Can Administrative Data Be Used to Analyze Complications Following Total Joint Arthroplasty?

Assessment of Patient Satisfaction and Outcomes After Outpatient Joint Arthroplasty in Academic Medical Centers

Background

There is limited literature evaluating patient satisfaction and outcomes after outpatient joint arthroplasty procedures in academic medical centers (AMCs). The aims of this study are to determine: (1) patients' desires to repeat their procedures and be discharged on the same day, (2) patient-reported outcome measures (PROMs), (3) time to discharge, (4) readmission rates, and (5) factors that predict PROMs in patients undergoing outpatient joint arthroplasty in AMCs.

Methods

A prospective survey was completed by 66 total hip arthroplasty (THA), 35 total knee arthroplasty (TKA), and 180 unicondylar knee arthroplasty (UKA) outpatients who underwent surgery from May 2018 to December 2020 in 2 AMCs. The survey consisted of questions regarding hip or knee PROMs (Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement), satisfaction with outpatient procedures and discharges, and reasons for readmissions. Linear regression analysis was conducted with statistical significance set at P < .05.

Results

100% of THA, 93.8% of TKA, and 93.0% of UKA outpatients stated that they would re-elect to undergo their respective procedure. Furthermore, 94% of THA, 81% of TKA, and 95% of UKA patients stated they would like same-day discharge again. THA, TKA, and UKA patients reported respective mean PROM scores of 94.7, 89.9, and 86.1. Readmission rates were 1.5%, 0.0%, and 0.5%, for THA, TKA, and UKA, respectively.

Conclusions

Patients who underwent outpatient joint arthroplasty procedures at 2 AMCs experienced minimal readmissions and reported a high desire to repeat their outpatient procedures.

Hospital spending and length of stay attributable to perioperative adverse events for inpatient hip, knee, and spine surgery: a retrospective cohort study

BACKGROUND

The incremental hospital cost and length of stay (LOS) associated with adverse events (AEs) has not been well characterized for planned and unplanned inpatient spine, hip, and knee surgeries.

METHODS

Retrospective cohort study of hip, knee, and spine surgeries at an academic hospital in 2011-2012. Adverse events were prospectively collected for 3,063 inpatient cases using the Orthopaedic Surgical AdVerse Event Severity (OrthoSAVES) reporting tool. Case costs were retrospectively obtained and inflated to equivalent 2021 CAD values. Propensity score methodology was used to assess the cost and LOS attributable to AEs, controlling for a variety of patient and procedure factors.

RESULTS

The sample was 55% female and average age was 64; 79% of admissions were planned. 30% of cases had one or more AEs (82% had low-severity AEs at worst). The incremental cost and LOS attributable to AEs were $8,500 (95% confidence interval [CI]: 5100-11,800) and 4.7 days (95% CI: 3.4-5.9) per admission. This corresponded to a cumulative $7.8 M (14% of total cohort cost) and 4,290 bed-days (19% of cohort bed-days) attributable to AEs. Incremental estimates varied substantially by (1) admission type (planned: $4,700/2.4 days; unplanned: $20,700/11.5 days), (2) AE severity (low: $4,000/3.1 days; high: $29,500/11.9 days), and (3) anatomical region (spine: $19,800/9 days; hip: $4,900/3.8 days; knee: $1,900/1.5 days). Despite only 21% of admissions being unplanned, adverse events in these admissions cumulatively accounted for 59% of costs and 62% of bed-days attributable to AEs.

CONCLUSIONS

This study comprehensively demonstrates the considerable cost and LOS attributable to AEs in orthopaedic and spine admissions. In particular, the incremental cost and LOS attributable to AEs per admission were almost five times as high among unplanned admissions compared to planned admissions. Mitigation strategies focused on unplanned surgeries may result in significant quality improvement and cost savings in the healthcare system.

Modeling Coding Intensity of Procedures in a U.S. Population-Based Hip/Knee Arthroplasty Inpatient Cohort Adjusting for Patient- and Facility-Level Characteristics

Variations in procedure coding intensity, defined as excess coding of procedures versus industry (instead of clinical) standards, can result in differentials in quality of care for patients and have additional implications for facilities and payors. The literature regarding coding intensity of procedures is limited, with a need for risk-adjusted methods that help identify over- and under-coding using commonly available data, such as administrative claims. Risk-adjusted metrics are needed for quality control and enhancement. We propose a two-step approach to risk adjustment, using a zero-inflated Poisson model, applied to a hip-knee arthroplasty cohort discharged during 2019 (n = 313,477) for patient-level risk adjustment, and a potential additional layer for adjustment based on facility-level characteristics, when desired. A 21.41% reduction in root-mean-square error was achieved upon risk adjustment for patient-level factors alone. Furthermore, we identified facilities that over- and under-code versus industry coding expectations, adjusting for both patient-level and facility-level factors. Excess coding intensity was found to vary across multiple levels: (1) geographically across U.S. Census regional divisions; (2) temporally with marked seasonal components; (3) by facility, with some facilities largely departing from industry standards, even after adjusting for both patient- and facility-level characteristics. Our proposed method is simple to implement, generalizable, it can be used across cohorts with different sets of information available, and it is not limited by the accessibility and sparsity of electronic health records. By identifying potential over- and under-coding of procedures, quality control personnel can explore and assess internal needs for enhancements in their health delivery services and monitor subsequent quality improvements.

Does Risk Mitigation Reduce 90-Day Complications in Patients Undergoing Total Knee Arthroplasty? A Cohort Study

Background

With ever-increasing demand for total knee arthroplasty (TKA), most healthcare systems around the world are concerned about its socioeconomic burden. Most centers have universally adopted well-defined clinical care pathways to minimize adverse outcomes, maximize volume, and limit costs. However, there are no prospective comparative trials reporting benefits of these risk mitigation (RM) strategies.

Methods

This is a prospective cohort study comparing post-TKA 90-day complications between patients undergoing RM before surgery and those following a standard protocol (SP). In the RM group, we used a 20-point checklist to screen for modifiable risk factors and evaluate the need for optimizing non-modifiable comorbidities. Only when optimization goals were achieved, patients were offered TKA.

Results

TKA was performed in 811 patients in the SP group and in 829 in the RM group, 40% of which were simultaneous bilateral TKA. In both groups, hypertension was the most prevalent comorbidity (48%), followed by diabetes (20%). A total of 43 (5.3%) procedure-related complications were seen over the 90-day postoperative period in the SP group, which was significantly greater than 26 (3.1%) seen in the RM group (p = 0.039). The commonest complication was pulmonary thromboembolic, 6 in each group. Blood transfusion rate was higher in the SP group (6%) than in the RM group (< 1%).

Conclusions

Screening and RM can reduce 90-day complications in patients undergoing TKA.

Venous thromboprophylaxis after total hip arthroplasty: aspirin, warfarin, enoxaparin, or factor Xa inhibitors?

INTRODUCTION

Debate over the ideal agent for venous thromboembolism (VTE) prophylaxis after total hip arthroplasty (THA) has led to changes in prescribing trends of commonly used agents. We investigate variation in utilisation and the differences in VTE incidence and bleeding risk in primary THA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors.

METHODS

8829 patients were age/sex matched from a large database of primary THAs performed between 2007 and 2016. Utilisation was calculated using compound annual growth rate. Incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications, postoperative anaemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days.

RESULTS

Aspirin use increased by 33%, enoxaparin by 7%, and factor Xa inhibitors by 31%. Warfarin use decreased by 1%. Factor Xa inhibitors (1.7%) and aspirin (1.7%) had the lowest incidence of DVT followed by enoxaparin (2.6%), and warfarin (3.7%) at 90 days. Factor Xa inhibitors (12%) and aspirin (12%) had the lowest incidence of blood transfusion followed by warfarin (15%) and enoxaparin (17%) at 90 days. There was no difference in incidence of blood transfusion or bleeding-related complications nor any detectable difference in symptomatic PE incidence.

CONCLUSIONS

The utilisation of aspirin and factor Xa inhibitors increased over time. Aspirin and factor Xa inhibitors provided improved DVT prophylaxis with lower rates of postoperative anaemia compared to enoxaparin and warfarin.

Reimbursement and Complications in Outpatient vs Inpatient Unicompartmental Arthroplasty

BACKGROUND

Increasing utilization of unicompartmental knee arthroplasty (UKA) has driven a greater push for outpatient treatment and cost containment in the setting of bundled payments. The purpose of this study is to evaluate utilization trends of inpatient vs outpatient UKA, index episode and 90-day reimbursement, and any differences in medical or surgical complications.

METHODS

The PearlDiver database was employed to identify all inpatient and outpatient UKAs performed between 2007 and 2016 with 2-year follow-up. Patients were matched by age, gender, and Elixhauser Comorbidity Index. We tracked index procedure and global period reimbursement, 90-day medical and surgical complications, and 2-year surgical complications.

RESULTS

The reimbursement and utilization cohort included 3181 outpatient and 5490 inpatient UKAs. Outpatient UKA and overall utilization of UKA increased over the study period. Mean index reimbursement of inpatient UKA was $2486.16 higher per procedure (P < .001) while mean global period reimbursement was $2782.13 higher per inpatient procedure (P < .001). Ninety-day medical complications including postoperative anemia (P < .001), transfusion (P = .024), and arrhythmia (P = .004) were more common with inpatient UKAs, whereas surgical wound complications (P = .001) and operative debridement (P = .028) were more common among outpatient UKAs. Outpatient UKA was not associated with an increased risk of periprosthetic joint infection (P > .05), aseptic loosening (P > .05), or revision surgery (P > .05) when compared to inpatient UKA.

CONCLUSION

Outpatient UKA utilization is increasing and is associated with decreased reimbursement compared to inpatient UKA without increased risk of major medical complications, although it is associated with increased risk of wound complication and need for operative debridement at 90 days.

The Cost of Malnutrition in Total Joint Arthroplasty

BACKGROUND

Malnutrition is a known risk factor for complications and adverse outcomes after elective total joint arthroplasty (TJA), but little is known about the burden this risk factor places on the healthcare system. The purpose of this study was to evaluate the 90-day impact of malnutrition on medical and surgical complications and understand the increase in global reimbursements associated with TJA in malnourished patients.

METHODS

We queried a combined private-payer and Medicare database from 2007 to 2016 for TJA using International Classification of Diseases, 9th revision and Current Procedural Terminology codes. Patients with serum albumin level of <3.5 g/dL were gender, age, and mean Elixhauser Comorbidity Index matched against a cohort with a normal serum albumin level. Odds ratios and confidence intervals were calculated for complications at 90 days postoperatively. Mean index and 90-day global reimbursements were calculated for the two matched groups and compared using P-values.

RESULTS

3053 protein malnourished patients receiving TJA were identified, and 12,202 matched protein nourished patients receiving TJA served as controls. At 90 days, the malnourished groups had increased risk for failure of multiple organ systems, periprosthetic joint infection, and reoperation. The mean 90-day increase in reimbursement was $3875 associated with performing a TJA on a protein malnourished patient (P < .001).

CONCLUSION

This study demonstrates an association between malnourished patients and postoperative complications as well as significantly increased reimbursements. Understanding the reimbursement increases at 90 days for TJA in protein malnourished patients is important in the era of bundled payments.

Trends in knee arthroscopy utilization: a gap in knowledge translation

PURPOSE

To evaluate the longitudinal trends in knee arthroscopy utilization in relation to published negative randomized controlled trials, focusing on annual rates, patient demographics and associated 30-day post-operative complications.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried using Current Procedural Terminology billing codes to identify arthroscopy cases between 2006 and 2016. 30-day post-operative complications were identified, and potential risk factors analysed using univariate and multivariate analyses.

RESULTS

68,346 patients underwent knee arthroscopy, of which 47,446 (69.5%) represented partial meniscectomies. The annual procedural rate, as a proportion of all reported cases, increased significantly from 2006 (0.3%) to 2016 (1.6%; p < 0.001), along with a significant increase in average patient age (44.3 ± 15.5 to 48.4 ± 14.5; p < 0.001). Specifically focusing on the meniscectomy cohort, average patient age significantly increased from 47.9 ± 15.1 to 50.7 ± 13.5 (p = 0.001). The overall incidence of complications was 2.0% (n = 1333), with major complications in 0.9% (n = 639) and minor complications in 1.0% (n = 701). Common complications included a return to the operating room (0.5%), deep vein thrombosis/thrombophlebitis (0.4%), and superficial infection (0.2%). Operating time > 90 min, diabetes, steroid use, ASA class 2+, and dialysis-dependency were the predictors of overall complication rates.

CONCLUSION

Despite the publication of negative trials and new clinical practice guidelines, knee arthroscopy utilization and average patient age continue to increase. Given the high utilization, even low adverse event rates equate to substantial numbers of patients with minor and major complications. The NSQIP data show a gap in knowledge translation to clinical practice and highlight the need for improved clinical guidelines.

LEVEL OF EVIDENCE

Cohort study; Level III.

Capturing adverse events in elective orthopedic surgery: comparison of administrative, surgeon and reviewer reporting

Summary

Ensuring adverse event (AE) recording is standardized and accurate is paramount for patient safety. In this discussion, we outline our comparison of AE data collected by orthopedic surgeons and independent clinical reviewers using the Spine Adverse Events Severity System (SAVES) and Orthopedic Surgical Adverse Events Severity System (OrthoSAVES) against AE data recorded by hospital administrative discharge abstract coders. In 164 spine, hip, knee and shoulder patients, reviewers recorded significantly more AEs than coders, and coders recorded significantly more AEs than surgeons. The AEs were recorded similarly by reviewers using SAVES and OrthoSAVES in 48 spine patients. Despite our small sample size and use of different AE tools, we believe it is important to highlight that coders, surgeons and reviewers recorded AEs differently. While further investigations on its utility and cost-effectiveness are necessary, we assert that it is feasible to use Ortho-SAVES to prospectively record AEs across all orthopedic subspecialties.

Timing of Lumbar Spinal Fusion Affects Total Hip Arthroplasty Outcomes

Many patients are affected by concurrent disease of the hip and spine, undergoing both total hip arthroplasty (THA) and lumbar spinal fusion (LSF). Recent literature demonstrates increased prosthetic dislocation rates in patients with THA done after LSF. Evidence is lacking on which surgery to do first to minimize complications. The purpose of this study was to evaluate the effect of timing between the two procedures on postoperative outcomes.

Statin use is associated with less postoperative cardiac arrhythmia after total hip arthroplasty

INTRODUCTION

While statins have been found to reduce postoperative atrial fibrillation after cardiac surgery, little is known about their use in total hip arthroplasty (THA). This study investigated if statins would similarly reduce postoperative arrhythmias in patients undergoing THA.

METHODS

We queried a large Medicare and private-payer database from 2005 to 2012 and identified 12,075 patients who were on a statin prior to THA. We then age and sex matched 34,446 non-statin users who underwent THA. Baseline comorbidities and postoperative complications were obtained and assessed via standard descriptive statistics.

RESULTS

The statin users had more preoperative comorbidities including congestive heart failure, valvular heart disease, pulmonary and renal disease, diabetes, hypertension, obesity, and anaemia (all p values < 0.001). Postoperatively, the statin users had a statistically higher 90-day incidence of transfusion, acute renal failure, heart failure, pneumonia, and sepsis/shock. All new-onset cardiac arrhythmia was significantly less frequent in the statin group at 2 weeks (3.88% vs. 4.72%, p < 0.001), 30 days (4.47% vs. 5.29%, p < 0.001), and 90 days (5.44% vs. 6.31%, p = 0.001) postoperative. There was no difference in the frequency of venous thromboembolism, myocardial infarction, postoperative anaemia, or bleeding at 90 days postoperative.

DISCUSSION

Despite being medically sicker at baseline with multiple risk factors for atrial fibrillation compared to the non-statin users, the statin users displayed a consistently lower occurrence of postoperative cardiac arrhythmia in this retrospective cohort study. Statins may therefore be beneficial in the preoperative optimisation of medically complex patients undergoing THA.

Mechanical Complications Following Total Hip Arthroplasty Based on Surgical Approach: A Large, Single-Institution Cohort Study

BACKGROUND

The influence of surgical approach on risk of early postoperative mechanical complications after total hip arthroplasty (THA) continues to be a focus of debate. We performed the first single-institution study on risk of early operative and nonoperative mechanical complications after THA based on approach, with the hypothesis that there would be no clinically significant difference with modern surgical methods.

METHODS

A retrospective study was conducted on 16,186 consecutive THA performed from 2010 to 2016. Revision or conversion THA and cases performed for hip fracture, with recalled prostheses, or during a surgeon's learning period were excluded. THAs were performed using direct anterior (DA; n = 5465), direct lateral (DL; n = 8561), or posterolateral approach with soft tissue repair (PL; n = 2160). All mechanical complications within the first 2 years were identified. The primary analysis was a time to event Cox regression, accounting for both patient and surgeon characteristics.

RESULTS

Compared with the DL approach, risk of mechanical complications was higher for both DA and PL. Adjusted risk of instability within 2 years was 0.17%, 0.74%, and 1.74% for DL, DA, and PL, respectively. While occurring at similar rates with the PL and DL approaches, the risk of periprosthetic fracture and loosening increased with DA. Consequently, femoral failure, including fracture or loosening, occurred more frequently for DA, with an adjusted incidence of 1.20% vs 0.58% and 0.47%, with DL and PL.

CONCLUSION

Even with soft tissue repair, instability continues to occur with increased frequency with the PL approach. While reducing dislocation, a higher risk of femoral failure with DA must also be considered. Nevertheless, the DL approach appears to confer the lowest overall risk of mechanical complications.

Medicaid Insurance Correlates With Increased Resource Utilization Following Total Hip Arthroplasty

BACKGROUND

With increased restraints and efforts to contain costs in total hip arthroplasty (THA), an emphasis has been placed on risk stratification. The purpose of this study was to determine whether Medicaid patients have increased resource utilization (including 90-day emergency department [ED] visits and readmissions) compared to Medicare or commercial insurance carriers. The study hypothesized that the Medicaid population would represent a high-risk cohort with increased resource utilization.

METHODS

The institutional database was retrospectively queried for primary THAs from 2013 to 2017 based on Current Procedural Terminology codes and patients undergoing revision surgery were excluded. Demographic information including age, sex, and body mass index (BMI) and medical comorbidities including American Society of Anesthesiologists (ASA) scores were evaluated. Patients were stratified by insurance type and length of stay (LOS), and 90-day ED visits and 90-day readmissions were assessed in univariable and multivariable analysis.

RESULTS

A total of 3674 primary THA patients were included in the analysis (including 116 with Medicaid, 1713 with Medicare, and 1845 with other insurance providers). Medicaid patients had significantly higher ASA scores (P < .001) and BMI (P < .001), with corresponding increase in procedure duration (115 vs 99 vs 105 minutes; P < .001). They had a prolonged LOS (2.5 vs 2.5 vs 1.5 days; P < .001) compared with other insurances, but similar to Medicare patients. Following discharge, in multivariable analysis controlling for age, BMI, and ASA score, Medicare patients were significantly more likely to return to the ED (odds ratio, 3.15; 95% confidence interval, 1.88-5.27; P < .001) and be readmitted (odds ratio, 2.46; 95% confidence interval, 1.26-4.81; P = .009).

CONCLUSION

Medicaid patients represent a higher risk cohort with increased resource utilization perioperatively, including longer LOS, and more 90-day ED visits and readmissions. This should be considered in outcome assessments and alternative expectations for the episode of care should be set for this population.

Emergency Department Visits Within Thirty Days of Discharge After Primary Total Hip Arthroplasty: A Hidden Quality Measure

BACKGROUND

Thirty-day hospital readmissions following total hip arthroplasty (THA) have received increasing scrutiny by policy makers and hospitals. Emergency department (ED) visits may not necessarily result in an inpatient readmission but can be a measure of performance and can incur costs to the health system. The purpose of this study is to describe the following: (1) the frequency and subsequent disposition; (2) patient characteristics; (3) reasons; and (4) potential risk factors for ED visits that did not result in a readmission within 30 days of discharge after THA.

METHODS

All primary THAs performed at a large healthcare system between 2013 and 2015 were identified. Patients who received unplanned hospital services for complications within 30 days following surgery were identified and analyzed. A multiple regression analysis was utilized to identify risk factors predisposing for returning to the ED without readmission.

RESULTS

From a total of 6270 primary THAs, 440 patients (7%) had an unplanned return to the hospital within 30 days. Of those, 227 (3.6%) patients presented to the ED and were not readmitted. Higher percentage of African Americans was noted among patients who returned to the ED versus those who did not (20.2% vs 9.8%, P < .01). The most common medical diagnoses were nonspecific medical symptoms (24.8%) followed by minor gastrointestinal problems (10.5%). The most common surgery-related diagnoses were pain and swelling (35%), followed by wound complications (12%) and hip dislocations (7.3%). Nearly 50% of wound complications and 40% of hip dislocations were managed and discharged from the ED without a readmission. Both African Americans (odds ratio 2.28, 95% confidence interval 1.55-3.36) and home discharge (odds ratio 1.90, 95% confidence interval 1.28-2.82) were independent risk factors for return to the ED without readmission.

CONCLUSION

ED visits that do not result in hospital readmissions, many of which may be due to serious complications, are more frequent than inpatient readmission. This is extremely relevant to policy makers and quality metrics, especially as comprehensive and bundled payment initiatives become more prevalent.

Effect of Computer Navigation on Complication Rates Following Unicompartmental Knee Arthroplasty

BACKGROUND

We evaluated whether the complication and revision rates of unicompartmental knee arthroplasty (UKA) performed with intraoperative computer-based navigation differ from standard UKAs performed without intraoperative computer-based navigation.

METHODS

A Medicare database containing administrative claims data from 2005 to 2014 was queried. Patients who underwent a single UKA and had a minimum of 2 years of follow-up were included in the study. Data from 1025 UKAs performed with navigation were compared against 9228 age and gender-matched UKAs performed without it. Postoperative complications were identified using International Classification of Diseases, Ninth Revision, codes and evaluated at 30 days, 90 days, and 2 years.

RESULTS

Orthopedic complications after UKA are rare, and the use of navigation did not affect the rate of conversion to total knee arthroplasty at 2-year follow-up (3.8% in navigated UKAs vs 4.7% in standard UKAs, P = .218). There were also no significant differences in the rates of knee arthrotomy at 2-year follow-up (1.3% in navigated UKAs vs 1.6% in standard UKAs, P = .379). The rates of deep vein thrombosis at 90-day follow-up did not significantly differ between the 2 groups (1.4% in navigated UKAs vs 2.0% in standard UKAs, P = .157).

CONCLUSION

This is one of the first studies to use a large cohort to compare outcomes in computer-assisted surgery-UKA against standard UKAs without navigation. The results, particularly that there was not a difference in the rate of conversion to total knee arthroplasty, are directly relevant to clinical decision-making when surgeons are considering employing navigation during UKA.

Preoperative Patient Profile in Total Hip and Knee Arthroplasty: Predictive of Increased Medicare Payments in a Bundled Payment Model

BACKGROUND

The shift toward value-based bundled payment models in total joint arthroplasty highlights the need for identification of modifiable risk factors for increased spending as well as opportunities to mitigate perioperative treatment of chronic disease. The purpose of this study was to identify preoperative comorbidities that result in an increased financial burden using institutional data at a single institution.

METHODS

We conducted a retrospective review of total joint arthroplasty patients and collected payment data from the Center for Medicare and Medicaid Services for each patient up to 90 days after surgery in accordance with the regulations of the Comprehensive Care for Joint Replacement initiative. Statistical analysis and comparison of preoperative profile and Medicare payments as a surrogate for cost were completed.

RESULTS

Six hundred ninety-four patients were identified over a 4-year time period who underwent surgery before adoption of the Comprehensive Care for Joint Replacement but that met criteria for inclusion. The median total payment per patient episode of care was $20,048. Preoperative diagnosis of alcoholism, anemia, diabetes, and obesity was found to have a statistically significant effect on total payments. The model predicted a geometric mean increase from $1425 to $9308 for patients bearing these comorbidities.

CONCLUSION

With Medicare payments as a surrogate for cost, we demonstrate that specific patient comorbidities and a cumulative increase in comorbidities predict increased costs. This study was based on institutional data rather than administrative data to gain actionable information on an institutional level and highlight potential flaws in research based on administrative data.

Human Immunodeficiency Virus Infection and Hip and Knee Arthroplasty

BACKGROUND

Modern management of human immunodeficiency virus (HIV) infection has afforded patients longevity while increasing the burden of arthroplasty procedures because of the increased risk of osteonecrosis, fragility fractures, and degenerative joint disease. Early publications on hip and knee arthroplasty in HIV-positive patients reported a high risk of complications, although some more recent publications demonstrated acceptable outcomes. Despite the widespread nature of the HIV pandemic, there is a paucity of literature addressing outcomes following joint arthroplasty in infected patients. We pooled available studies to obtain the best evidence regarding the safety of total hip and knee arthroplasty procedures in HIV-positive patients. The studies identified were heterogeneous, precluding a meta-analysis. However, we performed a review of the literature focusing on complications and outcomes.

METHODS

Twenty-one published English-language articles involving 6,516,186 joints were identified by a systematic review as suitable for inclusion in the study. The articles were analyzed for complication and prosthesis survivorship rates and relative risks.

RESULTS

An overall complication rate of 3.3% was found across the 19 articles that provided such data. HIV-positive patients had a significantly elevated risk of periprosthetic joint infection, at 7.6%, compared with HIV-negative patients, at 3.3% (relative risk = 2.28, 95% confidence interval = 2.14 to 2.43). Eleven articles were suitable for analysis of prosthesis survivorship, and survivorship rates did not differ significantly between HIV-positive and negative patients.

CONCLUSIONS

Total hip and total knee arthroplasty appear to be safe procedures with acceptable outcomes in HIV-positive patients.

LEVEL OF EVIDENCE

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

Trochanteric Bursitis Following Primary Total Hip Arthroplasty: Incidence, Predictors, and Treatment

BACKGROUND

Trochanteric bursitis (TB) remains a common complication after total hip arthroplasty (THA), with an incidence between 3% and 17%, depending on the surgical approach, with the posterior approach (PA) being relatively protective compared to the lateral approach. The purposes of this study were to determine the incidence of TB after primary THA, identify potential risk factors for TB, and examine the utility of different modes of treatment.

METHODS

Retrospective cohort data of 990 primary THAs performed in a single institution, including 613 PAs and 377 direct anterior approaches (DAAs), were analyzed. Data abstracted included demographic data, operative diagnosis, comorbidities, radiographic assessment, and other specific predictors of interest that were compared between patients diagnosed with TB following THA and controls.

RESULTS

The incidence of TB following primary THA was 5.4% (54/990) for the entire cohort. The incidence did not differ significantly between the PA and DAA (5% vs 6.1%, respectively; P = .47). Charlson comorbidity index and American Society of Anesthesiology did not differ significantly in the TB group. Lumbar spinal stenosis and history of past smoking were significantly more common in patients who developed TB (P = .03, P = .01, respectively), but did not continue to be significant risk factors on multivariate analysis. All patients were treated nonoperatively by the time of final follow-up. Seventy-four percent required a local steroid injection and 30% required treatment with more than one modality.

CONCLUSION

The occurrence of TB is not influenced by the surgical approach (PA or DAA), and could not be predicted by specific comorbidities or radiographic measurements. However, it can be effectively treated conservatively in most cases.

The Shift to Same-Day Outpatient Joint Arthroplasty: A Systematic Review

BACKGROUND

Hip and knee arthroplasties length of stay continues to shorten after advances in perioperative and intraoperative management, as well as financial incentives. Some authors have demonstrated good results with outpatient arthroplasty, but safety and general feasibility of such procedures remain unclear. Our hypothesis is that outpatient arthroplasty would demonstrate higher readmission and complication rates than inpatient arthroplasty.

METHODS

We performed a systematic review of all publications on outpatient arthroplasty between January 1, 2000 and June 1, 2016. Included publications had to demonstrate a specific outpatient protocol and have reported perioperative complications and unplanned readmissions. Patient demographics, surgical variables, and protocol details were recorded in addition to complications, readmission, and reoperation.

RESULTS

Ten manuscripts accounting for 1009 patients demonstrated that 955 (94.7%) were discharged the same day as planned, with the majority of failures to discharge being secondary to pain, hypotension, and nausea. There were no deaths and only 1 major complication. Only 20 patients (1.98%) required reoperation and 20 (1.98%) had readmission or visited the emergency room within 90 days of their operation. In the 2 series recording patient outcomes, 80% and 96% of patients reported that they would choose to undergo outpatient arthroplasty again.

CONCLUSION

For carefully selected patients with experienced surgeons in major centers, outpatient arthroplasty may be a safe and effective procedure. Although our data is promising, further study is required to better elucidate the differences between inpatient and outpatient arthroplasty outcomes.

Metal-on-metal total hip arthroplasty is not associated with cardiac disease

AIMS

Many case reports and small studies have suggested that cobalt ions are a potential cause of cardiac complications, specifically cardiomyopathy, after metal-on-metal (MoM) total hip arthroplasty (THA). The impact of metal ions on the incidence of cardiac disease after MoM THA has not been evaluated in large studies. The aim of this study was to compare the rate of onset of new cardiac symptoms in patients who have undergone MoM THA with those who have undergone metal-on-polyethylene (MoP) THA.

PATIENTS AND METHODS

Data were extracted from the Standard Analytics Files database for patients who underwent MoM THA between 2005 and 2012. Bearing surface was selected using International Classification of Diseases ninth revision codes. Patients with a minimum five-year follow-up were selected. An age and gender-matched cohort of patients who underwent MoP THA served as a comparison group. New diagnoses of cardiac disease were collected during the follow-up period. Comorbidities and demographics were identified and routine descriptive statistics were used.

RESULTS

We identified 29 483 patients who underwent MoM THA and 24 175 matched patients who underwent MoP THA. Both groups had a mean Charlson comorbidity index score of 4. There were no statistically significant differences in 30 of 31 pre-existing comorbidities. Patients undergoing MoM THA had a slightly lower incidence of cardiac failure compared with those undergoing MoP THA at three years (6.60% versus 7.06%, odds ratio (OR) 0.93, 95% confidence interval (CI) 0.87 to 0.99) and four years (8.73% versus 9.49%, OR 0.91, 95% CI 0.86 to 0.97) postoperatively, with no difference in the incidence of new cardiac failure in between the groups at five years. There was no statistically significant difference in the incidence of arrhythmia, myocardial infarction and cardiomyopathy at any time between the two groups.

CONCLUSION

MoM THA is not associated with cardiac complications. Initial reports may have represented individual instances of cardiac disease in patients with a failing MoM articulation rather than an emerging epidemiological trend. Cite this article: Bone Joint J 2018;100-B:28-32.

Incidence, Risk Factors, and Impact of Clostridium difficile Colitis Following Primary Total Hip and Knee Arthroplasty

BACKGROUND

An improved understanding of Clostridium difficile is important as it is used as a measure of hospital quality and is associated with substantial morbidity. This study utilizes the National Surgical Quality Improvement Program to determine the incidence, timing, risk factors, and clinical implications of C difficile colitis in patients undergoing primary total hip or knee arthroplasty (THA or TKA).

METHODS

Patients who underwent primary THA or TKA as part of the 2015 National Surgical Quality Improvement Program were identified. The primary outcome was a diagnosis of C difficile colitis within the 30-day postoperative period. Risk factors for the development of C difficile colitis were identified using Poisson multivariate regression.

RESULTS

A total of 39,172 patients who underwent primary THA or TKA were identified. The incidence of C difficile colitis was 0.10% (95% confidence interval [CI] 0.07-0.13). Of the cases that developed C difficile colitis, 79% were diagnosed after discharge and 84% had not had a preceding infection diagnosed. Independent preoperative and procedural risk factors for the development of C difficile colitis were greater age (most notably ≥80 years old, relative risk [RR] 5.28, 95% CI 1.65-16.92, P = .008), dependent functional status (RR 4.05, 95% CI 1.44-11.36, P = .008), preoperative anemia (RR 2.52, 95% CI 1.28-4.97, P = .007), hypertension (RR 2.51, 95% CI 1.06-5.98, P = .037), and THA (vs TKA; RR 2.25, 95% CI 1.16-4.36, P = .017). Postoperative infectious risk factors were urinary tract infection (RR 10.66, 95% CI 3.77-30.12, P < .001), sepsis (RR 17.80, 95% CI 3.77-84.00, P < .001), and "any infection" (RR 6.60, 95% CI 2.66-16.34, P < .001).

CONCLUSION

High-risk patients identified in this study should be targeted with preventative interventions and have perioperative antibiotics judiciously managed.

Impact of Definition and Timeframe on Capturing Surgery-Related Readmissions After Primary Joint Arthroplasty

BACKGROUND

Readmission rate has emerged as an important metric to measure quality, but varying definitions and timeframes are used. We aimed to evaluate the impact of different readmission definitions (postoperative vs postdischarge) and timeframes (30 vs 90-day) on capturing surgery-related readmissions after primary total joint arthroplasty.

METHODS

Patients who underwent primary total hip or knee arthroplasty between January 1, 2013 and December 31, 2015 were included. The electronic medical records of readmitted patients were reviewed to determine whether a surgery-related event was most responsible for readmission. The performances of 4 definition-timeframe combinations in capturing surgery-related readmissions were evaluated.

RESULTS

A total of 2586 patients were included. Using both postoperative and postdischarge definitions, there were no differences in the proportion of readmissions that were surgery-related when comparing 30 and 90-day timeframes (postoperative: 71% vs 60%, P = .118; postdischarge: 68% vs 60%, P = .219). Greater proportion of readmissions between days 0 and 30 were for surgery-related reasons compared with readmissions between days 31 and 90 using both postoperative and postdischarge definitions (postoperative: 71% vs 47%, P = .005; postdischarge: 68% vs 49%, P = .022). Among 104 patients readmitted for surgery-related reasons within 1 year of discharge, 52% were readmitted within 30 days of surgery compared with 79% within 90 days (P < .001). Similarly, 53% and 81% of readmissions were captured by the 30 and 90-day postdischarge definitions, respectively (P < .001).

CONCLUSION

A 90-day timeframe is superior in capturing surgery-related readmissions after total joint arthroplasty. Important Total hip and knee arthroplasty adverse events may be missed using a 30-day timeframe.

Comparison of Perioperative Adverse Event Rates After Total Knee Arthroplasty in Patients With Diabetes: Insulin Dependence Makes a Difference

BACKGROUND

Total knee arthroplasty (TKA) is an effective treatment option for patients with advanced osteoarthritis and has become one of the most frequently performed orthopedic procedures. With the increasing prevalence of diabetes mellitus (DM), the burden of its sequela and associated surgical complications has also increased. For these reasons, it is important to understand the association between DM and the rates of perioperative adverse events after TKA.

METHODS

A retrospective cohort study was conducted using the American College of Surgeons National Surgical Quality Improvement Program database. Patients who underwent TKA between 2005 and 2014 were identified and characterized as having insulin-dependent DM (IDDM), non-insulin-dependent DM (NIDDM), or not having DM. Multivariate Poisson regression was used to control for demographic and comorbid factors and to assess the relative risks of multiple adverse events in the initial 30 postoperative days.

RESULTS

A total of 114,102 patients who underwent TKA were selected (IDDM = 4881 [4.3%]; NIDDM = 15,367 [13.5%]; and no DM = 93,854 [82.2%]). Patients with NIDDM were found to be at greater risk for 2 of 17 adverse events studied relative to patients without DM. However, patients with IDDM were found to be at greater risk for 12 of 17 adverse events studied relative to patients without DM.

CONCLUSION

In comparison with patients with NIDDM, patients with IDDM are at greater risk for many more perioperative adverse outcomes relative to patients without DM. These findings have important implications for patient selection, preoperative risk stratification, and postoperative expectations.

Venous Thromboembolism Prophylaxis After TKA: Aspirin, Warfarin, Enoxaparin, or Factor Xa Inhibitors?

BACKGROUND

There is considerable debate regarding the ideal agent for venous thromboembolism (VTE) prophylaxis after TKA. Numerous studies and meta-analyses have yet to provide a clear answer and often omit one or more of the commonly used agents such as aspirin, warfarin, enoxaparin, and factor Xa inhibitors.

QUESTIONS/PURPOSES

Using a large database analysis, we asked: (1) What are the differences in VTE incidence in primary TKA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors? (2) What are the differences in bleeding risk among these four agents? (3) How has use of these agents changed with time?

METHODS

We queried a combined Humana and Medicare database between 2007 and Quarter 1 of 2016, and identified all primary TKAs performed using ICD-9 and Current Procedural Terminology codes. All patients who had any form of antiplatelet or anticoagulation prescribed within 1 year before TKA were excluded from our study cohort. We then identified patients who had either aspirin, warfarin, enoxaparin, or factor Xa inhibitors prescribed within 2 weeks of primary TKA. Each cohort was matched by age and sex. Elixhauser comorbidities and Charlson Comorbidity Index for each group were calculated. We identified 1016 patients with aspirin, and age- and sex-matched 6096 patients with enoxaparin, 6096 patients with warfarin, and 5080 patients with factor Xa inhibitors. Using ICD-9 codes, with the understanding that patients at greater risk may have had more-attentive surveillance, the incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications (bleeding requiring surgical intervention, hemorrhage, hematoma, hemarthrosis), postoperative anemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days postoperatively. A four-way chi-squared test was used to determine statistical significance. Utilization was calculated using compound annual growth rate.

RESULTS

There was a difference in the incidence of DVT at 90 days (p < 0.01). Factor Xa inhibitors (2.9%) had the lowest incidence of DVT followed by aspirin (3.0%) and enoxaparin (3.5%), and warfarin (4.8%). There was a difference in the incidence of PE at 90 days (p < 0.01). Factor Xa inhibitors (0.9%) had the lowest incidence of PE followed by enoxaparin (1.1%), aspirin (1.2%), and warfarin (1.6%). There was a difference in the incidence of postoperative anemia at 90 days (p < 0.01). Aspirin (19%) had the lowest incidence of postoperative anemia followed by warfarin (22%), enoxaparin (23%), and factor Xa inhibitors (23%). There was a difference in the incidence of a blood transfusion at 90 days (p < 0.01). Aspirin (7%) had the lowest incidence of a blood transfusion followed by factor Xa inhibitors (9%), warfarin (12%), and enoxaparin (13%). There were no differences in bleeding-related complications (p = 0.81) between the groups. Aspirin use increased at a compound annual growth rate of 30%, enoxaparin at 3%, and factor Xa inhibitors at 43%, while warfarin use decreased at a compound annual growth rate of -3%.

CONCLUSIONS

Factor Xa inhibitors had the highest growth in utilization during our study period, followed by aspirin, when compared with enoxaparin and warfarin. When selected for the right patient, factor Xa inhibitors provided improved VTE prophylaxis compared with enoxaparin and warfarin, with a lower rate of blood transfusion. Aspirin provided comparable VTE prophylaxis compared with factor Xa inhibitors with improved VTE prophylaxis compared with enoxaparin and warfarin with the lowest risk of bleeding.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The Implications of Inaccuracy: Comparison of Coding in Heterotopic Ossification and Associated Trauma

Retrospective studies using large databases serve a major purpose in providing evidence in the current literature. However, the quality of medical coding is highly variable. This retrospective cohort study aimed to evaluate the documentation regarding the diagnosis of heterotopic ossification (HO) and the implications it may have for conducting retrospective research using electronic medical records (EMRs). A retrospective chart review using the EMR was performed to identify all patients with a diagnosis of HO within 7 university-affiliated hospital facilities. A limited data set request was conducted for all patients with HO-specific International Classification of Diseases, Ninth Revision (ICD-9) codes and additional nonspecific musculoskeletal codes to capture patients with HO who were improperly coded. A total of 522 patients were identified-26 patients with specific HO codes and 496 patients with nonspecific codes. Imaging and clinical notes were inspected for evidence and location of HO, and histories were reviewed for traumatic injury mechanism. Two-thirds of the patients with HO were discovered by reviewing miscellaneous musculoskeletal ICD-9 codes. Thirty-eight percent of the patients with an HO-specific ICD-9 code had no evidence of HO in their EMR. Thirty-three patients had a clinical history of a traumatic injury preceding HO formation, but only 16 of the 33 had documented ICD-9 codes for the injury. The utility of databases in retrospective research is dependent on the integrity of the coding. This study questions the use of retrospective reviews for patients with uncommon diagnoses and shows how painstaking verification may be necessary to ensure that research conclusions are based on accurate data. [Orthopedics. 2017; 40(4):237-241.].

Ten-Year Trends and Independent Risk Factors for Unplanned Readmission Following Elective Total Joint Arthroplasty at a Large Urban Academic Hospital

BACKGROUND

Total joint arthroplasty procedures continue to provide consistent, long-term success and high patient satisfaction scores. However, early unplanned readmission to the hospital imparts significant financial risks to individual institutions as we shift away from the traditional fee-for-service payment model.

METHODS

Using a combination of our hospital's administrative database and retrospective chart reviews, we report the 30-day and 90-day readmission rates and all causes of readmission following all unilateral, primary elective total hip and knee arthroplasty procedures at a large, urban, academic hospital from 2004 to 2013.

RESULTS

In total, 1165 primary total hip (511) and knee (654) arthroplasty procedures were identified, and the 30-day and 90-day unplanned readmission rates were 4.6% and 7.3%, respectively. A multivariate regression model controlled for a variety of potential clinical and surgical confounders. Increasing body mass index levels, an American Society of Anesthesiologists score of ≥3, and discharge to an inpatient rehab facility each independently correlated with risk of both 30-day and 90-day unplanned readmission to our institution. Additionally, use of general anesthesia during the procedure independently correlated with risk of readmission at 30 days only, while congestive heart failure independently correlated with risk of 90-day unplanned readmission. Readmissions related directly to the surgical site accounted for 47% of the cases, and collectively totaled more than any single medical or clinical complication leading to unplanned readmission within the 90-day period.

CONCLUSION

Increasing body mass index values, general anesthesia, an American Society of Anesthesiologists score of ≥3, and discharge to an inpatient rehab facility each were independent risk factors for early unplanned readmission.

American Association of Hip and Knee Surgeons-Endorsed Comorbidity Coding for Total Joint Arthroplasty: How Often Did We Hit the Mark With International Classification of Diseases, Ninth Revision?

BACKGROUND

Initiatives led by the American Academy of Orthopaedic Surgeons and the American Association of Hip and Knee Surgeons (AAHKS) have indicated a number of clinical risk factors associated with total joint arthroplasty that might reflect the complexity of contemporary hip and knee care. This study sought to examine the prevalence of specific International Classification of Diseases, Ninth Revision (ICD-9), coding with respect to an AAHKS-endorsed list of comorbidity codes.

METHODS

An administrative data set from an academic arthroplasty referral center was analyzed in an attempt to measure the prevalence of clinical risk factors (ICD-9) endorsed by AAHKS. Total, partial, and revision joint arthroplasty procedures from January 1, 2012, to April 27, 2015, were included. Demographic data, along with diagnosis and procedural coding data, were collected and analyzed.

RESULTS

Results analysis found a number of poorly coded variables. The following variables were omitted in the data: narcotic use, worker's compensation status, previous intra-articular infection, previous open reduction and internal fixation knee, and depression/psychiatric disease. Likewise, there was a discrepancy between the rate of ICD coding for obesity and body mass index measurements and categorization recorded in the clinic.

CONCLUSION

From this single-center study, there remain opportunities for coding to adequately reflect the comorbidities and complexities of patients undergoing arthroplasty.

Planning, Building, and Maintaining a Successful Musculoskeletal Service Line

Within the past 3 decades, a recent trend in the growth of musculoskeletal service lines has been seen nationally. Orthopedics offers an appealing concourse for implementation of service-line care. Within this review, the authors address the components involved in planning and building a musculoskeletal service line. The authors also address methods by which orthopedic surgeons can maintain the efficacy of their service lines by examining how orthopedic surgeons can navigate their service line through recent advents in health care reform. Finally, the authors review successful examples of musculoskeletal service lines currently in practice within the orthopedic community.

Hospital Discharge within 2 Days Following Total Hip or Knee Arthroplasty Does Not Increase Major-Complication and Readmission Rates

BACKGROUND

The rising costs of total knee arthroplasty (TKA) and total hip arthroplasty (THA) have resulted in a substantial economic burden on the U.S. health-care system. Recent efforts to contain these costs have targeted hospital length of stay. However, shorter hospital admissions have raised concerns over possible increases in complications and readmission rates. The purpose of this study was to assess whether early discharge, from 0 to 2 days postoperatively, was associated with increased 30-day major complications and readmissions compared with standard discharge, 3 to 4 days following THA or TKA.

METHODS

The National Surgical Quality Improvement Program (NSQIP) database was queried to identify all patients who underwent an elective, primary unilateral THA or TKA between 2011 and 2012. For each procedure, 2 groups were created consisting of patients discharged from 0 to 2 days (early discharge) and those discharged from 3 to 4 days (standard discharge). Patient demographics and perioperative variables were compared between both discharge groups. Multivariable logistic-regression models were used to assess the independent effect of length of stay on 30-day major-complication and readmission rates.

RESULTS

A total of 31,044 patients who underwent TKA and 19,909 patients who underwent THA were included. Overall, patients who were discharged early were younger and had fewer medical comorbidities and a lower American Society of Anesthesiologists (ASA) score. The multivariable logistic-regression model revealed that early discharge was not associated with increased odds of major complications following TKA (odds ratio [OR] = 0.95; 95% confidence interval [CI] = 0.75 to 1.20; p = 0.64). Furthermore, early discharge following THA was found to be an independent predictor against major complications (OR = 0.75; 95% CI = 0.58 to 0.95; p = 0.02). Lastly, early discharge was not an independent risk factor for hospital readmission following THA or TKA.

CONCLUSIONS

Early discharge was not an independent risk factor for 30-day major complications or readmissions following THA or TKA. Rather, increased major complications and readmissions were attributed to patient comorbidities and perioperative variables. Early discharge within the first 2 days postoperatively for risk-stratified patients appears feasible without compromising patient care.

LEVEL OF EVIDENCE

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

Is Metal-On-Metal Total Hip Arthroplasty Associated With Neurotoxicity?

BACKGROUND

Isolated case reports in the literature describe systemic neurologic side effects associated with metal-on-metal (MOM) bearing surfaces, yet the incidence of these effects have not been evaluated beyond individual cases. The purpose of this study was to compare new diagnoses of these side effects described in isolated cases in large patient cohorts of MOM vs metal on polyethylene (MOP).

METHODS

We queried the entire Medicare database from 2005 to 2012. Total hip arthroplasty (THA) and bearing surface were determined using International Classification of Diseases, 9th revision procedure codes. Patients with 5-year follow-up were selected. Using International Classification of Diseases, 9th revision codes, we identified new diagnoses of previously reported neurologic side effects: peripheral neuropathy, sensorineural hearing loss, visual impairment, paresthesias, tinnitus, and vertigo. Comorbidities and demographics were collected. Odds ratios, CIs, and P values were calculated.

RESULTS

Overall, 29,483 MOM THAs and 23,587 age- and gender-matched MOP THAs were identified. The average Charlson Comorbidity Index was 5 for both groups. MOM and MOP patients had 26 of 30 identical prevalence of Elixhauser-measure comorbidities. There was no statistically significant difference in new diagnoses of any of the side effects at any time point between the 2 groups over 5 years.

CONCLUSION

This study represents, to our knowledge, the first longitudinal analysis of systemic neurotoxicity after THA in a large cohort of patients. The results of our study suggest that on the large scale, neurologic side effects previously described do not occur as a common attributable complication. Rather, these cases may be due to individual patient hypersensitivity to metal ions.