- Email: [email protected]
Orthopaedic Shoulder Surgery in the Ambulatory Surgical Center: Safety and Outcomes
Orthopaedic Shoulder Surgery in the Ambulatory Surgical Center: Safety and Outcomes Charles Qin, M.D., Daniel M. Curtis, M.D., Bruce Reider, M.D., Lewis L. Shi, M.D., Michael J. Lee, M.D., and Aravind Athiviraham, M.D.
Purpose: To determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events. Methods: The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the hospital-based outpatient department (HOPD) or ambulatory surgical center (ASC) setting, using the PearlDiver supercomputer. Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures. Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis, pulmonary embolism, and wound infection within 90 days of surgery. The ASC and HOPD cohorts were propensity score matched, and outcomes were compared between them. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery. Results: A total of 84,658 patients met the inclusion criteria for the study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. The rates of all queried outcomes were greater in the HOPD cohort and achieved statistical significance. Sex, region, race, insurance status, comorbidity burden, anesthesia type, and procedural type were included in the regression analysis of unplanned admission. Factors associated with unplanned admission included increasing Charlson Comorbidity Index (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.08-1.59; P ¼ .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P ¼ .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001). Conclusions: The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe. Level of Evidence: Level III, comparative study.
See commentary on page 2551
T
he shift toward performing orthopaedic surgical procedures in the outpatient setting and in ambulatory surgical centers (ASCs) is a recognized trend of the past 2 decades.1 The number of carpal tunnel and knee arthroscopies performed in ASCs increased more than 3fold over the span of a decade.2,3 In addition, a 272% increase in rotator cuff repairs performed in the outpatient setting occurred between 1996 and 2006.4 With recent From the Department of Orthopaedic Surgery and Rehabilitation, University of Chicago, Chicago, Illinois, U.S.A. The authors report no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received November 9, 2018; accepted March 11, 2019. Address correspondence to Charles Qin, M.D., 211 E Ohio St, Apt 2704, Chicago, IL 60611, U.S.A. E-mail: [email protected] Ó 2019 by the Arthroscopy Association of North America 0749-8063/181334/$36.00 https://doi.org/10.1016/j.arthro.2019.03.031
policy changes, the use of freestanding surgical centers for shoulder arthroscopy has increased, with a corresponding decrease in the use of hospital outpatient departments.5 A multitude of patient, surgeon, and facility factors have led to the explosive growth of ambulatory orthopaedic surgery.1 Most notably, the shift toward an outpatient model of care has shown significant cost savings in the fields of hand surgery and fracture care.6-9 An additional reduction in cost can be realized by performing surgical procedures in ASCs rather than hospital-based outpatient departments (HOPDs). ASCs are associated with improved surgical efficiency because of more experienced surgical teams with greater familiarity with surgeon preferences, faster turnover times, differing staff management practices, and even faster regional anesthesia times.1,10 Given that current practices that champion ASCbased orthopaedic care are driven largely by surgeon preference and anecdotal evidence of safety and success, further investigation into adverse events after
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 35, No 9 (September), 2019: pp 2545-2550
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ambulatory surgery and their risk factors is warranted. However, current research is limited because of difficulty defining pertinent surgery-related adverse events, and it is unknown whether the risks of these events are influenced by the outpatient setting of surgical care.11,12 The purposes of this study were to determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events.
Outcomes Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis (DVT), pulmonary embolism (PE), and wound infection within 90 days of surgery. The aforementioned medical complications were identified by the appropriate International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes. The incidences of these events were compared in patients undergoing orthopaedic shoulder surgery in the ASC setting versus the HOPD setting.
Population The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the HOPD or ASC setting performed between 2007 and 2016, using the PearlDiver supercomputer (PearlDiver Technologies, Colorado Springs, CO). Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures.13 The Humana Claims Database contains medical, prescription, and laboratory claims data from 20.9 million privately insured and Medicare Advantage patients from 2007 to 2016. Patients of interest were identified by Current Procedural Terminology codes; a breakdown of patients by Current Procedural Terminology code is provided in Appendix Table 1 (available at www.arthroscopyjournal.org). Only patients undergoing surgery in the ASC or HOPD setting were included. An ASC is defined by the Centers for Medicare & Medicaid Services as a facility with the sole purpose of providing outpatient surgical services to patients. ASCs are structurally separate from a hospital system and must be administratively and financially independent and distinct from operations of a hospital. An HOPD is owned entirely by a hospital and is fully integrated with the hospital financially, administratively, and organizationally, including for quality assurance and medical oversight. The location is treated as part of the main hospital.
Statistical Analysis Univariate comparisons between ASC and HOPD shoulder surgical procedures were drawn with c2 tests for categorical variables and t tests for continuous variables. To eliminate selection bias in this study, propensity score matching was performed. In short, this is a previously applied methodology that creates cohorts with similar baseline demographic characteristics and comorbidities through a derived propensity score.15-17 Pairs with similar scores were matched in a 1:2 ratio, which was determined based on the relative number of cases in each cohort, with the goal of minimizing the number of cases that had to be eliminated to achieve a matched study. The attrition chart in Figure 1 captures the exclusion and inclusion criteria and the process of propensity score matching. Procedural type, anesthesia type, CCI, age, race, sex, and region were included in the matching process. Comparisons between the matched ASC and HOPD cohorts were made using the same statistical analysis. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery while adjusting for patient age, sex, race, year of surgery, region, insurance type, comorbidity burden, procedural type, and anesthesia type. A subanalysis stratified by open and arthroscopic surgery was performed. For all comparisons, statistical significance was defined as P .05. All statistics were performed in the R package (version 2.13.1; R Foundation for Statistical Computing, Vienna, Austria).
Demographic Characteristics The study population was divided into 2 cohorts based on the surgical setting: ASC or HOPD. Each cohort was then queried for patient age, sex, race, geographic region (Midwest, Northeast, South, or West), year of surgery, insurance type, anesthesia type (regional anesthesia with or without the use of general anesthesia vs general alone), and Charlson Comorbidity Index (CCI). The CCI, a validated method to capture comorbidity burden, was created using a scoring system incorporating differentially weighted comorbidities and age classes.14 Specific to the Humana Claims Database, only age groupings by decade of life, not the actual age, are available.
A total of 84,658 patients met the inclusion criteria for this study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. A breakdown of demographic characteristics, CCI, anesthesia type, and procedural type with c2 comparisons is listed in Table 1. Notably, the use of regional anesthesia was greater in the ASC cohort (P < .001), open shoulder surgical procedures were more commonly performed in the HOPD cohort (P ¼ .028), and surgical volume increased every year (P < .001). Comparisons of unmatched cohorts using the c2 test revealed that the HOPD cohort had greater rates of all outcomes studied. The findings were all statistically
Methods
Results
SHOULDER SURGERY IN AMBULATORY SETTING
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Fig 1. Attrition chart. (ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CPT, Current Procedural Terminology code; HOPD, hospital-based outpatient department.)
significant: unexpected admission (0.52% vs 0.22%, P < .001); 90-day readmission (4.09% vs 2.9%, P < .001); DVT (0.68% vs 0.49%, P ¼ .001); PE (0.56% vs 0.36%, P < .001); and wound infection (0.47% vs 0.3%, P ¼ .001) (Table 2). Propensity score matching yielded 23,780 patients in the ASC cohort and 47,279 in the HOPD cohort. Rates of all queried outcomes were greater in the HOPD cohort: unexpected admission (0.5% vs 0.2%, P < .001); 90-day readmission (3.7% vs 3.0%, P < .001); DVT (0.6% vs 0.5%, P ¼ .05); PE (0.5% vs 0.4%, P ¼ .006); and wound infection (0.5% vs 0.3%, P ¼ .002) (Table 3). Factors associated with unplanned admission as identified by logistic regression included CCI (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.081.59; P ¼ .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P ¼ .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001) (Table 4). A subanalysis stratified by open and arthroscopic shoulder surgery revealed similar significant predictors of unplanned admission to the analysis of the entire study population (Table 5).
Discussion Statistically greater rates of unplanned admission, readmission, DVT, PE, and wound infection were found in the HOPD cohort after matching of the 2 study groups to eliminate differences in baseline demographic characteristics, comorbidity burden, and operative factors. Factors associated with unanticipated admission after surgery included HOPD service location, general
anesthesia, open surgery, male sex, and increasing comorbidity burden as identified by the CCI. These findings did not change on subanalysis stratified by open and arthroscopic procedures. The cost-effectiveness of the outpatient model of orthopaedic care, as well as the convenience it provides patients, is reliant on minimizing unplanned admissions after surgery. Although there has been a significant decrease in the unplanned admission rate after shoulder surgery from 21.5% in 1996 to 4.8% in 2006, it is still higher than that of other outpatient orthopaedic procedures.11 Moreover, data on risk factors for unplanned admission after shoulder procedures and comparisons between ASC and HOPD practice settings in the orthopaedic literature are sparse. In the anesthesia literature, Memtsoudis et al.11 found that outpatient knee and shoulder procedures performed in hospital-based versus freestanding facilities were associated with unplanned admission. They attributed their findings in part to stricter patient selection for ASCs, although their study was unable to account for specific patient comorbidities. In our study, the HOPD cohort was 2.3 times more likely to be admitted after surgery. In addition, comorbidity burden in this study was greater in the HOPD cohort, lending support to the hypothesis put forth by Memtsoudis et al. Comorbidity burden was identified to be independently associated with an increased risk of unplanned admission in this study. The CCI, which can be reliably used across surgeons, may assist in safer patient selection for ASCs. In a study of 222 arthroscopic shoulder surgical procedures performed at a hospital-based facility, including subacromial depression, rotator cuff repair, and
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Table 1. Demographic Characteristics ASC (n ¼ 28,730) 12,912 (44.9)
Female sex Region Midwest Northeast South West Insurance Medicare Commercial Medicaid CCI
6,035 462 18,332 3,901
(21.0) (1.6) (63.8) (13.6)
17,687 (61.6) 10,982 (38.2) 61 (0.2) Mean, 1.22 (SD, 1.91)
Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Race White Black Asian Hispanic Anesthesia type General Regional Procedural type Arthroscopic Open
Table 3. Univariate Comparison of Outcomes for Post-matched Data
HOPD (n ¼ 56,819) 26,321 (46.3) (28.8) (1.8) (59.8) (9.6)
<.001
40,461 (71.2) 16,086 (28.3) 272 (0.5) Mean, 1.53 (SD, 2.13)
<.001
16,357 1,013 34,002 5,447
.026
1,557 2,064 2,255 2,513 2,650 2,974 3,389 4,083 4,850 3,531
(5.4) (7.2) (7.8) (8.7) (9.2) (10.4) (11.8) (14.2) (16.9) (12.3)
3,454 4,535 4,985 5,323 5,730 5,897 6,598 7,545 8,599 6,059
(6.1) (8.0) (8.8) (9.4) (10.1) (10.4) (11.6) (13.3) (15.1) (10.7)
<.001
14,905 1,414 82 209
(51.9) (4.9) (0.3) (0.7)
34,290 3,157 134 374
(60.3) (5.6) (0.2) (0.7)
<.001
9,446 (32.9) 19,824 (69.0)
33,525 (59.0) 23,294 (41.0)
<.001
27,141 (94.5) 1,589 (5.5)
51,046 (89.8) 5,773 (10.2)
.028
NOTE. Data are presented as number (percentage of total) unless otherwise indicated. ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; HOPD, hospital-based outpatient department; SD, standard deviation.
arthroscopic stabilization, Sultan et al.12 identified age greater than 65 years, increasing American Society of Anesthesiologists class, increased case complexity, and less experienced anesthesiologists as predictors of Table 2. Univariate Comparison of Outcomes for Prematched Data ASC (n ¼ 28,730)
Unexpected admission Readmission Deep vein thrombosis Pulmonary embolism Wound infection
ASC (n ¼ 23,780)
P Value .01
HOPD (n ¼ 56,819)
n 62
% of Total 0.22
n 297
% of Total 0.52
P Value <.001
832 140
2.90 0.49
2,326 386
4.09 0.68
<.001 .001
103
0.36
318
0.56
<.001
86
0.30
267
0.47
.001
ASC, ambulatory surgical center; HOPD, hospital-based outpatient department.
Unexpected admission Readmission Deep vein thrombosis Pulmonary embolism Wound infection
n 51
% of Total 0.2
723 118
3.0 0.5
85 70
HOPD (n ¼ 47,279) % of Total 0.5
P Value <.001
1,751 292
3.7 0.6
<.001 .05
0.4
240
0.5
.006
0.3
214
0.5
.002
n 214
ASC, ambulatory surgical center; HOPD, hospital-based outpatient department.
unplanned admission. In our study, open shoulder surgery, which may be a surrogate for increased case complexity, was associated with an over 2 times greater likelihood of admission. Longer surgical time, incisional pain, and more bony manipulation may explain these findings, although this is certainly just a hypothesis. Although elderly patients have been identified as an atrisk population, particularly when coupled with recent inpatient hospitalization and greater comorbidity burden, age alone was not found to be associated with unplanned admission.18,19 Unfortunately, age was indirectly analyzed in the regression analysis as the CCI incorporates age into the scoring system. The Humana database’s inability to identify the exact age of the patient should also be noted; only the decade of life is available, which prohibited us from establishing a cutoff for age. Data on the role of anesthesia type after shoulder surgery in overnight admissions are mixed. Recent studies have found no association between use of regional nerve blocks and overnight admission.11,12 For example, Sultan et al.12 reported that although there was no direct association with the use of an interscalene nerve block, less experienced anesthesiologists were not as likely to perform a nerve block. Sultan et al. speculated that regional anesthesia may be indirectly associated with an increased likelihood of unplanned admission. However, older studies have shown the benefit of regional anesthesia in terms of shorter postanesthesia care unit stays,
Table 4. Factors Associated With Unexpected Admission Anesthesia type (reference group: regional) Male sex (reference group: female) CCI (OR represents increased odds for every point increase in CCI) HOPD (reference group: ASC)
OR 1.34 2.58 1.16
95% CI P Value 1.08-1.59 .008 2.17-3.15 .007 1.12-1.17 <.001
2.37 2.18-2.58 <.001
ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CI, confidence interval; HOPD, hospital-based outpatient department; OR, odds ratio.
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SHOULDER SURGERY IN AMBULATORY SETTING Table 5. Subanalysis of Factors Associated With Unexpected Admission Open Shoulder Surgery Anesthesia type (reference group: regional) Male sex (reference group: female) CCI (OR represents increased odds for every point increase in CCI) HOPD (reference group: ASC)
OR 1.45 2.09 1.14 2.43
95% CI 1.23-1.96 1.26-3.49 1.04-1.23 1.57-3.49
Arthroscopic Shoulder Surgery
P Value .02 .03 .002 .04
OR 1.36 2.60 1.16 2.57
95% CI 1.12-1.65 2.35-2.86 1.14-1.2 2.21-2.74
P Value .03 .003 <.001 <.001
ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CI, confidence interval; HOPD, hospital-based outpatient department; OR, odds ratio.
earlier readiness for discharge, improved patient satisfaction, and reduced rates of overnight admissions.20,21 Although this study was unable to account for time spent in the postanesthesia care unit or patient satisfaction, regional anesthesia, with or without the use of general anesthesia, did not impact the likelihood of unplanned admission. Additional factors, unaccounted for in this study, that may affect this relation include recovery protocols that focus on diet advancement to avoid postoperative nausea and vomiting and multimodal analgesia.22 Further prospective investigation is warranted because interscalene nerve blocks carry a small but significant risk of respiratory complications from phrenic nerve paresis, neurologic sequelae, and local anesthetic toxicity.23,24 Identifying risk factors for unplanned admission may have implications when selecting the proper surgical setting for outpatient shoulder surgery. Male patients, patients with higher comorbidity burden, and patients undergoing open surgery may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe. Moreover, this study’s data suggest that these factors are important to consider for both open and arthroscopic surgery. This is particularly germane because some employers and insurers are establishing contribution limits that incentivize patients to select lower-priced freestanding facilities for acute treatments such as arthroplasty and arthroscopy.9 Data on adverse events after shoulder surgery in the ASC setting are limited. Kuremsky et al.25 reported a thromboembolism rate of 0.31% in a series of 1,908 shoulder arthroscopies, which was comparable to the rates in this study. Rates of infection range from 0.77% to 2.1%, with the data largely coming from singleinstitution or single-surgeon series.1,26-28 Our study is unique in its ability to compare these complication rates by the setting of surgery. Although lower rates of thromboembolic events, infection, and 90-day readmission were detected in the ASC cohort after matching for demographic factors and comorbidity burden, the absolute differences in the incidence of any outcome between cohorts were less than 1%, suggesting that these differences may not be very clinically meaningful. Nevertheless, the overall low rate of complications after
shoulder surgery in both ASC and HOPD settings suggests that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Limitations This study is not without limitations. Data on the number of related emergency department visits in the perioperative period could not be reliably obtained. This may comprise a significant proportion of resource utilization after outpatient shoulder surgery, given that 6.9% of patients undergoing rotator cuff repair in 1 study made a visit to an emergency department or urgent care facility within 7 days after surgery for reasons including pain, constipation, urinary retention, nausea, and vomiting.22 This constitutes a significant burden of postoperative care utilization and will be an important data point moving forward in any analysis of outcomes after surgery in an ASC. Our study could not account for surgeon and anesthesiologist experience, surgical time, and proximity of an ASC to a nearby hospital; these factors may impact the likelihood of an overnight stay. Finally, the confounding effect of general anesthesia on the analysis of anesthesia type could not be eliminated because a subset of patients in the regional anesthesia group also received general anesthesia. This weakens the ability to make conclusions regarding the association of anesthesia type with unplanned admission.
Conclusions The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe.
References 1. Goldfarb CA, Bansal A, Brophy RH. Ambulatory surgical centers: A review of complications and adverse events. J Am Acad Orthop Surg 2017;25:12-22.
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2. Fajardo M, Kim SH, Szabo RM. Incidence of carpal tunnel release: Trends and implications within the United States ambulatory care setting. J Hand Surg Am 2012;37: 1599-1605. 3. Kim S, Bosque J, Meehan JP, Jamali A, Marder R. Increase in outpatient knee arthroscopy in the United States: A comparison of National Surveys of Ambulatory Surgery, 1996 and 2006. J Bone Joint Surg Am 2011;93:994-1000. 4. Colvin AC, Egorova N, Harrison AK, Moskowitz A, Flatow EL. National trends in rotator cuff repair. J Bone Joint Surg Am 2012;94:227-233. 5. Buterbaugh KL, Liu SY, Krajewski A, Buterbaugh GA, Imbriglia JE. Safety of outpatient shoulder surgery at a freestanding ambulatory surgery center in patients aged 65 years and older: A review of 640 cases. J Am Acad Orthop Surg Glob Res Rev 2018;2:e075. 6. Nguyen C, Milstein A, Hernandez-Boussard T, Curtin CM. The effect of moving carpal tunnel releases out of hospitals on reducing United States health care charges. J Hand Surg Am 2015;40:1657-1662. 7. Mather RC III, Wysocki RW, Mack Aldridge J III, Pietrobon R, Nunley JA. Effect of facility on the operative costs of distal radius fractures. J Hand Surg Am 2011;36: 1142-1148. 8. Cancienne JM, Brockmeier SF, Gulotta LV, Dines DM, Werner BC. Ambulatory total shoulder arthroplasty: A comprehensive analysis of current trends, complications, readmissions, and costs. J Bone Joint Surg Am 2017;99: 629-637. 9. Robinson JC, Brown TT, Whaley C, Bozic KJ. Consumer choice between hospital-based and freestanding facilities for arthroscopy: Impact on prices, spending, and surgical complications. J Bone Joint Surg Am 2015;97:1473-1481. 10. Kadhim M, Gans I, Baldwin K, Flynn J, Ganley T. Do surgical times and efficiency differ between inpatient and ambulatory surgery centers that are both hospital owned? J Pediatr Orthop 2016;36:423-428. 11. Memtsoudis SG, Ma Y, Swamidoss CP, Edwards AM, Mazumdar M, Liguori GA. Factors influencing unexpected disposition after orthopedic ambulatory surgery. J Clin Anesth 2012;24:89-95. 12. Sultan J, Marflow KZ, Roy B. Unplanned overnight admissions in day-case arthroscopic shoulder surgery. Surgeon 2012;10:16-19. 13. Bean BA, Connor PM, Schiffern SC, Hamid N. Outpatient shoulder arthroplasty at an ambulatory surgery center using a multimodal pain management approach. J Am Acad Orthop Surg Glob Res Rev 2018;2:e064. 14. Simard M, Sirois C, Candas B. Validation of the Combined Comorbidity Index of Charlson and Elixhauser to predict 30-day mortality across ICD-9 and ICD-10. Med Care 2018;56:441-447. 15. Austin PC. Optimal caliper widths for propensity-score matching when estimating differences in means and
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differences in proportions in observational studies. Pharm Stat 2011;10:150-161. Lovecchio F, Alvi H, Sahota S, Beal M, Manning D. Is outpatient arthroplasty as safe as fast-track inpatient arthroplasty? A propensity score matched analysis. J Arthroplasty 2016;31:197-201. Schairer WW, Lane JM, Halsey DA, Iorio R, Padgett DE, McLawhorn AS. The Frank Stinchfield Award: Total hip arthroplasty for femoral neck fracture is not a typical DRG 470: A propensity-matched cohort study. Clin Orthop Relat Res 2017;475:353-360. Fleisher LA, Pasternak LR, Herbert R, Anderson GF. Inpatient hospital admission and death after outpatient surgery in elderly patients: Importance of patient and system characteristics and location of care. Arch Surg 2004;139:67-72. De Oliveira GS Jr, Holl JL, Lindquist LA, Hackett NJ, Kim JY, McCarthy RJ. Older adults and unanticipated hospital admission within 30 days of ambulatory surgery: An analysis of 53,667 ambulatory surgical procedures. J Am Geriatr Soc 2015;63:1679-1685. Hadzic A, Williams BA, Karaca PE, et al. For outpatient rotator cuff surgery, nerve block anesthesia provides superior same-day recovery over general anesthesia. Anesthesiology 2005;102:1001-1007. Singh A, Kelly C, O’Brien T, Wilson J, Warner JJ. Ultrasound-guided interscalene block anesthesia for shoulder arthroscopy: A prospective study of 1319 patients. J Bone Joint Surg Am 2012;94:2040-2046. Navarro RA, Lin CC, Foroohar A, Crain SR, Hall MP. Unplanned emergency department or urgent care visits after outpatient rotator cuff repair: Potential for avoidance. J Shoulder Elbow Surg 2018;27:993-997. Hussain N, Goldar G, Ragina N, Banfield L, Laffey JG, Abdallah FW. Suprascapular and interscalene nerve block for shoulder surgery: A systematic review and metaanalysis. Anesthesiology 2017;127:998-1013. Marty P, Ferre F, Basset B, et al. Diaphragmatic paralysis in obese patients in arthroscopic shoulder surgery: Consequences and causes. J Anesth 2018;32:333-340. Kuremsky MA, Cain EL Jr, Fleischli JE. Thromboembolic phenomena after arthroscopic shoulder surgery. Arthroscopy 2011;27:1614-1619. Owens BD, Williams AE, Wolf JM. Risk factors for surgical complications in rotator cuff repair in a veteran population. J Shoulder Elbow Surg 2015;24: 1707-1712. Pauzenberger L, Grieb A, Hexel M, Laky B, Anderl W, Heuberer P. Infections following arthroscopic rotator cuff repair: Incidence, risk factors, and prophylaxis. Knee Surg Sports Traumatol Arthrosc 2017;25:595-601. Vopat BG, Lee BJ, DeStefano S, et al. Risk factors for infection after rotator cuff repair. Arthroscopy 2016;32: 428-434.
SHOULDER SURGERY IN AMBULATORY SETTING Appendix Table 1. Current Procedural Terminology Codes Code Arthroscopic 29805 29806 29807 29819 29820 29821 29823 29824 29826 29827 29828 Open 23130 23405 23410 23412 23430 23450 23455 23460 23462 23465 23466 23660
Description Diagnostic Bankart repair SLAP repair Loose body removal Partial synovectomy Complete synovectomy Extensive debridement Distal clavicle resection Subacromial decompression Rotator cuff repair Arthroscopic biceps tenodesis Acromioplasty or acromionectomy Biceps tenotomy Open rotator cuff repair Open rotator cuff repair Biceps tenodesis Capsulorrhaphy, anterior Open Bankart repair Capsulorrhaphy, anterior, with bone block Latarjet procedure Capsulorrhaphy, posterior, with or without bone block Capsulorrhaphy, any type, with multidirectional instability Open treatment of anterior shoulder dislocation
2550.e1
Purpose: To determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events. Methods: The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the hospital-based outpatient department (HOPD) or ambulatory surgical center (ASC) setting, using the PearlDiver supercomputer. Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures. Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis, pulmonary embolism, and wound infection within 90 days of surgery. The ASC and HOPD cohorts were propensity score matched, and outcomes were compared between them. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery. Results: A total of 84,658 patients met the inclusion criteria for the study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. The rates of all queried outcomes were greater in the HOPD cohort and achieved statistical significance. Sex, region, race, insurance status, comorbidity burden, anesthesia type, and procedural type were included in the regression analysis of unplanned admission. Factors associated with unplanned admission included increasing Charlson Comorbidity Index (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.08-1.59; P ¼ .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P ¼ .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001). Conclusions: The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe. Level of Evidence: Level III, comparative study.
See commentary on page 2551
T
he shift toward performing orthopaedic surgical procedures in the outpatient setting and in ambulatory surgical centers (ASCs) is a recognized trend of the past 2 decades.1 The number of carpal tunnel and knee arthroscopies performed in ASCs increased more than 3fold over the span of a decade.2,3 In addition, a 272% increase in rotator cuff repairs performed in the outpatient setting occurred between 1996 and 2006.4 With recent From the Department of Orthopaedic Surgery and Rehabilitation, University of Chicago, Chicago, Illinois, U.S.A. The authors report no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received November 9, 2018; accepted March 11, 2019. Address correspondence to Charles Qin, M.D., 211 E Ohio St, Apt 2704, Chicago, IL 60611, U.S.A. E-mail: [email protected] Ó 2019 by the Arthroscopy Association of North America 0749-8063/181334/$36.00 https://doi.org/10.1016/j.arthro.2019.03.031
policy changes, the use of freestanding surgical centers for shoulder arthroscopy has increased, with a corresponding decrease in the use of hospital outpatient departments.5 A multitude of patient, surgeon, and facility factors have led to the explosive growth of ambulatory orthopaedic surgery.1 Most notably, the shift toward an outpatient model of care has shown significant cost savings in the fields of hand surgery and fracture care.6-9 An additional reduction in cost can be realized by performing surgical procedures in ASCs rather than hospital-based outpatient departments (HOPDs). ASCs are associated with improved surgical efficiency because of more experienced surgical teams with greater familiarity with surgeon preferences, faster turnover times, differing staff management practices, and even faster regional anesthesia times.1,10 Given that current practices that champion ASCbased orthopaedic care are driven largely by surgeon preference and anecdotal evidence of safety and success, further investigation into adverse events after
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ambulatory surgery and their risk factors is warranted. However, current research is limited because of difficulty defining pertinent surgery-related adverse events, and it is unknown whether the risks of these events are influenced by the outpatient setting of surgical care.11,12 The purposes of this study were to determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events.
Outcomes Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis (DVT), pulmonary embolism (PE), and wound infection within 90 days of surgery. The aforementioned medical complications were identified by the appropriate International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes. The incidences of these events were compared in patients undergoing orthopaedic shoulder surgery in the ASC setting versus the HOPD setting.
Population The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the HOPD or ASC setting performed between 2007 and 2016, using the PearlDiver supercomputer (PearlDiver Technologies, Colorado Springs, CO). Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures.13 The Humana Claims Database contains medical, prescription, and laboratory claims data from 20.9 million privately insured and Medicare Advantage patients from 2007 to 2016. Patients of interest were identified by Current Procedural Terminology codes; a breakdown of patients by Current Procedural Terminology code is provided in Appendix Table 1 (available at www.arthroscopyjournal.org). Only patients undergoing surgery in the ASC or HOPD setting were included. An ASC is defined by the Centers for Medicare & Medicaid Services as a facility with the sole purpose of providing outpatient surgical services to patients. ASCs are structurally separate from a hospital system and must be administratively and financially independent and distinct from operations of a hospital. An HOPD is owned entirely by a hospital and is fully integrated with the hospital financially, administratively, and organizationally, including for quality assurance and medical oversight. The location is treated as part of the main hospital.
Statistical Analysis Univariate comparisons between ASC and HOPD shoulder surgical procedures were drawn with c2 tests for categorical variables and t tests for continuous variables. To eliminate selection bias in this study, propensity score matching was performed. In short, this is a previously applied methodology that creates cohorts with similar baseline demographic characteristics and comorbidities through a derived propensity score.15-17 Pairs with similar scores were matched in a 1:2 ratio, which was determined based on the relative number of cases in each cohort, with the goal of minimizing the number of cases that had to be eliminated to achieve a matched study. The attrition chart in Figure 1 captures the exclusion and inclusion criteria and the process of propensity score matching. Procedural type, anesthesia type, CCI, age, race, sex, and region were included in the matching process. Comparisons between the matched ASC and HOPD cohorts were made using the same statistical analysis. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery while adjusting for patient age, sex, race, year of surgery, region, insurance type, comorbidity burden, procedural type, and anesthesia type. A subanalysis stratified by open and arthroscopic surgery was performed. For all comparisons, statistical significance was defined as P .05. All statistics were performed in the R package (version 2.13.1; R Foundation for Statistical Computing, Vienna, Austria).
Demographic Characteristics The study population was divided into 2 cohorts based on the surgical setting: ASC or HOPD. Each cohort was then queried for patient age, sex, race, geographic region (Midwest, Northeast, South, or West), year of surgery, insurance type, anesthesia type (regional anesthesia with or without the use of general anesthesia vs general alone), and Charlson Comorbidity Index (CCI). The CCI, a validated method to capture comorbidity burden, was created using a scoring system incorporating differentially weighted comorbidities and age classes.14 Specific to the Humana Claims Database, only age groupings by decade of life, not the actual age, are available.
A total of 84,658 patients met the inclusion criteria for this study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. A breakdown of demographic characteristics, CCI, anesthesia type, and procedural type with c2 comparisons is listed in Table 1. Notably, the use of regional anesthesia was greater in the ASC cohort (P < .001), open shoulder surgical procedures were more commonly performed in the HOPD cohort (P ¼ .028), and surgical volume increased every year (P < .001). Comparisons of unmatched cohorts using the c2 test revealed that the HOPD cohort had greater rates of all outcomes studied. The findings were all statistically
Methods
Results
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Fig 1. Attrition chart. (ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CPT, Current Procedural Terminology code; HOPD, hospital-based outpatient department.)
significant: unexpected admission (0.52% vs 0.22%, P < .001); 90-day readmission (4.09% vs 2.9%, P < .001); DVT (0.68% vs 0.49%, P ¼ .001); PE (0.56% vs 0.36%, P < .001); and wound infection (0.47% vs 0.3%, P ¼ .001) (Table 2). Propensity score matching yielded 23,780 patients in the ASC cohort and 47,279 in the HOPD cohort. Rates of all queried outcomes were greater in the HOPD cohort: unexpected admission (0.5% vs 0.2%, P < .001); 90-day readmission (3.7% vs 3.0%, P < .001); DVT (0.6% vs 0.5%, P ¼ .05); PE (0.5% vs 0.4%, P ¼ .006); and wound infection (0.5% vs 0.3%, P ¼ .002) (Table 3). Factors associated with unplanned admission as identified by logistic regression included CCI (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.081.59; P ¼ .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P ¼ .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001) (Table 4). A subanalysis stratified by open and arthroscopic shoulder surgery revealed similar significant predictors of unplanned admission to the analysis of the entire study population (Table 5).
Discussion Statistically greater rates of unplanned admission, readmission, DVT, PE, and wound infection were found in the HOPD cohort after matching of the 2 study groups to eliminate differences in baseline demographic characteristics, comorbidity burden, and operative factors. Factors associated with unanticipated admission after surgery included HOPD service location, general
anesthesia, open surgery, male sex, and increasing comorbidity burden as identified by the CCI. These findings did not change on subanalysis stratified by open and arthroscopic procedures. The cost-effectiveness of the outpatient model of orthopaedic care, as well as the convenience it provides patients, is reliant on minimizing unplanned admissions after surgery. Although there has been a significant decrease in the unplanned admission rate after shoulder surgery from 21.5% in 1996 to 4.8% in 2006, it is still higher than that of other outpatient orthopaedic procedures.11 Moreover, data on risk factors for unplanned admission after shoulder procedures and comparisons between ASC and HOPD practice settings in the orthopaedic literature are sparse. In the anesthesia literature, Memtsoudis et al.11 found that outpatient knee and shoulder procedures performed in hospital-based versus freestanding facilities were associated with unplanned admission. They attributed their findings in part to stricter patient selection for ASCs, although their study was unable to account for specific patient comorbidities. In our study, the HOPD cohort was 2.3 times more likely to be admitted after surgery. In addition, comorbidity burden in this study was greater in the HOPD cohort, lending support to the hypothesis put forth by Memtsoudis et al. Comorbidity burden was identified to be independently associated with an increased risk of unplanned admission in this study. The CCI, which can be reliably used across surgeons, may assist in safer patient selection for ASCs. In a study of 222 arthroscopic shoulder surgical procedures performed at a hospital-based facility, including subacromial depression, rotator cuff repair, and
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Table 1. Demographic Characteristics ASC (n ¼ 28,730) 12,912 (44.9)
Female sex Region Midwest Northeast South West Insurance Medicare Commercial Medicaid CCI
6,035 462 18,332 3,901
(21.0) (1.6) (63.8) (13.6)
17,687 (61.6) 10,982 (38.2) 61 (0.2) Mean, 1.22 (SD, 1.91)
Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Race White Black Asian Hispanic Anesthesia type General Regional Procedural type Arthroscopic Open
Table 3. Univariate Comparison of Outcomes for Post-matched Data
HOPD (n ¼ 56,819) 26,321 (46.3) (28.8) (1.8) (59.8) (9.6)
<.001
40,461 (71.2) 16,086 (28.3) 272 (0.5) Mean, 1.53 (SD, 2.13)
<.001
16,357 1,013 34,002 5,447
.026
1,557 2,064 2,255 2,513 2,650 2,974 3,389 4,083 4,850 3,531
(5.4) (7.2) (7.8) (8.7) (9.2) (10.4) (11.8) (14.2) (16.9) (12.3)
3,454 4,535 4,985 5,323 5,730 5,897 6,598 7,545 8,599 6,059
(6.1) (8.0) (8.8) (9.4) (10.1) (10.4) (11.6) (13.3) (15.1) (10.7)
<.001
14,905 1,414 82 209
(51.9) (4.9) (0.3) (0.7)
34,290 3,157 134 374
(60.3) (5.6) (0.2) (0.7)
<.001
9,446 (32.9) 19,824 (69.0)
33,525 (59.0) 23,294 (41.0)
<.001
27,141 (94.5) 1,589 (5.5)
51,046 (89.8) 5,773 (10.2)
.028
NOTE. Data are presented as number (percentage of total) unless otherwise indicated. ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; HOPD, hospital-based outpatient department; SD, standard deviation.
arthroscopic stabilization, Sultan et al.12 identified age greater than 65 years, increasing American Society of Anesthesiologists class, increased case complexity, and less experienced anesthesiologists as predictors of Table 2. Univariate Comparison of Outcomes for Prematched Data ASC (n ¼ 28,730)
Unexpected admission Readmission Deep vein thrombosis Pulmonary embolism Wound infection
ASC (n ¼ 23,780)
P Value .01
HOPD (n ¼ 56,819)
n 62
% of Total 0.22
n 297
% of Total 0.52
P Value <.001
832 140
2.90 0.49
2,326 386
4.09 0.68
<.001 .001
103
0.36
318
0.56
<.001
86
0.30
267
0.47
.001
ASC, ambulatory surgical center; HOPD, hospital-based outpatient department.
Unexpected admission Readmission Deep vein thrombosis Pulmonary embolism Wound infection
n 51
% of Total 0.2
723 118
3.0 0.5
85 70
HOPD (n ¼ 47,279) % of Total 0.5
P Value <.001
1,751 292
3.7 0.6
<.001 .05
0.4
240
0.5
.006
0.3
214
0.5
.002
n 214
ASC, ambulatory surgical center; HOPD, hospital-based outpatient department.
unplanned admission. In our study, open shoulder surgery, which may be a surrogate for increased case complexity, was associated with an over 2 times greater likelihood of admission. Longer surgical time, incisional pain, and more bony manipulation may explain these findings, although this is certainly just a hypothesis. Although elderly patients have been identified as an atrisk population, particularly when coupled with recent inpatient hospitalization and greater comorbidity burden, age alone was not found to be associated with unplanned admission.18,19 Unfortunately, age was indirectly analyzed in the regression analysis as the CCI incorporates age into the scoring system. The Humana database’s inability to identify the exact age of the patient should also be noted; only the decade of life is available, which prohibited us from establishing a cutoff for age. Data on the role of anesthesia type after shoulder surgery in overnight admissions are mixed. Recent studies have found no association between use of regional nerve blocks and overnight admission.11,12 For example, Sultan et al.12 reported that although there was no direct association with the use of an interscalene nerve block, less experienced anesthesiologists were not as likely to perform a nerve block. Sultan et al. speculated that regional anesthesia may be indirectly associated with an increased likelihood of unplanned admission. However, older studies have shown the benefit of regional anesthesia in terms of shorter postanesthesia care unit stays,
Table 4. Factors Associated With Unexpected Admission Anesthesia type (reference group: regional) Male sex (reference group: female) CCI (OR represents increased odds for every point increase in CCI) HOPD (reference group: ASC)
OR 1.34 2.58 1.16
95% CI P Value 1.08-1.59 .008 2.17-3.15 .007 1.12-1.17 <.001
2.37 2.18-2.58 <.001
ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CI, confidence interval; HOPD, hospital-based outpatient department; OR, odds ratio.
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SHOULDER SURGERY IN AMBULATORY SETTING Table 5. Subanalysis of Factors Associated With Unexpected Admission Open Shoulder Surgery Anesthesia type (reference group: regional) Male sex (reference group: female) CCI (OR represents increased odds for every point increase in CCI) HOPD (reference group: ASC)
OR 1.45 2.09 1.14 2.43
95% CI 1.23-1.96 1.26-3.49 1.04-1.23 1.57-3.49
Arthroscopic Shoulder Surgery
P Value .02 .03 .002 .04
OR 1.36 2.60 1.16 2.57
95% CI 1.12-1.65 2.35-2.86 1.14-1.2 2.21-2.74
P Value .03 .003 <.001 <.001
ASC, ambulatory surgical center; CCI, Charlson Comorbidity Index; CI, confidence interval; HOPD, hospital-based outpatient department; OR, odds ratio.
earlier readiness for discharge, improved patient satisfaction, and reduced rates of overnight admissions.20,21 Although this study was unable to account for time spent in the postanesthesia care unit or patient satisfaction, regional anesthesia, with or without the use of general anesthesia, did not impact the likelihood of unplanned admission. Additional factors, unaccounted for in this study, that may affect this relation include recovery protocols that focus on diet advancement to avoid postoperative nausea and vomiting and multimodal analgesia.22 Further prospective investigation is warranted because interscalene nerve blocks carry a small but significant risk of respiratory complications from phrenic nerve paresis, neurologic sequelae, and local anesthetic toxicity.23,24 Identifying risk factors for unplanned admission may have implications when selecting the proper surgical setting for outpatient shoulder surgery. Male patients, patients with higher comorbidity burden, and patients undergoing open surgery may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe. Moreover, this study’s data suggest that these factors are important to consider for both open and arthroscopic surgery. This is particularly germane because some employers and insurers are establishing contribution limits that incentivize patients to select lower-priced freestanding facilities for acute treatments such as arthroplasty and arthroscopy.9 Data on adverse events after shoulder surgery in the ASC setting are limited. Kuremsky et al.25 reported a thromboembolism rate of 0.31% in a series of 1,908 shoulder arthroscopies, which was comparable to the rates in this study. Rates of infection range from 0.77% to 2.1%, with the data largely coming from singleinstitution or single-surgeon series.1,26-28 Our study is unique in its ability to compare these complication rates by the setting of surgery. Although lower rates of thromboembolic events, infection, and 90-day readmission were detected in the ASC cohort after matching for demographic factors and comorbidity burden, the absolute differences in the incidence of any outcome between cohorts were less than 1%, suggesting that these differences may not be very clinically meaningful. Nevertheless, the overall low rate of complications after
shoulder surgery in both ASC and HOPD settings suggests that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Limitations This study is not without limitations. Data on the number of related emergency department visits in the perioperative period could not be reliably obtained. This may comprise a significant proportion of resource utilization after outpatient shoulder surgery, given that 6.9% of patients undergoing rotator cuff repair in 1 study made a visit to an emergency department or urgent care facility within 7 days after surgery for reasons including pain, constipation, urinary retention, nausea, and vomiting.22 This constitutes a significant burden of postoperative care utilization and will be an important data point moving forward in any analysis of outcomes after surgery in an ASC. Our study could not account for surgeon and anesthesiologist experience, surgical time, and proximity of an ASC to a nearby hospital; these factors may impact the likelihood of an overnight stay. Finally, the confounding effect of general anesthesia on the analysis of anesthesia type could not be eliminated because a subset of patients in the regional anesthesia group also received general anesthesia. This weakens the ability to make conclusions regarding the association of anesthesia type with unplanned admission.
Conclusions The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe.
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2. Fajardo M, Kim SH, Szabo RM. Incidence of carpal tunnel release: Trends and implications within the United States ambulatory care setting. J Hand Surg Am 2012;37: 1599-1605. 3. Kim S, Bosque J, Meehan JP, Jamali A, Marder R. Increase in outpatient knee arthroscopy in the United States: A comparison of National Surveys of Ambulatory Surgery, 1996 and 2006. J Bone Joint Surg Am 2011;93:994-1000. 4. Colvin AC, Egorova N, Harrison AK, Moskowitz A, Flatow EL. National trends in rotator cuff repair. J Bone Joint Surg Am 2012;94:227-233. 5. Buterbaugh KL, Liu SY, Krajewski A, Buterbaugh GA, Imbriglia JE. Safety of outpatient shoulder surgery at a freestanding ambulatory surgery center in patients aged 65 years and older: A review of 640 cases. J Am Acad Orthop Surg Glob Res Rev 2018;2:e075. 6. Nguyen C, Milstein A, Hernandez-Boussard T, Curtin CM. The effect of moving carpal tunnel releases out of hospitals on reducing United States health care charges. J Hand Surg Am 2015;40:1657-1662. 7. Mather RC III, Wysocki RW, Mack Aldridge J III, Pietrobon R, Nunley JA. Effect of facility on the operative costs of distal radius fractures. J Hand Surg Am 2011;36: 1142-1148. 8. Cancienne JM, Brockmeier SF, Gulotta LV, Dines DM, Werner BC. Ambulatory total shoulder arthroplasty: A comprehensive analysis of current trends, complications, readmissions, and costs. J Bone Joint Surg Am 2017;99: 629-637. 9. Robinson JC, Brown TT, Whaley C, Bozic KJ. Consumer choice between hospital-based and freestanding facilities for arthroscopy: Impact on prices, spending, and surgical complications. J Bone Joint Surg Am 2015;97:1473-1481. 10. Kadhim M, Gans I, Baldwin K, Flynn J, Ganley T. Do surgical times and efficiency differ between inpatient and ambulatory surgery centers that are both hospital owned? J Pediatr Orthop 2016;36:423-428. 11. Memtsoudis SG, Ma Y, Swamidoss CP, Edwards AM, Mazumdar M, Liguori GA. Factors influencing unexpected disposition after orthopedic ambulatory surgery. J Clin Anesth 2012;24:89-95. 12. Sultan J, Marflow KZ, Roy B. Unplanned overnight admissions in day-case arthroscopic shoulder surgery. Surgeon 2012;10:16-19. 13. Bean BA, Connor PM, Schiffern SC, Hamid N. Outpatient shoulder arthroplasty at an ambulatory surgery center using a multimodal pain management approach. J Am Acad Orthop Surg Glob Res Rev 2018;2:e064. 14. Simard M, Sirois C, Candas B. Validation of the Combined Comorbidity Index of Charlson and Elixhauser to predict 30-day mortality across ICD-9 and ICD-10. Med Care 2018;56:441-447. 15. Austin PC. Optimal caliper widths for propensity-score matching when estimating differences in means and
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SHOULDER SURGERY IN AMBULATORY SETTING Appendix Table 1. Current Procedural Terminology Codes Code Arthroscopic 29805 29806 29807 29819 29820 29821 29823 29824 29826 29827 29828 Open 23130 23405 23410 23412 23430 23450 23455 23460 23462 23465 23466 23660
Description Diagnostic Bankart repair SLAP repair Loose body removal Partial synovectomy Complete synovectomy Extensive debridement Distal clavicle resection Subacromial decompression Rotator cuff repair Arthroscopic biceps tenodesis Acromioplasty or acromionectomy Biceps tenotomy Open rotator cuff repair Open rotator cuff repair Biceps tenodesis Capsulorrhaphy, anterior Open Bankart repair Capsulorrhaphy, anterior, with bone block Latarjet procedure Capsulorrhaphy, posterior, with or without bone block Capsulorrhaphy, any type, with multidirectional instability Open treatment of anterior shoulder dislocation
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