Benjamin Zmistowski

New Definition for Periprosthetic Joint Infection: From the Workgroup of the Musculoskeletal Infection Society

Based on the proposed criteria, definite PJI exists when: (1) There is a sinus tract communicating with the prosthesis; or (2) A pathogen is isolated by culture from at least two separate tissue or fluid samples obtained from the affected prosthetic joint; or (3) Four of the following six criteria exist: (a) Elevated serum erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) concentration, (b) Elevated synovial leukocyte count, (c) Elevated synovial neutrophil percentage (PMN%), (d) Presence of purulence in the affected joint, (e) Isolation of a microorganism in one culture of periprosthetic tissue or fluid, or (f) Greater than five neutrophils per high-power field in five high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification. PJI may be present if fewer than four of these criteria are met.

Management of periprosthetic joint infection: the current knowledge: AAOS exhibit selection.

Periprosthetic joint infection continues to frustrate the medical community. Although the demand for total joint arthroplasty is increasing, the burden of such infections is increasing even more rapidly, and they pose a unique challenge because their accurate diagnosis and eradication can prove elusive. This review describes the current knowledge regarding diagnosis and treatment of periprosthetic joint infection. A number of tools are available to aid in establishing a diagnosis of periprosthetic joint infection. These include the erythrocyte sedimentation rate, serum C-reactive protein concentration, synovial white blood-cell count and differential, imaging studies, tissue specimen culturing, and histological analysis. Multiple definitions of periprosthetic joint infection have been proposed but there is no consensus. Tools under investigation to diagnose such infections include the C-reactive protein concentration in the joint fluid, point-of-care strip tests for the leukocyte esterase concentration in the joint fluid, and other molecular markers of periprosthetic joint infection. Treatment options include irrigation and debridement with prosthesis retention, one-stage prosthesis exchange, two-stage prosthesis exchange with intervening placement of an antibiotic-loaded spacer, and salvage treatments such as joint arthrodesis and amputation. Treatment selection is dependent on multiple factors including the timing of the symptom onset, patient health, the infecting organism, and a history of infection in the joint. Although prosthesis retention has the theoretical advantages of decreased morbidity and improved return to function, two-stage exchange provides a lower rate of recurrent infection. As the burden of periprosthetic joint infection increases, the orthopaedic and medical community should become more familiar with the disease. It is hoped that the tools currently under investigation will aid clinicians in diagnosing periprosthetic joint infection in an accurate and timely fashion to allow appropriate treatment. Given the current knowledge and planned future research, the medical community should be prepared to effectively manage this increasingly prevalent disease.

Periprosthetic Joint Infection Increases the Risk of One-Year Mortality

BACKGROUND Periprosthetic joint infection continues to potentially complicate an otherwise successful joint replacement. The treatment of this infection often requires multiple surgical procedures associated with increased complications and morbidity. This study examined the relationship between periprosthetic joint infection and mortality and aimed to determine the effect of periprosthetic joint infection on mortality and any predictors of mortality in patients with periprosthetic joint infection. METHODS Four hundred and thirty-six patients with at least one surgical intervention secondary to confirmed periprosthetic joint infection were compared with 2342 patients undergoing revision arthroplasty for aseptic failure. The incidence of mortality at thirty days, ninety days, one year, two years, and five years after surgery was assessed. Multivariate analysis was used to assess periprosthetic joint infection as an independent predictor of mortality. In the periprosthetic joint infection population, variables investigated as potential risk factors for mortality were evaluated. RESULTS Mortality was significantly greater (p < 0.001) in patients with periprosthetic joint infection compared with those undergoing aseptic revision arthroplasty at ninety days (3.7% versus 0.8%), one year (10.6% versus 2.0%), two years (13.6% versus 3.9%), and five years (25.9% versus 12.9%). After controlling for age, sex, ethnicity, number of procedures, involved joint, body mass index, and Charlson Comorbidity Index, revision arthroplasty for periprosthetic joint infection was associated with a fivefold increase in mortality compared with revision arthroplasty for aseptic failures. In the periprosthetic joint infection population, independent predictors of mortality included increasing age, higher Charlson Comorbidity Index, history of stroke, polymicrobial infections, and cardiac disease. CONCLUSIONS Although it is well known that periprosthetic joint infection is a devastating complication that severely limits joint function and is consistently difficult to eradicate, surgeons must also be cognizant of the systemic impact of periprosthetic joint infection and its major influence on fatal outcome in patients.

The Chitranjan Ranawat Award: Fate of Two-stage Reimplantation After Failed Irrigation and Débridement for Periprosthetic Knee Infection

BackgroundIrrigation and débridement is an attractive low morbidity solution for acute periprosthetic knee infection. However, the failure rate in the literature is high, averaging 68% (range, 61%–82%). Patients who fail subsequently undergo two-stage reimplantation after a prolonged period of illness. This leads to higher surgical risk and further delays in rehabilitation and may contribute to failure of subsequent revision surgery.Questions/purposesWe determined the rerevision rate due to infection after two-stage reimplantation performed for failed irrigation and débridement of infected TKA.MethodsWe performed a multicenter retrospective review of periprosthetic knee infections treated with a two-stage procedure from 1994 to 2008. Selection criteria for the study included initial treatment with irrigation and débridement and subsequent two-stage revision surgery. Failure of two-stage revision was defined as the need for any additional surgery due to infection.ResultsOf the 83 knees that had undergone previous irrigation and débridement, 28 (34%) failed subsequent two-stage revision and required reoperation for persistent infection.ConclusionsThe failure rate in this series of two-stage revisions for periprosthetic knee infection in patients treated with previous irrigation and débridement is considerably higher than previously reported failure rates of two-stage revision. Factors affecting the failure rate may include host quality, thoroughness of débridement, and organism virulence. Patients and surgeons must understand that irrigation and débridement, while initially attractive, may lead to high failure rates of subsequent two-stage reimplantation.Level of EvidenceLevel III, therapeutic study. See the guidelines online for a complete description of level of evidence.

Definition of periprosthetic joint infection: is there a consensus?

BackgroundThe diagnosis of periprosthetic joint infection (PJI) continues to pose a challenge. While many diagnostic criteria have been proposed, a gold standard for diagnosis is lacking. Use of multiple diagnostic criteria within the joint arthroplasty community raises concerns in patient treatment and comparison of research pertaining to PJI.Questions/purposesWe (1) determined the variation in existing diagnostic criteria, (2) compared the existing criteria to a proposed new set of criteria that incorporates aspirate cell count analysis, and (3) investigated the variations between the existing criteria and the proposed criteria.Patients and MethodsWe retrospectively identified 182 patients undergoing 192 revision knee arthroplasties who had a preoperative joint aspiration analysis at our institution between April 2002 and November 2009. We excluded 20 cases due to insufficient laboratory parameters, leaving 172 cases for analysis. We applied six previously published sets of diagnostic criteria for PJI to determine the variation in its incidence using each set of criteria. We then compared these diagnostic criteria to our proposed new criteria and investigated cases where disagreement occurred.ResultsWe identified 41 cases (24%) in which at least one established criteria set classified the case as infected while at least one other criteria set classified the case as uninfected. With our proposed criteria, the infected/uninfected ratio was 92/80. The proposed criteria had a large variance in sensitivity (54%–100%), specificity (39%–100%), and accuracy (53%–100%) when using each of the established criteria sets as the reference standard.ConclusionsThe discrepancy between definitions of infection complicates interpretation of the literature and the treatment of failed TKAs owing to PJI. Based on our findings, we suggest establishing a common set of diagnostic criteria utilizing aspirate analysis to improve the treatment of PJI and facilitate interpretation of the literature.Level of Evidence Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Prosthetic joint infection caused by gram-negative organisms.

Traditionally, periprosthetic joint infections (PJIs) due to gram-negative organisms are considered more difficult to manage; however, little literature exists with regard to outcome of PJI caused by gram-negative organisms. We identified 277 patients with 282 culture-positive PJI receiving surgical treatment. Thirty-one joints were treated for gram-negative PJI. The gram-negative group was then compared with the gram-positive and polymicrobial PJI. A single debridement and retention of prosthesis were successful in 70% (7/10) of isolated gram negative compared with 33.3% (13/39) of methicillin-sensitive gram positive, 48.9% (23/47) of methicillin-resistant gram positive, and 57.1% (4/7) of polymicrobial. Of those patients undergoing a planned 2-stage exchange, a successful reimplantation was performed in 52% (12/23) of gram-negative, 51% (52/103) of methicillin-resistant gram-positive, 69% (65/94) of methicillin-sensitive gram-positive, and 0% (0/8) of polymicrobial PJI cases. These results indicate that PJI due to gram-negative pathogens, although less common, is difficult to treat and is associated with limited success.

Diagnosis of periprosthetic joint infection

Liaison: Benjamin Zmistowski BS Leaders: Craig Della Valle MD (US), Thomas W Bauer MD (US), Konstantinos N. Malizos MD, PhD (International) Delegates: Abbas Alavi MD, Hani Bedair MD, Robert E Booth MD, Peter Choong MD, Carl Deirmengian MD, Garth D Ehrlich PhD, Anil Gambir MD, Ronald Huang MD, Yair Kissin MD, Hideo Kobayashi MD, Naomi Kobayashi MD, Veit Krenn MD, Drago Lorenzo MD, SB Marston MD, Geert Meermans MD, Javier Perez MD, JJ Ploegmakers MD, Aaron Rosenberg MD, C Simpfendorfer MD, Peter Thomas MD, Stephan Tohtz MD, Jorge A Villafuerte MD, Peter Wahl MD, Frank-Christiaan Wagenaar MD, Eivind Witzo MD

Periprosthetic joint infection diagnosis: a complete understanding of white blood cell count and differential.

Recent research has raised doubts regarding the utility of serum white blood cell count (WBC) for diagnosis of periprosthetic joint infection (PJI). As synovial WBC and neutrophil (PMN) percentage have been adopted as accurate markers of PJI, this study investigated the correlation of WBC in serum versus joint fluid and diagnostic value of all WBC levels for failed arthroplasty patients. 153 patients (73 PJI) undergoing revision knee arthroplasty were identified. Weak correlations between joint fluid and serum for WBC (R = 0.19), PMN count (R = 0.31), and lymphocyte count (R = -0.22) were observed. Diagnostic accuracy of PMN (93%) and WBC (93%) synovial count relative to serum was similar to synovial WBC (93%) and PMN% (95%) alone. Serum WBC analysis does little to improve the accurate diagnosis of PJI.

Management of Acetabular Bone Loss in Revision Total Hip Arthroplasty

Most acetabular revisions can be managed with a hemispherical component with screw fixation. Areas of segmental bone loss that preclude acetabular component stability may be managed with structural allograft or second-generation porous metal augments. Acetabular cages have a limited application but can be a useful tool in the management of massive bone loss and pelvic discontinuity.

Recurrent periprosthetic joint infection: persistent or new infection?

It is unclear if recurrent periprosthetic joint infection (PJI) is a result of failed pathogen eradication. This study addresses this issue. We identified 92 patients from three institutions who failed two-stage exchange. Cultured organisms at each stage of treatment were compared to determine whether these were persistent or new infections. Only twenty-nine of the 92 patients (31.5%) had identical organisms at treatment failure. Of the failures associated with Staphylococcus as the original infecting organism, 37% (25 of 67) failed due to the same organism compared to only 16% (four of 25) caused by other organisms. Positive cultures at reimplantation and poor health status were associated with higher rates of recurrent infection due to new organisms. Successful management of PJI with a two-stage exchange must stress minimization of comorbid risk factors that may contribute to the low success rate of PJI treatment and recurrence of infection.