Prosthetic Joint Infection

Article Author:
Folusakin Ayoade
Article Editor:
John Todd
12/16/2019 11:46:25 PM
PubMed Link:
Prosthetic Joint Infection


There is no uniformly accepted definition for prosthetic joint infection. The presentation is often varied, and the classical features of infection, such as fever, leukocytosis, and other typical signs of sepsis, are often absent. A prosthesis is a foreign body, and its presence alone is a risk factor for infection. Also, the microorganism load that will produce an established infection in a prosthetic joint is often less compared to a native joint.

The strongest factor that defines prosthetic joint infection is perhaps the recovery of a microorganism from a joint aspirate or surgically obtained peri-prosthetic material. Other factors that support prosthetic joint infection include the presence of a sinus tract communicating with the joint space, wound dehiscence, purulence around the joint without an alternative explanation, loosening of the prosthesis, elevated synovial fluid leukocyte count with neutrophil predominance, and elevated inflammatory markers. However, failure to identify a pathogen does not rule out infection.[1][2]


The implicated pathogens of prosthetic joint infection are best categorized into three groups based on when they are likely to be isolated from culture materials in relation to the duration of the implant.[3][4]

Early infection, which is less than three months of implant placement), is typically caused by highly virulent organisms including Staphylococcus aureus, aerobic gram-negative Bacilli, and beta-hemolytic Streptococcus.

Delayed infection, from 3 months to 1 year, is typically caused by low virulent organisms including coagulase-negative Staphylococcus, Propionibacterium acnes, and Enterococci. To a lesser extent, S. aureus may also be implicated.

Late infection (over one year; some authors use over 2 years) are typically hematogenous and often caused by Staphylococcus aureus, coagulase-negative Staphylococcus, viridans streptococcus, Enterococciand occasionally gram-negative bacilli. See figure.

In summary, Staphylococci account for more than 50% of total prosthetic joint infections. Approximately 20% may be polymicrobial, 15% caused by gram-negative, and about 10% are culture negative.[5][6]


Currently, in the United States, physicians perform about one million total hip and knee arthroplasties, but this number is expected to quadruple over the next one to two decades. With increasing number of surgeries, it is expected there will be more infections. The current rate of prosthetic joint infection varies from one center to another but typically range between 0.5% to 1.0% for hip and shoulder replacements, and 0.5% to 2% for knee replacements.[7][8]

Infection rates are higher in the first 2 years compared to after two years following surgery.

The risk factors for infection include:

  • Host factors which are diabetes mellitus, obesity, rheumatoid arthritis, malignancy, and use of immunosuppressive therapy
  • Surgery-related factors which are complexity and surgery duration
  • Postoperative factors with are a hematoma, seroma, and wound dehiscence.


Underlying the pathogenesis of prosthetic joint infection is the simple fact that prostheses are foreign bodies and they can promote the formation of biofilm by several notable organisms. Biofilm is a thin film of microorganism-embedded glycocalyx (exopolysaccharides) which often coats the surface of the prosthesis and create a barrier against antimicrobial agents. Also, certain forms of Staphylococcus aureus, a notable player in prosthetic joint infections may form small colony variants which often grow slowly and are associated with recurrent and difficult-to-treat infections.

History and Physical

The presentation can be early, delayed, or late as outlined previously. Virulent pathogens typically cause early infections, most of which are acquired around the time of surgery and usually are accompanied with erythema, induration at the incision site, and wound drainage. Delayed infections may also be acquired around the time of surgery, but low virulent organisms typically cause them. Late infections, however, are mostly hematogenous and often without fever, draining wounds, or local signs of infection. Overall, symptoms are very non-specific, and most patients present with joint swelling or pain. Other common clinical presentations include wound dehiscence, purulence around the prosthesis, sinus tract communicating with the joint cavity, joint instability and ambulation difficulties.


The accurate diagnosis of prosthetic joint infection often involves the combination of multiple factors including symptoms, signs, synovial fluid cell count, serum inflammatory markers, and culture.[3][9][10]

The threshold for diagnosing a prosthetic joint infection using some of these parameters is much lower compared to septic arthritis of a native joint. For example, unlike septic arthritis, when synovial fluid cell counts are typically tens of thousands, a synovial fluid white blood cell count (WBC) of more than 4200 cells/microliter supports hip prosthetic joint infection, while a WBC count of more than 1700 cells/microliter supports knee prosthetic joint infection. Neutrophil predominance is typically a common feature.

A culture is an important tool for the diagnosis of prosthetic joint infection. Aspirated joint fluid culture should be sent in multiple sets of culture media. Also, obtaining multiple intraoperative culture samples is encouraged. This is especially important for the recovery and accurate diagnosis of prosthetic joint infection caused by low virulence organisms because having just one positive culture is not enough to make a diagnosis. The sensitivity of synovial fluid culture is only 85%, so a negative culture does not rule out infection. However, the specificity of synovial fluid culture is approximately 95%, and positive cultures often imply the presence of prosthetic joint infection.

Imaging may have some role in diagnosis, but it is mostly complimentary. Perhaps the most important study is a plain film of the affected joint. Even though overall sensitivity and specificity are low, plain imaging may provide useful clues about joint effusion, joint alignment, bone-cement interface lucencies, and periosteal reactions.[11]

Physicians seldom order CT and MRI scans, but when requested, the scans may show bony erosion, abscess, sinus tract, or loosening of the prosthesis. Technetium bone scans have poor specificity and typically are not helpful in early and delayed infections. FDG-PET scan and WBC scans have high specificities and sensitivities and may be a good adjunct to diagnosis.

Current Classification of Prosthetic Joint Infection

  • Presence of a sinus tract that communicates with the prosthesis
  • Two different fluid samples from the joint yield positive cultures
  • Elevated ESR and CRP
  • Elevated WBC in synovial fluid
  • Frank purulence in the joint
  • At least one positive culture

Treatment / Management

Treatment of prosthetic joint infection often includes a combination of medical (antibiotics) and surgical methods. Treatment principles include:

  • Cure (eradication of infection, return of joint function and alleviation of symptoms)
  • Palliative approach (may include suppressive antibiotics, joint fusion, and symptom control).

Antibiotic therapy is often necessary but should be delayed until after culture materials (at least joint aspiration culture) are obtained. The exception is in the rare situation of sepsis or overwhelming infection. Empirical antibiotic therapy should be tailored according to the timing of infection. As a general guide, the antibiotic choice should at least provide adequate coverage against Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus (MRSA)), coagulase negative staphylococcus and aerobic gram-negative bacilli. Antibiotics with excellent activity against biofilms such as Rifampin and fluoroquinolones are often included in treatment. Other possible oral antibiotic choices for prosthetic joint infection include minocycline, linezolid, and trimethoprim-sulfamethoxazole.[12][13][14]

Surgical options can be further categorized into five options as follow:

  • Debridement and retention: As the name implies, the implant is left in place, but the joint cavity is debrided with or without removal of the synovial polyethylene lining. This is typically the surgical approach for early prosthetic joint infection provided the implant is stable, symptom duration is less than 3 weeks, there are no sinus tracts, and the isolated pathogen is susceptible to active biofilm antibiotics. Prolonged antibiotics for 3 to 6 months are often necessary (three months for retained hip and 6 months for retained knee joint).
  • One-stage exchange: This is the surgical approach commonly employed in Europe but not the standard of care in the United States. It involves removal of the infected prosthesis and simultaneously replaced with a new one. It is often accompanied by two weeks of intravenous antibiotics followed by 3 to 6 months of oral antibiotics.
  • Two-stage exchange: This is the standard of care in the United States and offers the best chance of cure especially for delayed and late prosthetic joint infections. In its simplified version, it involves complete removal of the infected prosthesis, placement of a joint spacer (which could be antibiotic-impregnated), antibiotic therapy for two to eight weeks, and subsequent placement of a new prosthesis.
  • Implant removal without replacement: This is a reasonable approach for patients with high operative risks or when there is no functional benefit expected by prosthesis exchange. Arthrodesis often accompanies it.
  • Suppressive antibiotic therapy: This is often employed when surgery is not an option, for example, bedridden debilitated patients or those with multiple severe co-morbidities.

Pearls and Other Issues

Two novel methods recently added to the diagnostic armamentarium of prosthetic joint infection include:

  • Sonification: This employs the use of sound energy to agitate particles in a tissue sample with the goal of increasing the yield of culture from the explanted prosthetic material.
  • Synovial fluid Alpha Defensin and leukocyte esterase: These are two markers which can be easily assessed from synovial fluid, and both correlate nicely with the presence of prosthetic joint infection.

Enhancing Healthcare Team Outcomes

The management of a prosthetic joint infection is best done with an interprofessional team consisting of an orthopedic surgeon, infectious disease expert, rehabilitation specialist, nurse and pharmacist. These patients are often left bedridden for long periods, and hence a physical therapy consult is recommended for joint movement and muscle training. A dietary consult may help prevent muscle wasting, and the nurse should ensure that the patient has prophylaxis against deep vein thrombosis and pressure ulcers. The pharmacist should check up on cultures and make sure that the patient is on the right antibiotics. After discharge, most patients need active physical therapy for months to regain joint motion and muscle strength.[15][16][17] (Level V)


There are no large randomized clinical trials on prosthetic joint infections and outcomes are based on small retrospective case series and case reports. The success of the different procedures varies from 0-100%, depending on the severity of the infection, time of treatment, patient co-morbidity and duration of infection. The difficulty in dealing with prosthetic joint infections is whether to remove all the hardware but this also leaves the patient with a disability. Use of spacers has been useful, but it is not the answer to all type of prosthetic joint infections. Overall, good results have been obtained with delayed exchange arthroplasty with success rates ranging from 40-80%. Unfortunately, the majority of patients do have some degree of pain, joint instability and limited use of the joint after an infection.[18][13][19] (Level 5)

  • Contributed by Folusakin Ayoade
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[1] Wagenaar FBM,Löwik CAM,Zahar A,Jutte PC,Gehrke T,Parvizi J, Persistent Wound Drainage After Total Joint Arthroplasty: A Narrative Review. The Journal of arthroplasty. 2018 Sep 3     [PubMed PMID: 30245124]
[2] Beam E,Osmon D, Prosthetic Joint Infection Update. Infectious disease clinics of North America. 2018 Sep 18     [PubMed PMID: 30241717]
[3] Slullitel PA,Oñativia JI,Buttaro MA,Sánchez ML,Comba F,Zanotti G,Piccaluga F, State-of-the-art diagnosis and surgical treatment of acute peri-prosthetic joint infection following primary total hip arthroplasty. EFORT open reviews. 2018 Jul     [PubMed PMID: 30233819]
[4] Wang YP,Chen CF,Chen HP,Wang FD, The incidence rate, trend and microbiological aetiology of prosthetic joint infection after total knee arthroplasty: A 13 years' experience from a tertiary medical center in Taiwan. Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi. 2018 Sep 5     [PubMed PMID: 30228089]
[5] Askar M,Bloch B,Bayston R, Small-colony variant of {i}Staphylococcus lugdunensis{/i} in prosthetic joint infection. Arthroplasty today. 2018 Sep     [PubMed PMID: 30186900]
[6] Premkumar A,Morse K,Levack AE,Bostrom MP,Carli AV, Periprosthetic Joint Infection in Patients with Inflammatory Joint Disease: Prevention and Diagnosis. Current rheumatology reports. 2018 Sep 10     [PubMed PMID: 30203376]
[7] Triffault-Fillit C,Ferry T,Laurent F,Pradat P,Dupieux C,Conrad A,Becker A,Lustig S,Fessy MH,Chidiac C,Valour F, Microbiologic epidemiology depending on time to occurrence of prosthetic joint infection: a prospective cohort study. Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. 2018 May 25     [PubMed PMID: 29803842]
[8] Nair R,Schweizer ML,Singh N, Septic Arthritis and Prosthetic Joint Infections in Older Adults. Infectious disease clinics of North America. 2017 Dec     [PubMed PMID: 29079156]
[9] Dudareva M,Barrett L,Figtree M,Scarborough M,Watanabe M,Newnham R,Wallis R,Oakley S,Kendrick B,Stubbs D,McNally MA,Bejon P,Atkins BA,Taylor A,Brent AJ, Sonication versus tissue sampling for diagnosis of prosthetic joint and other orthopaedic device-related infections. Journal of clinical microbiology. 2018 Sep 12     [PubMed PMID: 30209185]
[10] Stylianakis A,Schinas G,Thomaidis PC,Papaparaskevas J,Ziogas DC,Gamaletsou MN,Daikos GL,Pneumaticos S,Sipsas NV, Combination of conventional culture, vial culture, and broad-range PCR of sonication fluid for the diagnosis of prosthetic joint infection. Diagnostic microbiology and infectious disease. 2018 Sep     [PubMed PMID: 30099992]
[11] Arvieux C,Common H, New Diagnostic Tools for Prosthetic Joint Infection. Orthopaedics     [PubMed PMID: 30056239]
[12] Keely Boyle K,Rachala S,Nodzo SR, Centers for Disease Control and Prevention 2017 Guidelines for Prevention of Surgical Site Infections: Review and Relevant Recommendations. Current reviews in musculoskeletal medicine. 2018 Jun 16     [PubMed PMID: 29909445]
[13] Zaruta DA,Qiu B,Liu AY,Ricciardi BF, Indications and Guidelines for Debridement and Implant Retention for Periprosthetic Hip and Knee Infection. Current reviews in musculoskeletal medicine. 2018 Sep     [PubMed PMID: 29869769]
[14] Sebastian S,Malhotra R,Pande A,Gautam D,Xess I,Dhawan B, Staged Reimplantation of a Total Hip Prosthesis After Co-infection with Candida tropicalis and Staphylococcus haemolyticus: A Case Report. Mycopathologia. 2018 Jun     [PubMed PMID: 28735470]
[15] Chang CY,Chien WC,Chung CH,Tsao CH,Lin FH,Chang FY,Shang ST,Wang YC, Protective effect of N-acetylcysteine in prosthetic joint infection: A nationwide population-based cohort study. Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi. 2018 Sep 12     [PubMed PMID: 30253996]
[16] Suleiman LI,Mesko DR,Nam D, Intraoperative Considerations for Treatment/Prevention of Prosthetic Joint Infection. Current reviews in musculoskeletal medicine. 2018 Jun 23     [PubMed PMID: 29936680]
[17] Marmor S,Kerroumi Y, Patient-specific risk factors for infection in arthroplasty procedure. Orthopaedics     [PubMed PMID: 26867708]
[18] Teo BJX,Yeo W,Chong HC,Tan AHC, Surgical site infection after primary total knee arthroplasty is associated with a longer duration of surgery. Journal of orthopaedic surgery (Hong Kong). 2018 May-Aug     [PubMed PMID: 30010488]
[19] Baert IAC,Lluch E,Van Glabbeek F,Nuyts R,Rufai S,Tuynman J,Struyf F,Meeus M, Short stem total hip arthroplasty: Potential explanations for persistent post-surgical thigh pain. Medical hypotheses. 2017 Sep     [PubMed PMID: 28915961]