Evaluating the Association between Anesthesia Type and Postoperative Complications for Patients Receiving Total Ankle Arthroplasty

Abstract

Background

Total ankle arthroplasty (TAA) is performed for ankle arthritis and there has been interest investigating which anesthetic method is the best choice in order to optimize perioperative outcomes. In this study, we compared postoperative complications after TAA for patients receiving either 1) general anesthesia alone or 2) general anesthesia plus regional anesthesia.

Methods

Patients undergoing primary TAA from 2007 to 2018 were identified in a national database. Patients were stratified into 2 cohorts: general anesthesia and general anesthesia combined with regional anesthesia. In this analysis, 30-day wound, cardiac, pulmonary, renal, thromboembolic, and sepsis complications, as well mortality, postoperative transfusion, urinary tract infection, extended length of stay, and reoperation were assessed. Bivariate analyses and multivariable logistical regression were performed.

Results

Of 1,084 total patients undergoing TAA, 878 patients (81.0%) had general anesthesia and 206 (19.0%) had general anesthesia combined with regional anesthesia. Following adjustment, there were no increased risk of postoperative complications in the combined general and regional anesthesia group compared to those who only underwent general anesthesia.

Conclusion

Compared to general anesthesia alone, the addition of regional anesthesia to general anesthesia for TAA is not associated with increased risk of complications in the perioperative period.

Level of Evidence: III

Introduction

Total ankle arthroplasty (TAA) is a common treatment option for patients with posttraumatic arthritis, osteoarthritis, or inflammatory arthritis of the ankle. With the rise of better weight-bearing implants that have shown to be successful for use in ankle arthroplasty, TAA is becoming an increasingly common procedure for patients with ankle arthritis.¹ The incidence of ankle osteoarthritis is about 1% of the world population and TAA rates are expected to rise.^1-4 Given that TAA has emerged as an excellent treatment option for ankle arthritis and a significant proportion of the world population has ankle arthritis, there has been great interest in seeing how best to optimize outcomes for patients receiving TAA.

Regional anesthesia and general anesthesia can be used for TAA and both have their advantages and disadvantages. The most common regional anesthesia block given for TAA is a sciatic block in the popliteal fossa which can be approached from either lateral or posterior aspect of the popliteal fossa.⁵ Local anesthetic introduced into the popliteal space through either approach targets the sciatic nerve and provides adequate anesthetic for all downstream branches of the sciatic nerve, which covers the surgical area of a TAA. However, the saphenous nerve is not targeted with a sciatic popliteal block and anesthetic must also be introduced at the medial proximal tibia to cover the superficial region of the TAA surgical field. Relative contraindications to this regional anesthesia include bleeding disorders, hematoma or local infection at the injection site. On the other hand, general anesthesia has also been used for these procedures. An advantage of general anesthesia is that the patient has a protected airway whereas patients receiving regional anesthesia do not have a protected airway even though they are still sedated, which can be dangerous if complications arise during surgery that necessitate emergency airway management. An advantage of regional anesthesia for TAA is that it has been proposed to improve pain, patient satisfaction, and reduce hospital costs after foot and ankle surgery compared to general anesthesia.^6,7

Various previous studies have investigated anesthesia effects on perioperative outcomes related to TAA. In their randomized control trial, YaDeau et al. found that general anesthesia combined with regional anesthesia was associated with earlier readiness for discharge compared to neuraxial anesthesia combined with regional anesthesia. They also found that pain scores and side effects were the same for patients receiving lower extremity surgeries.⁸ Matsumoto et al. found that anesthesia time over 200 minutes was an independent risk factor that is associated with increased rates of adverse events after TAA.⁹ Borenstein et al. found that the combination of regional anesthesia saphenous/popliteal nerve blocks with opioids after surgery was associated with satisfactory patient experiences and no readmission for pain control for TAA.¹⁰ While all of these studies investigated perioperative outcomes for patients receiving TAA in different clinical contexts, none of these studies investigated if general anesthesia versus general anesthesia combined with regional anesthesia was associated with differences in perioperative outcomes within 1 month of surgery. While Matsumoto et al. found that longer anesthesia time was associated with increased complications, they did not stratify anesthesia type into general anesthesia, regional anesthesia or both.⁹ While Borenstein et al. found that regional anesthesia combined with postoperative opioids was associated with no adverse outcomes, they did not compare this to general anesthesia.¹⁰

To our knowledge, we are the first study to compare postoperative outcomes for patients receiving general anesthesia versus combined general anesthesia and regional anesthesia for TAA procedures. We hypothesized that the addition of regional anesthesia to general anesthesia would affect length-of-stay which could then affect postoperative complications in the perioperative period. In this study, a national database was used to study differences in perioperative outcomes for patients receiving general anesthesia versus combined general anesthesia and regional anesthesia for TAA.

Methods

A retrospective cohort study of all patients who underwent primary TAA was performed. Data were collected through the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, which is a national database that includes data from more than 700 participating institutions. This data is collected by trained clinical reviewers and it includes preoperative, demographic, comorbidity, and postoperative data.^11-13 This database has been widely used in orthopedic surgery to track the clinical course of patients.^14,15

Patient Selection

From the years 2007 to 2018, patients who underwent primary TAA were identified using Current Procedural Terminology (CPT) code 27702. Patients were excluded from this study if they had missing data, such as if their sex, race, and American Society of Anesthesiologists (ASA) classification were unknown. Patients were also excluded if they were classified as ASA grade V, or if they were <18-years-old. In this study, two subgroups were used to evaluate the impact of anesthesia type on complications following TAA: general anesthesia and general anesthesia combined with regional anesthesia.

Baseline Patient Characteristics

Patients’ baseline demographics data and clinical characteristics included age, sex, race, BMI, ASA classification, smoking status, and functional status. Patient comorbidities included chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hypertension, dialysis, steroid use, bleeding disorder, diabetes, and dyspnea. Weight loss was defined as >10% loss of body weight in the last 6 months.

Postoperative Complications

The outcomes were classified into clinically relevant groups based on the type of complication. These groups included wound (superficial surgical site infection, deep surgical site infection, organ or space infections, and/ or wound disruption), cardiac (cardiac arrest and/ or myocardial infarction), pulmonary (pneumonia, reintubation, and/or failure to wean off ventilator for more than 48 hours), renal (renal failure and/ or renal insufficiency), thromboembolic (deep vein thrombosis, pulmonary embolism, and/ or stroke), and sepsis (sepsis and/ or septic shock). Based on existing literature, major complications (cardiac arrest, pulmonary embolism, intubation, myocardial infarction, sepsis, septic shock, renal failure, and/ or mortality) and minor complications (urinary tract infection, deep vein thrombosis, pneumonia, superficial surgical site infection, and/ or deep surgical site infection) were categorized.^16,17 Mortality, urinary tract infection, bleeding requiring transfusion, extended length of hospital stay, and reoperation were also recorded. Extended length of stay was defined as > 3 days based on previous studies.¹⁸

Statistical Analysis

The Statistical Package for the Social Sciences (SPSS; Version 26; Armonk, NY) software was utilized in this study to conduct bivariate and multivariate analyses. Using Pearson’s Chi-squared test and analysis of variance where appropriate, data on patient demographics, comorbidities, and postoperative complications were analyzed with bivariate analysis. Demographics, clinical characteristics, and comorbidities were included in the multivariate analysis for p-values < 0.20.^19,20 Postoperative complication variables with a p-value < 0.05 were selected for multivariate analyses. Multivariate analysis results were reported as odds ratios with 95% confidence intervals. A p-value of < 0.05 was the cut-off value for statistical significance in this study.

Results

Demographics

In total, 1,084 primary TAA patients were included in the analysis after the exclusion criteria was applied. There were 878 patients (81.0%) in the general anesthesia group and 206 (19.0%) in the general anesthesia combined with regional anesthesia group. There were no differences in age, sex, race, ASA classification, BMI, smoking status, and functional status when comparing patients who underwent general anesthesia to those who had general anesthesia combined with regional anesthesia (Table 1).

Table 1.

Demographics and Comorbidities Among Patients Undergoing Total Ankle Arthroplasty

Demographics/ Comorbidities	General Anesthesia	General + Regional Anesthesia	p-value: general + regional anesthesia vs general anesthesia
Total patients, n	878	206
Sex, n (%)			0.713¶
Female	418 (47.6)	101 (49.0)
Male	460 (52.4)	105 (51.0)
Ethnicity, n (%)			0.176¶
Caucasian	791 (90.1)	193 (93.7)
Black or African American	29 (3.3)	9 (4.4)
Hispanic	43 (4.9)	4 (1.9)
American Indian or Alaska Native	1 (0.1)	0 (0.0)
Asian	12 (1.4)	0 (0.0)
Native Hawaiian or Pacific Islander	2 (0.2)	0 (0.0)
ASA, n (%)			0.892¶
I	33 (3.8)	7 (3.4)
II	495 (56.4)	112 (54.4)
III	341 (38.8)	84 (40.8)
IV	9 (1.0)	3 (1.5)
Smoker, n (%)	81 (9.2)	18 (8.7)	0.827¶
Functional status preoperative, n (%)			0.469¶
Independent	865 (99.1)	199 (98.5)
Partially dependent	8 (0.9)	3 (1.5)
Mean age, yrs (SD)	63.92 (10.31)	63.70 (10.19)	0.782**
Mean BMI (SD)	31.37 (6.00)	31.31 (5.52)	0.904**
COPD, n (%)	23 (2.6)	6 (2.9)	0.815
CHF, n (%)	5 (0.6)	1 (0.5)	0.884
Hypertension, n (%)	490 (55.8)	127 (61.7)	0.128
Dialysis, n (%)	3 (0.3)	0 (0.0)	0.401
Steroid use, n (%)	31 (3.5)	14 (6.8)	0.034
Bleeding disorder, n (%)	28 (3.2)	7 (3.4)	0.879
DM status, n (%)			0.032
No DM	778 (88.6)	169 (82.0)
Noninsulin-dependent DM	80 (9.1)	28 (13.6)
Insulin-dependent DM	20 (2.3)	9 (4.4)
Dyspnea, n (%)			0.060
No dyspnea	851 (96.9)	194 (94.2)
Moderate exertion	24 (2.7)	12 (5.8)
At rest	3 (0.3)	0 (0.0)

¶Pearson’s chi-squared test

**Analysis of variance

Bolding equals significance p<0.05

ASA, American Society of Anesthesiologists; SD, standard deviation; BMI, body mass index; COPD, chronic obstructive pulmonary disease; CHF, congestive heart failure; DM, diabetes mellitus.

Comorbidities

When compared to patients who underwent general anesthesia, those who had general anesthesia combined with regional anesthesia were more likely to use steroids (p=0.034) and have diabetes mellitus (p=0.032) (Table 1). Also, there was no significant difference in operative time between the two groups.

Complications

Following TAA, on bivariate analysis, compared to patients who underwent general anesthesia, patients who underwent combined general and regional anesthesia were more likely to develop postoperative complications within the first 30 days, such as cardiac problems (p=0.039), thromboembolic complications (p=0.035), and urinary tract infections (p=0.004) (Table 2).

Table 2.

Bivariate Analysis of Postoperative Complications of Patients Following Total Ankle Arthroplasty

Complications	General Anesthesia	General + Regional Anesthesia	p-value: general + regional anesthesia vs general anesthesia¶
Total patients, n	878	206
Any complication, n (%)	19 (2.2)	8 (3.9)	0.154
Major complication, n (%)**	5 (0.6)	3 (1.5)	0.181
Minor complication, n (%)††	9 (1.0)	5 (2.4)	0.109
Death, n (%)	3 (0.3)	0 (0.0)	0.401
Wound complication, n (%)	8 (0.9)	1 (0.5)	0.544
Cardiac complication, n (%)	0 (0.0)	1 (0.5)	0.039
Pulmonary complication, n (%)	2 (0.2)	2 (1.0)	0.113
Renal complication, n (%)	1 (0.1)	0 (0.0)	0.628
Thromboembolic complication, n (%)	1 (0.1)	2 (1.0)	0.035
Sepsis complication, n (%)	1 (0.1)	1 (0.5)	0.263
Urinary tract infection, n (%)	1 (0.1)	3 (1.5)	0.004
Postoperative transfusion, n (%)	5 (0.6)	0 (0.0)	0.278
Extended length of stay (> 3 days), n (%)	54 (6.2)	12 (5.8)	0.861
Reoperation, n (%)	6 (0.7)	1 (0.5)	0.750

¶Pearson’s chi-squared test

**Includes cardiac arrest, pulmonary embolism, myocardial infarction, unplanned intubation, sepsis, septic shock, acute renal failure, or mortality.

††Includes urinary tract infection, pneumonia, deep venous thrombosis, superficial surgical site infection, or deep surgical site infection.

Bolding equals significance p<0.05

Following adjustment for covariates on multivariate analysis, patients who had combined general and regional anesthesia did not have significantly increased risk of cardiac problems, thromboembolic complications or urinary tract infections compared to patients who only underwent general anesthesia (Table 3).

Table 3.

Multivariate Analysis of Postoperative Complications of Patients Following Total Ankle Arthroplasty

Complications	General + Regional Anesthesia
	p-value	Odds ratio (general + regional anesthesia/general anesthesia) (95% CI)
Cardiac complication	0.659	1.724 (0.153 to 19.370)
Thromboembolic complication	0.083	10.550 (0.736 to 151.289)
Urinary tract infection	0.051	9.940 (0.988 to 99.995)

Bolding equals significance p<0.05

CI, confidence interval.

Discussion

To our best knowledge, this is the first study to use the ACS-NSQIP database to assess the association of anesthesia types with regards to postoperative complications after TAA. After adjusting for preoperative comorbidities, we found that the combinatory use of general and regional anesthesia was not associated with increased risk of complications within 30 days following TAA in the NSQIP database.

No prior studies have compared the effects of general anesthesia versus general anesthesia combined with regional anesthesia on postoperative complications after TAA. While YaDeau et al. found that general anesthesia with regional anesthesia was associated with increased readiness for discharge compared to neuraxial and regional anesthesia for lower extremity surgery, they did not explore rates of postoperative complications within a 1-month window after TAA or examine general anesthesia alone.⁸ Borenstein et al. and Matsumoto et al. did not stratify by anesthesia type and compare general anesthesia against regional anesthesia for TAA procedures.^9,10

To begin, patients who underwent combined general plus regional anesthesia did not show a significant difference in need for extended length of hospital stay (defined as greater than 3 days) following TAA compared to those in the general anesthesia only group. This was a major factor in our initial hypothesis that combined general and would cause longer hospital stays in the combined group, resulting in a higher rate of postoperative complications. The fact that the two groups did not show a difference in extended hospital stay may explain why there was no significant difference in the rate of complications.

It was also interesting that, in this cohort, more of the combined general and regional anesthesia patients tended to have diabetes mellitus and chronic steroid use. Diabetes mellitus can alter platelet function, cause vasculopathy, and is a known risk factor for increasing thromboembolic events, such as deep venous thromboembolism (DVT), in total joint arthroplasties.^21,22 Diabetic neuropathy is also a known risk factor for postoperative urinary retention, leading to increased risks for UTI during orthopedic procedures.^22,23 The current literature regarding the risk of chronic steroid use for thromboembolic events is conflicting. In vivo studies have shown that corticosteroid use promotes decreased platelet aggregation, while other in vivo studies have shown that corticosteroids promote production of hypercoagulable proteins.²⁴ Retrospective surgical studies have also reported variable findings regarding whether chronic steroid use could promote thromboembolic events.^24-26 Additionally, chronic steroid use can increase risk for UTI following total joint arthroplasties given its immunosuppressive effects on top of anesthetic effects of causing postoperative urinary retention.²⁷ After adjustment for multivariate analysis, rates of thromboembolic events and UTI were not significantly different between groups. This may suggest that these complications were in fact due to comorbidities like diabetes mellitus and steroid use, but further study of these factors and outcomes following TAA would be needed to confirm.

In sum, our data suggest that there is no difference in postoperative complications between using combined general anesthesia with regional anesthesia versus general anesthesia alone following TAA. As suggested previously, addition of regional anesthesia has been suggested to improve pain, patient satisfaction, and reduce hospital costs after foot and ankle surgery compared to general anesthesia.^6,7 While Matsumoto et al. found that anesthesia time over 200 minutes was independently associated with increased rates of adverse events after TAA, our study showed no difference in operative time between groups.⁹ Although we do not have specific data on total anesthesia time of the patients in this study, our data does suggest that addition of regional anesthesia did not significantly increase total anesthesia time during TAA. Considering this data in combination, we argue this method of anesthesia should be considered for patients undergoing this procedure going forward.

There are several limitations of this study. As with any database study, the NSQIP database is subject to coding error. However, coding error is assumed to be equally distributed between both groups (general anesthesia and general plus regional anesthesia). Another limitation is that we only had 206 patients receiving general anesthesia plus regional anesthesia compared to 878 receiving general anesthesia alone. While we did not find that there were statistically significant differences in postoperative complications, future studies that have more patients should be performed as it would have more power. In addition, future studies may investigate longer-term pain and function scores related to general versus regional anesthesia and compare these differences to different 1-month perioperative outcomes we have captured in our study. Another limitation to this study was that we were not able to elucidate specifically which TAA systems were used in our patient population, as this information is not available in the NSQIP database. Nevertheless, it is important to identify which systems were used, therefore future studies should evaluate the different TAA systems in this patient population to provide more information on this topic.

Compared to general anesthesia alone, the addition of regional anesthesia to general anesthesia for total ankle arthroplasty is not associated with increased risk of postoperative complications.