dedicated orthopedic operating room unit improves operating room efficiency

The Journal of Arthroplasty 28 (2013) 1066–1071.e2

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The Journal of Arthroplasty

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Dedicated Orthopedic Operating Room Unit Improves Operating Room Efficiency

Travis J. Small DO a, Bishoy V. Gad MD a, Alison K. Klika MS a, Loran S. Mounir-Soliman MD b,Ryan L. Gerritsen BA a, Wael K. Barsoum MD a

a Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohiob Department of General Anesthesiology, Cleveland Clinic, Cleveland, Ohio

Supplementary material available at www.arthroplaThe Conflict of Interest statement associated with th

dx.doi.org/10.1016/j.arth.2013.01.033.Reprint requests: Alison Klika, MS, Research Prog

Orthopaedic Surgery, Cleveland Clinic – A41, 9500 Eucli

0883-5403/2807-0003$36.00/0 – see front matter © 20http://dx.doi.org/10.1016/j.arth.2013.01.033

a b s t r a c t
a r t i c l e i n f o
Article history:Received 15 November 2012Accepted 27 January 2013

Keywords:total knee arthroplastytotal hip arthroplastyoperating timeturnover timeprocedure timethroughput

We investigated the effectiveness of dedicated orthopedic operating rooms (OR) onminimizing time spent onperioperative processes to increase OR throughput in total knee and hip arthroplasty procedures. The use of adedicated orthopedic unit that included 6 ORs with staff allocated only for those ORs was compared to the useof a traditional staffing model. After matching to simulate randomization, each group consisted of422 procedures. The dedicated orthopedic unit improved average anesthesia controlled time by 4 minutes(Pb .001), operative time by 7 minutes (P=.004) and turnover time by 8 minutes (Pb .001). An overallimprovement of 19 minutes per procedure using the dedicated unit was observed. Utilizing a dedicatedorthopedic unit can save time without increasing adverse events.

styjournal.org.is article can be found at http://

ram Manager, Department ofd Ave., Cleveland, OH 44195.

13 Elsevier Inc. All rights reserved.

© 2013 Elsevier Inc. All rights reserved.

The health-care system currently faces many challenges includingdiminishing resources, increasing costs and changes in reimburse-ment [1–4]. These economic pressures require hospitals to frequentlyevaluate operating room (OR) processes to improve efficiencywithout undermining patient safety and care. System design iscited as the most effective method for improving OR procedures[5–8] and increasing OR capacity. Effectively managing OR processesis critical for maximizing OR utilization, diminishing resourcedowntime and facilitating an effective team dynamic. The classicsystem of running an OR involves placing staff (e.g., anesthesia,surgical technicians and nurses) wherever needed. Sharing staffamongst various specialties is referred to as a traditional OR staffingmodel. In contrast, a dedicated OR is considered to be an OR unit withcommitted staff to only one specialty with specific cases. Otherstudies have analyzed multidisciplinary team assessment to improveprocess [6,9–12] and using parallel processing to improve operativeand non-operative times [7].

Improving OR utilization requires understanding of 3 parame-ters: time required for surgery, case scheduling, and minimizingtime between surgeries [5]. First, technological advances andimprovements in surgical technique may decrease time requiredfor surgery [5], while process improvements may also decrease

surgical time. Secondly, time required for surgery is often thoughtof as surgeon and procedure dependent. However, studies haveshown that there are consistent relationships established amongstsurgeons for each procedure [13,14]. Estimation for procedure timeserves as an effective tool to improve scheduling difficulties [15–18]. Lastly, analyzing sources of increased non-operative timesubdivided into anesthesia controlled time (ACT) and turnovertime (TOT), through a multidisciplinary (nursing, anesthesia, andsurgical team) approach has proven effective in previous studies[6,7]. All of these parameters must be investigated to fullymaximize patient throughput.

Our institution has decreased both operative and non-operativetime by making system improvements using high throughputprocesses which led to an increase in contribution margin (differencebetween direct cost and revenue) of 19.6% over a 2-year period [7].This was accomplished through redesign of the operative system toinclude perioperative induction rooms [15], and block rooms forregional anesthesia [8]. Other improvements were achieved by addingdedicated circulating nurses and enhancing communication betweenOR technicians with handheld radios [19]. These successful maneu-vers can be attributed to a multidisciplinary approach consisting oforthopedic surgeons, anesthesiologists, nurses, nurse managers, andsupport staff [6,8]. A limitation in this design was that it concentratedadded resources on only one room each day.

The primary objective of this study was to determine whether theuse of a dedicated orthopedic unit, encompassing an average of 6rooms per day, would decrease overall OR time, including ACT,operative time, and TOT. A secondary goal of the study was tocompare amount, type and severity of complications for traditional

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1067T.J. Small et al. / The Journal of Arthroplasty 28 (2013) 1066–1071.e2

and dedicated orthopedic units. We hypothesized that the dedicatedorthopedic unit would allow for decreased OR time, withoutincreasing complication rates.

Materials and Methods

The Institutional Review Board reviewed and approved the study.A process improvement commission was created in 2008 by thesurgical operations department of a tertiary medical center toreorganize the flow of orthopedic ORs performing total kneearthroplasty (TKA) and total hip arthroplasty (THA) procedures.Beginning on April 1, 2009, the total joints orthopedic ORs at ourInstitution began to function as an isolated unit (i.e., dedicated OR)from other services. The unit remained “dedicated” until 7:30 pm atwhich time staffing and call responsibilities were shared with the restof the surgical suite. The 6 dedicated ORs were allocated nurses,anesthesiologists, orthopedic surgeons and OR technicians whoexclusively performed primary total joint arthroplasty procedures.At preset intervals, the anesthesia staff from the orthopedic teamrotated through different subspecialty anesthesia services. In addition,measures were taken to avoid penalizing OR staff for being efficient byprohibiting staff members from floating to other cases outside thededicated OR, unless by choice. Once staff completed their assignedtasks in the OR they were either delegated to educational or servicework, or allowed to go home. Patient flow into and out of thededicated OR was similar to traditional OR services as described byKrupta [5]. There were no changes in anticoagulation protocols orstandard of care protocols between the two time periods.

Cases for a retrospective review were identified using ouroperating room information system to query Current ProceduralTerminology codes [20] for primary TKA (27447) and primary THA(27130) cases from 2 time periods. Cases from September 1, 2008 toFebruary 28, 2009 defined the control group (i.e., traditional), andcases from September 1, 2009 to February 28, 2010 defined thededicated OR group.

Time interval definitions by the American Association of ClinicalDirectors Procedural Times [21] were used to define the metrics. Thesequence of time intervals is summarized in Fig. 1. Specific parametersstudied were patient in room (PIR) times, procedure start times (PST),and patient out of room times (POR). PIR to PST was referred to asACT, PST to POR was called operative time, and POR from the first caseto PIR of the second case was referred to as turnover time (TOT).Intervals between PIR and POR, PST and POR, PIR for one case to PIR ofthe following case, and POR from one case to PIR of the following casewere then examined. Data were collected and analyzed for the eachcohort as a whole, then as TKA and THA subgroups. PIR 1 to PIR 2intervals of greater than 500 minutes (8 hr 20 min) were excludeddue to unrealistic room TOT and OR times. These were likely non-

Fig. 1. Summary of OR times in linear time format.

contiguous cases, meaning that the long TOT was due to a case endingthe previous day and a new case being the first case of the followingsurgical day. All cases greater than 500 minutes and negative timeswere excluded as these were most likely due to errors in computerreporting, CPT recording, or inexplicably long cases due to non-procedure related complications.

Acute and in-house complications were recorded for all patients.In-house complications were defined as any adverse event thatoccurred immediately after surgery until discharge from the hospital.Acute complications were defined as any readmission within 90 daysof the surgical date following discharge from the hospital. Any patientthat did not have contact with his/her surgeon within 90 days wasexcluded from the study (n=12 control; n=5 dedicated). Compli-cations were categorized based on type (i.e., infection, hematomas/deep vein thrombosis, fractures, mechanical failures, other) andseverity (grade 1 to 5) of the complication following Dindo et al. [22].Complications listed as ‘other’ consisted of arthrofibrosis andemergency room visits as well as unrelated procedures of transure-thral prostectomy, CHF exacerbation, laparscopic cholesycectomy,and sickle-cell crisis. Grade 1 complications were defined as anydeviation from normal post-operative course excluding the followingtreatments: antiemetics, antipyretics, analgetics, diuretics, electro-lytes, and physiotherapy. Grade 2 complications required any drugsother then allowed in grade one complications including bloodtransfusions and total parenteral nutrition. Grade 3 complicationsrequired surgical, endoscopic and/or radiographic intervention. Grade4 complications were life-threatening including CNS complicationsrequiring IC/ICU management. Grade 5 complications included deathof the patient.

Statistical Methods

Baseline characteristics were first evaluated to determine areas ofstatistical significance between groups so that they could beappropriately adjusted for in the models. Descriptive statistics werecomputed comparing the OR groups (traditional vs dedicated).Subgroup analyses evaluating TKA and THA procedures were alsoevaluated. Categorical data were compared using chi-square tests formeasures of association. The Fisher's exact test was applied forexpected cell countsb5 and the Cochran Mantel–Haenszel chi-squaretests were used for ordinal data. Continuous data were comparedusing the student's t-tests for normally distributed data; non-normaldata were compared using the non-parametric Wilcoxon tests.

Since dedicated and traditional ORs differed significantly for someof the demographic and comorbidity variables; in order to makeappropriate comparisons a propensity matching analysis was per-formed. Demographics utilized for matching consisted of: age, bodymass index (BMI), gender, surgeon, laterality, and indications forsurgery (Table 1 and Appendix 1). Comorbidities applied formatching were hypertension, diabetes, osteoporosis, cancer, hyper-lipidemia, coronary artery disease, congestive heart failure, lungdisease, tobacco use, alcohol use, and illicit drug use as well asAmerican Society of Anesthesiologists (ASA) Classification (Tables 2,3 and Appendixes 2, 3). Logistic regression was used to estimate apropensity score (PS), which represents the probability a patientwould be in the treatment group (i.e. dedicated OR) rather than thecontrol group (i.e., traditional OR) [23]. Propensity scoring removedany significant variations between the two groups to simulaterandomization. Greedy 1 to 1 matching techniques were then usedto pair patients who were in dedicated OR with those were intraditional OR by choosing the patients with the nearest PS [24].Comparisons of perioperative times and complications were madebetween the PS-matched patients with Chi-square or Fisher's exacttest or Wilcoxon rank sum test where appropriate. The process wasrepeated for both the TKA and THA subgroups.

Table 1Demographics by OR Group: After Matching.

Total Knee Arthroplasty

Traditional OR (N=233)Mean±SD or N (%)

Dedicated OR (N=233)Mean±SD or N (%) P Value

Age (years) 65.7±11.0 65.4±11.0 0.76BMI 32.4±7.2 32.6±7.2 0.77Gender (Female=266) 134 (57.5) 132 (56.7) 0.85⁎SurgeonFellowship-trained (418) 208 (89.3) 210 (90.1) 0.76⁎Non-fellowship-trained (48) 25 (89.3) 23 (9.9)LateralityLeft (230) 117 (50.2) 113 (48.5) 0.71⁎Right (236) 116 (49.8) 120 (51.5)IndicationsOsteoarthritis (448) 225 (96.6) 223 (95.7) 0.63⁎AVN/Osteonecrosis (1) 0 (0.0) 1 (0.43) 0.99⁎⁎RA (12) 6 (2.6) 6 (2.6) 0.99⁎Other (5) 2 (0.86) 3 (1.3) 0.99⁎⁎

Total Hip Arthroplasty

Traditional OR (N=157) Dedicated OR (N=157) P Value

Age (years) 59.5±14.0 59.0±13.0 0.78BMI 30.2±6.6 30.3±6.6 0.89Gender (Male=168) 83 (52.9) 85 (54.1) 0.82⁎SurgeonFellowship-trained (279) 139 (88.5) 140(89.2) 0.86⁎Non-fellowship-trained (35) 18(11.5) 17(10.8)LateralityLeft (151) 76 (48.4) 75 (47.8) 0.91⁎Right (163) 81 (51.6) 82 (52.2)IndicationsOsteoarthritis (257) 128 (81.5) 129 (82.2) 0.88⁎AVN/Osteonecrosis (34) 17 (10.8) 17 (10.8) 0.99⁎RA (4) 2 (1.3) 2 (1.3) 0.99⁎⁎Other (17) 9 (5.7) 8 (5.1) 0.80⁎

Student's t-test, unless noted otherwise.Note: There were 2 surgeons who did not perform any THA procedures.⁎ Chi-square test.⁎⁎ Fisher's exact test.

1068 T.J. Small et al. / The Journal of Arthroplasty 28 (2013) 1066–1071.e2

Results

There were 475 cases (n=200 primary THA; n=275 primaryTKA) in the traditional OR control group spanning 181 OR days(Appendix 1). In the dedicated OR study group, 529 cases (n=215

Table 2Comorbidities by OR Group: After Matching.

Total Knee Art

Traditional OR (N=233)N (%)

Medical historyHypertension (326) 165 (70.8)Diabetes (93) 48 (20.6)Osteoporosis (13) 7 (3.0)Cancer (81) 42 (18.0)Hyperlipidemia (211) 105 (45.1)Coronary artery disease (79) 41 (17.6)Congestive heart failure (19) 9 (3.9)Lung disease (56) 26 (11.2)Social historyTobacco use (225) 112 (48.1)Alcohol use (221) 108 (46.4)Illicit drugs use (4) 2 (0.86)ASA classification2 (n=199) 98 (42.1)3 (n=252) 128 (54.9)4 (n=15) 7 (3.0)

⁎ Chi-square test, unless noted otherwise.⁎⁎ Fisher's exact test.+ Cochran-Mantel-Haenszel test.

primary THA; n=314 TKA) spanning 181 OR days were performed(Appendix 1). Turnover time was recorded for 164 cases in thecontrol group and 209 cases in the dedicated group from the totalcases as described above. Before PS matching there were differencesbetween the number of TKA procedures performed by adult

hroplasty

Dedicated OR (N=233)N (%) P Value⁎

161 (69.1) 0.6945 (19.3) 0.736 (2.6) 0.78

39 (16.7) 0.71106 (45.5) 0.9338 (16.3) 0.7110 (4.3) 0.8130 (12.9) 0.57

113 (48.5) 0.93113 (48.5) 0.64

2 (0.86) 0.99⁎⁎

101 (43.4) 0.87+

124 (53.2)8 (3.4)

Table 3Comorbidities by OR Group: After Matching.



Dedicated OR (N=157)N (%) P Value⁎

Medical historyHypertension (160) 79 (50.3) 81 (51.6) 0.82Diabetes (29) 13 (8.3) 16 (10.2) 0.56Osteoporosis (5) 2 (1.3) 3 (1.9) 0.99⁎⁎Cancer (31) 15 (9.6) 16 (10.2) 0.85Hyperlipidemia (108) 55 (35.0) 53 (33.8) 0.81Coronary artery disease (34) 17 (10.8) 17 (10.8) 0.99Congestive heart failure (1) 0 (0.00) 1 (0.64) 0.99⁎⁎Lung disease (38) 18 (11.5) 20 (12.7) 0.73

Social historyTobacco use (167) 82 (52.2) 85 (54.9) 0.73Alcohol use (163) 81 (51.6) 82 (52.2) 0.91Illicit drugs use (4) 2 (1.3) 2 (1.3) 0.99⁎⁎

ASA classification1 (n=9) 6 (3.8) 3 (1.9) 0.64+

2 (n=149) 74 (47.1) 75 (47.8)3 (n=148) 73 (46.5) 75 (47.8)4 (n=8) 4 (2.6) 4 (2.6)



reconstruction fellowship-trained surgeons and non-fellowshiptrained surgeons (P=0.022) (Appendix 1). Before matching therewas a difference in TKA patients for osteoporosis (P = 0.027), andthe THA group had differences in diabetes (P=0.011) and lungdisease (P=0.030) (Appendixes 2 and 3). The final overall PSmatched cohort simulated a randomized control trial to eliminatethe differences between cohorts consisted of 780 patients (n=390paired traditional OR unit procedures, n=390 dedicated OR unitprocedures). The TKA subgroup consisted of 466 patients (n=233paired traditional OR, n=233 dedicated OR). The THA subgroupconsisted of 314 patients (n=157 paired traditional OR, n=157dedicated OR).

Time improvements were found in combined TKA and THA groups,including ACT (4.0 minutes, Pb .001), operative time (7.0 minutes,

Table 4Perioperative Times by OR Group: After Matching.

Total Hip and Knee

Traditional OR (N=422)Median

(25th Percentile, 75th Percentile)

Anesthesia controlled time (min) 47.0 (40.0, 56.0)Operating room time (min) 141.0 (119.0, 161.0)

Traditional OR (N=147)Turnover time (min) 42.0 (32.0, 48.0)

Total Knee Art

Traditional OR (N=233)



Total Hip Arth

Traditional OR (N=157)



++ Non-parametric Wilcoxon rank sum test data.

P=.012), and TOT (8.0 minutes, Pb .001) (Table 5).When consideringthe TKA only subgroup, ACT (3.0 minutes, Pb .001) and TOT(5.5 minutes, Pb .001) were reduced in the dedicated subgroupcompared to the traditional subgroup (Table 5). Patients receivingTHA had improvements in ACT (4.0 minutes, P=.010), operative time(9.0 minutes, P=.019), and TOT (5.0 minutes, P=.017) (Table 4).

In the TKA subgroup, there were more hematoma complications(n=17, 7.3%) in the traditional OR group compared to the dedicatedOR group (n=6, 2.6%; P=0.019) (Table 5). The subgroup of THAprocedures had an increase in total complications for the traditionalOR (n=22, 14.0%) compared to the dedicated OR group (n=10, 6.4%;P=.025 (Table 5). In terms of severity of complications, thetraditional OR group had more severe complications compared tothe dedicated OR group (P=.03) (Table 5). The traditional OR had one

Arthroplasty

Dedicated OR (N=422)Median

(25th Percentile, 75th Percentile)

Improvement P Value ++

43.0 (36.0, 52.0) 4.0 b0.001134.0 (113.0, 154.0)

Dedicated OR (N=167)7.0 0.012

34.0 (26.0, 43.0) 8.0 b0.001

hroplasty

Dedicated OR (N=233) Improvement P Value ++

41.0 (35.0, 47.0) 3.0 b0.001137.0 (117.0, 157.0)


34.0 (24.0, 41.0) 5.5 b0.001

roplasty

Dedicated OR (N=157) Improvement P Value ++

47.0 (38.0, 55.0) 4.0 0.010132.0 (108.0, 154.0)


34.0 (27.0, 45.0) 5.0 0.017

Table 5Complications by OR Group: After Matching.



Dedicated OR (N=233)N (%)

P Value⁎

Infection (n=21) 9 (3.9) 12 (5.2) 0.50Fracture (n=1) 0 (0.00) 1 (0.43) 0.99⁎⁎Hematoma (n=23) 17 (7.3) 6 (2.6) 0.019Mechanical failure (n=0) 0 (0.00) 0 (0.00) N/AOther (n=47) 19 (8.2) 28 (12.0) 0.17Total1 (90) 43 (18.5) 47 (20.2) 0.72+

2 (1) 1 (0.43) 0 (0.00)Grade of severity1 (22) 9 (3.9) 13 (5.6) 0.91+

2 (53) 27 (11.6) 26 (11.2)3 (16) 8 (3.4) 8 (3.4)4 (0) 0 (0.00) 0 (0.00)5 (0) 0 (0.00) 0 (0.00)


Traditional OR (N=157) Dedicated OR (N=157) P Value⁎

Infection (n=5) 5 (3.2) 0 (0.00) 0.061⁎⁎Fracture (n=1) 1 (0.64) 0 (0.00) 0.99⁎⁎Hematoma (n=7) 5 (3.2) 2 (1.3) 0.45⁎⁎Mechanical failure (n=0) 0 (0.00) 0 (0.00) N/AOther (n=19) 11 (7.0) 8 (5.1) 0.48⁎⁎Total (n=32) 22 (14.0) 10 (6.4) 0.025Grade of severity1 (9) 6 (3.8) 3 (1.9) 0.03+

2 (14) 9 (5.7) 5 (3.2)3 (8) 6 (3.8) 2 (1.3)4 (1) 1 (0.64) 0 (0.00)5 (0) 0 (0.00) 0 (0.00)


1070 T.J. Small et al. / The Journal of Arthroplasty 28 (2013) 1066–1071.e2

grade 4 complication in the THA subgroup compared to zero in thededicated OR subgroup.

Discussion

Process redesign in large teaching hospitals may substantiallyimprove operational performance without compromising patientsafety. These data demonstrate that using staff members familiarwith orthopedic equipment and procedural needs can decreaseoperative time by an average of 19 minutes per operation, whichextrapolates to a total average savings of just over 1.25 hours for asurgeon who performs 4 primary arthroplasty procedures per day.Unlike previous studies which have required additional staff todecrease both operative and non-operative times [25–27], our studymaintained the same amount of staff for each unit.With the additionaltime gained from a dedicated OR unit, staff can be offered efficiencyincentives, more time off, or time to do other activities.

Several studies have looked to improve OR throughput byadjusting parameters either directly or indirectly involved with ORprocesses [5,15–19]. With regards to non-operative time Smith et al.[7] reported a parallel process that involved using a procedural blockroom for total joint arthroplasty ORs which led to substantiallyincreased OR throughput. Also, Harders et al. [10] showed that processredesign decreased non-operative time from 65 to 42.2 minuteswhencomparing similar cases at a large tertiary county-owned hospital.Their report illustrated process improvements resulting in a signifi-cant decrease in operative time with a precisely selected group ofpredictably routine operations, including anterior cruciate ligamentreconstructions, total and reverse shoulder arthroplasties, andlaparoscopic cholecystectomies. Non-operative time encompassesactivities which engage the entire OR team. Our study demonstrated

an improvement in non-operative time parameters with ACTimproving by 4 minutes (Pb .001) and TOT by 8 minutes (Pb .001).An estimated 12 minute improvement per case should not beminimized as these savings may provide the opportunity to add anadditional procedure or for staff to leave work early, which couldultimately increase employee satisfaction and decrease staff turnover.

Operative time has traditionally been viewed as being related to asurgeon's proficiency for a particular procedure. This study is the firstin the current orthopedic literature to suggest a surgeon's interactionwith his/her team substantially reduces operative time due tofamiliarity of anesthesiologists, nurses and support staff withparticular surgical needs. This improved surgical time may also bedue to effect of working in a high throughput environment causingthe surgical team to work more efficiently. Improved times may beobtained with continued use of the system as employees becomemore experienced within the dedicated unit.

The increase in efficiency did not compromise patient care asshown by the complication rate comparisons. The complications inthe traditional OR were significantly higher for hematomas in TKAprocedures, which consisted of deep vein thrombosis, pulmonaryembolism, and surgical wound hematomas. Total complications inTHA patients were significantly lower and less severe in the dedicatedOR compared to the traditional unit. Our high rate of complicationscould be due to the inclusion of any patient admitted within 90 daysof surgery (i.e. emergency room visit, possibly unrelated surgicalprocedure/condition).

There are a few limitations to this study. First, this model is not asapplicable to operations that are un-predictable, challenging, orrequire difficult intra-operative decision making. It is suggested that adedicated OR unit for complicated cases be designed to accommodatefor difficult surgical needs. Additionally, these results may not be


germane to situations in which there cannot be a dedicated OR whereanesthesiologists, nurses and technicians who are familiar withprimary TKA and THA can be isolated. Our study occurred over twodifferent time periods, the traditional OR group being first prior toswitching to a dedicated OR system. Conducting a randomized trial byallocating procedures to a traditional or dedicated unit would be ideal,but not practical at our institution. We simulated randomization byusing propensity score matching to correct for differences in surgeontraining and patient demographics and comorbidities. Finally, ourstudy was conducted at a single institution, which is a large academictertiary care center. For more generalized conclusions, a study oflarger scale involving multiple institutions would lead to more inciteon the feasibility of a dedicated OR outside of our institution.Unfortunately some smaller hospitals or ambulatory surgery centersmay not benefit from our work if they have a highly diverse mix ofoperations being performed in the same ORs.

In summary, the utilization of a dedicated OR can be applied inappropriate institutions with the right patient population andpersonnel to increase throughput without compromising patientcare or requiring additional staff. The dedicated OR system signifi-cantly decreased operative time, anesthesia controlled time, andturnover time for TKA and THA procedures, without increasingcomplication rates. Further studies are required to determine whatbenefits are made possible by these time savings, but may includeimprovements in employee satisfaction and retention, cost savings tothe hospital, and/or opportunity to increase surgical volume.

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Appendix 2Comorbidities by OR Group: Before Matching.


Traditional OR(N = 275) N (%)

Dedicated OR(N = 314) N (%) P Value⁎

Medical historyHypertension (412) 198 (72.0) 214 (68.2) 0.31Diabetes (125) 52 (18.9) 73 (23.3) 0.20Osteoporosis (27) 7 (2.6) 20 (6.4) 0.027Cancer (93) 46 (16.7) 47 (15.0) 0.56Hyperlipidemia (272) 136 (49.5) 136 (43.3) 0.14Coronary artery disease (101) 51 (18.6) 50 (15.9) 0.40Congestive heart failure (24) 14 (5.1) 10 (3.2) 0.24Lung disease (75) 34 (12.4) 41 (13.1) 0.80Social historyTobacco use (295) 126 (45.8) 169 (53.8) 0.053Alcohol use (271) 117 (42.6) 154 (49.0) 0.11Illicit drugs use (9) 2 (0.73) 7 (2.2) 0.19⁎⁎ASA classification2 (n = 227) 111 (40.4) 142 (45.2) 0.24+

3 (n = 296) 150 (54.6) 163 (51.9)4 (n = 23) 14 (5.1) 9 (2.9)


Appendix 1Demographics by Group Traditional vs Dedicated: Before Matching.


Traditional OR (N = 275)Mean ± SD or N (%)

Dedicated OR (N = 314)Mean ± SD or N (%) P Value⁎

Age (years) 65.9 ± 11.0 65.6 ± 10.8 0.68BMI 32.3 ± 7.1 32.8 ± 7.1 0.35Gender (female, n = 335) 156 (56.7) 179 (57.0) 0.95SurgeonFellowship-trained (523) 235 (85.8) 288 (91.7) 0.022Non-fellowship-trained (65) 39 (14.2) 26 (8.3)LateralityLeft (294) 148 (53.8) 146 (46.5) 0.076Right (295) 127 (46.2) 168 (53.5)IndicationsOsteoarthritis (561) 263 (95.6) 298 (94.9) 0.68AVN/osteonecrosis (4) 2 (0.73) 2 (0.64) 0.99⁎⁎RA (13) 6 (2.2) 7 (2.2) 0.97Other (9) 4 (1.5) 5 (1.6) 0.99⁎⁎


Traditional OR (N = 200) Dedicated OR (N = 215) P Value

Age (years) 59.3 ± 14.2 60.0 ± 13.0 0.60BMI 30.1 ± 6.4 30.1 ± 7.0 0.97Gender ( male, n= 215) 106 (53.0) 109 (50.7) 0.64⁎SurgeonFellowship-trained (367) 174 (87.4) 193 (89.8) 0.46⁎Non-fellowship-trained (47) 25 (12.6) 22 (10.2)LateralityLeft (200) 92 (46.0) 108 (50.2) 0.39⁎Right (215) 108 (54.0) 107 (49.8)IndicationsOsteoarthritis (342) 165 (82.5) 177 (82.3) 0.96AVN/osteonecrosis (45) 22 (11.0) 23 (10.7) 0.92RA (6) 3 (1.5) 3 (1.4) 0.99⁎⁎Other (20) 9 (4.5) 11 (5.1) 0.77

Student's t-test, unless noted otherwise.⁎ chi-Square test.

⁎⁎ Fisher's exact test.

1071.e1T.J. Small et al. / The Journal of Arthroplasty 28 (2013) 1066–1071.e2

Appendix 3Comorbidities by OR Group: Before Matching.


Traditional OR (N = 200) N (%) Dedicated OR (N = 215) N (%) P Value⁎

Medical historyHypertension (213) 104 (52.0) 109 (50.7) 0.79Diabetes (49) 32 (16.0) 17 (7.9) 0.011Osteoporosis (8) 2 (1.0) 6 (2.8) 0.29⁎⁎Cancer (50) 27 (13.5) 23 (10.7) 0.38Hyperlipidemia (146) 78 (39.0) 68 (31.6) 0.12Coronary artery disease (51) 27 (13.5) 24 (11.2) 0.47Congestive heart failure (7) 5 (2.5) 2 (0.93) 0.27⁎⁎Lung disease (62) 22 (11.0) 40 (18.6) 0.030

Social historyTobacco use (235) 116 (58.0) 119 (55.4) 0.59Alcohol use (218) 101 (50.5) 117 (54.4) 0.42Illicit drugs use (8) 6 (3.0) 2 (0.93) 0.16⁎⁎

ASA classification1 (n = 13) 8 (4.0) 5 (2.3) 0.90+

2 (n = 195) 89 (44.5) 106 (49.3)3 (n = 193) 97 (48.5) 96 (44.7)4 (n = 14) 6 (3.0) 8 (3.7)


1071.e2 T.J. Small et al. / The Journal of Arthroplasty 28 (2013) 1066–1071.e2

dedicated orthopedic operating room unit improves operating room efficiency

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