Incidence of and Preoperative Risk Factors for Surgical Delay in Primary Total Hip Arthroplasty: Analysis From the American College of Surgeons National Surgical Quality Improvement Program

Declining Inflation-Adjusted Medicare Physician Fees: An Unsustainable Trend in Hip Arthroscopy

INTRODUCTION

Although hip arthroscopy continues to be one of the most used arthroscopic procedures, no focused, comprehensive evaluation of reimbursement trends has been conducted. The purpose of this study was to analyze the temporal Medicare reimbursement trends for hip arthroscopy procedures.

METHODS

From 2011 to 2021, the Medicare Physician Fee Schedule Look-Up Tool was queried for Current Procedural Terminology (CPT) codes related to hip arthroscopy (29860 to 29863, 29914 to 29916). All monetary data were adjusted to 2021 US dollars. The compound annual growth rate and total percentage change were calculated. Mann-Kendall trend tests were used to evaluate the reimbursement trends.

RESULTS

Based on the unadjusted values, a significant increase in physician fee was observed from 2011 to 2021 for CPT codes 29861 (removal of loose or foreign bodies; % change: 3.49, P = 0.03) and 29862 (chondroplasty, abrasion arthroplasty, labral resection; % change: 3.19, P = 0.03). The remaining CPT codes experienced no notable changes in reimbursement based on the unadjusted values. After adjusting for inflation, all seven of the hip arthroscopy CPT codes were observed to experience a notable decline in Medicare reimbursement. Hip arthroscopy with acetabuloplasty (CPT: 29915) and labral repair (CPT: 29916) exhibited the greatest reduction in reimbursement with a decrease in physician fee of 24.69% ( P < 0.001) and 24.64% ( P < 0.001), respectively, over the study period.

DISCUSSION

Medicare reimbursement for all seven of the commonly used hip arthroscopy services did not keep up with inflation, demonstrating marked reductions from 2011 to 2021. Specifically, the inflation-adjusted reimbursements decreased between 19.23% and 24.69% between 2011 and 2021.

Mark-Up Trends in Contemporary Medicare Primary and Revision Total Joint Arthroplasty

BACKGROUND

Understanding mark-up ratios (MRs), the ratio between a healthcare institution's submitted charge and the Medicare payment received, for high-volume orthopaedic procedures is imperative to inform policy about price transparency and reducing surprise billing. This analysis examined the MRs for primary and revision total hip and knee arthroplasty (THA and TKA) services to Medicare beneficiaries between 2013 and 2019 across healthcare settings and geographic regions.

METHODS

A large dataset was queried for all THA and TKA procedures performed by orthopaedic surgeons between 2013 and 2019, using Healthcare Common Procedure Coding System (HCPCS) codes for the most frequently used services. Yearly MRs, service counts, average submitted charges, average allowed payments, and average Medicare payments were analyzed. Trends in MRs were assessed. We evaluated 9 THA HCPCS codes, averaging 159,297 procedures a year provided by a mean of 5,330 surgeons. We evaluated 6 TKA HCPCS codes, averaging 290,244 procedures a year provided by a mean of 7,308 surgeons.

RESULTS

For knee arthroplasty procedures, a decrease was noted for HCPCS code 27438 (patellar arthroplasty with prosthesis) over the study period (8.30 to 6.62; P = .016) and HCPCS code 27447 (TKA) had the highest median (interquartile range [IQR]) MR (4.73 [3.64 to 6.30]). For revision knee procedures, the highest median (IQR) MR was for HCPCS code 27488 (removal of knee prosthesis; 6.12 [3.83-8.22]). While no trends were noted for both primary and revision hip arthroplasty, median (IQR) MRs in 2019 for primary hip procedures ranged from 3.83 (hemiarthroplasty) to 5.06 (conversion of previous hip surgery to THA) and HCPCS code 27130 (total hip arthroplasty) had a median (IQR) MR of 4.66 (3.58-6.44). For revision hip procedures, MRs ranged from 3.79 (open treatment of femoral fracture or prosthetic arthroplasty) to 6.10 (revision of THA femoral component). Wisconsin had the highest median MR by state (>9) for primary knee, revision knee, and primary hip procedures.

CONCLUSION

The MRs for primary and revision THA and TKA procedures were strikingly high, as compared to nonorthopaedic procedures. These findings represent high levels of excess charges billed, which may pose serious financial burdens to patients and must be taken into consideration in future policy discussions to avoid price inflation.

Patient Out-of-Pocket Cost Burden With Elective Orthopaedic Surgery

INTRODUCTION

Out-of-pocket (OOP) costs for medical and surgical care can result in substantial financial burden for patients and families. Relatively little is known regarding OOP costs for commercially insured patients receiving orthopaedic surgery. The aim of this study is to analyze the trends in OOP costs for common, elective orthopaedic surgeries performed in the hospital inpatient setting.

METHODS

This study used an employer-sponsored insurance claims database to analyze billing data of commercially insured patients who underwent elective orthopaedic surgery between 2014 and 2019. Patients who received single-level anterior cervical diskectomy and fusion (ACDF), single-level posterior lumbar fusion (PLF), total knee arthroplasty (TKA), and total hip arthroplasty (THA) were identified. OOP costs associated with the surgical episode were calculated as the sum of deductible payments, copayments, and coinsurance. Monetary data were adjusted to 2019 dollars. General linear regression, Wilcoxon-Mann-Whitney, and Kruskal-Wallis tests were used for analysis, as appropriate.

RESULTS

In total, 10,225 ACDF, 28,841 PLF, 70,815 THA, and 108,940 TKA patients were analyzed. Most patients in our study sample had preferred provider organization insurance plans (ACDF 70.3%, PLF 66.9%, THA 66.2%, and TKA 67.0%). The mean OOP costs for patients, by procedure, were as follows: ACDF $3,180 (SD = 2,495), PLF $3,166 (SD = 2,529), THA $2,884 (SD = 2,100), and TKA $2,733 (SD = 1,994). Total OOP costs increased significantly from 2014 to 2019 for all procedures (P < 0.0001). Among the insurance plans examined, patients with high-deductible health plans had the highest episodic OOP costs. The ratio of patient contribution (OOP costs) to total insurer contribution (payments from insurers to providers) was 0.07 for ACDF, 0.04 for PLF, 0.07 for THA, and 0.07 for TKA.

CONCLUSION

Among commercially insured patients who underwent elective spinal fusion and major lower extremity joint arthroplasty surgery, OOP costs increased from 2014 to 2019. The OOP costs for elective orthopaedic surgery represent a substantial and increasing financial burden for patients.

Effects of Comorbidities on Pain and Function After Total Hip Arthroplasty

Background

The growing number of patients undergoing total hip arthroplasty (THA) and postoperative outcomes receive increasing attention from doctors and patients. This study aimed to elucidate the effects of comorbidities on postoperative function, pain, complications, readmission rate, and mortality.

Methods

We included consecutive patients who underwent primary unilateral THA between 2017 and 2019. The Charlson comorbidity index (CCI) and the WOMAC and SF-36 (physical function, body pain) scales were assessed preoperatively and at 3, 6, 12, and 24 months postoperatively. The complications, 30-day readmission, and mortality rates assessed the impact of comorbidities and their changes over time on the WOMAC and SF-36 scores during follow-up. We used mixed model linear regression to examine the association of worsening comorbidity post-THA with change in WOMAC and SF-36 scores in the subsequent follow-up periods, controlling for age, length of follow-up, and repeated observations.

Results

This study included 468 patients, divided into four groups based on comorbidity burden (CCI-0, 1, 2, and ≥3). The physiological function recovery and pain scores in the CCI ≥ 3 group were inferior to the other groups and took longer than the other groups (6 vs. 3 months) to reach their best level. The four groups preoperative waiting times were 2.41 ± 0.74, 2.97 ± 0.65, 3.80 ± 0.53, and 5.01 ± 0.71 days, respectively. The complications, 30-day readmission, and 1-year mortality rates for the overall and the CCI ≥ 3 group were 1.92% and 4.69%, 0.85% and 2.01%, and 0.43% and 1.34%, respectively, with no mortality in the other groups.

Conclusion

Patients with higher CCI were more susceptible to physical function and pain outcome deterioration, experienced longer waiting time before surgery, took longer to recover, and had higher rates of complications, 30-day readmission, and mortality after THA. Older age in the group led to a greater impact.

The Incidence, Risk Factors, and Complications Associated With Surgical Delay in Multilevel Fusion for Adult Spinal Deformity

STUDY DESIGN

Retrospective database review.

OBJECTIVES

The incidence and risk factors for surgical delay of multilevel spine fusion for adult spinal deformity (ASD), and the complications corresponding therewith, remain unknown. The objectives of this study are to assess the incidence and risk factors for unexpected delay of elective multilevel spinal fusions on the date of surgery as well as the postoperative complications associated with these delays.

METHODS

We conducted a retrospective review of the ACS-NSQIP database on patients undergoing elective spinal instrumentation of greater than 7 levels for ASD between the years 2005 and 2015. Preoperative risk factors for delay and postoperative complications were compared between the cohorts of patients with and without surgical delays.

RESULTS

Multivariate analysis of 1570 (15.6%) patients identified advanced age, male sex, American Society of Anesthesiologists (ASA) Class 4, and history of smoking as independent risk factors for delay. Patients experiencing surgical delay demonstrated longer operative times, increased intraoperative bleeding, longer hospitalizations, and significantly higher rates of postoperative complications. Patients experiencing delay demonstrated an almost 7-fold increase in mortality rate (3.4% vs 0.5%, P < .001).

CONCLUSIONS

Delays in elective surgical care for spinal deformity are negatively related to patient outcomes. Advanced age, male sex, increased ASA class, and a history of smoking cigarettes place patients at risk for surgical delay of multilevel spinal fusion. Patients experiencing surgical delay are at higher risk for postoperative complications, including a 7-fold increase in mortality. These findings suggest that ASD surgery should be postponed in patients experiencing a delay, until modifiable risk factors can be medically optimized, and perhaps postponed indefinitely in those with nonmodifiable risk factors.

The Update on Instruments Used for Evaluation of Comorbidities in Total Hip Arthroplasty

INTRODUCTION

It is a well-established fact that concomitant diseases can affect the outcome of total hip arthroplasty (THA). Therefore, careful preoperative assessment of a patient's comorbidity burden is a necessity, and it should be a part of routine screening as THA is associated with a significant number of complications. To measure the multimorbidity, dedicated clinical tools are used.

METHODS

The article is a systematic review of instruments used to evaluate comorbidities in THA studies. To create a list of available instruments for assessing patient's comorbidities, the search of medical databases (PubMed, Web of Science, Embase) for indices with proven impact on revision risk, adverse events, mortality, or patient's physical functioning was performed by two independent researchers.

RESULTS

The initial search led to identifying 564 articles from which 26 were included in this review. The measurement tools used were: The Charlson Comorbidity Index (18/26), Society of Anesthesiology classification (10/26), Elixhauser Comorbidity Method (6/26), and modified Frailty Index (5/26). The following outcomes were measured: quality of life and physical function (8/26), complications (10/26), mortality (8/26), length of stay (6/26), readmission (5/26), reoperation (2/26), satisfaction (2/26), blood transfusion (2/26), surgery delay or cancelation (1/26), cost of care (1/26), risk of falls (1/26), and use of painkillers (1/26). Further research resulted in a comprehensive list of eleven indices suitable for use in THA outcomes studies.

CONCLUSION

The comorbidity assessment tools used in THA studies present a high heterogeneity level, and there is no particular system that has been uniformly adopted. This review can serve as a help and an essential guide for researchers in the field.

Predictors for readmission following primary total hip and total knee arthroplasty

BACKGROUND

Readmission following total joint arthroplasty has become a closely watched metric for many hospitals in the United States due to financial penalties imposed by Centers for Medicare and Medicaid Services. The purpose of this study was to identify both preoperative and postoperative reasons for readmission within 30 days following primary total hip and total knee arthroplasty (TKA).

METHODS

Retrospective data were collected for patients who underwent elective primary total hip arthroplasty (THA; CPT code 27130) and TKA (27447) from 2008 to 2013 at our institution. The sample was separated into readmitted and nonreadmitted cohorts. Demography, comorbidities, Charlson comorbidity index (CCI), operative parameters, readmission rates, and causes of readmission were compared between the groups using univariate and multivariate regression analysis.

RESULTS

There were 42 (3.4%) and 28 (2.2%) readmissions within 30 days for THA and TKA, respectively. The most common cause of readmission within 30 days following total joint arthroplasty was infection. Trauma was the second most common reason for readmission of a THA while wound dehiscence was the second most common cause for readmission following TKA. With univariate regression, there were multiple associated factors for readmission among THA and TKA patients, including body mass index, metabolic equivalent (MET), and CCI. Multivariate regression revealed that hospital length of stay was significantly associated with 30-day readmission after THA and TKA.

CONCLUSION

Patient comorbidities and preoperative functional capacity significantly affect 30-day readmission rate following total joint arthroplasty. Adjustments for these parameters should be considered and we recommend the use of CCI and METs in risk adjustment models that use 30-day readmission as a marker for quality of patient care.

LEVEL OF EVIDENCE

Level III/Retrospective cohort study.

Effect of Novel Anteromedial Approach on Wound Complications Following Ankle Arthroplasty

BACKGROUND

The purpose of this study was to evaluate all wound complications following total ankle arthroplasty (TAA) before and after the implementation of a novel extensile anteromedial surgical approach. We further investigated patients and operative factors associated with wound complications.

METHODS

A series of 660 TAAs were collected. The median follow-up was 84 months (range, 12-204 months). Minor wound complications included discoloration, swelling, or clinical concern that merited bringing the patient back sooner for review. Major wound complications included plastic surgical consultation, debridement by the nurse specialist, negative pressure therapy, or reoperation. All major complications initially had a course of empirical oral antibiotics. Since 2011, higher-risk patients have had their TAA performed through an extensile anteromedial approach.

RESULTS

Fifty-six patients (8.5%) had wound healing issues (17 major [2.6%], 39 minor [5.9%]). All issues became evident <21 days postoperatively. Inflammatory arthritis, smoking, and coronary disease were patient factors associated with major wound complications. Four patients were treated with negative pressure therapy, 4 with debridement in the operating room, and 2 eventually converted to fusions. Fourteen patients (82%) who had major complications had an ancillary procedure to balance the TAA through a separate incision. All major wound complications had an anterior surgical approach for their TAA. Before 2011, there were 13 major wound complications. Since 2012, there have been 4 major wound complications overall, with no wound complications in the anteromedial approach cohort.

CONCLUSION

We recommend an extensile anteromedial approach for smokers and patients with heart disease or inflammatory arthritis undergoing TAA. If a wound complication developed, a multidisciplinary team to evaluate wounds was useful.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Novel Machine Learning Approach to Identify Preoperative Risk Factors Associated With Super-Utilization of Medicare Expenditure Following Surgery

Importance

Typically defined as the top 5% of health care users, super-utilizers are responsible for an estimated 40% to 55% of all health care costs. Little is known about which factors may be associated with increased risk of long-term postoperative super-utilization.

Objective

To identify clusters of patients with distinct constellations of clinical and comorbid patterns who may be associated with an elevated risk of super-utilization in the year following elective surgery.

Design, Setting, and Participants

A retrospective longitudinal cohort study of 1 049 160 patients who underwent abdominal aortic aneurysm repair, coronary artery bypass graft, colectomy, total hip arthroplasty, total knee arthroplasty, or lung resection were identified from the 100% Medicare inpatient and outpatient Standard Analytic Files at all inpatient facilities performing 1 or more of the evaluated surgical procedures from 2013 to 2015. Data from 2012 to 2016 were used to evaluate expenditures in the year preceding and following surgery. Using a machine learning approach known as Logic Forest, comorbidities and interactions of comorbidities that put patients at an increased chance of becoming a super-utilizer were identified. All comorbidities, as defined by the Charlson (range, 0-24) and Elixhauser (range, 0-29) comorbidity indices, were used in the analysis. Higher scores indicated higher comorbidity burden. Data analysis was completed on November 16, 2018.

Main Outcome and Measures

Super-utilization of health care in the year following surgery.

Results

In total, 1 049 160 patients met inclusion criteria and were included in the analytic cohort. Their median (interquartile range) age was 73 (69-78) years, and approximately 40% were male. Super-utilizers comprised 4.8% of the overall cohort (n = 79 746) yet incurred 31.7% of the expenditures. Although the difference in overall expenditures per person between super-utilizers ($4049) and low users ($2148) was relatively modest prior to surgery, the difference in expenditures between super-utilizers ($79 698) vs low users ($2977) was marked in the year following surgery. Risk factors associated with super-utilization of health care included hemiplegia/paraplegia (odds ratio, 5.2; 95% CI, 4.4-6.2), weight loss (odds ratio, 3.5; 95% CI, 2.9-4.2), and congestive heart failure with chronic kidney disease stages I to IV (odds ratio, 3.4; 95% CI, 3.0-3.9).

Conclusions and Relevance

Super-utilizers comprised only a small fraction of the surgical population yet were responsible for a disproportionate amount of Medicare expenditure. Certain subpopulations were associated with super-utilization of health care following surgical intervention despite having lower overall use in the preoperative period.

Risk factors for delay in surgery for patients undergoing elective anterior cervical discectomy and fusion

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is well-tolerated by most patients and commonly necessitates only a short hospital admission. Surgical delay after hospital admission, however, may result in longer hospital stays, consequently increasing hospital resource utilization. The current study evaluates risk factors for surgical delay in patients undergoing elective ACDF.

METHODS

A retrospective analysis of ACS-NSQIP data from 2006-2015 was performed. Patients undergoing elective ACDF were selected using current procedural terminology (CPT) codes (22251, 22252, 22554). A surgical delay was defined as surgery that occurred one day or later after initial hospital admission. Differences in outcomes between the non-delayed and delayed cohorts were evaluated with univariate analysis. Multivariate logistic regression was performed to identify risk factors for surgical delay.

RESULTS

There were a total of 771 (2.0%) surgical delays out of 39,371 patients undergoing elective ACDF from 2006-2015. Multivariate analysis found partially dependent functional status (OR 5.88; 95% CI: 4.48-7.71; P<0.001), totally dependent functional status (OR 18.22; 95% CI: 9.60-34.59; P<0.001), ASA class 4 (OR 2.73; 95% CI: 1.70-4.38; P<0.001), bleeding disorders (OR 1.75; 95% CI: 1.08-2.85; P=0.024), male sex (OR 1.19; 95% CI: 1.03-1.38; P=0.019), and chronic steroid use (OR 1.76; 95% CI: 1.30-2.37; P<0.001) as independent predictors of delay. Univariate analysis found surgical delay was associated with a higher rate of post-operative major adverse events (4.8% vs. 1.1%; P<0.001), mortality (1.0% vs. 0.2%; P<0.001) and greater than five-fold increase in total length of stay (9.52 vs. 1.65 days; P<0.001).

CONCLUSIONS

Impaired pre-operative functional status, a higher comorbidity burden, and chronic steroid use are risk factors for surgical delay, increased complications, and length of stay in patients undergoing elective ACDF. This is helpful information to consider given a rising incidence of cervical fusions in the Medicare population, a wide variation in costs, and increasing popularity of bundled-payment models.

LEVEL OF EVIDENCE

3.

The Use of Older Versus Newer Data in the National Surgical Quality Improvement Program Database Influences the Results of Total Hip Arthroplasty Outcomes Studies

Introduction

National databases, such as the National Surgical Quality Improvement Program (NSQIP) database, are frequently used for total hip arthroplasty (THA) studies. NSQIP variables and the population included in the database have evolved over time. These changes may influence the results of studies using different periods of data.

Methods

THA patients were aggregated from the 2005 to 2010 and 2011 to 2015 NSQIP data sets to define two era groups. Demographic data and 30-day perioperative outcomes were compared between the groups. As an example analysis, multivariate Poisson regression was used to determine the correlation between age and perioperative outcomes for each group.

Results

Of 102,411 THA patients identified, 8098 cases were from 2005 to 2010 and 94,313 were from 2011 to 2015. A number of preoperative characteristics and perioperative outcomes were significantly different between the era groups. Multivariate analysis of the 2005 to 2010 group showed that increasing age was significantly associated with urinary tract infection and length of stay (LOS), and multivariate analysis of the 2011 to 2015 group showed that age was significantly associated with urinary tract infection, LOS, 30-day mortality, unplanned reintubation, extended LOS, pneumonia, deep vein thrombosis/thrombophlebitis, blood transfusion, and return to the operating room.

Conclusion

Significantly more THA patients were enrolled in the NSQIP in the years between 2005 and 2015. Populations in 2005 to 2010 versus 2011 to 2015 were associated with differences in preoperative characteristics and perioperative outcomes. In an example analysis, it was shown that these differences together lead to different study results and conclusions. This needs to be considered when interpreting and conducting studies using earlier NSQIP data.

Preoperative Patient Functional Status Is an Independent Predictor of Outcomes After Primary Total Hip Arthroplasty

This study was designed to determine whether preoperative functional status of patients with osteoarthritis predicts outcomes after primary total hip arthroplasty. The American College of Surgeons National Surgical Quality Improvement Program database was queried for records of patients who underwent primary total hip arthroplasty for a principal diagnosis of osteoarthritis from 2009 to 2013 (N=43,179). Patients were categorized as dependent or independent according to their preoperative functional status. The groups were compared regarding several potential confounders using Student's t and chi-square tests. Logistic and Poisson regression models (inclusion threshold of P<.1) were used to assess the associations of functional status with outcomes. The alpha level was set at 0.05. Compared with independent patients, dependent patients were likely to be older (mean, 70 vs 66 years, P<.01) and to have more preoperative comorbidities. After controlling for potential confounders, preoperative dependent functional status was predictive of major complications (odds ratio, 2.34; 95% confidence interval, 1.67-3.28), nonroutine discharge (odds ratio, 2.80; 95% confidence interval, 2.35-3.34), and longer hospital stay (incidence risk ratio, 1.19; 95% confidence interval, 1.12-1.27). Rates of unplanned reoperation were similar between groups on multivariate analysis. Compared with preoperative independent functional status, preoperative dependent functional status was independently associated with worse outcomes after primary total hip arthroplasty for osteoarthritis. [Orthopedics. 2019; 42(3):e326-e330.].

Trends in Inpatient Resource Utilization and Complications Among Total Joint Arthroplasty Recipients: A Retrospective Cohort Study

INTRODUCTION

Joint arthroplasty practice is highly dynamic to adapt to economic changes and advances in medicine. This study provides updates of the current perioperative practice on healthcare resource utilization.

METHODS

The study included total knee arthroplasty, total hip arthroplasty, and total shoulder arthroplasty within the healthcare cost and utilization project New York State database from 2007 to 2013 (ie, 202,100, 127,872, and 8858 cases, respectively).

RESULTS

A higher proportion of sicker patients were prevalent over time. The length of stay decreased continuously. However, total hospital charges increased after adjusting for inflation. The incidence of wound infection and transfusion decreased steadily over time, whereas acute renal failure has been on the rise. There was an increased utilization of echocardiography, while decreased among other resources.

DISCUSSION

Total knee arthroplasty, total hip arthroplasty, and total shoulder arthroplasty changed toward sicker patients with shorter length of stay, fewer complications, and less resource utilization. However, overall costs increased over time.

Re-admissions treble the risk of late mortality after primary total hip arthroplasty

BACKGROUND

Following a total hip arthroplasty (THA), early hospital re-admission rates of 3-11% are considered as 'acceptable' in terms of medical care cost policies. Surprisingly, the impact of re-admissions on mortality has not been priorly portrayed. Therefore, we sought to determine the mortality rate after 90-day re-admissions following a THA in a series of patients from a captive medical care program.

PATIENTS AND METHODS

We prospectively analysed 90-day readmissions of 815 unilateral, elective THA patients operated upon between 2010 and 2014 whose medical care was the one offered by our institution. We stratified our sample into readmitted and non-readmitted cohorts. Through a Cox proportional hazards model, we compared demographic characteristics, clinical comorbidities, surgical outcomes and laboratory values between both groups in order to determine association with early and late mortality.

RESULTS

We found 37 (4.53%) re-admissions at a median time of 40.44 days (IQR 17.46-60.69). Factors associated with re-admission were hospital stay (p = 0.00); surgical time (p = 0.01); chronic renal insufficiency (p = 0.03); ASA class 4 (p = 0.00); morbid obesity (p = 0.006); diabetes (p = 0.04) and a high Charlson index (p = 0.00). Overall mortality rate of the series was 3.31% (27/815). Median time to mortality was 455.5 days (IQR 297.58-1170.65). One-third (11/37) of the re-admitted patients died, being sepsis non-related to the THA the most common cause of death. After adjusting for confounders, 90-day re-admissions remained associated with mortality with an adjusted HR of 3.14 (CI95% 1.05-9.36, p = 0.04).

CONCLUSIONS

Unplanned re-admissions were an independent risk factor for future mortality, increasing three times the risk of mortality.

Treatments of Missing Values in Large National Data Affect Conclusions: The Impact of Multiple Imputation on Arthroplasty Research

BACKGROUND

Despite the advantages of large, national datasets, one continuing concern is missing data values. Complete case analysis, where only cases with complete data are analyzed, is commonly used rather than more statistically rigorous approaches such as multiple imputation. This study characterizes the potential selection bias introduced using complete case analysis and compares the results of common regressions using both techniques following unicompartmental knee arthroplasty.

METHODS

Patients undergoing unicompartmental knee arthroplasty were extracted from the 2005 to 2015 National Surgical Quality Improvement Program. As examples, the demographics of patients with and without missing preoperative albumin and hematocrit values were compared. Missing data were then treated with both complete case analysis and multiple imputation (an approach that reproduces the variation and associations that would have been present in a full dataset) and the conclusions of common regressions for adverse outcomes were compared.

RESULTS

A total of 6117 patients were included, of which 56.7% were missing at least one value. Younger, female, and healthier patients were more likely to have missing preoperative albumin and hematocrit values. The use of complete case analysis removed 3467 patients from the study in comparison with multiple imputation which included all 6117 patients. The 2 methods of handling missing values led to differing associations of low preoperative laboratory values with commonly studied adverse outcomes.

CONCLUSION

The use of complete case analysis can introduce selection bias and may lead to different conclusions in comparison with the statistically rigorous multiple imputation approach. Joint surgeons should consider the methods of handling missing values when interpreting arthroplasty research.

Risk Factors for and Complications After Surgical Delay in Elective Single-Level Lumbar Fusion

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To assess the incidence of and risk factors for delay of elective lumbar fusion surgery, as well as medical and surgical complications associated with surgical delay.

SUMMARY OF BACKGROUND DATA

Lumbar fusion is a well-established treatment for patients with degenerative spondylolisthesis with stenosis who have failed conservative management. Rarely, patients admitted for elective lumbar fusion may experience a delay in surgery past the day of admission. The incidence of, and risk factors for, delay of elective lumbar fusion surgery and the complications associated therewith have never been previously evaluated.

METHODS

We retrospectively reviewed the ACS-NSQIP registry utilizing Current Procedural Terminology (CPT) codes 22612, 22558, 22630, and 22633 to identify all patients undergoing a single level spinal fusion. The data were then subdivided into cohorts consisting of patients with and without surgical delay. Demographic information, preoperative risk factors for delay, as well as intraoperative and postoperative complications were compared between the groups.

RESULTS

We identified 2758 (5.46%) patients as experiencing a delay before lumbar fusion. Multivariate analysis was then performed and identified male sex, American Society of Anesthesiologists classes 3 and 4, and chronic steroid use as risk factors increasing the rate of surgical delay. Multiple complication rates were also significantly higher in the delayed group, including an almost 10-fold increase in mortality rate (0.2% vs. 1.9%, respectively, P < 0.001).

CONCLUSION

Delays in elective surgery can affect medical system resource utilization, increasing costs and leading to worse patient outcomes. Patients with chronic steroid use and higher American Society of Anesthesiologists class may be at risk for surgical delay in lumbar fusion beyond the day of admission, and are at increased risk for significant complications postoperatively. Thorough medical evaluation and preoperative optimization may be indicated for these patients.

LEVEL OF EVIDENCE

4.

The Influence of Presurgical Factors on the Rehabilitation Outcome of Patients Following Hip Arthroplasty

PURPOSE

The aims of this study were to evaluate the relationship between sociodemographic information, anthropometric values, clinical and presurgery factors, and length of stay (LOS) in older adult patients undergoing total hip arthroplasty (THA) and to predict which factors can delay the start of the rehabilitation program and increase the corresponding LOS.

METHODS

A prospective cohort study was conducted in an orthopedic inpatient unit with 40 patients undergoing THA.

FINDINGS

The Morse Fall Scale scores and pain intensity scores delayed the commencement of the rehabilitation program. Gender and social support were important determinants of LOS and rehabilitation outcome following THA. The weight of the lower limb without osteoarthritis followed by pain intensity and overweight patients also influenced LOS.

CONCLUSIONS/CLINICAL RELEVANCE

Functional outcomes after THA are variable, and the rehabilitation process is an important factor to regain their normal level of physical functioning. This factor can have an impact in the discharge of patients, in resource allocation and in health care of older adult patients.

Hip Fractures: Appropriate Timing to Operative Intervention

BACKGROUND

The purpose of this study is to (1) identify the incidence of surgical delay in hip fractures, (2) evaluate the time point surgical delay puts patients at increased risk for complications, and (3) identify risk factors for surgical delay in the setting of surgical management of hip fractures.

METHODS

A multi-center database was queried for patients of 60 years of age or older undergoing surgical treatment of a hip fracture. Surgical delay was defined by days from admission until surgical intervention. Univariate analyses and multivariate analyses were performed on all groups.

RESULTS

A total of 4215 patients underwent surgery for their hip fracture. Of those experiencing surgical delay, 3304 (78%) patients experienced surgical delay of ≥1 day, 1314 (31%) had delay of ≥2 days, and 480 (11%) experienced delay of ≥3 days. There was a significant difference in complications if patients experienced surgical delay of ≥2 days (P ≤ .01). Multivariate analyses identified multiple risk factors for delay of ≥2 days including congestive heart failure (odds ratio 3.09, 95% confidence interval 2.04-4.66) and body mass index ≥40 (odds ratio 2.31, 95% confidence interval 1.31-4.08). Subgroup analysis identified that patients undergoing total hip arthroplasty were not at risk for complications with surgical delay of ≥2 days.

CONCLUSION

Surgical delay of ≥2 days in the setting of hip fractures is common and confers an increased risk of complications in those undergoing non-total hip arthroplasty procedures. We recommend surgical intervention prior to 48 hours from hospital admission when possible. Healthcare systems can utilize our non-modifiable risk factors when performing quality assessment and cost accounting.