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Periprosthetic Knee Infection - Part 1: Risk Factors, Classification and Diagnosis

Abstract

Infection is one of the most feared complications in the postoperative period of knee arthroplasties. With the progressive aging of the population and the increased incidence of degenerative joint diseases, there is an exponential increase in the number of arthroplasties performed and, consequently, in the number of postoperative infections. The diagnosis of these should follow a hierarchical protocol, with welldefined criteria, which lead to diagnostic conclusion, thus guiding the most appropriate treatment. The aim of the present update article is to present the main risk factors, classifications and, mainly, to guide diagnostic investigation in an organized manner.

Keywords:
arthroplasty; replacement; knee; surgical site infection; risk factors; diagnosis

Resumo

A infecção é uma das complicações mais temidas no pós-operatório de artroplastias do joelho. Com o envelhecimento populacional progressivo e o aumento da incidência de doenças degenerativas articulares, observa-se um aumento exponencial do número de artroplastias realizadas e, consequentemente, do número de infecções pós-operatórias. O diagnóstico destas devem seguir um protocolo hierarquizado, com critérios bem definidos, que conduzam à conclusão diagnóstica, orientando, assim, o tratamento mais adequado. O objetivo do presente artigo de atualização é apresentar os principais fatores de risco, as classificações e, principalmente, guiar de forma organizada a investigação diagnóstica.

Palavras-chave
artroplastia do joelho; infecção de sítio cirúrgico; fatores de risco; diagnóstico

Introduction

In the last 20 years, the longevity of the world population has been increasing in developed and developing countries. This fact increases the incidence and prevalence of degenerative diseases in general, including joint diseases.11 Beard JR, Officer A, de Carvalho IA, et al. The World report on ageing and health: a policy framework for healthy ageing. Lancet 2016;387(10033):2145-2154,22 Cross M, Smith E, Hoy D, et al. The global burden of hip and knee osteoarthritis: estimates from the global burden of disease 2010 study. Ann Rheum Dis 2014;73(07):1323-1330 Thus, it is natural and expected an increasing number of primary arthroplasties and revisions33 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(01):45-51 performed as treatment of these diseases.33 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(01):45-51,44 Patel A, Pavlou G, Mújica-Mota RE, Toms AD. The epidemiology of revision total knee and hip arthroplasty in England and Wales: a comparative analysis with projections for the United States. A study using the National Joint Registry dataset. Bone Joint J 2015; 97-B(08):1076-1081,55 Delanois RE, Mistry JB, Gwam CU, Mohamed NS, Choksi US, Mont MA. Current Epidemiology of Revision Total Knee Arthroplasty in the United States. J Arthroplasty 2017;32(09):2663-2668

The socioeconomic impact on health systems is significant, particularly in the treatment of possible infections.66 Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am 2007;89(04): 780-785,77 Kurtz SM, Lau E, Watson H, Schmier JK, Parvizi J. Economic burden of periprosthetic joint infection in the United States. J Arthroplasty 2012;27(8, Suppl):61-5.e1,88 Hoy DG, Smith E, Cross M, et al. The global burden of musculoskeletal conditions for 2010: an overview of methods. Ann Rheum Dis 2014;73(06):982-989

The incidence of periprosthetic knee infections in 2001 was of 2.09% and, in 2009, it was of 2.18%, with an increasing trend.77 Kurtz SM, Lau E, Watson H, Schmier JK, Parvizi J. Economic burden of periprosthetic joint infection in the United States. J Arthroplasty 2012;27(8, Suppl):61-5.e1 This complication is one of the main causes of rehospitalization,99 Kurtz SM, Lau EC, Ong KL, Adler EM, Kolisek FR, Manley MT. Which Clinical and Patient Factors Influence the National Economic Burden of Hospital Readmissions After Total Joint Arthroplasty? Clin Orthop Relat Res 2017;475(12):2926-2937 accounting for between 13 and 25% of the reviews performed.33 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(01):45-51,55 Delanois RE, Mistry JB, Gwam CU, Mohamed NS, Choksi US, Mont MA. Current Epidemiology of Revision Total Knee Arthroplasty in the United States. J Arthroplasty 2017;32(09):2663-2668,1010 Evangelopoulos DS, Ahmad SS, Krismer AM, et al. Periprosthetic Infection: Major Cause of Early Failure of Primary and Revision Total Knee Arthroplasty. J Knee Surg 2019;32(10):941-946 The estimated cost of treating periprosthetic infection is between 3 and 4 times higher than that of primary arthroplasty.99 Kurtz SM, Lau EC, Ong KL, Adler EM, Kolisek FR, Manley MT. Which Clinical and Patient Factors Influence the National Economic Burden of Hospital Readmissions After Total Joint Arthroplasty? Clin Orthop Relat Res 2017;475(12):2926-2937,1111 Kapadia BH, Banerjee S, Cherian JJ, Bozic KJ, Mont MA. The Economic Impact of Periprosthetic Infections After Total Hip Arthroplasty at a Specialized Tertiary-Care Center. J Arthroplasty 2016;31(07):1422-1426,1212 Akindolire J, Morcos MW, Marsh JD, Howard JL, Lanting BA, Vasarhelyi EM. The economic impact of periprosthetic infection in total hip arthroplasty. Can J Surg 2020;63(01):E52-E56

The objective of the present work is to review the most current information on the prevention, diagnosis and treatment of periprosthetic knee infection.

Risk Factors

Risk factors for periprosthetic infection may be modifiable or nonmodifiable (Figure 1).1313 Parvizi J, Gehrke T. Anais do 2o Encontro do Consenso Internacional (ICM) em Infecção Musculoesqueletica [Internet]. ICM Philly 2019 [citado 22 de março de 2020]. Disponível em: https://icmphilly.com/document/icm-document-translations/icm-document-portugues-brasil-translation/
https://icmphilly.com/document/icm-docum...

Fig. 1
Risk factors for periprosthetic infection - reproduction of the International Consensus on Musculoskeletal Infections 2018 (ICM-2018).1313 Parvizi J, Gehrke T. Anais do 2o Encontro do Consenso Internacional (ICM) em Infecção Musculoesqueletica [Internet]. ICM Philly 2019 [citado 22 de março de 2020]. Disponível em: https://icmphilly.com/document/icm-document-translations/icm-document-portugues-brasil-translation/
https://icmphilly.com/document/icm-docum...

The modifiable factors most constantly found in literature and clinical practice are rheumatoid arthritis, diabetes mellitus, obesity (body mass index [BMI] > 30), corticosteroid therapy, alcoholism, smoking, and malnutrition, with hypoalbuminemia as reference.1414 Blanco JF, Díaz A, Melchor FR, da Casa C, Pescador D. Risk factors for periprosthetic joint infection after total knee arthroplasty. Arch Orthop Trauma Surg 2020;140(02):239-245,1515 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(05):675-687,1616 Kunutsor SK, Whitehouse MR, Blom AW, Beswick ADINFORM Team. Patient-Related Risk Factors for Periprosthetic Joint Infection after Total Joint Arthroplasty: A Systematic Reviewand MetaAnalysis. PLoS One 2016;11(03):e0150866,1717 Zhu Y, Zhang F, Chen W, Liu S, Zhang Q, Zhang Y. Risk factors for periprosthetic joint infection after total joint arthroplasty: a systematic review and meta-analysis. J Hosp Infect 2015;89 (02):82-89,1818 Rotevatn TA, Bøggild H, Olesen CR, et al. Alcohol consumption and the risk of postoperative mortality and morbidity after primary hip or knee arthroplasty - A register-based cohort study. PLoS One 2017;12(03):e0173083,1919 Nelson CL, Elkassabany NM, Kamath AF, Liu J. Low Albumin Levels, More Than Morbid Obesity, Are Associated With Complications After TKA. Clin Orthop Relat Res 2015;473(10):3163-3172,2020 Cordtz RL, Zobbe K, Højgaard P, et al. Predictors of revision, prosthetic joint infection and mortality following total hip or total knee arthroplasty in patients with rheumatoid arthritis: a nationwide cohort study using Danish healthcare registers. Ann Rheum Dis 2018;77(02):281-288,2121 Zainul-Abidin S, Amanatullah DF, Anderson MB, et al. General Assembly, Prevention, Host Related General: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S13-S35

Some other clinical and social conditions are also described as associated with a higher rate of periprosthetic infection (PPI), such as preoperative American Society of Anesthesiologists (ASA) classification > 2, low income, peripheral vascular disease and others listed in Table 1.1414 Blanco JF, Díaz A, Melchor FR, da Casa C, Pescador D. Risk factors for periprosthetic joint infection after total knee arthroplasty. Arch Orthop Trauma Surg 2020;140(02):239-245,2121 Zainul-Abidin S, Amanatullah DF, Anderson MB, et al. General Assembly, Prevention, Host Related General: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S13-S35,2222 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(09):775-782

Table 1
McPherson classification for periprosthetic infection

Active skin lesions, either near the site or at a distance, have a potentially increased risk of periprosthetic articular infection, as well as surgery or previous joint infection.1616 Kunutsor SK, Whitehouse MR, Blom AW, Beswick ADINFORM Team. Patient-Related Risk Factors for Periprosthetic Joint Infection after Total Joint Arthroplasty: A Systematic Reviewand MetaAnalysis. PLoS One 2016;11(03):e0150866,2020 Cordtz RL, Zobbe K, Højgaard P, et al. Predictors of revision, prosthetic joint infection and mortality following total hip or total knee arthroplasty in patients with rheumatoid arthritis: a nationwide cohort study using Danish healthcare registers. Ann Rheum Dis 2018;77(02):281-288,2323 Ares O, Arnold WV, Atilla B, et al. General Assembly, Prevention, Host Related Local: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S3-S12

Some studies report an increased rate of infection in total knee arthroplasty (TKA) by post-traumatic arthrosis, mainly with previous surgery and retained implants.2424 Bala A, Penrose CT, Seyler TM, Mather RC 3rd, Wellman SS, Bolognesi MP. Outcomes after Total Knee Arthroplasty for posttraumatic arthritis. Knee 2015;22(06):630-639,2525 Aalirezaie A, Anoushiravani A, Cashman J, et al. General Assembly, Prevention, Host Risk Mitigation - Local Factors: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S37-S41

Bergen et al.2626 Bergen MA, Ryan SP, Hong CS, Bolognesi MP, Seyler TM. Conversion Total Knee Arthroplasty: A Distinct Surgical Procedure With Increased Resource Utilization. J Arthroplasty 2019;34(7S): S114-S120 found in a comparative retrospective cohort (109 patients with implants and 109 patients without) an increase in the infection rate in patients undergoing TKA with knee implant (osteosynthesis or osteotomies). However, there was no difference when comparing the groups with previous removal of the implants (n = 43) with those removed during the TKA procedure (n = 46).

There is controversy regarding the increase rate of infection after TKA in patients undergoing previous joint infiltration. Some studies have shown an increased risk of infection when TKA is performed up to 3 months after joint infiltration.2727 Cancienne JM, Werner BC, Luetkemeyer LM, Browne JA. Does Timing of Previous Intra-Articular Steroid Injection Affect the Post-Operative Rate of Infection in Total Knee Arthroplasty? J Arthroplasty 2015;30(11):1879-1882,2828 Richardson SS, Schairer WW, Sculco TP, Sculco PK. Comparison of Infection Risk with Corticosteroid or Hyaluronic Acid Injection Prior to Total Knee Arthroplasty. J Bone Joint Surg Am 2019;101 (02):112-118 On the other hand, other studies did not find significant differences, even in short periods after infiltration (10 weeks)2929 Khanuja HS, Banerjee S, Sodhi GS, Mont MA. Do Prior IntraArticular Corticosteroid Injections or Time of Administration Increase the Risks of Subsequent Periprosthetic Joint Infections after Total Knee Arthroplasty? J Long Term Eff Med Implants 2016;26(03):191-197 or in patients submitted to multiple infiltrations.3030 Kokubun BA, Manista GC, Courtney PM, Kearns SM, Levine BR. Intra-Articular Knee Injections Before Total Knee Arthroplasty: Outcomes and Complication Rates. J Arthroplasty 2017;32(06): 1798-1802 The II-ICM-2018 (II International Consensus on Muscleskeletal Infection - 2018) suggests waiting at least 3 months after infiltration to perform arthroplasty.3131 Cizmic Z, Feng JE, Huang R, et al. Hip and Knee Section, Prevention, Host Related: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S)S255-S270

Regarding the nonmodifiable factors, age alone does not seem to be a predisposing factor for infection.1515 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(05):675-687,1616 Kunutsor SK, Whitehouse MR, Blom AW, Beswick ADINFORM Team. Patient-Related Risk Factors for Periprosthetic Joint Infection after Total Joint Arthroplasty: A Systematic Reviewand MetaAnalysis. PLoS One 2016;11(03):e0150866 Regarding gender, some studies show a higher infection rate in men than in women1515 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(05):675-687,1616 Kunutsor SK, Whitehouse MR, Blom AW, Beswick ADINFORM Team. Patient-Related Risk Factors for Periprosthetic Joint Infection after Total Joint Arthroplasty: A Systematic Reviewand MetaAnalysis. PLoS One 2016;11(03):e0150866 Afro descendants also have higher percentage of infection when compared with Caucasians.2121 Zainul-Abidin S, Amanatullah DF, Anderson MB, et al. General Assembly, Prevention, Host Related General: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S13-S35

Komnos et al.3232 Komnos GA, Manrique J, Goswami K, et al. Periprosthetic Joint Infection in Patients Who Have Multiple Prostheses in Place: What Should Be Done with the Silent Prosthetic Joints. J Bone Joint Surg Am 2020;102(13):1160-1168 retrospectively evaluated patients with arthroplasties in more than one joint. In this study, they concluded that periprosthetic infection of a joint may predispose to hematogenous infection in another prosthetic site. The risk situations for this complication are: female gender, rheumatoid arthritis, Methicillin-Resistant Staphylococcus aureus (MRSA) infection and patients with fever at the time of diagnosis of the first infected joint.

Classification

Classifications are important to stratify and guide management in various clinical conditions, as well as to standardize communication between colleagues.3333 Meinberg EG, Agel J, Roberts CS, Karam MD, Kellam JF. Fracture and Dislocation Classification Compendium-2018. J Orthop Trauma 2018;32(Suppl 1):S1-S170

Segawa et al.,3434 Segawa H, Tsukayama DT, Kyle RF, Becker DA, Gustilo RB. Infection after total knee arthroplasty. A retrospective study of the treatment of eighty-one infections. J Bone Joint Surg Am 1999;81(10): 1434-1445 in 1999, published a retrospective study proposing a classification and its respective treatment based on the chronology of the infection and its etiology, dividing periprosthetic infections into: positive cultures in revision perioperative harvest, acute superficial infection, acute deep infection, chronic infection, and acute hematogenous infection. However, the classification does not consider the conditions of the patient, local and systemic, or the etiological agent.3333 Meinberg EG, Agel J, Roberts CS, Karam MD, Kellam JF. Fracture and Dislocation Classification Compendium-2018. J Orthop Trauma 2018;32(Suppl 1):S1-S170

McPherson et al.3535 McPherson EJ, Tontz W Jr, Patzakis M, et al. Outcome of infected total knee utilizing a staging system for prosthetic joint infection. Am J Orthop 1999;28(03):161-165,3636 McPherson EJ, Woodson C, Holtom P, Roidis N, Shufelt C, Patzakis M. Periprosthetic total hip infection: outcomes using a staging system. Clin Orthop Relat Res 2002;(403):8-15 described a classification system for hip and knee periprosthetic infection based on a retrospective analysis of cases evaluating three factors: type of infection (acute, acute or chronic hematogenous), host factors, and local factors (Table 2). This classification was validated by the International Consensus on Musculoskeletal Infection with moderate evidence index and 74% of panel agreement.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

Table 2
Local and systemic factors for the McPherson classification

Alt et al.3838 Alt V, Rupp M, Langer M, Baumann F, Trampuz A. Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system Bone Joint Res 2020;9(02):79-81 proposed a new classification based on the TNM classification for tumors, adapting it to periprosthetic infection, which emphasizes the pathogenicity of the etiological agent.

In the proposed classification, "T" would be tissue evaluation, "N," non-human cellular factor (etiological agent), and "M", host morbidity, according to the Charlson comorbidities classification (Figure 2).3838 Alt V, Rupp M, Langer M, Baumann F, Trampuz A. Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system Bone Joint Res 2020;9(02):79-81,3939 Alt V, Rupp M, Langer M, Baumann F, Trampuz A. Infographic: Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system Bone Joint Res 2020;9(02):77-78,4040 Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40(05):373-383

Fig. 2
TNM classification for PPI.4040 Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40(05):373-383

The idea of classifying these three factors seems the most appropriate approach; however, we did not find any studies validating this classification.

Diagnosis

The diagnosis of post knee arthroplasty infection has been a challenge. In the first weeks postoperatively, the occurrence of pain, local heat, and functional disability may be normal and not related to any type of bacterial infection.

Thus, it is essential to define reproducible and objective criteria that charaterize the presence of infection.

Following the concept that the diagnosis of infection is often a multifactorial analysis - clinical, laboratory, imaging data and synovial fluid analysis - it is very important to hierarchize the actions in order to build this same diagnosis within a logical and progressive clinical reasoning.

We consider the strategy defined by ICM-2018 the most appropriate research option. In addition to guiding the researcher to the next step towards the diagnostic's conclusion, it brings scientific knowledge of better available evidence and the experience of hundreds of orthopedists, infectologists and microbiologists around the world. The proposed algorithm was tested and validated, presenting high sensitivity (96.9%) and specificity (99.5%) rates.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337,4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350

Following this criterion, the diagnosis of infection is defined by the presence of one of the so-called major criteria - fistula with joint communication or two positive cultures for the same microorganism identified using culture media - or by scoring clinical, serum or scoring from analysis of the synovial fluid obtained by joint puncture (Figure 3).3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

Fig. 3
Diagnostic criteria of the Musculoskeletal Infection Society (CIIM reproduction).

The occurrence of fistula is found in ∼ 13% of cases.3838 Alt V, Rupp M, Langer M, Baumann F, Trampuz A. Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system Bone Joint Res 2020;9(02):79-81 In its absence, when the patient presents with pain in the operated knee, heat and, often, decreased range of motion, it is imperative to request blood tests for evaluation of the white series, Erythrocyte Sedimentation Rate (ESR), C-reactive protein (PCR), and D-dimer.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

ESR and PCR are inflammatory markers used as the first line in the screening of patients with suspected infection, with a sensitivity of ∼75 88% and a specificity of 70 74%, respectively.4242 Berbari E, Mabry T, Tsaras G, et al. Inflammatory blood laboratory levels as markers of prosthetic joint infection: a systematic review and meta-analysis. J Bone Joint Surg Am 2010;92(11):2102-2109 The sensitivity of both combined ranges from 84 to 86%, and the specificity from 47 to 72.3%.4343 Shahi A, Kheir MM, Tarabichi M, Hosseinzadeh HRS, Tan TL, Parvizi J. Serum D-Dimer Test Is Promising for the Diagnosis of Periprosthetic Joint Infection and Timing of Reimplantation. J Bone Joint Surg Am 2017;99(17):1419-1427,4444 Huerfano E, Bautista M, Huerfano M, Bonilla G, Llinas A. Screening for Infection Before Revision Hip Arthroplasty: A Meta-analysis of Likelihood Ratios of Erythrocyte Sedimentation Rate and Serum C-reactive Protein Levels. J Am Acad Orthop Surg 2017;25(12): 809-817 C-reactive protein reaches its highest value on the 3rd postoperative day and remains above normal for ∼ ≥ 3 weeks.4545 Barretto JM, Loures FB, Albuquerque RS, Bezerra FD, Faro RV, Cavanellas NT. Evaluation of serum levels of C-reactive protein after total knee arthroplasty. Rev Bras Ortop 2017;52(02):176-181 VHS remains elevated for at least 6 weeks.4646 Lee YS, Lee YK, Han SB, Nam CH, Parvizi J, Koo KH. Natural progress of D-dimer following total joint arthroplasty: a baseline for the diagnosis of the early postoperative infection. J Orthop Surg Res 2018;13(01):36 Noting that, in patients with inflammatory arthritis, the cutoff value of these markers may be higher due to the influence of the underlying disease,4747 Cipriano CA, Brown NM, Michael AM, Moric M, Sporer SM, Della Valle CJ. Serum and synovial fluid analysis for diagnosing chronic periprosthetic infection in patients with inflammatory arthritis. J Bone Joint Surg Am 2012;94(07):594-600 just as the use of antibiotics can generate false-negatives.4848 Shahi A, Deirmengian C, Higuera C, et al. Premature Therapeutic Antimicrobial Treatments Can Compromise the Diagnosis of Late Periprosthetic Joint Infection. Clin Orthop Relat Res 2015;473 (07):2244-2249 A recent study showed greater sensitivity (89%) and specificity (93%) for D-dimer in relation to traditional ESR and PCR.4343 Shahi A, Kheir MM, Tarabichi M, Hosseinzadeh HRS, Tan TL, Parvizi J. Serum D-Dimer Test Is Promising for the Diagnosis of Periprosthetic Joint Infection and Timing of Reimplantation. J Bone Joint Surg Am 2017;99(17):1419-1427 Another study observed a decline in basal D-dimer levels on the second postoperative day.4646 Lee YS, Lee YK, Han SB, Nam CH, Parvizi J, Koo KH. Natural progress of D-dimer following total joint arthroplasty: a baseline for the diagnosis of the early postoperative infection. J Orthop Surg Res 2018;13(01):36 It is important to note that ∼ 2.5% of the infections do not present alterations in the aforementioned tests.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

The next step following the investigation is arthrocentesis, sending the synovial fluid for laboratory analysis of cellularity (cytometry) and culture/antibiogram. There is no formal contraindication to joint aspiration.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337,4949 Yui JC, Preskill C, Greenlund LS. Arthrocentesis and Joint Injection in Patients Receiving Direct Oral Anticoagulants. Mayo Clin Proc 2017;92(08):1223-1226 In this procedure, which concludes the diagnosis in 65% of the cases, it is essential that the criteria of maximum barrier to contamination are met, performed by an experienced professional with adequatev packaging, and immediate shipment of the material to the laboratory.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

In the acute phase, the presence in the synovial fluid of ≥ 10,000 leukocytes/μL, with at least 90% polymorphonuclear (PMN), and ≥ 3,000 leukocytes/μL in the chronic phase, with at least 70% PMN, indicate infection.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

As for the culture of the aspirated liquid, some criteria should be followed to minimize the risk of false-negative. It is important to perform a prolonged time of culture, since most of the negative samples are infections by bacteria of time-consuming growth, interrupted before the appropriate time.5050 Yoon HK, Cho SH, Lee DY. et al. A Review of the Literature on Culture-Negative Periprosthetic Joint Infection: Epidemiology, Diagnosis and Treatment. Knee Surg Relat Res 2017;29(03):155-164

The collected joint fluid can also be used for 2 other tests: alpha-defensin and leukocyte esterase.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337

Alpha-defensin is an antimicrobial peptide produced by neutrophils in response to pathogens.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337,5151 Gehrke T, Lausmann C, Citak M, Bonanzinga T, Frommelt L, Zahar A. The Accuracy of the Alpha Defensin Lateral Flow Device for Diagnosis of Periprosthetic Joint Infection: Comparison with a Gold Standard. J Bone Joint Surg Am 2018;100 (01):42-48,5252 Frangiamore SJ, Gajewski ND, Saleh A, Farias-Kovac M, Barsoum WK, Higuera CA. α-Defensin Accuracy to Diagnose Periprosthetic Joint Infection-Best Available Test? J Arthroplasty 2016;31(02): 456-460 This marker can be researched in the synovial fluid by laboratory immunoassay or by the lateral flow test, which is a rapid test with a specific kit that can be performed in the operating room with results in a few minutes. The lateral flow test presents a sensitivity rate of 78.5% and a specificity rate of 93.3%, according to a systematic review conducted by the CIIM-2018 with grouped data from 486 patients.4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350 Immunoassay has a sensitivity rate of 98.1% and a specificity rate of 96.4%.5454 Shahi A, Parvizi J, Kazarian GS, et al. The Alpha-defensin Test for Periprosthetic Joint Infections Is Not Affected by Prior Antibiotic Administration. Clin Orthop Relat Res 2016;474(07):1610-1615 Alpha-defensin is not influenced by recent antibiotic use, traces of blood in the sample, or comorbidities such as inflammatory diseases. The rapid test requires a small volume of synovial fluid (15 μL), which can be a great advantage in cases of absence of joint effusion.5353 Bauer TW, Bedair H, Creech JD, et al. Hip and Knee Section, Diagnosis, Laboratory Tests: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S351-S359,5454 Shahi A, Parvizi J, Kazarian GS, et al. The Alpha-defensin Test for Periprosthetic Joint Infections Is Not Affected by Prior Antibiotic Administration. Clin Orthop Relat Res 2016;474(07):1610-1615 On the other hand, in the presence of metallomy, it may present false-negative in up to 30% of cases; it can also be influenced by crystal arthropathy (gout) and should not be done in hematoma aspirate.5353 Bauer TW, Bedair H, Creech JD, et al. Hip and Knee Section, Diagnosis, Laboratory Tests: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S351-S359

Leukocyte esterase is a test with a sensitivity of 85.7% and a specificity of 94.4% according to the systematic review conducted by the CIIM-2018 with grouped data from 2,061 patients.4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350 This test is also not influenced by recent antibiotic use, but the presence of blood in the sample alters the readability of the test, and centrifugation may be necessary to neutralize erythrocyte interference.3737 Amanatullah D, Dennis D, Oltra EG, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S329-S337,5656 Li X, Li R, Ni M, et al. Leukocyte Esterase Strip Test: A Rapid and Reliable Method for the Diagnosis of Infections in Arthroplasty. Orthopedics 2018;41(02):e189-e193

In cases in which it is not possible to aspirate enough content for analysis (dry puncture) or whose cultures are negative, which correspond to ∼ 17% of cases, intraoperative findings of pus, histological analysis, tissue culture, and new generation sequencing may help in the diagnosis of infection.4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350 It is not appropriate to perform joint washing in cases of dry puncture.4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350

Even with the entire arsenal of tests and the algorithm structured and validated, in ∼ 5% of cases the diagnosis of infection cannot be confirmed.4141 Abdel Karim M, Andrawis J, Bengoa F, et al. Hip and Knee Section, Diagnosis, Algorithm: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S339-S350

Some imaging tests may help in the planning of treatment but have low specificity regarding diagnosis.5757 Diaz-Ledezma C, Espinosa-Mendoza R, Gallo J, et al. General Assembly, Diagnosis, Imaging: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S215-S223 Signs of early release on conventional radiography lead to suspected infection.5858 Springer BD. The Diagnosis of Periprosthetic Joint Infection. J Arthroplasty 2015;30(06):908-911 Computed tomography (CT) (especially arthrotomography) and magnetic resonance imaging (MRI) with metal suppression may also show signs of loosening, bone defects and, occasionally, osteomyelitis;5757 Diaz-Ledezma C, Espinosa-Mendoza R, Gallo J, et al. General Assembly, Diagnosis, Imaging: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S215-S223 however, due to their high cost and low specificity, these tests are not recommended as diagnostic measures.5858 Springer BD. The Diagnosis of Periprosthetic Joint Infection. J Arthroplasty 2015;30(06):908-911,5959 Della Valle C, Parvizi J, Bauer TW, et al; American Academy of Orthopaedic Surgeons. American Academy of Orthopaedic Surgeons clinical practice guideline on: the diagnosis of periprosthetic joint infections of the hip and knee. J Bone Joint Surg Am 2011;93(14):1355-1357

On the other hand, other tests have been used to differentiate aseptic loosening from infection, especially in cases of dry puncture, such as the combination of scintigraphy with marked leukocytes and single photon emission computed tomography (SPECT-CT), which also has the advantage of showing the extent of infection impairment, both in bone and soft tissue, and may be of great value in the planning of surgery.5757 Diaz-Ledezma C, Espinosa-Mendoza R, Gallo J, et al. General Assembly, Diagnosis, Imaging: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019;34(2S):S215-S223

  • Financial Support
    There authors declare they have received no financial support from public, commercial, or non-profit sources.

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Publication Dates

  • Publication in this collection
    06 July 2022
  • Date of issue
    2022

History

  • Received
    06 Nov 2020
  • Accepted
    17 Dec 2020
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