty. Propensity score matching addressed demographic differences between the total and unicompartmental knee arthroplasty cohorts.

RESULTS

A total of 29,333 patients were identified; 27,745 (94.6%) underwent total knee arthroplasty and 1588 (5.41%) underwent unicompartmental knee arthroplasty. Prior to matching, the total knee arthroplasty cohort was 63.7% female and had a mean BMI of 32.8 ± 7.3 kg/m(2), whereas the values for the unicompartmental cohort were 55.3% and 31.5 ± 6.5 kg/m(2) (p < 0.0001). The mean ages of these cohorts were 67.2 ± 10.1 and 64.0 ± 10.7 years, respectively (p < 0.0001). A previously developed and implemented propensity score matching algorithm was used to address the demographic differences. Following matching, the total complication rate did not differ significantly between the total and unicompartmental knee arthroplasty cohorts (5.29% compared with 4.16%, p = 0.35), whereas the rate of deep venous thrombosis (1.50% compared with 0.50%, p = 0.02) and the duration of hospital stay (3.4 compared with 2.2 days, p < 0.0001) were significantly higher in the total knee arthroplasty cohort.

CONCLUSIONS

Comparison of total and unicompartmental knee arthroplasty revealed no differences in overall short-term (thirty-day) morbidity and mortality. Although this study does not address long-term subjective outcomes or implant survival, these findings should provide helpful information for surgeons counseling patients considering total and/or unicompartmental knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Thirty-day readmission following total hip and knee arthroplasty - a preliminary single institution predictive model

We sought to identify demographic or care process variables associated with increased 30-day readmission within the total hip and knee arthroplasty patient population. Using this information, we generated a model to predict 30-day readmission risk following total hip and knee arthroplasty procedures. Longer index length of stay, discharge disposition to a nursing facility, blood transfusion, general anesthesia, anemia, anticoagulation status prior to index admission, and Charlson Comorbidity Index greater than 2 were identified as independent risk factors for readmission. Care process factors during the hospital stay appear to have a large predictive value for 30-day readmission. Specific comorbidities and patient demographic factors showed less significance. The predictive nomogram constructed for primary total joint readmission had a bootstrap-corrected concordance statistic of 0.76.

Does preoperative American Society of Anesthesiologists score relate to complications after total shoulder arthroplasty?

BACKGROUND

For hip and knee arthroplasties, an American Society of Anesthesiologists (ASA) score greater than 2 is associated with an increased risk of medical and surgical complications. No study, to our knowledge, has evaluated this relationship for total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (reverse TSA).

QUESTIONS/PURPOSES

We aimed to assess the relationship between the ASA score and (1) surgical complications, (2) medical complications, and (3) hospitalization length after TSA, reverse TSA, and revision arthroplasty.

METHODS

We retrospectively analyzed all patients who had undergone TSAs, reverse TSAs, or revision arthroplasties by the senior author (EGM) from November 1999 through July 2011 who had at least 6 months' followup. Of the 485 procedures, 452 (93.2%) met the inclusion criteria. Data were collected on patient demographics, comorbidities, hospitalization length, and short-term (≤ 6 months) medical and surgical complications. Logistic regression analysis modeled the risk of having postoperative complications develop as a function of the ASA score.

RESULTS

Patients with an ASA score greater than 2 had a greater risk of having a surgical complication develop (p < 0.001; OR, 2.27; 95% CI, 1.36-3.70) and three times the risk of prosthesis failure (ie, component dislocation, component loosening, and hardware failure) (p < 0.001; OR, 3.23; 95% CI, 1.54-6.67). Higher ASA scores were associated with prolonged length of hospitalization (effect size 0.46, p < 0.001), but not medical complications.

CONCLUSIONS

ASA score is associated with surgical, but not medical, complications after TSA and reverse TSA. The ASA score could be used for risk assessment and preoperative counseling.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Complications, mortality, and costs for outpatient and short-stay total knee arthroplasty patients in comparison to standard-stay patients

The purpose of the present study is to determine the differences in cost, complications, and mortality between knee arthroplasty (TKA) patients who stay the standard 3-4 nights in a hospital compared to patients who undergo an outpatient procedure, a shortened stay or an extended stay. TKA patients were identified in the Medicare 5% sample (1997-2009) and separated into the following groups: outpatient, 1-2 days, 3-4 days, or 5+ days inpatient. At two years, costs associated with the outpatient and the 1-2 day stay groups were $8527 and $1967 lower than the 3-4 day stay group, respectively. Out to 2 years, the outpatient and 1-2 day stay groups reported less pain and stiffness, respectively, though the 1-2 day group also had a higher risk for revision.

National trends in patient safety for four common conditions, 2005-2011

BACKGROUND

Changes in adverse-event rates among Medicare patients with common medical conditions and conditions requiring surgery remain largely unknown.

METHODS

We used Medicare Patient Safety Monitoring System data abstracted from medical records on 21 adverse events in patients hospitalized in the United States between 2005 and 2011 for acute myocardial infarction, congestive heart failure, pneumonia, or conditions requiring surgery. We estimated trends in the rate of occurrence of adverse events for which patients were at risk, the proportion of patients with one or more adverse events, and the number of adverse events per 1000 hospitalizations.

RESULTS

The study included 61,523 patients hospitalized for acute myocardial infarction (19%), congestive heart failure (25%), pneumonia (30%), and conditions requiring surgery (27%). From 2005 through 2011, among patients with acute myocardial infarction, the rate of occurrence of adverse events declined from 5.0% to 3.7% (difference, 1.3 percentage points; 95% confidence interval [CI], 0.7 to 1.9), the proportion of patients with one or more adverse events declined from 26.0% to 19.4% (difference, 6.6 percentage points; 95% CI, 3.3 to 10.2), and the number of adverse events per 1000 hospitalizations declined from 401.9 to 262.2 (difference, 139.7; 95% CI, 90.6 to 189.0). Among patients with congestive heart failure, the rate of occurrence of adverse events declined from 3.7% to 2.7% (difference, 1.0 percentage points; 95% CI, 0.5 to 1.4), the proportion of patients with one or more adverse events declined from 17.5% to 14.2% (difference, 3.3 percentage points; 95% CI, 1.0 to 5.5), and the number of adverse events per 1000 hospitalizations declined from 235.2 to 166.9 (difference, 68.3; 95% CI, 39.9 to 96.7). Patients with pneumonia and those with conditions requiring surgery had no significant declines in adverse-event rates.

CONCLUSIONS

From 2005 through 2011, adverse-event rates declined substantially among patients hospitalized for acute myocardial infarction or congestive heart failure but not among those hospitalized for pneumonia or conditions requiring surgery. (Funded by the Agency for Healthcare Research and Quality and others.).

What are the rates and causes of hospital readmission after total knee arthroplasty?

BACKGROUND

Total knee arthroplasty (TKA) and related interventions such as revision TKA and the treatment of infected TKAs are commonly performed procedures. Hospital readmission rates are used to measure hospital performance, but risk factors (both medical and surgical) for readmission after TKA, revision TKA, and treatment for the infected TKA have not been well characterized.

QUESTIONS/PURPOSES

We measured (1) the unplanned hospital readmission rate in primary TKA and revision TKA, including antibiotic-spacer staged revision TKA to treat infection. We also evaluated (2) the medical and surgical causes of readmission and (3) risk factors associated with unplanned hospital readmission.

METHODS

This retrospective cohort study included a total of 1408 patients (1032 primary TKAs, 262 revision TKAs, 113 revision of infected TKAs) from one institution. All hospital readmissions within 90 days of discharge were evaluated for timing and cause. Diagnoses at readmission were categorized as surgical or medical. Readmission risk was assessed using a Cox proportional hazards model that incorporated patient demographics and medical comorbidities.

RESULTS

The unplanned readmission rate for the entire cohort was 4% at 30 days and 8% at 90 days. At 90 days postoperatively, revision of an infected TKA had the highest readmission rate, followed by revision TKA, with primary TKA having the lowest rate. Approximately three-fourths of readmissions were the result of surgical causes, mostly infection, arthrofibrosis, and cellulitis, whereas the remainder of readmissions were the result of medical causes. Procedure type (primary TKA versus revision TKA or staged treatment for infected TKA), hospital stay more than 5 days, discharge destination, and a fluid/electrolyte abnormality were each associated with risk of unplanned readmission.

CONCLUSIONS

Patients having revision TKA, whether for infection or other causes, are more likely to have an unplanned readmission to the hospital than are patients having primary TKA. When assessing hospital performance for TKA, it is important to distinguish among these surgical procedures.

Older age increases short-term surgical complications after primary knee arthroplasty

BACKGROUND

Age is a known risk factor for complications after knee arthroplasty; however, age-related risks for a variety of complications of total and partial knee arthroplasties have not been well quantified.

QUESTIONS/PURPOSES

Our study addressed three questions to better understand age-related risk of complications: (1) At what age do different types of complications increase? (2) Is the increase in complications with age resulting from age-related patient comorbidities, sociodemographic characteristics, and surgical conditions? (3) What is the probability of complications at different ages for an average patient?

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database from 2005 to 2009 was used to analyze complications for 8950 patients. Complications included NSQIP events, and complications described by the 2003 National Institutes of Health (NIH) consensus statement on total knee arthroplasty as well as 30-day mortality, deep vein thrombosis, return to the operating room, extended length of stay, and technical aspects of the surgery itself. Logistic regression analysis was performed.

RESULTS

Mortality was higher for those aged 85 and older. NSQIP complications increased starting at age 70 years and NIH complications at 85 years. Age remained an independent risk factor for multiple complications with controls. The predicted risk for an average patient ranged from 4% (40-64 years old) to 17% (90 years or older) for NSQIP complications and 2.8% to 8.8% for NIH complications.

CONCLUSIONS

Age is an important independent predictor of surgical complications after knee arthroplasties. Surgeons can share these quantified age-specific risks with patients to guide management decisions.

Prevalência de incidentes sem dano e eventos adversos em uma clínica cirúrgica

OBJETIVO: Estimar a prevalência de incidentes sem dano e eventos adversos em uma clínica cirúrgica. MÉTODOS: Estudo transversal conduzido com amostra de 750 internações ocorridas na clínica cirúrgica de um hospital da região centro-oeste. Realizou-se análise descritiva e calculou-se a prevalência dos incidentes. RESULTADOS: Evidenciou-se que 615 internações foram expostas ao incidente sem dano e 140 ao evento adverso. Dos 5.672 registros de incidentes, 218 foram caracterizados como evento adverso por causarem dano ao paciente. Os demais não evidenciaram dano, entretanto apontaram necessidade de adequação dos processos de trabalho. CONCLUSÃO: Estimou-se prevalência de 82% de incidentes sem dano e 18,7% de eventos adversos.

Validity of patient-reported comorbidities before total knee and hip arthroplasty in patients older than 65 years

Obtaining preoperative medical histories in elderly patients can be challenging, and tools have been developed to aid in history gathering. The purpose of this study is to determine the agreement between patient- and physician-reported histories before total knee or hip arthroplasty. Three hundred eighty-two patients older than 65 years completed a preoperative morbidity assessment form preoperatively. Sensitivity, specificity, κ, and agreement were calculated for each dichotomous response. Diabetes (κ = 0.77) and lung disease (κ = 0.68) had substantial agreement. Fourteen comorbidities ranged from slight to moderate agreement. Osteoarthritis and peripheral vascular disease had no agreement. These results highlight the incongruence between patient- and physician-reported comorbidities and emphasizes the need for detailed histories by health care professionals for medically complicated elderly patients preoperatively.

Preoperative risk stratification reduces the incidence of perioperative complications after total knee arthroplasty

The purpose of this study was to validate a screening and management protocol to identify and reduce risk of renal, pulmonary, and delirium complications. A cohort study comparing incidence of perioperative complications on a consecutive series of patients undergoing total knee arthroplasty with a historical control group was conducted. The study cohort was evaluated prospectively to identify and reduce noncardiac medical complications. Medical records were reviewed for in-hospital complications. There were 623 patients in the study cohort and 493 patients in the control population. There was a statistically significant decrease in the incidence of delirium (control, 10.4% vs study, 0.8%; P = .0001), renal (4.9% vs 0.6%, P = .0001), cardiac (16.3% vs 2.1%, P = .0001), and pulmonary complications (5.7% vs 0.8%, P = .0001) in the screened patients vs control. Preoperative screening and management for medical complications resulted in a significant decrease in renal, pulmonary, delirium, and cardiac complications.

Rationing of total knee replacement: a cost-effectiveness analysis on a large trial data set

Objectives Many UK primary care trusts have recently introduced eligibility criteria restricting total knee replacement (TKR) to patients with low pre-operative Oxford Knee Scores (OKS) to cut expenditure. We evaluate these criteria by assessing the cost-effectiveness of TKR compared with no knee replacement for patients with different baseline characteristics from an NHS perspective. Design The cost-effectiveness of TKR in different patient subgroups was assessed using regression analyses of patient-level data from the Knee Arthroplasty Trial, a large, pragmatic randomised trial comparing knee prostheses. Setting 34 UK hospitals. Participants 2131 osteoarthritis patients undergoing TKR. Interventions and outcome measures Costs and quality-adjusted life years (QALYs) observed in the Knee Arthroplasty Trial within 5 years of TKR were compared with conservative assumptions about the costs and outcomes that would have been accrued had TKR not been performed. Results On average, primary TKR and 5 years of subsequent care cost £7458 per patient (SD: £4058), and patients gained an average of 1.33 (SD: 1.43) QALYs. As a result, TKR cost £5623/QALY gained. Although costs and health outcomes varied with age and sex, TKR cost <£20 000/QALY gained for patients with American Society of Anaesthesiologists grades 1-2 who had baseline OKS <40 and for American Society of Anaesthesiologists grade 3 patients with OKS <35, even with highly conservative assumptions about costs and outcomes without TKR. Body mass index had no significant effect on costs or outcomes. Restricting TKR to patients with pre-operative OKS <27 would inappropriately deny a highly cost-effective treatment to >10 000 patients annually. Conclusions TKR is highly cost-effective for most current patients if the NHS is willing to pay £20 000-£30 000/QALY gained. At least 97% of TKR patients in England have more severe symptoms than the thresholds we have identified, suggesting that further rationing by OKS is probably unjustified. Trial registration number ISRCTN 45837371.