Abstract
To explore whether season is a risk factor of periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) and explain it with the theory of traditional Chinese medicine. This was a retrospective cohort study. Only patients who suffered from PJI within 1 month after TJA were included in the study. Occurrence of PJI was the outcome of this study. Chi-squared test and t test was used to assess differences for baseline characteristics. Chi-square test was used to analyze whether season was related to the occurrence of PJI. Logistic regression was used to evaluate the association between season and occurrence of PJI. The incidence of PJI in summer is significantly higher than that in winter, whether after total knee arthroplasty (Chi-square value = 6.455, P = .011) or total hip arthroplasty (Chi-square value = 6.141, P = .013). Summer was an independent risk factor for PJI (OR = 4.373, 95% confidence interval = 1.899–10.673, P = .004). To be more exact, compared to nonlate summer (19.51%), and PJI is mainly concentrated in late summer (80.49%). Late summer was an independent risk factor of PJI after TJA. The infection rate of PJI after TJA in late summer is higher than other seasons. A more thorough preoperative disinfection procedure is needed in late summer.
Keywords: periprosthetic joint infection, risk factor, season, total joint arthroplasty, traditional Chinese medicine
1. Introduction
Total joint arthroplasty (TJA) is 1 of the most common elective orthopedic surgeries,[1,2] which is a successful method and cost-effective intervention that can relieve pain and improve function for patients who are in end-stage knee and hip arthritis.[3–6] Periprosthetic joint infection (PJI) is the main cause of TJA failure, although the incidence rate is < 2% in most national centers.[7,8] It is a severe complication of TJA,[9] and is commonly an important reason for patients to undergo 1- or 2-stage revision surgery, moreover, resulting in severe pain, functional deficits, as well as prolonged inpatient stays and even death.[10–12] In traditional Chinese medicine (TCM), infection is considered as an exterior pathogen entering interior, heat and dampness in Six Yin are especially important pathogens. Hyperactivity of heat brings about the rottenness of muscle, which then leads to suppuration, which is the pathogenesis of infection. In TCM, there are 5 seasons, including spring, summer, late summer, autumn, and winter. Summer is known as “TaiYang,” that means Yang within Yang, and it governs heat and fire. Late summer is from Xiazhi (around June 21–22 in the Gregorian calendar) to Chushu (around August 22–24 in the Gregorian calendar), and it governs the dampness. According to the meteorological classification method: June to August is summer, that is to say, summer includes late summer in general meteorology. On the contrary, winter is known as “Tai Yin,” that means Yin within Yin, it governs coldness, and it is the season for hiding and storage. Therefore, summer (including late summer) has more conditions that can cause postoperative infection.
Therefore, we proposed the following hypothesis: Season is the influencing factor of PJI after TJA. Compared with winter, the incidence of PJI is higher in summer.
2. Materials and methods
2.1. Study design and data source
This was a retrospective cohort study. We performed this study in the Department of Orthopedics, the First Affiliated Hospital of Zhejiang Traditional Chinese Medicine University. The research project obtained approval of the Ethics committee at The First Affiliated Hospital of Zhejiang Chinese Medical University (No. 2019-K-306-01). The procedures used in this study adhere to the tenets of the Declaration of Helsinki. Prior to participation in the study, all patients signed informed consent. Besides, we have access to information that can identify individual participants after data collection.
2.2. Inclusion and exclusion criteria
Inclusion criteria were as follows: Patients who underwent primary total knee arthroplasty (TKA) surgery and total hip arthroplasty (THA) surgery in summer and winter between 2011 to 2020; No other infections during the incubation period were identified upon admission; Comply with the diagnostic criteria for PJI; PJI occurring within 1 month after surgery; Infections that occur in the hip or knee surgery area.
Exclusion criteria were as follows: Other infections in the incubation period cannot be excluded; Infections occurring more than 1 month after surgery; Infections occurring other than hip and knee joints; Multiple joint surgery or revision surgery.
2.3. Season classification and grouping
According to the meteorological classification method: June to August is summer, December to February is winter. Thus, all patients who met inclusion criteria between June to August and December to February from 2011 to 2020 were included.
2.4. Postoperative management and outcome measures
Postoperative management included: Conventional antibiotics were applied intraoperatively to prevent infection, and antibacterial drugs were applied prophylactically within 24 hours postoperatively. Tranexamic acid 1 was given intravenously 3 hours postoperatively. Subcutaneous anticoagulation with 4100 U of low-molecular heparin was started 10 hours after surgery, qd × 5 days. After discharge, the patient was given oral rivaroxaban 10 mg, qd × 14 days. Ice packs were applied intermittently for 48 hours after surgery, and the dressing was changed every other day. The incision was removed at 12 to 14 days postoperatively with outpatient review. The patient started normal weight-bearing walking with the aid of a walker 1 day after surgery THA. Patients were instructed to actively flex and extend the knee joint, perform ankle pump exercises and quadriceps isometric contraction exercises as well as passive exercises 1 day after surgery.
Validated updated version of diagnostic criteria for PJI in 2018 are as follows[13] (based on the diagnostic criteria of PJI proposed by the Musculoskeletal infection society in 2011):
Two positive cultures or the presence of a sinus tract were considered major criteria and diagnostic of PJI. The calculated weights of an elevated serum CRP (>1 mg/dL), D-dimer(>860ng/mL) and ESR (>30mm/hour) were 2, 2 and 1 points, respectively. Elevated synovial fluid WBC count (>3000 cells/µL), alpha-defensin (signal-to cutoff ratio > 1), LE (++), PMN% (>80%) and synovial CRP (>6.9mg/L) received 3, 3, 3, 2 and 1 points, respectively. Patients with an aggregate score of greater than or equal to 6 were considered infected while a score between 2 and 5, required the inclusion of intraoperative findings for confirming or refuting the diagnosis. Intraoperative findings of positive histology, purulence and single positive culture were assigned 3, 3, and 2 points, respectively. Combined with the preoperative score, a total of greater than or equal to 6 was considered infected, a score between 4 and 5 was inconclusive, and a score of 3 or less was not infected.
2.5. Statistical analysis
Chi-squared test was used to assess differences in dichotomous variables in demographics factors, t test was used to assess differences in continuous variable.
Chi-square test was used to analyze whether season was related to the occurrence of PJI. While controlling for all queried demographic factors as covariates, a multivariate logistic regression was analogously performed to adjust for potential confounding bias and was performed to determine whether there is causality among factors and PJI. Reference events were “female,” “winter,” and “no” for categorical variables “gender,” “season,” and “transfusion.” Increasing increments of 1 for continuous variables “age,” “body mass index (BMI),” and “time of hospital stay,” 100 for continuous variables “operative time,” “amount of blood loss during the operation.” All data were carried out using SPSS Version 25.0 (International Business Machines Corporation, Armonk, NY) statistical software for statistical analysis, the test level α value is taken as 0.05. P < .05 meant the difference was statistically significant.
3. Results
3.1. Study population
From 2011 to 2020, there were 3303 patients who underwent TJA who met the inclusion criteria, including 1572 patients who underwent TKA (841 in summer, 731 in winter) and 1731 THA patients (919 in summer, 812 in winter). Among them, 52 patients suffered from PJI (41 in summer, 11 in winter), 23 were after TKA, 29 were after THA, and included 21 male patients and 31 female patients, age (72.04 ± 6.34) years old.
3.2. Characteristics of population
The demographic and clinical characteristics between the 2 groups are shown in Table 1 and Table 2. There were no statistically significant differences in between the groups for age (year), gender (female/male), BMI (kg/m2), operative time (minute), time of hospital stay (day), transfusion (yes/no), and amount of blood loss during the operation (mL).
Table 1.
Characteristics of the study population for TKA.
| Item | Summer | Winter | P value |
|---|---|---|---|
| Age (yr) | 67.57 ± 11.94 | 66.71 ± 15.98 | .891 |
| Female (%) | 35.79 | 56.36 | .350 |
| BMI (kg/m2) | 21.28 ± 2.09 | 22.61 ± 2.23 | .194 |
| Operative time (min) | 168.57 ± 31.95 | 157.86 ± 34.38 | .505 |
| Time of Hospital Stay (d) | 23.79 ± 7.26 | 25.71 ± 5.99 | .552 |
| Transfusion (%) | 78.72 | 84.13 | .694 |
| Amount of blood loss during operation (mL) | 250 ± 164.08 | 221.43 ± 146.79 | .702 |
BMI = body mass index, TKA = total knee arthroplasty.
Table 2.
Characteristics of the study population for THA.
| Item | Summer | Winter | P value |
|---|---|---|---|
| Age (yr) | 66.20 ± 11.85 | 64.36 ± 9.30 | .647 |
| Female (%) | 46.03 | 65.52 | .340 |
| BMI (kg/m2) | 21.98 ± 2.40 | 22.36 ± 2.73 | .697 |
| Operative time (min) | 170.00 ± 33.33 | 166.79 ± 36.35 | .806 |
| Time of Hospital Stay (d) | 22.87 ± 5.29 | 23.93 ± 6.29 | .626 |
| Transfusion (%) | 91.62 | 88.05 | .501 |
| Amount of blood loss during operation (mL) | 260.00 ± 135.22 | 253.57 ± 168.09 | .910 |
BMI = body mass index, THA = total hip arthroplasty.
3.3. Outcomes
The incidence of PJI in summer is significantly higher than that in winter, whether after TKA (Chi-square value = 6.455, P = .011) (Table 3) or THA (Chi-square value = 6.141, P = .013) (Table 4). A total of 65 pathogenic bacteria were cultured from 52 patients infected after TJA. Among them, there were 47 strains of Gram-positive bacteria (72.31%), 14 strains of Gram-negative bacteria (21.54%) and 4 strains of fungi (6.15%). The details are shown in Table 5. A logistic regression analysis was conducted to adjust for the influence of the confounding factors on the main outcome (PJI). The regression model included the following factors: age (continuous variable), BMI (continuous variable), gender(female/male), season (summer/winter), operative time (continuous variable), time of hospital stay (continuous variable), transfusion (yes/no), and amount of blood loss during operation (continuous variable). Compared with winter, the season of summer was an independent risk factor for PJI (OR = 4.373, 95% confidence interval [CI] = 1.899–10.673, P = .004). In addition, age (OR = 1.221, 95% CI = 1.022–1.415, P = .035), BMI (OR = 1.117, 95% CI = 0.831–1.502, P = .028), operative time (OR = 1.796, 95% CI = 1.057–2.984, P = .041), transfusion (OR = 2.347, 95% CI = 1.725–4.832, P = .029), amount of blood loss during operation (OR = 1.987, 95% CI = 1.334–3.567, P = .031) were risk factors for PJI after TJA. Gender (OR = 1.117, 95% CI = 0.831–1.502, P = .462), and time of hospital stay (OR = 1.215, 95% CI = 0.671–1.756, P = .125) showed no significant difference(Table 6). To be more exact, compared to nonlate summer (19.51%), PJI is mainly concentrated in late summer (80.49%) (Fig. 1).
Table 3.
Comparison of incidence of PJI after TKA between 2 groups.
| Chi-square test | |||||
|---|---|---|---|---|---|
| Group | Total | PJI | None | Chi-square value | P value |
| Summer | 841 | 19 | 822 | 6.455 | .011 |
| Winter | 731 | 4 | 727 | ||
PJI = periprosthetic joint infection, TKA = total knee arthroplasty.
Table 4.
Comparison of incidence of PJI after THA between 2 groups.
| Chi-square test | |||||
|---|---|---|---|---|---|
| Group | Total | PJI | None | Chi-square value | P value |
| Summer | 919 | 22 | 897 | 6.141 | .013 |
| Winter | 812 | 7 | 805 | ||
PJI = periprosthetic joint infection, THA = total hip arthroplasty.
Table 5.
Distribution of infectious pathogens of PJI patients
| Category | Pathogenic bacteria | Number of strains (n = 65) | Composition ratio (%) |
|---|---|---|---|
| Gram-positive bacteria | Staphylococcus aureus | 25 | 38.46 |
| Staphylococcus epidermidis | 13 | 20 | |
| Staphylococcus haemolyticus | 4 | 6.15 | |
| Streptococcus pneumoniae | 3 | 4.61 | |
| Enterococcus faecalis | 2 | 3.08 | |
| Gram-negative bacteria | Pseudomonas aeruginosa | 7 | 10.77 |
| Escherichia coli | 5 | 7.69 | |
| Klebsiella pneumoniae | 2 | 3.08 | |
| Fungus | Candida albicans | 2 | 3.08 |
| Pseudomonas albicans | 2 | 3.08 |
PJI = periprosthetic joint infection.
Table 6.
Logistic regression analysis to account for confounding variables of PJI after TJA.
| Factors | P value | OR value (95% CI) |
|---|---|---|
| Age (yr) | .035 | 1.221(1.022-1.415) |
| Gender (female/male) | .462 | 1.117(0.831-1.502) |
| BMI (kg/m2) | .028 | 2.362(1.824-3.275) |
| Season (winter/summer) | .004 | 4.373(1.899-10.673) |
| Operative time (min) | .041 | 1.796(1.057-2.984) |
| Time of hospital stay (d) | .125 | 1.215(0.671,1.756) |
| Transfusion (no/yes) | .029 | 2.347(1.725,4.832) |
| Amount of blood loss during operation (mL) | .031 | 1.987(1.334,3.567) |
BMI = body mass index, CI = confidence interval, PJI = periprosthetic joint infection, TJA = total joint arthroplasty.
Figure 1.
Percentage diagram of occurrence of PJI in late summer and nonlate summer. PJI = periprosthetic joint infection.
4. Discussion
TJA is a successful treatment which improves joint function, relieves pain, and increases the overall quality of life.[14] With the popularity of TJA, the number of PJI, which is one of the most dreaded complications of TJA, has also increased.[15] It requires multiple surgical procedures, which may further increase morbidity and even mortality.[16,17]
The results of this study confirmed that the incidence of PJI in patients undergone TJA in summer (2.33%) is significantly higher than that in winter (0.58%). This result is consistent with other studies. Parkinson et al[18] reported the rate of revision for PJI will be higher during the warmer monsoon wet season of summer and fall.
Ryota et al[19] reported that summer season was associated with PJI. Samuel et al[20] reported rates of PJI were more frequent in the summer than other seasons. For the reasons, western medicine (WM) explained that in summer, there is increased temperature and humidity, which causes the cutaneous environment becoming optimal for both gram-negative and gram-positive infections, including methicillin-resistant Staphylococcus aureus and impetigo.[18,21,22] Increased skin colonization rates of both patients and hospital staff in summer and increased skin bacterial load are thought to contribute to an increased risk of infection.[23] Also, higher temperatures in summer will increase more sweating, which provides a suitable environment for the reproduction of pathogenic bacteria no matter for surgeon during surgery or for patients. Mills et al[24] reported that a sweating surgeon was significantly more likely to contaminate the surgical field than a nonsweating surgeon.
In TCM, it is considered that infections are caused by exterior pathogen entering the interior. The pathogenic bacteria that cause PJI are exactly exogenous pathogen. Among the 6 Yin, heat and dampness invading the body and leading to the symptoms like high fever, regional redness, swelling and purulent are most similar to the symptoms of PJI after TJA. Summer’s property is heat and late summer is dampness, while winter governs coldness. Hyperactivity of heat and dampness bring about rottenness of muscle, then lead to suppuration, which is the pathogenesis of PJI. Thus, the incidence of PJI in summer is higher than that in winter.
Besides, TCM hold the views that excessive sweating will open up the interstices and pores and provides conditions for dampness and heat to enter into body. The property of summer is heat, evaporation of which can make body fluid to flow outwards. In winter, it means hiding and storing, and the property is coldness, which causes contracture and tension, as well as coagulation and stagnation. Thus, there is more sweating in summer than that in winter. In other words, interstices and pores are more closed in winter. Moreover, the accumulation of excessive sweat on the body surface will turns into dampness, thus intensifies the negative influence on human. PJI concentrating mainly in late summer shows dampness is an indispensable factor of it. Although dampness exists in all seasons of the year, it is most obvious in the late summer. The property of dampness is lingering and sticky, so when dampness and heat combine, the heat will be more difficult to eliminate, which leads to a greater chance of PJI.
Besides season, the factors of age, BMI, operative time, transfusion, and amount of blood loss during operation were also risk factors of PJI; gender and time of hospital stay showed no significant difference. They are consistent with some other studies.[25–30] But Chen et al[31] reported that gender was a potential risk factor for PJI, and man had a higher incidence of PJI than women. Kerstin et al[32] reported that length of hospital stay was significantly related to PJI in TJA.
The current study is unique in that it demonstrates summer season is a risk factor of PJI after TJA, and PJI is more concentrated in late summer, using the theory of TCM to explain it.
To the best of our knowledge, this is the first study to report season being an independent risk factor of PJI from perspective of TCM. However, we acknowledge the limitations of this study. We only divided into 2 groups: summer group and winter group, rather than a group for each season. It was a retrospective cohort study and did not further explore the relevant biological mechanism by which season influences the incidence of PJI after TJA.
Being aware of these risk factors will help surgeons estimate the risk of every patient in advance and optimize surgical procedure and help decrease the incidence of PJI. This well-documented seasonal variation effectively guides us to pay more attention to skin disinfection in summer and a more thorough preoperative disinfection procedure is required. Reducing the sweat of surgeons during surgery, cleaning and managing the skin of patients after surgery, minimizing the operation time, reducing intraoperative blood loss, and reducing blood transfusions especially in summer, or more exactly in late summer, thereby effectively decrease the occurrence of PJI.
5. Conclusion
In conclusion, our study showed that summer season was significantly correlated with PJI after TJA and was an independent risk factor for it. To be more exact, PJI is mainly concentrated in late summer. A more thorough preoperative disinfection procedure is needed when a patient is undergoing TJA in summer.[33] During this period, it may be necessary to strictly observe the disinfection and sterilization of operating room personnel and equipment. These findings should be confirmed in further studies that can better control for possible confounding variables.
Author contributions
Conceptualization: Ze Yang, Xiang Wang.
Data curation: Ze Yang, Xiang Wang.
Formal analysis: Ze Yang.
Investigation: Weifeng Ji.
Methodology: Ze Yang, Weifeng Ji, Yongliang Xia.
Project administration: Yongliang Xia, Xiang Wang.
Resources: Xiang Wang.
Supervision: Weifeng Ji, Yongliang Xia, Xiang Wang.
Validation: Weifeng Ji, Yongliang Xia.
Visualization: Yongliang Xia, Xiang Wang.
Writing – original draft: Ze Yang, Xiang Wang.
Writing – review & editing: Weifeng Ji, Yongliang Xia.
Abbreviations:
- BMI
- body mass index
- PJI
- periprosthetic joint infection
- TCM
- traditional Chinese medicine
- THA
- total hip arthroplasty
- TJA
- total joint arthroplasty
- TKA
- total knee arthroplasty
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
This study was approved by the ethics committee of the First Affiliated Hospital of Zhejiang Chinese Medical University.
The authors have no funding and conflicts of interest to disclose.
How to cite this article: Yang Z, Ji W, Xia Y, Wang X. Late summer is a risk factor for periprosthetic joint infection after total joint arthroplasty: A retrospective cohort study. Medicine 2023;102:10(e33089).
Contributor Information
Ze Yang, Email: 995651045@qq.com.
Weifeng Ji, Email: yz19980121doctor@163.com.
Yongliang Xia, Email: 20043077@zcmu.edu.cn.
References
- [1].Bozic KJ, Kurtz SM, Lau E, et al. The epidemiology of revision total knee arthroplasty in the United States. Clin Orthop Relat Res. 2010;468:45–51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [2].Schrama JC, Espehaug B, Hallan G, et al. Risk of revision for infection in primary total hip and knee arthroplasty in patients with rheumatoid arthritis compared with osteoarthritis: a prospective, population-based study on 108,786 hip and knee joint arthroplasties from the Norwegian arthroplasty register. Arthritis Care Res (Hoboken). 2010;62:473–9. [DOI] [PubMed] [Google Scholar]
- [3].Berry DJ, Harmsen WS, Cabanela ME, et al. Twenty-five-year survivorship of two thousand consecutive primary Charnley total hip replacements: factors affecting survivorship of acetabular and femoral components. J Bone Joint Surg Am. 2002;84:171–7. [DOI] [PubMed] [Google Scholar]
- [4].Fortin PR, Clarke AE, Joseph L, et al. Outcomes of total hip and knee replacement: preoperative functional status predicts outcomes at six months after surgery. Arthritis Rheum. 1999;42:1722–8. [DOI] [PubMed] [Google Scholar]
- [5].Söderman P, Malchau H, Herberts P. Outcome after total hip arthroplasty: part I. General health evaluation in relation to definition of failure in the Swedish National Total Hip Arthoplasty register. Acta Orthop Scand. 2000;71:354–9. [DOI] [PubMed] [Google Scholar]
- [6].Healy WL, Sharma S, Schwartz B, et al. Athletic activity after total joint arthroplasty. J Bone Joint Surg Am. 2008;90:2245–52. [DOI] [PubMed] [Google Scholar]
- [7].Namba RS, Inacio MC, Paxton EW. Risk factors associated with deep surgical site infections after primary total knee arthroplasty: an analysis of 56,216 knees. J Bone Joint Surg Am. 2013;95:775–82. [DOI] [PubMed] [Google Scholar]
- [8].NIH consensus conference: total hip replacement. NIH consensus development panel on total hip replacement. JAMA. 1995;273:1950–6. [PubMed] [Google Scholar]
- [9].Kunutsor SK, Whitehouse MR, Blom AW, et al. Patient-related risk factors for periprosthetic joint infection after total joint arthroplasty: a systematic review and meta-analysis. PLoS One. 2016;11:e0150866. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [10].Andersson AE, Bergh I, Karlsson J, et al. Patients’ experiences of acquiring a deep surgical site infection: an interview study. Am J Infect Control. 2010;38:711–7. [DOI] [PubMed] [Google Scholar]
- [11].Cahill JL, Shadbolt B, Scarvell JM, et al. Quality of life after infection in total joint replacement. J Orthop Surg (Hong Kong). 2008;16:58–65. [DOI] [PubMed] [Google Scholar]
- [12].Ting NT, Della Valle CJ. Diagnosis of periprosthetic joint infection-an algorithm-based approach. J Arthroplasty. 2017;32:2047–50. [DOI] [PubMed] [Google Scholar]
- [13].Parvizi J, Tan TL, Goswami K, et al. The 2018 definition of periprosthetic hip and knee infection: an evidence-based and validated criteria. J Arthroplasty. 2018;33:1309–1314.e1302. [DOI] [PubMed] [Google Scholar]
- [14].Jones CA, Voaklander DC, Johnston DW, et al. Health related quality of life outcomes after total hip and knee arthroplasties in a community based population. J Rheumatol. 2000;27:1745–52. [PubMed] [Google Scholar]
- [15].Kurtz SM, Lau EC, Son MS, et al. Are we winning or losing the battle with periprosthetic joint infection: trends in periprosthetic joint infection and mortality risk for the medicare population. J Arthroplasty. 2018;33:3238–45. [DOI] [PubMed] [Google Scholar]
- [16].Zmistowski B, Karam JA, Durinka JB, et al. Periprosthetic joint infection increases the risk of one-year mortality. J Bone Joint Surg Am. 2013;95:2177–84. [DOI] [PubMed] [Google Scholar]
- [17].Achermann Y, Vogt M, Spormann C, et al. Characteristics and outcome of 27 elbow periprosthetic joint infections: results from a 14-year cohort study of 358 elbow prostheses. Clin Microbiol Infect. 2011;17:432–8. [DOI] [PubMed] [Google Scholar]
- [18].Parkinson B, Armit D, McEwen P, et al. Is climate associated with revision for prosthetic joint infection after primary TKA? Clin Orthop Relat Res. 2018;476:1200–4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [19].Yamagami R, Inui H, Jo T, et al. Unicompartmental knee arthroplasty is associated with lower proportions of surgical site infection compared with total knee arthroplasty: a retrospective nationwide database study. Knee. 2021;28:124–30. [DOI] [PubMed] [Google Scholar]
- [20].Rosas S, Ong AC, Buller LT, et al. Season of the year influences infection rates following total hip arthroplasty. World J Orthop. 2017;8:895–901. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [21].Eber MR, Shardell M, Schweizer ML, et al. Seasonal and temperature-associated increases in gram-negative bacterial bloodstream infections among hospitalized patients. PLoS One. 2011;6:e25298. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [22].Kaier K, Frank U, Conrad A, et al. Seasonal and ascending trends in the incidence of carriage of extended-spectrum ß-lactamase-producing Escherichia coli and Klebsiella species in 2 German hospitals. Infect Control Hosp Epidemiol. 2010;31:1154–9. [DOI] [PubMed] [Google Scholar]
- [23].Walling HW. Primary hyperhidrosis increases the risk of cutaneous infection: a case-control study of 387 patients. J Am Acad Dermatol. 2009;61:242–6. [DOI] [PubMed] [Google Scholar]
- [24].Mills SJ, Holland DJ, Hardy AE. Operative field contamination by the sweating surgeon. Aust N Z J Surg. 2000;70:837–9. [DOI] [PubMed] [Google Scholar]
- [25].Zheng XQ, Huang JF, Lin JL, et al. Effects of preoperative warming on the occurrence of surgical site infection: a systematic review and meta-analysis. Int J Surg. 2020;77:40–7. [DOI] [PubMed] [Google Scholar]
- [26].Dowsey MM, Choong PF. Obesity is a major risk factor for prosthetic infection after primary hip arthroplasty. Clin Orthop Relat Res. 2008;466:153–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [27].Ren X, Ling L, Qi L, et al. Patients’ risk factors for periprosthetic joint infection in primary total hip arthroplasty: a meta-analysis of 40 studies. BMC Musculoskelet Disord. 2021;22:776. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [28].Blanco JF, Díaz A, Melchor FR, et al. Risk factors for periprosthetic joint infection after total knee arthroplasty. Arch Orthop Trauma Surg. 2020;140:239–45. [DOI] [PubMed] [Google Scholar]
- [29].Guo H, Xu C, Chen J. Risk factors for periprosthetic joint infection after primary artificial hip and knee joint replacements. J Infect Dev Ctries. 2020;14:565–71. [DOI] [PubMed] [Google Scholar]
- [30].Anis HK, Sodhi N, Klika AK, et al. Is operative time a predictor for post-operative infection in primary total knee arthroplasty? J Arthroplasty. 2019;34:S331–6. [DOI] [PubMed] [Google Scholar]
- [31].Chen J, Cui Y, Li X, et al. Risk factors for deep infection after total knee arthroplasty: a meta-analysis. Arch Orthop Trauma Surg. 2013;133:675–87. [DOI] [PubMed] [Google Scholar]
- [32].Radtke K, Tetzlaff T, Vaske B, et al. Arthroplasty-center related retrospective analysis of risk factors for periprosthetic joint infection after primary and after revision total hip arthroplasty. Technol Health Care. 2016;24:721–8. [DOI] [PubMed] [Google Scholar]
- [33].Kane P, Chen C, Post Z, et al. Seasonality of infection rates after total joint arthroplasty. Orthopedics. 2014;37:e182–186. [DOI] [PubMed] [Google Scholar]