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Trends and Outcomes in the Treatment of Failed Septic Total Knee Arthroplasty: Comparing Arthrodesis and Above-Knee Amputation
The Journal of Arthroplasty xxx (2016) 1e4
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Original article
Trends and Outcomes in the Treatment of Failed Septic Total Knee Arthroplasty: Comparing Arthrodesis and Above-Knee Amputation James B. Carr II, MD, Brian C. Werner, MD, James A. Browne, MD * Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 October 2015 Received in revised form 8 December 2015 Accepted 8 January 2016 Available online XXX
Background: Options for treatment of a failed septic total knee arthroplasty (TKA) include arthrodesis and above-knee amputation (AKA). Little comparative data exist to help clinicians when considering these alternatives. Methods: A national database was queried for patients who underwent either knee arthrodesis or AKA for an infected TKA between 2005 and 2012. Procedure volumes, postoperative complications, hospital charges, length of stay, and 90-day readmission rates were evaluated. Results: A total of 2634 patients underwent arthrodesis and 5001 patients underwent AKA for septic TKA. The percentage of total patients who underwent AKA increased significantly throughout the study period compared to knee arthrodesis. Patients who underwent AKA tended to be older and have more medical comorbidities. Arthrodesis patients had a significantly higher rate of postoperative infection (14.5% vs 8.3%, P < .0001) and transfusion (55.1% vs 46.8%, P < .0001), whereas AKA patients had a higher rate of systemic complications (31.5% vs 25.9%, P < .0001) and in-hospital mortality (3.7% vs 2.1%, P < .0001). The AKA cohort had lower hospital charges ($79,686 vs $84,747, P ¼ .004), longer length of stay (11 vs 7 days, P < .0001), and higher 90-day readmission rate (19.4% vs 16.9%). Conclusion: Our data suggest that there is an increasing trend toward AKA for the treatment of a failed infected TKA when compared to arthrodesis. Comparative analysis of the outcomes of these procedures should help the clinician when weighing these alternatives. © 2016 Elsevier Inc. All rights reserved.
Keywords: septic TKA knee arthrodesis above-knee amputation total knee arthroplasty periprosthetic joint infection
Periprosthetic joint infection is one of the most challenging and devastating complications after total knee arthroplasty (TKA). Unfortunately, it remains the most common reason for a failed TKA with a reported rate of septic TKA between 1% and 4% of primary TKA patients [1-5]. Treatment options for septic TKA vary depending on the timing and severity of infection and include irrigation and debridement, single vs staged revision arthroplasty, resection arthroplasty, or chronic-suppressive antibiotics. The standard of care in the United States is a 2-staged revision arthroplasty, which has a success rate reported at around 75% [2,6-16]. Recently, the use of single-stage revision arthroplasty has been advocated by some for select
One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.01.010. * Reprint requests: James A. Browne, MD, Department of Orthopaedic Surgery, University of Virginia, 545 Ray C. Hunt Drive, Charlottesville, VA, 22903. http://dx.doi.org/10.1016/j.arth.2016.01.010 0883-5403/© 2016 Elsevier Inc. All rights reserved.
situations with equivalent success rates reported [17-19]. Regardless of the revision approach, the goal is to fully eradicate the periprosthetic joint infection and ultimately reimplant a functional and sterile total knee prosthesis with durable results. Reinfection after a staged revision arthroplasty can be particularly challenging to treat as it portends a less favorable outcome. Risk factors for a failed staged revision arthroplasty for recurrent infection include mixed flora infections [1,20], culture-negative infections [21], infections caused by methicillin-resistant Staphylococcus aureus species [21-24], nicotine abuse [1], a higher Charlson Comorbidity Index score [1], increased reimplantation surgical time [21], and previous failed revision attempts [1,15,20,22,25]. If infection becomes uncontrollable despite multiple attempts at revision procedures, most surgeons pursue one of 2 options to eradicate the infection: knee arthrodesis or above-knee amputation (AKA). These are considered end-stage procedures that are performed once a patient has exhausted reasonable measures to salvage a functional TKA. Existing literature regarding either procedure for septic failure of TKA is mostly limited to small institutional series [22,26-35]. The purpose of
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the present study is to evaluate national trends for the use of knee arthrodesis and AKA for septic failure of TKA, as well as compare relevant postoperative complications, mortality, length of stay, hospital charges, and reimbursement between the procedures.
Materials and Methods All data for this study were retrieved from the PearlDiver Patient Records Database (www.pearldiverinc.com; PearlDiver Inc, Fort Wayne, IN), a publicly available, for-fee database of patients. The database contains demographics, procedure volumes, and average charge and reimbursement information for patients with International Classification of Diseases, 9th Revision (ICD-9) diagnoses and procedures or Current Procedural Terminology (CPT) codes. Data for the present study were derived from a Medicare database within over 100 million patient records from 2005 to 2012. Access to the database was granted by PearlDiver Technologies for the purpose of academic research. The Medicare database was chosen because of its size and prevalence of patients with a septic TKA. The database was stored on a password-protected server maintained by PearlDiver. Patients who underwent knee arthrodesis for an infected TKA were identified using ICD-9 procedure code 81.22 and/or CPT 27580 in combination with a code for an infected TKA on the same day or within 1 year prior (ICD-9 procedure codes 80.06, 84.57 with ICD-9 diagnostic code 996.66 or 996.67). Patients who underwent an AKA for an infected TKA were identified using ICD-9 procedure code 84.17 and/or CPT codes 27590, 27591, or 27592 with the previously mentioned ICD-9 codes for TKA. Patient demographics were recorded for both groups, including gender, age, incidence of tobacco abuse, and obesity. The incidence of medical comorbidities for all patients was also obtained, including diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease (PVD), congestive heart failure, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, and chronic liver disease. Postoperative complications within 6 months postoperatively were assessed using ICD-9 or CPT codes. Postoperative venous thromboembolism, including deep venous thrombosis and/or pulmonary embolism, was assessed using ICD-9 codes 415.11, 415.19, and 435.40-42. Postoperative infection was defined as a procedure for or a diagnosis of a postoperative infection, being careful to avoid using codes for preoperative infection, including CPT codes 10180, 20000, 20005, 27310 and/or ICD-9 codes 998.51 and 998.59. Postoperative blood transfusion was assessed using ICD-9 codes 990.0-4, V58.2 and/or CPT 36430. Postoperative systemic complications were grouped and were assessed using ICD-9 codes, including acute myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, and acute cholecystitis. In-hospital mortality within 1 year postoperatively was also assessed and compared between the 2 groups, along with hospital charges, reimbursement, length of stay, and 90-day readmission rates as reported by the database. Chi-square linear-by-linear association analysis was used to determine statistical significance with regard to trends over time in procedural volumes. Standard Pearson’s chi-square analysis was used to compare postoperative complications and mortality. Student's t tests were used to compare hospital charges, reimbursement, and length of stay between the groups. For all statistical comparisons, P < .01 was considered significant.
Results A total of 7635 patients were identified in the database search over the 8-year study period from 2005 to 2012. A total of 2634 patients underwent a knee arthrodesis and 5001 patients underwent an AKA for septic TKA. The percentage of total patients who underwent AKA increased significantly throughout the study period compared to knee arthrodesis (P < .0001; Fig. 1). A larger percentage of patients in the AKA group were above the age of 80 (24.9%) compared to the arthrodesis group (16.2%). The AKA cohort also had a larger percentage of patients with diabetes mellitus (65.5% vs 61.7%), PVD (48.8% vs 27.1%), congestive heart failure (59.0% vs 49.7%), coronary heart disease (60.2% vs 54.6%), chronic kidney disease (48.7% vs 41.7%), and chronic obstructive pulmonary disease (48.3% vs 43.5%) compared to the arthrodesis cohort (Table 1). There was a significantly higher rate of postoperative infection (14.5% vs 8.3%, P < .0001) and blood transfusions (55.1% vs 46.8%, P < .0001) in patients who underwent arthrodesis compared to AKA (Table 2). Patients who underwent AKA had higher rates of systemic complications (31.5% vs 25.9%, P < .0001) and in-hospital mortality (3.7% vs 2.1%, P < .0001) compared to knee arthrodesis. The percentage of patients experiencing a venous thromboembolism event was higher in the arthrodesis cohort than in the AKA cohort; however, this did not reach statistical significance (4.8% vs 3.8%, P ¼ .043). Hospital charges were significantly higher in the arthrodesis cohort ($84,747 vs $79,686, P ¼.0004), whereas reimbursement was significantly higher for AKA patients ($17,539 vs $15,415, P < .0001). Length of stay was significantly longer for AKA patients (11 days) than for arthrodesis patients (7 days, P < .0001), and the 90day readmission rate was significantly larger in the AKA group (19.4%) than in the arthrodesis group (16.9%, P ¼ .009; Table 2).
Discussion Deep periprosthetic infection remains a particularly devastating complication after TKA. Although 2-stage revision protocols have a high success rate, a percentage of infections cannot be eradicated and reimplantation of components is not possible. In these situations, the surgeon must often choose between a knee arthrodesis or AKA to effectively eradicate the infection. In the studied population,
Fig. 1. Percentage of Medicare database patients undergoing knee arthrodesis (blue line) compared to the percentage of patients undergoing above-knee amputation (red line) for septic total knee arthroplasty from 2005 to 2012.
J.B. Carr II et al. / The Journal of Arthroplasty xxx (2016) 1e4 Table 1 Comparison of Demographic Data and Incidence of Medical Comorbidities in Patients Undergoing Knee Arthrodesis vs Above-Knee Amputation. Variable
Arthrodesis
Above-Knee Amputation
Total number Demographics (%) Female Male Age <65 Age 65-80 Age >80 Tobacco use Obesity Comorbidities (%) DM OSA HLD HTN PVD CHF CAD CKD COPD CLD
2634
5001
56.9 43.1 30.6 53.2 16.2 22.9 52.6
51.7 48.3 28.0 47.1 24.9 24.7 42.3
61.7 23.6 73.1 94.8 27.1 49.7 54.6 41.7 43.5 0.4
65.5 19.2 68.3 94.8 48.8 59.0 60.2 48.7 48.3 0.6
DM, diabetes mellitus; OSA, obstructive sleep apnea; HLD, hyperlipidemia; HTN, hypertension; PVD, peripheral vascular disease; CHF, congestive heart failure, CAD, coronary heart disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CLD, chronic liver disease.
AKA was performed more frequently than knee arthrodesis for septic failure of TKA from 2005 to 2012 with a trend toward performing more AKA procedures. This trend could exist for a variety of reasons, including the potential of AKA to fully eradicate the infection and the relative ease of the surgery compared to performing a more technically challenging knee arthrodesis. AKA also does not rely on achieving bony union at the knee joint, whereas arthrodesis may be impossible in cases of severe bone loss. The present study suggests that both arthrodesis and AKA have complications that must be considered when deciding between salvage procedures for a persistently infected TKA. The rate of postoperative infection within 6 months after arthrodesis was nearly twice as high as the rate after AKA. This may be due to the presence of hardware in a knee that is still infected in patients who undergo arthrodesis. In addition, arthrodesis patients had a higher rate of blood transfusion, suggesting that the surgery is more extensive with a higher blood loss. Amputation patients had a higher rate of 1-year in-hospital mortality and systemic complications, which could reflect the choice of performing AKA in
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patients who are older or have more medical comorbidities at baseline. Overall, the AKA cohort did have a higher percentage of patients greater than the age of 80, and patients undergoing AKA did have a higher incidence of important medical comorbidities than the arthrodesis group, including PVD (48.8% vs 27.1%), diabetes mellitus (65.5% vs 61.7%), congestive heart failure (59.0% vs 49.7%), chronic kidney disease (48.7% vs 41.7%), and chronic obstructive pulmonary disease (48.3% vs 43.5%; Table 1). This suggests that patients with more medical comorbidities were more likely to receive an AKA than an arthrodesis for treatment of a septic TKA. Hospital charges were lower and reimbursement was higher in the AKA group. However, hospital costs do not reflect the total cost of a procedure, such as time lost from being out of work or additional outpatient charges, such as a prosthesis and physical therapy. Readmission rates within 90 days of the index procedure were higher in the AKA group, which could also increase the total cost of a procedure. However, readmission rates were relatively high in both groups, suggesting that both salvage procedures have associated complications that require readmission. In general, hospital costs alone should not guide the treatment offered. Rohner et al [30] recently published an institutional series of 26 patients who underwent knee arthrodesis with intramedullary nailing for recalcitrant TKA infection. Thirteen of the patients (50%) undergoing arthrodesis had persistent infection that required additional revision surgery. Nineteen patients (73%) reported persistent pain after arthrodesis, and all patients demonstrated substantial impairment on quality-of-life scoring metrics. The authors concluded that intramedullary nailing after septic failure of a revision TKA could not be recommended over AKA. Although our present study does not investigate recurrence of infection after arthrodesis or AKA, our data do suggest that more surgeons favor AKA over arthrodesis for persistent TKA infection. Panagiotopoulos et al [27] reported results of intramedullary nailing arthrodesis for a failed septic TKA revision in 9 patients. The authors reported eventual bony fusion in 8 of 9 patients (89%) at an average of 6.5 months. However, they also noted certain challenges for arthrodesis that should be considered, namely management of bone loss from prior revisions and demands of the surgical technique. In their study, patients had leg shortening on average of 3 cm, one patient had to be converted to an external fixator because of infectious nonunion, and 2 patients required dynamization of their construct to facilitate bony union. As noted by the authors, the need for bony fusion can be a unique challenge of arthrodesis compared to AKA, although arthrodesis does allow for early mobilization with the native leg.
Table 2 Comparison of Postoperative Complication Rates, Hospital Charges, Length of Hospital Stay, and 90-Day Readmission Rates in Knee Arthrodesis Patients vs Above-Knee Amputation Patients. Complications
Arthrodesis (Overall N ¼ 2634)
Above-Knee Amputation (Overall N ¼ 5001)
N
N
VTE (6 mo) Infection (6 mo) Systemic (6 mo) Transfusion (6 mo) Death (1 y) Readmission (3 mo)
%
%
Statistical Comparison Odds Ratio (95% CI), P Value
127 382 683 1451 55 446
4.8 14.5 25.9 55.1 2.1 16.9
191 416 1573 2340 185 971
3.8 8.3 31.5 46.8 3.7 19.4
Metrics
#
SD
#
SD
P Value
Charges ($) Reimbursement ($) LOS (d)
$84,747 $15,415 7
$56,867 $11,698 5.2
$79,686 $17,539 11
$60,111 $10,514 6.4
.0004 <.0001 <.0001
VTE, venous thromboembolism; SD, standard deviation; LOS, length of stay.
1.3 1.9 0.8 1.4 0.6 0.9
(1.0-1.6), (1.6-2.2), (0.7-0.8), (1.3-1.5), (0.4-0.8), (0.7-1.0),
.043 <.0001 <.0001 <.0001 <.0001 .009
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There are also many concerns related to AKA, most notably substantially decreased functional status in patients after AKA. Fedorka et al [26] analyzed functional ability of 35 patients who underwent AKA for septic revision TKA. A total of 15 patients died during the follow-up period, 9 patients required irrigation and debridement of nonhealing AKA wounds, and 2 patients had repeat AKA for nonhealing stumps. Fourteen patients were fitted for prostheses, and 8 of these patients were functionally independent outside of the home. Overall, the authors concluded that most patients had a low functional status after AKA was performed for infection with only half of the patients eventually returning to independent ambulation. The strengths of the present study include a very large patient population afforded by the use of a national database. This allowed for the reporting of statistically significant trends and differences between the arthrodesis and AKA cohorts, which would otherwise be difficult to accomplish in a small, single-institution series. The ability to analyze financial data related to each procedure is a unique feature allowed by this national database as well. Limitations of the study are mostly related to the nature of a national database study. It is possible that the cohorts do not represent national trends as the data were pooled from a Medicareonly database. In addition, the integrity of the data is dependent on the accuracy of proper coding at the time of data reporting, which is impossible to verify. Also, we were unable to account for differences in postoperative management, such as the use of intravenous or oral antibiotics or the need for revision surgery or conversion of arthrodesis to AKA. Furthermore, the heterogeneous nature of the 2 cohorts in regard to medical comorbidity prevalence may prevent direct comparison because patients who were less healthy tended to receive an AKA. Because this was a database study, we were also unable to report functional activity or clinical scores for patients in each cohort. Finally, a database study does not allow for multivariate analysis, which prevents analysis of multiple variable outcomes at the same time. This limits analysis to single-variable relationships with the outcome measures. Conclusion In the present study, AKA appears to be performed more frequently than knee arthrodesis for septic failure of TKA from 2005 to 2012. AKA was performed more frequently in older patients and in patients with a higher incidence of certain medical comorbidities. Arthrodesis for septic TKA is associated with significantly higher rates of postoperative infection and blood transfusion compared to AKA, whereas systemic complications and in-hospital mortality were more common after AKA. Arthrodesis had higher hospital charges, whereas AKA had higher reimbursement despite a significantly longer length of hospital stay and higher 90-day readmission rate. Although every case is unique, the data offered in this study can help orthopedic surgeons better understand the potential complications of surgical options for septic TKA, which is useful when providing patient guidance. References 1. Claassen L, Plaass C, Daniilidis K, et al. Two-stage revision total knee arthroplasty in cases of periprosthetic joint infection: an analysis of 50 cases. Open Orthop J 2015;9:49. 2. Mahmud T, Lyons MC, Naudie DD, et al. Assessing the gold standard: a review of 253 two-stage revisions for infected TKA. Clin Orthop Relat Res 2012;470(10): 2730. 3. Squire MW, Della Valle CJ, Parvizi J. Preoperative diagnosis of periprosthetic joint infection: role of aspiration. AJR Am J Roentgenol 2011;196(4):875. 4. Parvizi J, Jacovides C, Zmistowski B, et al. Definition of periprosthetic joint infection: is there a consensus? Clin Orthop Relat Res 2011;469(11):3022.
5. Laudermilch DJ, Fedorka CJ, Heyl A, et al. Outcomes of revision total knee arthroplasty after methicillin-resistant Staphylococcus aureus infection. Clin Orthop Relat Res 2010;468(8):2067. 6. Cuckler JM. The infected total knee: management options. J Arthroplasty 2005;20(4 Suppl 2):33. 7. Deirmengian C, Greenbaum J, Lotke PA, et al. Limited success with open debridement and retention of components in the treatment of acute Staphylococcus aureus infections after total knee arthroplasty. J Arthroplasty 2003;18(7 Suppl 1):22. 8. Durbhakula SM, Czajka J, Fuchs MD, et al. Antibiotic-loaded articulating cement spacer in the 2-stage exchange of infected total knee arthroplasty. J Arthroplasty 2004;19(6):768. 9. Fehring TK, Odum S, Calton TF, et al. Articulating versus static spacers in revision total knee arthroplasty for sepsis. The Ranawat Award. Clin Orthop Relat Res 2000;380:9. 10. Goldman RT, Scuderi GR, Insall JN. 2-stage reimplantation for infected total knee replacement. Clin Orthop Relat Res 1996;331:118. 11. Haleem AA, Berry DJ, Hanssen AD. Mid-term to long-term followup of twostage reimplantation for infected total knee arthroplasty. Clin Orthop Relat Res 2004;428:35. 12. Hanssen AD, Trousdale RT, Osmon DR. Patient outcome with reinfection following reimplantation for the infected total knee arthroplasty. Clin Orthop Relat Res 1995;321:55. 13. Hanssen AD. Managing the infected knee: as good as it gets. J Arthroplasty 2002;17(4 Suppl 1):98. 14. Hart WJ, Jones RS. Two-stage revision of infected total knee replacements using articulating cement spacers and short-term antibiotic therapy. J Bone Joint Surg Br 2006;88(8):1011. 15. Stammers J, Kahane S, Ranawat V, et al. Outcomes of infected revision knee arthroplasty managed by two-stage revision in a tertiary referral centre. Knee 2015;22(1):56. 16. Jamsen E, Stogiannidis I, Malmivaara A, et al. Outcome of prosthesis exchange for infected knee arthroplasty: the effect of treatment approach. Acta Orthop 2009;80(1):67. 17. Silva M, Tharani R, Schmalzried TP. Results of direct exchange or debridement of the infected total knee arthroplasty. Clin Orthop Relat Res 2002;404:125. 18. Buechel FF, Femino FP, D'Alessio J. Primary exchange revision arthroplasty for infected total knee replacement: a long-term study. Am J Orthop (Belle Mead NJ) 2004;33(4):190. discussion 198. 19. Haddad FS, Sukeik M, Alazzawi S. Is single-stage revision according to a strict protocol effective in treatment of chronic knee arthroplasty infections? Clin Orthop Relat Res 2015;473(1):8. 20. Pelt CE, Grijalva R, Anderson L, et al. Two-stage revision TKA is associated with high complication and failure rates. Adv Orthop 2014;2014:659047. 21. Mortazavi SM, Vegari D, Ho A, et al. Two-stage exchange arthroplasty for infected total knee arthroplasty: predictors of failure. Clin Orthop Relat Res 2011;469(11):3049. 22. Schwarzkopf R, Oh D, Wright E, et al. Treatment failure among infected periprosthetic patients at a highly specialized revision TKA referral practice. Open Orthop J 2013;7:264. 23. Nakano N, Matsumoto T, Ishida K, et al. Factors influencing the outcome of deep infection following total knee arthroplasty. Knee 2015;22(4):328. 24. Parvizi J, Azzam K, Ghanem E, et al. Periprosthetic infection due to resistant staphylococci: serious problems on the horizon. Clin Orthop Relat Res 2009;467(7):1732. 25. Kubista B, Hartzler RU, Wood CM, et al. Reinfection after two-stage revision for periprosthetic infection of total knee arthroplasty. Int Orthop 2012;36(1): 65. 26. Fedorka CJ, Chen AF, McGarry WM, et al. Functional ability after above-the-knee amputation for infected total knee arthroplasty. Clin Orthop Relat Res 2011;469(4):1024. 27. Panagiotopoulos E, Kouzelis A, Matzaroglou C, et al. Intramedullary knee arthrodesis as a salvage procedure after failed total knee replacement. Int Orthop 2006;30(6):545. 28. Wu CH, Gray CF, Lee GC. Arthrodesis should be strongly considered after failed two-stage reimplantation TKA. Clin Orthop Relat Res 2014;472(11): 3295. 29. Van Rensch PJ, Van de Pol GJ, Goosen JH, et al. Arthrodesis of the knee following failed arthroplasty. Knee Surg Sports Traumatol Arthrosc 2014;22(8):1940. 30. Rohner E, Windisch C, Nuetzmann K, et al. Unsatisfactory outcome of arthrodesis performed after septic failure of revision total knee arthroplasty. J Bone Joint Surg Am 2015;97(4):298. 31. Johannsen HG, Skov O, Weeth ER. Knee arthrodesis with external ring fixator after infected knee arthroplasty. Ugeskr Laeger 2005;167(35):3295. 32. Khanna V, Tushinski DM, Soever LJ, et al. Above knee amputation following total knee arthroplasty: when enough is enough. J Arthroplasty 2015;30(4):658. 33. Iacono F, Raspugli GF, Bruni D, et al. Arthrodesis after infected revision TKA: retrospective comparison of intramedullary nailing and external fixation. HSS J 2013;9(3):229. 34. Spina M, Gualdrini G, Fosco M, et al. Knee arthrodesis with the Ilizarov external fixator as treatment for septic failure of knee arthroplasty. J Orthop Traumatol 2010;11(2):81. 35. Hawi N, Kendoff D, Citak M, et al. Septic single-stage knee arthrodesis after failed total knee arthroplasty using a cemented coupled nail. Bone Joint J 2015;97-B(5):649.
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Original article
Trends and Outcomes in the Treatment of Failed Septic Total Knee Arthroplasty: Comparing Arthrodesis and Above-Knee Amputation James B. Carr II, MD, Brian C. Werner, MD, James A. Browne, MD * Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 October 2015 Received in revised form 8 December 2015 Accepted 8 January 2016 Available online XXX
Background: Options for treatment of a failed septic total knee arthroplasty (TKA) include arthrodesis and above-knee amputation (AKA). Little comparative data exist to help clinicians when considering these alternatives. Methods: A national database was queried for patients who underwent either knee arthrodesis or AKA for an infected TKA between 2005 and 2012. Procedure volumes, postoperative complications, hospital charges, length of stay, and 90-day readmission rates were evaluated. Results: A total of 2634 patients underwent arthrodesis and 5001 patients underwent AKA for septic TKA. The percentage of total patients who underwent AKA increased significantly throughout the study period compared to knee arthrodesis. Patients who underwent AKA tended to be older and have more medical comorbidities. Arthrodesis patients had a significantly higher rate of postoperative infection (14.5% vs 8.3%, P < .0001) and transfusion (55.1% vs 46.8%, P < .0001), whereas AKA patients had a higher rate of systemic complications (31.5% vs 25.9%, P < .0001) and in-hospital mortality (3.7% vs 2.1%, P < .0001). The AKA cohort had lower hospital charges ($79,686 vs $84,747, P ¼ .004), longer length of stay (11 vs 7 days, P < .0001), and higher 90-day readmission rate (19.4% vs 16.9%). Conclusion: Our data suggest that there is an increasing trend toward AKA for the treatment of a failed infected TKA when compared to arthrodesis. Comparative analysis of the outcomes of these procedures should help the clinician when weighing these alternatives. © 2016 Elsevier Inc. All rights reserved.
Keywords: septic TKA knee arthrodesis above-knee amputation total knee arthroplasty periprosthetic joint infection
Periprosthetic joint infection is one of the most challenging and devastating complications after total knee arthroplasty (TKA). Unfortunately, it remains the most common reason for a failed TKA with a reported rate of septic TKA between 1% and 4% of primary TKA patients [1-5]. Treatment options for septic TKA vary depending on the timing and severity of infection and include irrigation and debridement, single vs staged revision arthroplasty, resection arthroplasty, or chronic-suppressive antibiotics. The standard of care in the United States is a 2-staged revision arthroplasty, which has a success rate reported at around 75% [2,6-16]. Recently, the use of single-stage revision arthroplasty has been advocated by some for select
One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.01.010. * Reprint requests: James A. Browne, MD, Department of Orthopaedic Surgery, University of Virginia, 545 Ray C. Hunt Drive, Charlottesville, VA, 22903. http://dx.doi.org/10.1016/j.arth.2016.01.010 0883-5403/© 2016 Elsevier Inc. All rights reserved.
situations with equivalent success rates reported [17-19]. Regardless of the revision approach, the goal is to fully eradicate the periprosthetic joint infection and ultimately reimplant a functional and sterile total knee prosthesis with durable results. Reinfection after a staged revision arthroplasty can be particularly challenging to treat as it portends a less favorable outcome. Risk factors for a failed staged revision arthroplasty for recurrent infection include mixed flora infections [1,20], culture-negative infections [21], infections caused by methicillin-resistant Staphylococcus aureus species [21-24], nicotine abuse [1], a higher Charlson Comorbidity Index score [1], increased reimplantation surgical time [21], and previous failed revision attempts [1,15,20,22,25]. If infection becomes uncontrollable despite multiple attempts at revision procedures, most surgeons pursue one of 2 options to eradicate the infection: knee arthrodesis or above-knee amputation (AKA). These are considered end-stage procedures that are performed once a patient has exhausted reasonable measures to salvage a functional TKA. Existing literature regarding either procedure for septic failure of TKA is mostly limited to small institutional series [22,26-35]. The purpose of
2
J.B. Carr II et al. / The Journal of Arthroplasty xxx (2016) 1e4
the present study is to evaluate national trends for the use of knee arthrodesis and AKA for septic failure of TKA, as well as compare relevant postoperative complications, mortality, length of stay, hospital charges, and reimbursement between the procedures.
Materials and Methods All data for this study were retrieved from the PearlDiver Patient Records Database (www.pearldiverinc.com; PearlDiver Inc, Fort Wayne, IN), a publicly available, for-fee database of patients. The database contains demographics, procedure volumes, and average charge and reimbursement information for patients with International Classification of Diseases, 9th Revision (ICD-9) diagnoses and procedures or Current Procedural Terminology (CPT) codes. Data for the present study were derived from a Medicare database within over 100 million patient records from 2005 to 2012. Access to the database was granted by PearlDiver Technologies for the purpose of academic research. The Medicare database was chosen because of its size and prevalence of patients with a septic TKA. The database was stored on a password-protected server maintained by PearlDiver. Patients who underwent knee arthrodesis for an infected TKA were identified using ICD-9 procedure code 81.22 and/or CPT 27580 in combination with a code for an infected TKA on the same day or within 1 year prior (ICD-9 procedure codes 80.06, 84.57 with ICD-9 diagnostic code 996.66 or 996.67). Patients who underwent an AKA for an infected TKA were identified using ICD-9 procedure code 84.17 and/or CPT codes 27590, 27591, or 27592 with the previously mentioned ICD-9 codes for TKA. Patient demographics were recorded for both groups, including gender, age, incidence of tobacco abuse, and obesity. The incidence of medical comorbidities for all patients was also obtained, including diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease (PVD), congestive heart failure, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, and chronic liver disease. Postoperative complications within 6 months postoperatively were assessed using ICD-9 or CPT codes. Postoperative venous thromboembolism, including deep venous thrombosis and/or pulmonary embolism, was assessed using ICD-9 codes 415.11, 415.19, and 435.40-42. Postoperative infection was defined as a procedure for or a diagnosis of a postoperative infection, being careful to avoid using codes for preoperative infection, including CPT codes 10180, 20000, 20005, 27310 and/or ICD-9 codes 998.51 and 998.59. Postoperative blood transfusion was assessed using ICD-9 codes 990.0-4, V58.2 and/or CPT 36430. Postoperative systemic complications were grouped and were assessed using ICD-9 codes, including acute myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, and acute cholecystitis. In-hospital mortality within 1 year postoperatively was also assessed and compared between the 2 groups, along with hospital charges, reimbursement, length of stay, and 90-day readmission rates as reported by the database. Chi-square linear-by-linear association analysis was used to determine statistical significance with regard to trends over time in procedural volumes. Standard Pearson’s chi-square analysis was used to compare postoperative complications and mortality. Student's t tests were used to compare hospital charges, reimbursement, and length of stay between the groups. For all statistical comparisons, P < .01 was considered significant.
Results A total of 7635 patients were identified in the database search over the 8-year study period from 2005 to 2012. A total of 2634 patients underwent a knee arthrodesis and 5001 patients underwent an AKA for septic TKA. The percentage of total patients who underwent AKA increased significantly throughout the study period compared to knee arthrodesis (P < .0001; Fig. 1). A larger percentage of patients in the AKA group were above the age of 80 (24.9%) compared to the arthrodesis group (16.2%). The AKA cohort also had a larger percentage of patients with diabetes mellitus (65.5% vs 61.7%), PVD (48.8% vs 27.1%), congestive heart failure (59.0% vs 49.7%), coronary heart disease (60.2% vs 54.6%), chronic kidney disease (48.7% vs 41.7%), and chronic obstructive pulmonary disease (48.3% vs 43.5%) compared to the arthrodesis cohort (Table 1). There was a significantly higher rate of postoperative infection (14.5% vs 8.3%, P < .0001) and blood transfusions (55.1% vs 46.8%, P < .0001) in patients who underwent arthrodesis compared to AKA (Table 2). Patients who underwent AKA had higher rates of systemic complications (31.5% vs 25.9%, P < .0001) and in-hospital mortality (3.7% vs 2.1%, P < .0001) compared to knee arthrodesis. The percentage of patients experiencing a venous thromboembolism event was higher in the arthrodesis cohort than in the AKA cohort; however, this did not reach statistical significance (4.8% vs 3.8%, P ¼ .043). Hospital charges were significantly higher in the arthrodesis cohort ($84,747 vs $79,686, P ¼.0004), whereas reimbursement was significantly higher for AKA patients ($17,539 vs $15,415, P < .0001). Length of stay was significantly longer for AKA patients (11 days) than for arthrodesis patients (7 days, P < .0001), and the 90day readmission rate was significantly larger in the AKA group (19.4%) than in the arthrodesis group (16.9%, P ¼ .009; Table 2).
Discussion Deep periprosthetic infection remains a particularly devastating complication after TKA. Although 2-stage revision protocols have a high success rate, a percentage of infections cannot be eradicated and reimplantation of components is not possible. In these situations, the surgeon must often choose between a knee arthrodesis or AKA to effectively eradicate the infection. In the studied population,
Fig. 1. Percentage of Medicare database patients undergoing knee arthrodesis (blue line) compared to the percentage of patients undergoing above-knee amputation (red line) for septic total knee arthroplasty from 2005 to 2012.
J.B. Carr II et al. / The Journal of Arthroplasty xxx (2016) 1e4 Table 1 Comparison of Demographic Data and Incidence of Medical Comorbidities in Patients Undergoing Knee Arthrodesis vs Above-Knee Amputation. Variable
Arthrodesis
Above-Knee Amputation
Total number Demographics (%) Female Male Age <65 Age 65-80 Age >80 Tobacco use Obesity Comorbidities (%) DM OSA HLD HTN PVD CHF CAD CKD COPD CLD
2634
5001
56.9 43.1 30.6 53.2 16.2 22.9 52.6
51.7 48.3 28.0 47.1 24.9 24.7 42.3
61.7 23.6 73.1 94.8 27.1 49.7 54.6 41.7 43.5 0.4
65.5 19.2 68.3 94.8 48.8 59.0 60.2 48.7 48.3 0.6
DM, diabetes mellitus; OSA, obstructive sleep apnea; HLD, hyperlipidemia; HTN, hypertension; PVD, peripheral vascular disease; CHF, congestive heart failure, CAD, coronary heart disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CLD, chronic liver disease.
AKA was performed more frequently than knee arthrodesis for septic failure of TKA from 2005 to 2012 with a trend toward performing more AKA procedures. This trend could exist for a variety of reasons, including the potential of AKA to fully eradicate the infection and the relative ease of the surgery compared to performing a more technically challenging knee arthrodesis. AKA also does not rely on achieving bony union at the knee joint, whereas arthrodesis may be impossible in cases of severe bone loss. The present study suggests that both arthrodesis and AKA have complications that must be considered when deciding between salvage procedures for a persistently infected TKA. The rate of postoperative infection within 6 months after arthrodesis was nearly twice as high as the rate after AKA. This may be due to the presence of hardware in a knee that is still infected in patients who undergo arthrodesis. In addition, arthrodesis patients had a higher rate of blood transfusion, suggesting that the surgery is more extensive with a higher blood loss. Amputation patients had a higher rate of 1-year in-hospital mortality and systemic complications, which could reflect the choice of performing AKA in
3
patients who are older or have more medical comorbidities at baseline. Overall, the AKA cohort did have a higher percentage of patients greater than the age of 80, and patients undergoing AKA did have a higher incidence of important medical comorbidities than the arthrodesis group, including PVD (48.8% vs 27.1%), diabetes mellitus (65.5% vs 61.7%), congestive heart failure (59.0% vs 49.7%), chronic kidney disease (48.7% vs 41.7%), and chronic obstructive pulmonary disease (48.3% vs 43.5%; Table 1). This suggests that patients with more medical comorbidities were more likely to receive an AKA than an arthrodesis for treatment of a septic TKA. Hospital charges were lower and reimbursement was higher in the AKA group. However, hospital costs do not reflect the total cost of a procedure, such as time lost from being out of work or additional outpatient charges, such as a prosthesis and physical therapy. Readmission rates within 90 days of the index procedure were higher in the AKA group, which could also increase the total cost of a procedure. However, readmission rates were relatively high in both groups, suggesting that both salvage procedures have associated complications that require readmission. In general, hospital costs alone should not guide the treatment offered. Rohner et al [30] recently published an institutional series of 26 patients who underwent knee arthrodesis with intramedullary nailing for recalcitrant TKA infection. Thirteen of the patients (50%) undergoing arthrodesis had persistent infection that required additional revision surgery. Nineteen patients (73%) reported persistent pain after arthrodesis, and all patients demonstrated substantial impairment on quality-of-life scoring metrics. The authors concluded that intramedullary nailing after septic failure of a revision TKA could not be recommended over AKA. Although our present study does not investigate recurrence of infection after arthrodesis or AKA, our data do suggest that more surgeons favor AKA over arthrodesis for persistent TKA infection. Panagiotopoulos et al [27] reported results of intramedullary nailing arthrodesis for a failed septic TKA revision in 9 patients. The authors reported eventual bony fusion in 8 of 9 patients (89%) at an average of 6.5 months. However, they also noted certain challenges for arthrodesis that should be considered, namely management of bone loss from prior revisions and demands of the surgical technique. In their study, patients had leg shortening on average of 3 cm, one patient had to be converted to an external fixator because of infectious nonunion, and 2 patients required dynamization of their construct to facilitate bony union. As noted by the authors, the need for bony fusion can be a unique challenge of arthrodesis compared to AKA, although arthrodesis does allow for early mobilization with the native leg.
Table 2 Comparison of Postoperative Complication Rates, Hospital Charges, Length of Hospital Stay, and 90-Day Readmission Rates in Knee Arthrodesis Patients vs Above-Knee Amputation Patients. Complications
Arthrodesis (Overall N ¼ 2634)
Above-Knee Amputation (Overall N ¼ 5001)
N
N
VTE (6 mo) Infection (6 mo) Systemic (6 mo) Transfusion (6 mo) Death (1 y) Readmission (3 mo)
%
%
Statistical Comparison Odds Ratio (95% CI), P Value
127 382 683 1451 55 446
4.8 14.5 25.9 55.1 2.1 16.9
191 416 1573 2340 185 971
3.8 8.3 31.5 46.8 3.7 19.4
Metrics
#
SD
#
SD
P Value
Charges ($) Reimbursement ($) LOS (d)
$84,747 $15,415 7
$56,867 $11,698 5.2
$79,686 $17,539 11
$60,111 $10,514 6.4
.0004 <.0001 <.0001
VTE, venous thromboembolism; SD, standard deviation; LOS, length of stay.
1.3 1.9 0.8 1.4 0.6 0.9
(1.0-1.6), (1.6-2.2), (0.7-0.8), (1.3-1.5), (0.4-0.8), (0.7-1.0),
.043 <.0001 <.0001 <.0001 <.0001 .009
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J.B. Carr II et al. / The Journal of Arthroplasty xxx (2016) 1e4
There are also many concerns related to AKA, most notably substantially decreased functional status in patients after AKA. Fedorka et al [26] analyzed functional ability of 35 patients who underwent AKA for septic revision TKA. A total of 15 patients died during the follow-up period, 9 patients required irrigation and debridement of nonhealing AKA wounds, and 2 patients had repeat AKA for nonhealing stumps. Fourteen patients were fitted for prostheses, and 8 of these patients were functionally independent outside of the home. Overall, the authors concluded that most patients had a low functional status after AKA was performed for infection with only half of the patients eventually returning to independent ambulation. The strengths of the present study include a very large patient population afforded by the use of a national database. This allowed for the reporting of statistically significant trends and differences between the arthrodesis and AKA cohorts, which would otherwise be difficult to accomplish in a small, single-institution series. The ability to analyze financial data related to each procedure is a unique feature allowed by this national database as well. Limitations of the study are mostly related to the nature of a national database study. It is possible that the cohorts do not represent national trends as the data were pooled from a Medicareonly database. In addition, the integrity of the data is dependent on the accuracy of proper coding at the time of data reporting, which is impossible to verify. Also, we were unable to account for differences in postoperative management, such as the use of intravenous or oral antibiotics or the need for revision surgery or conversion of arthrodesis to AKA. Furthermore, the heterogeneous nature of the 2 cohorts in regard to medical comorbidity prevalence may prevent direct comparison because patients who were less healthy tended to receive an AKA. Because this was a database study, we were also unable to report functional activity or clinical scores for patients in each cohort. Finally, a database study does not allow for multivariate analysis, which prevents analysis of multiple variable outcomes at the same time. This limits analysis to single-variable relationships with the outcome measures. Conclusion In the present study, AKA appears to be performed more frequently than knee arthrodesis for septic failure of TKA from 2005 to 2012. AKA was performed more frequently in older patients and in patients with a higher incidence of certain medical comorbidities. Arthrodesis for septic TKA is associated with significantly higher rates of postoperative infection and blood transfusion compared to AKA, whereas systemic complications and in-hospital mortality were more common after AKA. Arthrodesis had higher hospital charges, whereas AKA had higher reimbursement despite a significantly longer length of hospital stay and higher 90-day readmission rate. Although every case is unique, the data offered in this study can help orthopedic surgeons better understand the potential complications of surgical options for septic TKA, which is useful when providing patient guidance. References 1. Claassen L, Plaass C, Daniilidis K, et al. Two-stage revision total knee arthroplasty in cases of periprosthetic joint infection: an analysis of 50 cases. Open Orthop J 2015;9:49. 2. Mahmud T, Lyons MC, Naudie DD, et al. Assessing the gold standard: a review of 253 two-stage revisions for infected TKA. Clin Orthop Relat Res 2012;470(10): 2730. 3. Squire MW, Della Valle CJ, Parvizi J. Preoperative diagnosis of periprosthetic joint infection: role of aspiration. AJR Am J Roentgenol 2011;196(4):875. 4. Parvizi J, Jacovides C, Zmistowski B, et al. Definition of periprosthetic joint infection: is there a consensus? Clin Orthop Relat Res 2011;469(11):3022.
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