The optimal surgical approach for total hip arthroplasty (THA) is one of the most hotly debated topics in total joint arthroplasty (TJA) today1-3. The majority of THAs that are performed worldwide are done through either a posterior or lateral approach4, but direct anterior approaches are gaining in popularity because of their marketability and a possible earlier functional recovery5-9. Unfortunately, there are a number of disadvantages with the direct anterior THA, one of which is an increased rate of wound complications and a higher risk of periprosthetic joint infection (PJI), especially in obese patients10-15. At our center, regardless of approach, prolonged wound drainage, superficial infections, and deep infections account for 55% of all THA complications16. Thus, there is substantial interest in identifying measures to prevent, detect, and treat wound complications following all variations of THA.
While relatively uncommon, a PJI is arguably the most devastating TJA complication. Despite developments in perioperative risk factor mitigation and infection prophylaxis, the incidence of PJI following THA still remains around 1%17. Importantly, the infecting pathogens impact treatment success following PJI. For example, gram-negative, methicillin-resistant Staphylococcus aureus (MRSA), and polymicrobial PJIs are negative predictors of treatment success18-24. The importance of understanding the specific organism profiles of each surgical procedure, as well as each surgical approach, is therefore paramount to successfully reducing the incidence and improving the treatment of PJIs.
Interestingly, to our knowledge, very few studies have evaluated the organism profiles of THA PJIs by approach. Ilchmann et al. found more gram-negative infections in anterior compared with lateral approach THAs, but this finding did not reach significance (p = 0.26)10. Achermann et al. noticed more Cutibacterium (formerly Propionibacterium) avidum infections after starting to perform more anterior-based THAs, but they attributed this finding to higher patient body mass index (BMI)25. Therefore, the purpose of our study was twofold. First, we sought to compare the organism profiles of THA PJIs by direct anterior and non-anterior approaches. Second, we wanted to compare the demographic and risk factor profiles of our patients with THA PJIs with direct anterior and non-anterior approaches. We hypothesized that direct anterior THAs would have a different organism profile than non-anterior THAs, and thus may require unique strategies to prevent PJI.
Materials and Methods
Direct anterior and non-anterior primary THA PJIs from a university-affiliated single-specialty orthopaedic hospital were retrospectively reviewed. Data from 12,549 patients who underwent primary THA from January 2012 to September 2019 were reviewed to identify cases of PJI that occurred within 90 days of the index arthroplasty. PJIs that occurred within 90 days were chosen because we believe that early infections are more likely related to approach, while late infections are more likely related to hematogenous spread. Infections were screened for with use of the Centers for Disease Control and Prevention National Healthcare Safety Network (NHSN) criteria26, and PJIs were confirmed using the Musculoskeletal Infection Society (MSIS) criteria27. To ensure that we captured all of the patients with early PJIs from our institution who may have sought treatment at another institution, our 90-day follow-up of all 12,549 patients was cross-referenced with data from both the Medicare Bundled Payments for Care Improvement (BPCI) program and the Statewide Planning and Research Cooperative System (SPARCS) database for New York State.
Standard operating rooms with similar staffing and personnel were used for all of the primary THAs. Institutional policy required that all of the scrubbed personnel wore a surgical helmet and a body exhaust suit. Primary THAs were performed by 20 experienced orthopaedic surgeons. Surgical approach was chosen based on surgeon preference and expertise. All of the direct anterior approaches were performed through the interval described by Matta et al.28. The non-anterior THA cohort included patients who underwent posterior, northern, direct lateral, and anterolateral approaches, all in the lateral decubitus position. Any patient with a confirmed PJI following primary THA for a femoral neck fracture, conversion THA, or simultaneous bilateral THA was excluded.
Over the study period, several notable changes occurred at our institution. Importantly, all of the changes occurred with both the direct anterior and non-anterior THA cohorts. Prior to 2013, thromboembolic prophylaxis was surgeon-dependent, although most preferred low-molecular-weight heparin. From January 2013 through April 2014, robust institutional guidelines recommended low-molecular-weight heparin for prophylaxis, and from May 2014 onward, those guidelines recommended aspirin instead of low-molecular-weight heparin. For preoperative antimicrobial prophylaxis, all of the patients undergoing primary THA received expanded gram-negative antimicrobial prophylaxis (EGNAP)29,30 with a gram-negative agent (1 dose of 2 g of aztreonam if the patient age was ≥75 years, the weight was ≥120 kg, or the creatinine clearance [CrCl] was <20 mL/min, or 3 to 5 mg/kg of gentamicin) and either 2 g of cefazolin for 24 hours, 1 preoperative dose of 15 to 20 mg/kg of vancomycin if MRSA-positive, or 1 preoperative dose of 900 mg of clindamycin if the patient was severely allergic to penicillin or cephalosporin for gram-positive coverage. Additionally, our institution began an intrawound vancomycin powder and dilute povidone-iodine lavage protocol (VIP) for high-risk patients undergoing THA in January 2014, as defined by Iorio et al.31, and began using VIP for all patients undergoing THA in January 2016, regardless of preoperative risk32. Based on a separate analysis that we performed, the VIP did not affect the organism profile of our 90-day primary THA PJIs. Finally, patients who were positive for S. aureus underwent preoperative nasal decolonization with chlorhexidine wipes and povidone-iodine ointment to the nares. All preoperative surgical site preparation was performed using chlorhexidine scrub or povidone-iodine wash if the patient was allergic to chlorhexidine.
After confirmation of PJI, the patient age, sex, BMI, presence of diabetes mellitus (DM) or rheumatoid arthritis (RA), American Society of Anesthesiologists (ASA) classification, and organism characteristics were collected via electronic medical database query, followed by manual chart review for confirmation. The infecting organisms were identified and grouped after consultation with our infectious disease colleagues and infection control department. The incidence of the following organisms and organism groups was then compared by approach: methicillin-sensitive S. aureus (MSSA), MRSA, coagulase-negative Staphylococcus species, gram-negative species, obligate anaerobes, polymicrobial infections, culture-negative infections, and “other” infections. Since polymicrobial PJIs are known to lead to worse outcomes compared with monomicrobial PJIs24, following the precedent set by Aggarwal et al.33, individual organisms in the polymicrobial category were excluded from grouping in any of the other categories. Additionally, none of the monomicrobial infections belonged to >1 category. Only organisms that were identified before or during the first revision for infection after primary THA, and not during any subsequent revision surgeries, were included in our analysis.
Statistical analyses were performed using GraphPad Prism version 8.3.0 (GraphPad Software). The demographics of patients with direct anterior and non-anterior THAs were compared using Fisher exact tests and t tests for categorial and numerical variables, respectively. The organism types were compared using Fisher exact tests. Significance was set at p < 0.05.
The present study was exempt from human-subjects review by our institutional review board as part of our institutional quality improvement program.
In total, we identified 84 patients with an early PJI following primary THA as defined by the NHSN and MSIS criteria26,27. Our overall primary THA PJI rate from January 2012 to September 2019 was 0.67% (84 of 12,549). Our direct anterior THA PJI rate was 0.84% (38 of 4,515) and our non-anterior THA PJI rate was 0.57% (46 of 8,034). Demographic data for the 2 PJI cohorts are listed in Table I.
TABLE I -
Patient Demographics of THA PJI by Approach*
||Anterior (N = 38)
||Non-Anterior (N = 46)
||63.0 ± 12.5
||60.8 ± 8.4
||29.5 ± 5.5
||35.2 ± 6.5
||2.29 ± 0.6
||2.63 ± 0.6
*THA = total hip arthroplasty, PJI = periprosthetic joint infection, BMI = body mass index, DM = diabetes mellitus, RA = rheumatoid arthritis, and ASA = American Society of Anesthesiologists. Boldface indicates p values that reached significance.
†The values are given as the mean and standard deviation.
On average, patients who underwent direct anterior THA complicated by PJI had significantly lower BMI and ASA scores than the non-anterior THA PJI cohort (29.5 versus 35.2 kg/m2, p < 0.001; 2.29 versus 2.63, p = 0.016, respectively). While the direct anterior cohort had more men, fewer patients with DM, and fewer patients with RA, these trends did not reach significance (p = 0.181, p = 0.210, and p = 0.248, respectively).
Importantly, analysis of organism profile by THA approach demonstrated that the direct anterior THA cohort had significantly more monomicrobial gram-negative infections than the non-anterior THA cohort (4 versus 0, p = 0.038) (Table II). Monomicrobial gram-negative infections included 2 cases of Enterobacter cloacae, 1 case of Klebsiella aerogenes, and 1 case of Citrobacter koseri. Only 1 of the 4 gram-negative THA PJIs occurred after starting the VIP protocol in all of the THAs that were performed from 2016 onward. Further demographic analyses comparing these 4 patients with those without monomicrobial or polymicrobial gram-negative growth revealed no significant differences or trends toward differences with sex, age, BMI, DM, RA, or ASA class. Additionally, none of these 4 patients were immunocompromised, were on chronic corticosteroids, or had any other documented gram-negative infection within the year prior to their THA.
TABLE II -
Infecting Organisms of THA PJI by Approach*
||Anterior (N = 38)
||Non-Anterior (N = 46)
*THA = total hip arthroplasty, PJI = periprosthetic joint infection, MRSA = methicillin-resistant Staphylococcus aureus, and MSSA = methicillin-sensitive S. aureus. Boldface indicates p values that reached significance.
Of the polymicrobial infections in the direct anterior THA cohort, 3 (60%) of the 5 patients had at least 1 gram-negative species, and 2 (40%) of the 5 patients had at least 1 Enterococcus species. Of the non-anterior THA cohort, only 2 (22%) of the 9 patients with polymicrobial infection had a gram-negative species, and 4 (44%) of the 9 patients had an Enterococcus species. The number of polymicrobial infections with gram-negative growth did not significantly differ by approach (60% versus 22%, p = 0.266). Individual organisms for each polymicrobial PJI are listed in Table III.
TABLE III -
Infecting Organisms of Polymicrobial THA PJI*
|Anterior (n = 5)
| Case 1
Streptococcus agalactiae, Peptostreptococcus asaccharolyticus
| Case 2
Pseudomonas aeruginosa†, Enterococcus faecalis, Corynebacterium species
| Case 3
Pseudomonas aeruginosa†, Enterococcus faecalis
| Case 4
||MRSA, Pseudomonas aeruginosa†
| Case 5
||MSSA, Cutibacterium acnes
|Non-anterior (n = 9)
| Case 1
||MSSA, MRSE‡, Enterococcus gallinarum
| Case 2
Finegoldia magna§, Enterococcus faecalis, Staphylococcus lugdunensis, Streptococcus agalactiae
| Case 3
||MSSA, Corynebacterium species
| Case 4
||MSSA, Streptococcus agalactiae
| Case 5
||MSSE‡, Pseudomonas aeruginosa†
| Case 6
Pseudomonas aeruginosa†, Providencia stuartii†, Enterococcus faecalis
| Case 7
||MSSA, Corynebacterium species
| Case 8
||MRSE‡, Enterococcus faecalis
| Case 9
||MRSE‡, Propionibacterium granulosum
*THA = total hip arthroscopy, PJI = periprosthetic joint infection, MRSA = methicillin-resistant Staphylococcus aureus, MSSA = methicillin-sensitive Staphylococcus aureus, MRSE = methicillin-resistant Staphylococcus epidermidis, and MSSE = methicillin-sensitive Staphylococcus epidermidis.
†Denotes gram-negative organism.
‡Denotes coagulase-negative Staphylococcus.
§Denotes obligate anaerobe.
No significant differences were found by approach for monomicrobial MRSA, MSSA, coagulase-negative Staphylococcus, culture-negative, obligate anaerobic, polymicrobial, or “other” infections. The 6 cases of monomicrobial “other” infections in the direct anterior cohort included 4 cases of Streptococcus agalactiae, 1 case of Streptococcus mitis, and 1 case of Streptococcus sanguinis. The 6 cases of monomicrobial “other” infections in the non-anterior cohort included 6 cases of S. agalactiae. No vancomycin-intermediate or resistant S. aureus, vancomycin-resistant Enterococcus, acid-fast bacteria, or fungal infections were identified in either cohort.
At our institution in 2019, Aggarwal et al. demonstrated that patients undergoing direct anterior THA are 2.2 times more likely to develop a PJI compared with patients undergoing non-anterior THA (odds ratio: 2.2, 95% confidence interval = 1.1 to 3.9, p = 0.006; infection rate: 1.22% direct anterior versus 0.63% non-anterior, p = 0.023)13. As a follow-up to that paper, the present study demonstrates that direct anterior and non-anterior approach THA PJIs have different organism profiles, which has important implications for infection prevention and treatment. Specifically, there were significantly more monomicrobial gram-negative PJIs with direct anterior THAs compared with non-anterior THAs (4 versus 0, p = 0.038). Furthermore, there was a trend toward more polymicrobial PJIs with gram-negative growth following direct anterior THAs compared with non-anterior THAs, but this finding did not reach significance (60% versus 22%, p = 0.266). Patients who had PJIs after undergoing direct anterior THA had a significantly lower BMI (29.5 versus 35.2 kg/m2, p < 0.001) and were of a significantly lower ASA class (2.29 versus 2.63, p = 0.016) compared with non-anterior THA PJIs.
Our findings of more gram-negative infections in the direct anterior cohort is novel but not surprising. It is well-described that humans have location-specific microbial colonization based on a number of factors, including skin folds and proximity to the genitourinary and gastrointestinal tracts34. Importantly, these differing microbiomes have been shown to cause location-specific surgical site infections. For example, Aboltins et al. reported that gram-negative infections are more common in the hip than in the knee35, which authors such as Tande and Patel believe reflects the influence of the body’s natural flora on inoculating skin incisions36-39. The upper-extremity literature suggests that the skin microbiome of the shoulder leads to high rates of Cutibacterium acnes after total shoulder arthroplasty and shoulder arthroscopy40-42. In spine surgery, lumbosacral operations appear to have the highest rate of gram-negative surgical site infections, a finding attributed to the lumbosacral area’s proximity to fecal and urinary flora43. Lastly, in the vascular literature, it appears that groin-based incisions for graft placement have higher infection rates and may be more susceptible to graft colonization with gram-negative species44,45.
While it is believed that most gram-negative PJIs are due to urinary tract infection-related bacteremia and urosepsis20, numerous authors report that the genitourinary tract, the gastrointestinal tract, and the inguinal fold harbor gram-negative species that can lead to surgical site infections29,35-39. Thus, the significantly greater incidence of early monomicrobial gram-negative PJIs in our direct anterior approach cohort supports the notion that surgical site affects the organism profile of PJIs. Additionally, since a lower BMI and lower ASA class do not appear to be associated with gram-negative infections, approach appeared to be the only risk factor for gram-negative THA PJI.
In response to an increase in gram-negative THA PJIs, our institution began using EGNAP for THA in 201229. Bosco et al. found that the introduction of EGNAP significantly decreased the overall THA PJI incidence as well as the incidence of monomicrobial gram-negative THA PJIs30. Furthermore, Aggarwal et al. reported that using EGNAP and VIP together led to a large decrease in direct anterior THA PJI and a moderate decrease in non-anterior THA PJI13. They hypothesized that the use of EGNAP was particularly effective at decreasing direct anterior THA PJI rates due to its higher risk of gram-negative infections.
In the current study, all of the monomicrobial gram-negative infections in the direct anterior THA cohort occurred after the introduction of EGNAP, although only 1 of the 4 infections occurred after the introduction of VIP in 2016 to all patients undergoing THA. Clearly, there is more to be learned regarding the prophylaxis of gram-negative PJI. These data have our institution considering additional measures to eliminate gram-negative PJI regardless of surgical approach. One possible intervention is the use of >1 dose of gram-negative antimicrobial prophylaxis, similar to the use of cefazolin for up to 24 hours after an incision, based on the Surgical Care Improvement Project guidelines46,47. Additionally, there may be some utility to culturing and decolonizing the inguinal fold prior to surgery, similar to the way we preoperatively decolonize the nares of MRSA. Despite the small number of early monomicrobial gram-negative THA PJIs reported in this series, we believe that both EGNAP and VIP play a role in reducing THA PJI, especially with THA that is performed using a direct anterior approach.
Importantly, while there was no significant difference in polymicrobial infection rates in our study or the study by Ilchmann et al.10, 22% of our non-anterior THA approach patients with polymicrobial PJIs had at least 1 gram-negative species. In contrast, 60% of our polymicrobial direct anterior THA PJIs had at least 1 gram-negative species. While these numbers still seem to favor more gram-negative species in the direct anterior THA cohort, it does suggest that there remains a nonzero chance that non-anterior approaches are at risk for gram-negative infections and thus may similarly benefit from EGNAP and VIP.
There are several limitations to this study. Most importantly, these data are from a single institution and, despite having performed nearly 13,000 THAs during the study period, due to our low infection rate, our PJI sample size was small. As a result, while there were significantly fewer gram-negative infections in our non-anterior THA cohort, larger multicenter trials could be performed to confirm our findings. Additionally, patient data from 20 different surgeons were included; thus, differing surgical techniques and experience could have impacted our findings. Importantly, having multiple surgeons is also beneficial since this may improve the general applicability of our findings; all of the institutional protocols were developed with input from these surgeons, and all of the surgeons were required to follow the same institutional protocols for TJA, allowing for a uniform data set. Since all of the patients in this study were treated in a major metropolitan area with its own bacterial profile, the findings may not be generalizable to other locales. This is especially important given that PJI organism profiles are known to differ geographically33. Finally, we do not know the percentage of patients who had postoperative follow-up; thus, it is possible that some early THA PJIs were missed. Despite the limitations of this study, we will continue to identify the organism profiles of different orthopaedic surgical site infections and work to improve our perioperative infection prophylaxis.
THA PJI organism profiles differ based on surgical approach. We found that direct anterior THA approaches were associated with more gram-negative infections compared with non-anterior THA approaches. While EGNAP and VIP may help reduce THA PJI after direct anterior THA, they are not effective on their own, and other infection prophylaxis measures must be considered. Future studies with larger sample sizes that help define the organism profiles of PJI after THA will allow us to further tailor our perioperative infection prophylaxis.
1. Aggarwal VK, Iorio R, Zuckerman JD, Long WJ. Surgical approaches for primary total hip arthroplasty from Charnley to now: the quest for the best approach. JBJS Rev. 2020 Jan;8(1):e0058.
2. Goodman SB. Editorial comment: 2017 Hip Society proceedings. Clin Orthop Relat Res. 2018 Feb;476(2):214-5.
3. Quinn RH, Murray J, Pezold R, Hall Q. Management of osteoarthritis of the hip. J Am Acad Orthop Surg. 2018 Oct 15;26(20):e434-6.
4. Chechik O, Khashan M, Lador R, Salai M, Amar E. Surgical approach and prosthesis fixation in hip arthroplasty world wide. Arch Orthop Trauma Surg. 2013 Nov;133(11):1595-600. Epub 2013 Aug 4.
5. Higgins BT, Barlow DR, Heagerty NE, Lin TJ. Anterior vs. posterior approach for total hip arthroplasty, a systematic review and meta-analysis. J Arthroplasty. 2015 Mar;30(3):419-34. Epub 2014 Oct 22.
6. Taunton MJ, Trousdale RT, Sierra RJ, Kaufman K, Pagnano MW. John Charnley Award: randomized clinical trial of direct anterior and miniposterior approach THA: which provides better functional recovery? Clin Orthop Relat Res. 2018 Feb;476(2):216-29.
7. Meermans G, Konan S, Das R, Volpin A, Haddad FS. The direct anterior approach in total hip arthroplasty: a systematic review of the literature. Bone Joint J. 2017 Jun;99-B(6):732-40.
8. Miller LE, Gondusky JS, Bhattacharyya S, Kamath AF, Boettner F, Wright J. Does surgical approach affect outcomes in total hip arthroplasty through 90 days of follow-up? A systematic review with meta-analysis. J Arthroplasty. 2018 Apr;33(4):1296-302. Epub 2017 Nov 14.
9. Shofoluwe AI, Naveen NB, Inabathula A, Ziemba-Davis M, Meneghini RM, Callaghan JJ, Warth LC. Internet promotion of direct anterior approach total hip arthroplasty by members of the American Association of Hip and Knee Surgeons. J Arthroplasty. 2018 Jan;33(1):167-170.e1. Epub 2017 Aug 23.
10. Ilchmann T, Zimmerli W, Bolliger L, Graber P, Clauss M. Risk of infection in primary, elective total hip arthroplasty with direct anterior approach or lateral transgluteal approach: a prospective cohort study of 1104 hips. BMC Musculoskelet Disord. 2016 Nov 14;17(1):471.
11. Christensen CP, Karthikeyan T, Jacobs CA. Greater prevalence of wound complications requiring reoperation with direct anterior approach total hip arthroplasty. J Arthroplasty. 2014 Sep;29(9):1839-41. Epub 2014 May 2.
12. Watts CD, Houdek MT, Wagner ER, Sculco PK, Chalmers BP, Taunton MJ. High risk of wound complications following direct anterior total hip arthroplasty in obese patients. J Arthroplasty. 2015 Dec;30(12):2296-8. Epub 2015 Jun 12.
13. Aggarwal VK, Weintraub S, Klock J, Stachel A, Phillips M, Schwarzkopf R, Iorio R, Bosco J, Zuckerman JD, Vigdorchik JM, Long WJ.2019 Frank Stinchfield Award: a comparison of prosthetic joint infection rates between direct anterior and non-anterior approach total hip arthroplasty. Bone Joint J. 2019 Jun;101-B(6_Supple_B):2-8.
14. Purcell RL, Parks NL, Cody JP, Hamilton WG. Comparison of wound complications and deep infections with direct anterior and posterior approaches in obese hip arthroplasty patients. J Arthroplasty. 2018 Jan;33(1):220-3. Epub 2017 Aug 4.
15. Meneghini RM, Elston AS, Chen AF, Kheir MM, Fehring TK, Springer BD. Direct anterior approach: risk factor for early femoral failure of cementless total hip arthroplasty: a multicenter study. J Bone Joint Surg Am. 2017 Jan 18;99(2):99-105.
16. Aggarwal VK, Elbuluk A, Dundon J, Herrero C, Hernandez C, Vigdorchik JM, Schwarzkopf R, Iorio R, Long WJ. Surgical approach significantly affects the complication rates associated with total hip arthroplasty. Bone Joint J. 2019 Jun;101-B(6):646-51.
17. Engesæter LB, Dale H, Schrama JC, Hallan G, Lie SA. Surgical procedures in the treatment of 784 infected THAs reported to the Norwegian Arthroplasty Register. Acta Orthop. 2011 Oct;82(5):530-7.
18. Kandel CE, Jenkinson R, Daneman N, Backstein D, Hansen BE, Muller MP, Katz KC, Widdifield J, Bogoch E, Ward S, Sajja A, Jeldes FG, McGeer A. Predictors of treatment failure for hip and knee prosthetic joint infections in the setting of 1- and 2-stage exchange arthroplasty: a multicenter retrospective cohort. Open Forum Infect Dis. 2019 Oct 21;6(11):ofz452.
19. Hsieh PH, Lee MS, Hsu KY, Chang YH, Shih HN, Ueng SW. Gram-negative prosthetic joint infections: risk factors and outcome of treatment. Clin Infect Dis. 2009 Oct 1;49(7):1036-43.
20. Zmistowski B, Fedorka CJ, Sheehan E, Deirmengian G, Austin MS, Parvizi J. Prosthetic joint infection caused by gram-negative organisms. J Arthroplasty. 2011 Sep;26(6)(Suppl):104-8. Epub 2011 Jun 8.
21. Mortazavi SM, Vegari D, Ho A, Zmistowski B, Parvizi J. Two-stage exchange arthroplasty for infected total knee arthroplasty: predictors of failure. Clin Orthop Relat Res. 2011 Nov;469(11):3049-54.
22. Parvizi J, Azzam K, Ghanem E, Austin MS, Rothman RH. Periprosthetic infection due to resistant staphylococci: serious problems on the horizon. Clin Orthop Relat Res. 2009 Jul;467(7):1732-9. Epub 2009 May 1.
23. Jhan SW, Lu YD, Lee MS, Lee CH, Wang JW, Kuo FC. The risk factors of failed reimplantation arthroplasty for periprosthetic hip infection. BMC Musculoskelet Disord. 2017 Jun 12;18(1):255.
24. Tan TL, Kheir MM, Tan DD, Parvizi J. Polymicrobial periprosthetic joint infections: outcome of treatment and identification of risk factors. J Bone Joint Surg Am. 2016 Dec 21;98(24):2082-8.
25. Achermann Y, Liu J, Zbinden R, Zingg PO, Anagnostopoulos A, Barnard E, Sutter R, Li H, McDowell A, Zinkernagel AS. Propionibacterium avidum: a virulent pathogen causing hip periprosthetic joint infection. Clin Infect Dis. 2018 Jan 6;66(1):54-63.
26. Centers for Disease Control and Prevention. 2020 NHSN surgical site infection (SSI) check list. 2020. Accessed 2020 Oct 5. https://www.cdc.gov/nhsn/pdfs/checklists/ssi-checklist-508.pdf
27. Parvizi J, Tan TL, Goswami K, Higuera C, Della Valle C, Chen AF, Shohat N. The 2018 definition of periprosthetic hip and knee infection: an evidence-based and validated criteria. J Arthroplasty. 2018 May;33(5):1309-1314.e2. Epub 2018 Feb 26.
28. Matta JM, Shahrdar C, Ferguson T. Single-incision anterior approach for total hip arthroplasty on an orthopaedic table. Clin Orthop Relat Res. 2005 Dec;441:115-24.
29. Norton TD, Skeete F, Dubrovskaya Y, Phillips MS, Bosco JD 3rd, Mehta SA. Orthopedic surgical site infections: analysis of causative bacteria and implications for antibiotic stewardship. Am J Orthop (Belle Mead NJ). 2014 May;43(5):E89-92.
30. Bosco JA, Bosco JA, Prince Rainier R Tejada, Catanzano AJ, Stachel AG, Phillips MS. Expanded gram-negative antimicrobial prophylaxis reduces surgical site infections in hip arthroplasty. J Arthroplasty. 2016 Mar;31(3):616-21. Epub 2015 Oct 9.
31. Iorio R, Yu S, Anoushiravani AA, Riesgo AM, Park B, Vigdorchik J, Slover J, Long WJ, Schwarzkopf R. Vancomycin powder and dilute povidone-iodine lavage for infection prophylaxis in high-risk total joint arthroplasty. J Arthroplasty. 2020 Jul;35(7):1933-6. Epub 2020 Mar 2.
32. Buchalter DB, Kirby DJ, Teo GM, Iorio R, Aggarwal VK, Long WJ. Topical vancomycin powder and dilute povidone-iodine lavage reduce the rate of early periprosthetic joint infection after primary total knee arthroplasty. J Arthroplasty. 2020 Jul 31. [Epub ahead of print].
33. Aggarwal VK, Bakhshi H, Ecker NU, Parvizi J, Gehrke T, Kendoff D. Organism profile in periprosthetic joint infection: pathogens differ at two arthroplasty infection referral centers in Europe and in the United States. J Knee Surg. 2014 Oct;27(5):399-406. Epub 2014 Jan 10.
34. Grice EA, Segre JA. The skin microbiome. Nat Rev Microbiol. 2011 Apr;9(4):244-53.
35. Aboltins CA, Dowsey MM, Buising KL, Peel TN, Daffy JR, Choong PF, Stanley PA. Gram-negative prosthetic joint infection treated with debridement, prosthesis retention and antibiotic regimens including a fluoroquinolone. Clin Microbiol Infect. 2011 Jun;17(6):862-7. Epub 2010 Oct 19.
36. Tande AJ, Patel R. Prosthetic joint infection. Clin Microbiol Rev. 2014 Apr;27(2):302-45.
37. Canny GO, McCormick BA. Bacteria in the intestine, helpful residents or enemies from within? Infect Immun. 2008 Aug;76(8):3360-73. Epub 2008 May 12.
38. Aragón IM, Herrera-Imbroda B, Queipo-Ortuño MI, Castillo E, Del Moral JS, Gómez-Millán J, Yucel G, Lara MF. The urinary tract microbiome in health and disease. Eur Urol Focus. 2018 Jan;4(1):128-38. Epub 2016 Nov 14.
39. Weintrob AC, Roediger MP, Barber M, Summers A, Fieberg AM, Dunn J, Seldon V, Leach F, Huang XZ, Nikolich MP, Wortmann GW. Natural history of colonization with gram-negative multidrug-resistant organisms among hospitalized patients. Infect Control Hosp Epidemiol. 2010 Apr;31(4):330-7.
40. Torrens C, Marí R, Alier A, Puig L, Santana F, Corvec S. Cutibacterium acnes in primary reverse shoulder arthroplasty: from skin to deep layers. J Shoulder Elbow Surg. 2019 May;28(5):839-46. Epub 2019 Jan 24.
41. Buchalter DB, Mahure SA, Mollon B, Yu S, Kwon YW, Zuckerman JD. Two-stage revision for infected shoulder arthroplasty. J Shoulder Elbow Surg. 2017 Jun;26(6):939-47. Epub 2016 Nov 22.
42. Chuang MJ, Jancosko JJ, Mendoza V, Nottage WM. The incidence of Propionibacterium acnes in shoulder arthroscopy. Arthroscopy. 2015 Sep;31(9):1702-7. Epub 2015 Mar 29.
43. Abdul-Jabbar A, Berven SH, Hu SS, Chou D, Mummaneni PV, Takemoto S, Ames C, Deviren V, Tay B, Weinstein P, Burch S, Liu C. Surgical site infections in spine surgery: identification of microbiologic and surgical characteristics in 239 cases. Spine (Phila Pa 1976). 2013 Oct 15;38(22):E1425-31.
44. Hodgkiss-Harlow KD, Bandyk DF. Antibiotic therapy of aortic graft infection: treatment and prevention recommendations. Semin Vasc Surg. 2011 Dec;24(4):191-8.
45. Kilic A, Arnaoutakis DJ, Reifsnyder T, Black JH 3rd, Abularrage CJ, Perler BA, Lum YW. Management of infected vascular grafts. Vasc Med. 2016 Feb;21(1):53-60. Epub 2015 Nov 19.
46. Bratzler DW, Dellinger EP, Olsen KM, Perl TM, Auwaerter PG, Bolon MK, Fish DN, Napolitano LM, Sawyer RG, Slain D, Steinberg JP, Weinstein RA; American Society of Health-System Pharmacists (ASHP); Infectious Diseases Society of America (IDSA); Surgical Infection Society (SIS); Society for Healthcare Epidemiology of America (SHEA). Clinical practice guidelines for antimicrobial prophylaxis in surgery. Surg Infect (Larchmt). 2013 Feb;14(1):73-156. Epub 2013 Mar 5.
47. Bratzler DW, Hunt DR. The surgical infection prevention and surgical care improvement projects: national initiatives to improve outcomes for patients having surgery. Clin Infect Dis. 2006 Aug 1;43(3):322-30. Epub 2006 Jun 16.