Total knee arthroplasty (TKA) has a well-established record of relieving pain associated with arthritis of the knee joint.1,2 It is one of the most gratifying orthopedic procedures in terms of patient satisfaction and improvement of functional measures.
Many patients suffer from painful arthritis in both knees. Options include bilateral TKA simultaneously or sequentially at 1 operative setting or TKA of 1 knee and staging of the contralateral TKA either during the same hospitalization or, more often, months later.
Despite having been performed for decades, a debate remains in the orthopedic literature regarding the safety and outcomes of simultaneous bilateral TKA. The terminology is unclear as to exactly what constitutes simultaneous. Total knee arthroplasties performed during 2 separate hospital stays are typically referred to as staged TKAs.3 The confusion lies in the use of the terms simultaneous and sequential. These terms have been used to describe 3 clearly distinct situations: TKAs performed on each knee by 2 separate surgeons who worked simultaneously; TKAs performed by a single surgeon, 1 after the other, under the same anesthetic; or TKAs performed by a single surgeon, days apart during different anesthetics, but during the same hospital stay.3–8 We refer to the first strategy as simultaneous, the second as sequential, and the third as staged.
Proponents of simultaneous bilateral TKA cite the potential advantages of shorter overall recovery time, less time off work, 1 anesthetic administration, and decreased total cost when compared with staged TKAs.9–12 Significant deformities, if present bilaterally, can be corrected simultaneously so that an uncorrected deformity does not compromise the recovery and result of the corrected knee. Patients often request simultaneous bilateral TKAs to lessen time needed off from work. Critics reported the risks of increased morbidity and mortality but often referenced studies that were sequential or ambiguous as to whether the procedures were truly simultaneous.13
Conflicting studies exist in the orthopedic literature, with some demonstrating increased morbidity and mortality with simultaneous bilateral TKA, particularly in older patients and those with significant medical comorbidities,3,6–8,13–19 and other studies showing similar safety profiles between simultaneous bilateral TKAs and unilateral or staged bilateral TKAs.5,12,20–26 We hypothesized that the morbidity and mortality rate of 2-team simultaneous bilateral TKAs was not significantly different compared with unilateral TKAs at our institution.
Materials and Methods
Institutional review board approval was obtained, and the surgical records from a single institution were reviewed. An initial list of patients who underwent simultaneous bilateral or unilateral TKA by the 2 senior authors (R.N.S., S.T.G.) between October 1997 and January 2003 was collected for retrospective review. Data collection continued between February 2003 and December 2007. Unicompartmental and revision TKAs were excluded.
The medical records of 227 patients who underwent consecutive simultaneous bilateral TKA and 216 patients who underwent consecutive unilateral TKAs (divided between the 2 authors: S.T.G., n=99; R.N.S., n=117) met the inclusion criteria and were reviewed. The simultaneous bilateral TKA group included 4 patients with rheumatoid arthritis, with the remainder of the patients having osteoarthritis. The uni-lateral TKA group included 7 patients with rheumatoid arthritis, with the remainder of the patients having osteoarthritis. The patients did not have significant demographic differences (Table 1).
Table 1: Demographic and Perioperative Data
The simultaneous bilateral TKAs were performed by 2 surgical teams under a single anesthetic. Tourniquets were used in each case, with inflation and incision time staggered by 5 minutes and tourniquet deflation staggered by at least 5 minutes. Each team consisted of an attending surgeon (R.N.S., S.T.G.), a surgical scrub technician, and a first assistant. A general anesthetic was used in all but a limited number of cases in which the surgery was performed under spinal or epidural anesthesia. Standard instrumentation was used in all cases. No cases involved computer navigation or patient-specific instrumentation. Separate instrument sets were used by the 2 surgical teams.
An intramedullary technique was used for placement of femoral guides; intra- or extramedullary technique was used on the tibia at the surgeons’ discretion. The decisions on whether to resurface the patella and retain the posterior cruciate ligament (PCL) were made intraoperatively. The decision for PCL retention or sacrifice was based on intraoperative assessment of the PCL’s effect on ligament balance, and appropriate posterior-stabilized or cruciate-retaining prostheses were implanted (98.7%, Biomet, Warsaw, Indiana; 0.6%, Smith & Nephew, Memphis, Tennessee; 0.7%, DePuy, Warsaw, Indiana). Polymethylmethacrylate cement (DePuy) was used for fixation of all components.
Standardized postoperative clinical pathways were used throughout the study period. Patients received antibiotics within 1 hour prior to incision (cefazolin or clindamycin if allergic to penicillin or cephalosporin), and antibiotics were continued for 24 hours perioperatively. Oral and parenteral narcotics were used for analgesic control. Patients were started on mechanical deep venous thrombosis (DVT) prophylaxis with thigh-high compression hose on the nonoperative limb (unilateral TKA group), as well as foot compression devices (both groups).
One surgeon (R.N.S.) used warfarin for his routine chemical DVT prophylaxis, which is started on the night of surgery. The other surgeon (S.T.G.) used low-molecular-weight heparin for his routine pharmacologic prophylaxis, which is started 18 hours postoperatively. Bilateral patients received low-molecular-weight heparin or warfarin based on their primary surgeon, which was divided almost evenly, with 49% receiving low-molecular-weight heparin. Dressings were changed on the second postoperative day and daily thereafter. The operative limb was placed in a thigh-high compression hose after the first dressing change. Patients were mobilized with physical therapy on the first postoperative day. Discharge planning needs were also assessed continuously throughout the patient’s stay, and the decision of disposition to home or rehabilitation facility was made on an individual basis. Patients were generally discharged on the third postoperative day.
Data were compiled retrospectively between October 1997 and January 2003 and prospectively between February 2003 and December 2007 from hospital and office records. Physicians’ office records were reviewed to ensure a minimum of 1 year of follow-up.
Demographic data, including patient age, sex, body mass index (BMI), and American Society of Anesthesiologists class, and perioperative data, including tourniquet time, total operative time, amount of estimated blood loss, number of patients who required transfusions, number of units transfused, preoperative and discharge hemoglobin values, length of stay in both the hospital and the intensive care unit, and the number of patients discharged to a skilled nursing facility, were collected (Table 1). Physician office records were reviewed for range of motion values and to ensure all perioperative complications, readmissions, and reoperations were captured. All perioperative complications were categorized as either major or minor. Major complications included deep infections, pulmonary embolism, cerebrovascular accident, myocardial infarction, death, or removal or revision of the implants within the 1-year follow-up period. All other complications were considered minor (Table 2). Deep venous thrombosis was diagnosed with duplex ultrasonography, which was performed when clinically indicated.
Table 2: Major and Minor Complications
Continuous variables were analyzed for significance using an independent t test using SPSS version 18 software (SPSS, Inc, Chicago, Illinois). Nonparametric variables were analyzed using a chi-square analysis. A P value <.05 was considered significant, and confidence intervals were calculated at the level of 95%. Participants were excluded from statistical analysis in a given category if data were missing from the chart. Most categories contained minimal (<5) empty data points.
Demographic data including age, sex, and BMI were not significantly different between the 2 groups. Operative time (124.8±19.5 vs 112.0±21.1 minutes, respectively) and tourniquet time (114.4±18.0 vs 109.4±17.6 minutes, respectively) were significantly longer for the bilateral TKA group compared with the unilateral TKA group (P<.001 and P=.004, respectively).
Estimated blood loss was significantly higher in the bilateral TKA group (161.7±214.2 mL) compared with the uni-lateral group (105±154.1 mL) (P=.002). The large standard deviations should be noted, and recognition should be given to the relatively subjective manner in which estimated blood loss is assigned during orthopedic procedures done under tourniquet control. Patients in the bilateral TKA group required postoperative blood transfusions at higher rates compared with patients in the unilateral TKA group (65% vs 14.4%, respectively), as well as a significantly higher average amount of blood transfused (1.4±1.3 vs 0.3±0.8 units of packed red blood cells, respectively) (P<.001).
Patients in the bilateral TKA group had a longer length of stay compared with patients in the unilateral TKA group (3.71±1.3 vs 3.38±0.98 days, respectively) (P=.002). They also required placement in an extended care facility (skilled nursing facilities or inpatient rehabilitation) more frequently (76% vs 27%, respectively) (P<.001).
No mortalities occurred in either group. Major and minor complications were slightly higher for the bilateral group, but neither reached statistical significance (P=.108 and P=.263, respectively).
In the unilateral TKA group, 1 non-ST elevation myocardial infarction occurred in the hospital, from which the patient recovered. The bilateral TKA group trended toward more major complications but did not reach statistical significance. The most noticeable were 5 nonfatal pulmonary emboli, 4 diagnosed using computed tomography and 1 with a ventilation-perfusion study. All of these patients went on to recovery and were discharged on long-term anticoagulation. Minor complication rates were also similar between the 2 groups.
The need for TKAs and the number of patients undergoing bilateral TKAs is increasing in the United States. Memtsoudis et al27 showed that TKA is being performed on an increasing number of patients at a decreasing average age. The total rate of bilateral TKAs has doubled over the past 2 decades, and the rate in women has tripled over that same time period.
In our study, the total number of major complications did not reach statistical significance between the 2 groups, but more major complications occurred in the bilateral TKA group. The increased rate of DVT and pulmonary embolism was notable in the bilateral group, a finding that has been demonstrated by other authors.6,26 Three of these patients received low-molecular-weight heparin postoperatively; the other 2 received warfarin. Although none of these events resulted in death, they highlight the need for vigilant DVT prophylaxis and early postoperative mobilization.
The difference in the number of minor complications between the 2 groups did not reach statistical significance. More instances of confusion were documented in the bilateral TKA group. Although other authors have found this same trend,4 we could not make a conclusion in our series. Transient episodes of confusion in the immediate postoperative period, whether from fat embolic load or side effects of narcotic pain medication, are not always clearly documented in the postoperative record and are likely underrepresented in both groups.
The debate over morbidity and mortality from bilateral TKAs, when compared with unilateral TKAs, must also recognize that a second surgical procedure and its potential complications are eliminated. When staged appropriately, the second TKA should carry the same risks as the first. Performing simultaneous bilateral TKAs eliminates 1 of these risk exposures.
The continued debate over the safety of simultaneous bilateral TKAs must be framed by the discussion of what is considered simultaneous. The literature on bilateral TKAs has little uniformity in terms of temporal designations, which makes drawing meaningful conclusions challenging.
There are several series on truly simultaneous bilateral TKAs in the literature. One of the earliest series by Hardaker et al23 compared the perioperative safety of 2-team simultaneous bilateral TKAs with staged TKAs. They found no differences in complication rates or outcomes. Their cohort sizes were small, but they set the stage for comparisons of larger groups.
Morrey et al28 retrospectively studied 290 simultaneous bilateral TKAs and compared them with staged bilateral TKAs in the same hospitalization, staged bilateral TKA procedures in different hospitalizations, and unilateral TKAs. They found similar rates of complications and mortality among all the groups.
McLaughlin and Fisher22 retrospectively compared 3 groups: simultaneous, staged during the same hospitalization, and staged months apart. They found no difference in complications among the groups, and they showed a significantly shorter length of stay in the simultaneous TKA group compared with each of the staged TKA groups.
A series by Stanley et al29 prospectively evaluated 50 patients with rheumatoid arthritis, comparing simultaneous TKAs with staged TKAs. They found no difference in complications or functional results. In addition, hospital length of stay for simultaneous TKAs was less than half the total length of stay of the staged TKAs. One of their conclusions was that patients who underwent staged bilateral TKA did not realize the full benefit of the first TKA until the second was completed.
Correcting significant deformity to both knees can be advantageous. If a patient with notable flexion contractures has 1 TKA, the nonreplaced knee does not allow the patient a symmetric gait and may promote return of the contracture to the operated knee.
In a time of cost containment, the potential economic benefit of simultaneous bilateral TKA can be significant. Decreases in total hospital length of stay, payer costs, and rehabilitation costs have been demonstrated with the simultaneous compared with the staged TKA.10,30
Our study had limitations. Potential variability exists in the data collection because some patient data were collected retrospectively and later patient data were collected prospectively. We did not measure patient-reported outcome measures because we were interested in morbidity and mortality data. Follow-up was relatively short because we were interested in perioperative morbidity and mortality, increasing the possibility that late complications are not included. We felt that if our study did not show statistically significant increased morbidity or mortality between 2-team simultaneous bilateral TKAs and unilateral TKAs, our study would confirm that 2-team bilateral TKA is a safe procedure.
Recent studies continue to demonstrate some series with increased complications from bilateral TKAs under the same anesthetic,3,6 whereas others show comparable safety profiles with good outcomes.4 Some authors have found complication rates to be higher in older patients and those with significant preexisting medical comorbidities,7,16,17 whereas others have not had the same experience.21
Computer navigation and customized cutting instrumentation represent possible tools to decrease the morbidity associated with simultaneous bilateral TKA. Some articles have shown decreased embolic events31 and decreased blood loss with computer navigation,32 whereas others have not shown the same decrease in embolism.33,34 This remains an area of needed research to demonstrate if these will be cost-effective strategies.
With no clear results from well-designed, prospective studies, critics argue that simultaneous bilateral TKA procedures expose the patient to a higher level of risk, whereas proponents counter that performing the TKAs simultaneously under acceptable risks prevents patients from a second exposure to the risks associated with TKAs.
Our data show that 2-team simultaneous bilateral TKA performed at our institution has a similar complication rate to uni-lateral TKA and remains a safe option for appropriately selected, motivated patients. Simultaneous bilateral TKA offers the potential benefits of decreased overall recovery time, decreased overall cost, decreased number of anesthetic administrations, and less time off work. It also allows simultaneous correction of significant deformities that could impair rehabilitation if 1 knee deformity is addressed and 1 remains. Evaluation of these potential benefits and patient-centered outcome measures represent potential areas for future study.
- Insall J, Tria AJ, Scott WN. The total condylar knee prosthesis: the first 5 years. Clin Orthop Relat Res. 1979; (145):68–77.
- Insall JN, Hood RW, Flawn LB, Sullivan DJ. The total condylar knee prosthesis in gonarthrosis. A five to nine-year follow-up of the first one hundred consecutive replacements. J Bone Joint Surg Am. 1983; 65(5):619–628.
- Yoon HS, Han CD, Yang IH. Comparison of simultaneous bilateral and staged bilateral total knee arthroplasty in terms of perioperative complications [published online ahead of print February 4, 2009]. J Arthroplasty. 2010; 25(2):179–185. doi:10.1016/j.arth.2008.11.103 [CrossRef]
- Shin YH, Kim MH, Ko JS, Park JA. The safety of simultaneous bilateral versus unilateral total knee arthropalsty: the experience in a Korean hospital. Singapore Med J. 2010; 51(1):44–49.
- Kim YH, Choi YW, Kim JS. Simultaneous bilateral sequential total knee replacement is as safe as unilateral total knee replacement. J Bone Joint Surg Br. 2009; 91(1):64–68. doi:10.1302/0301-620X.91B1.21320 [CrossRef]
- Oakes DA, Hanssen AD. Bilateral total knee replacement using the same anesthetic is not justified by assessment of the risks. Clin Orthop Relat Res. 2004; (428):87–91. doi:10.1097/01.blo.0000147133.75432.86 [CrossRef]
- Lombardi AV, Mallory TH, Fada RA, et al. Simultaneous bilateral total knee arthroplasties: who decides?Clin Orthop Relat Res. 2001; (392):319–329. doi:10.1097/00003086-200111000-00042 [CrossRef]
- Lane GJ, Hozack WJ, Shah S, et al. Simultaneous bilateral versus unilateral total knee arthroplasty. Outcomes analysis. Clin Orthop Relat Res. 1997; (345):106–112.
- Reuben JD, Meyers SJ, Cox DD, Elliott M, Watson M, Shim SD. Cost comparison between bilateral simultaneous, staged, and uni-lateral total joint arthroplasty. J Arthroplasty. 1998; 13(2):172–179. doi:10.1016/S0883-5403(98)90095-X [CrossRef]
- Brotherton SL, Roberson JR, de Andrade JR, Fleming LL. Staged versus simultaneous bilateral total knee replacement. J Arthroplasty. 1986; 1(4):221–228. doi:10.1016/S0883-5403(86)80011-0 [CrossRef]
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- Jankiewicz JJ, Sculco TP, Ranawat CS, Behr C, Tarrentino S. One-stage versus 2-stage bilateral total knee arthroplasty. Clin Orthop Relat Res. 1994; (309):94–101.
- Ritter M, Mamlin LA, Melfi CA, Katz BP, Freund DA, Arthur DS. Outcome implications for the timing of bilateral total knee arthroplasties. Clin Orthop Relat Res. 1997; (345):99–105.
- Lynch NM, Trousdale RT, Ilstrup DM. Complications after concomitant bilateral total knee arthroplasty in elderly patients. Mayo Clin Proc. 1997; 72(9):883–885. doi:10.4065/72.9.799 [CrossRef]
- Restrepo C, Parvizi J, Dietrich T, Einhorn TA. Safety of simultaneous bilateral total knee arthroplasty. A meta analysis. J Bone Joint Surg Am. 2007; 89(6):1220–1226. doi:10.2106/JBJS.F.01353 [CrossRef]
- McInnis DP, Devane PA, Horne G. Bilateral total knee arthroplasty: indications and complications. Curr Opin Orthop. 2003; 14(1):52–57. doi:10.1097/00001433-200302000-00012 [CrossRef]
- Adili A, Bhandari M, Petruccelli D, De Beer J. Sequential bilateral total knee arthroplasty under 1 anesthetic in patients > or = 75 years old: complications or functional outcomes. J Arthroplasty. 2001; 16(3):271–278. doi:10.1054/arth.2001.21495 [CrossRef]
- Bullock DP, Sporer SM, Shrirreffs TG Jr, . Comparison of simultaneous bilateral with unilateral total knee arthroplasty in terms of perioperative complications. J Bone Joint Surg Am. 2003; 85(10):1981–1986.
- Urban MK, Chisholm M, Wukovits B. Are Postoperative complications more common with single-stage bilateral (SBTKR) than with unilateral knee arthroplasty: guidelines for patients scheduled for SBTKR. HSS J. 2006; 2(1):78–82. doi:10.1007/s11420-005-0125-z [CrossRef]
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- Walmsley P, Murray A, Brenkel IJ. The practice of bilateral, simultaneous total knee replacement in Scotland over the last decade. Data from the Scottish Arthroplasty Project [published online ahead of print February 14, 2006]. Knee. 2006; 13(2):102–105. doi:10.1016/j.knee.2006.01.003 [CrossRef]
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- Memtsoudis SG, Besculides MC, Reid S, Gaber-Baylis LK, Gonzáles Della Valle A. Trends in bilateral total knee arthroplasties: 153,259 discharges between 1990 and 2004 [published online ahead of print November 11, 2008]. Clin Orthop Relat Res. 2009; 467(6):1568–1576. doi:10.1007/s11999-008-0610-z [CrossRef]
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- O’Connor MI, Brodersen MP, Feinglass NG, Leone BJ, Crook JE, Switzer BE. Fat emboli in total knee arthroplasty: a prospective randomized study of computer-assisted navigation vs standard surgical technique [published online ahead of print October 30, 2009]. J Arthroplasty. 2010; 25(7):1034–1040.
- Kim YH, Kim JS, Hong KS, Kim JY, Kim JH. Prevalence of fat embolism after total knee arthroplasty performed with or without computer navigation. J Bone Joint Surg Am. 2008; 90(1):123–128. doi:10.2106/JBJS.G.00176 [CrossRef]
Demographic and Perioperative Data
|Bilateral TKA Group (n=227)a||Unilateral TKA Group (n=216)b||P|
|Mean±SD age, y||65.7±4.1||66.0±4.1||.238|
|Sex, M:F (M%)||83:144 (36.6)||71:145 (32.9)|
|Mean±SD BMI, kg/m2 (range)||34.0±7.1 (19.2–61.4)||33.7±7.5 (19.8–67.8)||.646|
| ASA 4, n (%)||14 (6.2)||18 (8.3)|
| ASA 3, n (%)||126 (55.5)||131 (60.6)|
| ASA 2, n (%)||68 (30.0)||59 (27.3)|
| ASA 1, n (%)||3 (1.3)||3 (1.4)|
|Mean±SD tourniquet time, min||114.4±18.0||109.4±17.6||.004|
|Mean±SD estimated blood loss, mL||161.7±214.2||105.0±154.1||.002|
|Patients transfused, n (%)||148 (65.0)||31 (14.4)|
|Mean±SD units transfused||1.4±1.3||0.3±0.8||<.001|
|Mean±SD length of hospital stay, d||3.71±1.3||3.38±0.98||.002|
|Discharged to extended care facility, n (%)||168 (76)||60 (27)||<.001|
Major and Minor Complicationsa
|Bilateral TKA Group (n=227)||Unilateral TKA Group (n=216)|
|Major||7 (3.5)||2 (0.9)|
| Death||0 (0)||0 (0)|
| Pulmonary embolism||5 (2.2)||0 (0)|
| Myocardial infarction||1 (0.4)||1 (0.5)|
| Deep infection||0 (0)||0 (0)|
| Cerebrovascular accident||1 (0.4)||0 (0)|
| Revision of implant||0 (0)||1 (0.5)|
|Minor||45 (19.8)||35 (16.2)|
| Superficial infection||3 (1.3)||3 (1.4)|
| Distal deep venous thrombosis||6 (2.6)||2 (0.9)|
| Urinary tract infection||2 (0.8)||1 (0.5)|
| Urinary retention||6 (2.6)||6 (2.8)|
| Confusion||5 (2.2)||0 (0)|
| Ileus||2 (0.8)||2 (0.9)|
| Surgical hematoma||0 (0)||1 (0.5)|
| Need for knee manipulation||10 (4.4)||13 (6.0%)|
| Pneumonia||1 (0.4)||1 (0.5)|
| Clostridium difficile colitis||0 (0)||2 (0.9)|
| New onset arrhythmia||1 (0.4)||3 (1.4)|
| Transient acute renal failure||4 (1.7)||0 (0)|
| Extensor mechanism disruption||2 (0.8)||0 (0)|
| Heterotopic ossification||1 (0.4)||0 (0)|
| Medial collateral ligament laceration||1 (0.4)||0 (0)|
| Patellar component dislocation||1 (0.4)||1 (0.5)|