Functional Composite Spacer (Antibiotic Cement around a Hemiarthroplasty) for the Treatment of Shoulder Infections: Minimum 5-Year Outcomes.

BACKGROUND: Periprosthetic infections remain a challenging complication following shoulder arthroplasty and an ideal treatment protocol has yet to be established. Two-stage revision is a common approach. Historically, the first stage entails placement of an all-cement antibiotic spacer. While prior studies have reported on cement spacers as definitive management, persistent pain and inadequate function often lead many to later request a second stage procedure. The functional composite spacer consists of a humeral hemiarthroplasty implant with antibiotic cement coated around the stem alone to preserve the metallic humeral head-glenoid articulation. Functional composite spacers have demonstrated improvements in function and motion with high patient satisfaction at 25 months, but longer-term follow-up is needed to better understand the role it may play in the management of shoulder infections. The purpose of this study is to evaluate outcomes at a minimum of 5 years in patients who initially planned to undergo two-stage revision but elected to retain the functional spacer. METHODS: A retrospective review of a single institution's shoulder surgery repository from 2007 to 2018 identified 30 patients who underwent placement of a composite spacer. Overall, 5 patients underwent second stage reimplantation and 12 patients did not have 5-year follow-up (6 lost to follow-up and 6 deceased). A total 13 patients were included who maintained a functional composite spacer and had minimum 5-year follow-up. Patient-reported outcome measures (ASES, SST, SANE, VAS F and VAS P), satisfaction, range of motion, and radiographic estimation of glenoid wear were evaluated. RESULTS: Two of 13 patients (15%) required additional surgery: one secondary closure for early superficial wound dehiscence and one revision spacer for pain. There were no re-infections. At most recent follow-up patient satisfaction was high and significant improvements were noted for ASES (45.4; p<0.001), SST (5.3; p=0.003), SANE (47.3; p=0.002), VAS F (4.9; p=0.004), and VAS P (-4.4; p=0.007) as well as range of motion including abduction (39.2˚; p=0.005) and elevation (65.9˚; p=0.005). There was no significant change in humeral head medialization (p=0.11). CONCLUSIONS: Patients who do not undergo an early revision and retain a functional composite spacer maintain good function and range of motion with minimal pain at mid-term follow-up.

Revision Surgery for Shoulder Infection after Arthroscopic Rotator Cuff Repair: Functional Outcomes and Eradication Rate-A Systematic Review.

The outcomes after arthroscopic rotator cuff repair (RCR) have been reported to be successful. The incidence of deep infections (defined as an infection involving any part of the anatomy other than the skin and subcutaneous tissue) after surgery ranges between 0.03% and 3.4%. This systematic review aims to investigate the outcomes of revision surgery for infection following arthroscopic RCR. Clinical outcomes and eradication rates among patients treated with different surgical and antibiotic therapies are analyzed. A total of five studies were eligible for systematic review. A total of 146 patients were treated and evaluated, of whom 71 (48%) and 75 (52%) underwent arthroscopic and open surgery to manage the infection, respectively. The most common causative bacterium was Cutibacterium acnes (50.4%). Two studies reported the pre-and postoperative ASES score and Constant-Murley score (CMS), and a statistically significant improvement was found after surgery (p < 0.001 for both). Eradication was observed in a total of 138 patients (94.5%); no difference was found between arthroscopic and open revision surgery (92.8% and 96%, respectively, p = 0.90). The frequency-weighted mean duration of the intravenous antibiotic therapy was 6.6 ± 5.4 days, while the overall mean duration of antibiotic therapy, considering intravenous and oral administration, was 43.5 ± 40 days. Patients with infection following arthroscopic RCR undergoing revision surgery experienced a high rate of eradication. A significant improvement in shoulder functionality and less residual pain can be expected.

The predictive value and reliability of ultrasound-guided synovial aspiration and biopsies for diagnosing periprosthetic shoulder infections.

INTRODUCTION: Preoperative diagnosis of periprosthetic shoulder infections (PSI) is difficult. Infections are mostly caused by low virulence bacteria and patients do not show typical signs of infection. The aim of this study was to determine the diagnostic value and reliability of ultrasound-guided biopsies for cultures alone and in combination with multiplex polymerase chain reaction (mPCR), serum markers, and/or synovial markers for the preoperative diagnosis of PSI in patients undergoing revision shoulder surgery. MATERIALS AND METHODS: A prospective explorative diagnostic cohort study was performed including 55 patients undergoing revision shoulder replacement surgery. A shoulder puncture was performed preoperatively before incision to collect synovial fluid for mPCR analysis and for measurement of interleukin-6, calprotectin, white blood cell count (WBC), and polymorphonuclear cells. Also prior to revision surgery, six ultrasound-guided synovial tissue biopsies were collected for culture and two for mPCR analysis. A blood sample was obtained to determine serum C-reactive protein, WBC, and erythrocyte sedimentation rate. Six routine care tissue biopsies were taken during revision surgery and served as reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV; the primary outcome measure), and accuracy were calculated for ultrasound-guided biopsies, blood and synovial markers, mPCR, and combinations thereof. RESULTS: Routine tissue cultures were positive for infection in 24 patients. Cultures from ultrasound-guided biopsies diagnosed infection in 7 of these patients, yielding a sensitivity, specificity, PPV, NPV, and accuracy of 29.2%, 93.5%, 77.8%, 63.0%, and 65.6%, respectively. The best diagnostic value was found for the combination of ultrasound-guided biopsies for culture, synovial WBC, and calprotectin with a sensitivity of 69.2%, specificity of 80.0%, PPV of 69.2%, and NPV of 80.0%. CONCLUSION: Ultrasound-guided biopsies for cultures alone and in combination with mPCR, and/or blood and/or synovial markers are not reliable enough to use in clinical practice for the preoperative diagnosis of PSI. LEVEL OF EVIDENCE: Diagnostic study level II.

One- vs. Two-Stage Revision for Periprosthetic Shoulder Infections: A Systematic Review and Meta-Analysis.

Periprosthetic shoulder infection (PSI) remains a challenging complication after shoulder arthroplasty. Therapeutic options include one- or two-stage revision, irrigation and debridement, and resection arthroplasty. With our systematic review and meta-analysis, we aimed to compare one- and two-stage revisions for periprosthetic shoulder joint infections and determine the most appropriate therapeutic procedure. We performed an extensive literature search in PubMed, Ovid Medline, Cochrane Library, Web of Science, and CINAHL and filtered out all relevant studies. The meta-analysis was performed using the random-effects model, heterogeneity was analyzed using I2, and publication bias was assessed using the Egger's test. A total of 8 studies with one-stage revisions, 36 studies with two-stage revisions, and 12 studies with both one-stage and two-stage revisions were included. According to the random-effects model, the reinfection rate for the entirety of the studies was 12.3% (95% Cl: 9.6-15.3), with a low-to-moderate heterogeneity of I2 = 47.72%. The reinfection rate of the one-stage revisions was 10.9%, which was significantly lower than the reinfection rate of the two-stage revisions, which was 12.93% (p = 0.0062). The one-stage revision rate was significantly lower with 1.16 vs. 2.25 revisions in the two-stage revision group (p < 0.0001). The postoperative functional outcome in one-stage-revised patients was comparable but not statistically significant (p = 0.1523). In one- and two-stage revisions, most infections were caused by Cutibacterium acnes. In summary, our systematic review and meta-analysis show the superiority of single-stage revision regarding reinfection and revision rates in periprosthetic shoulder joint infection.

Transcutaneous compression suture with iodine gauze for wound closure in revision surgery for therapy-resistant periprosthetic shoulder infections.

Background: To successfully treat a periprosthetic infection, successful bacteria eradication and successful wound closure are mandatory. Despite adequate surgical débridement in the deep, persistence of wound drainage and subsequent persistence of periprosthetic infection may occur, especially in patients with compromised soft tissue conditions. This study presents a transcutaneous compression suture technique with iodine gauze that was used in patients with persistent wound secretion in therapy-resistant periprosthetic shoulder infections in order to achieve successful infection control and wound healing. Methods: All patients with persistent periprosthetic or implant-associated shoulder joint infections despite correct previous surgical and antibiotic therapy attempts were included in the study. In all patients, in addition to repeat deep surgical débridement, a transcutaneous "iodine-gauze-compression-suture" was performed with postoperative antibiotic therapy. The primary endpoint was infection control; the secondary endpoint was wound healing rate; and the third endpoint was complication rate after index surgery. Results: Ten consecutive patients with a mean age of 74 (±7.6) years and a mean follow-up of 14 (±2) months were included. All ten patients showed infection control and successful wound healing, with no need for further revision surgery. In 8 out of 10 patients, the wound healing was fast and completely uncomplicated. Two out of 10 patients showed delayed wound healing with fibrin coatings for 3 and 4 weeks, respectively. No additional intervention was necessary in both patients. Conclusions: Transcutaneous iodine gauze compression sutures were used to achieve successful infection control without additional revision surgery in 10 out of 10 patients who previously underwent surgery with failed infection control. This wound closure technique is a reliable adjunctive therapy method in the treatment of implant-associated infections of the shoulder in patients with fragile wound conditions.

Serratia marcescens prosthetic joint infection: two case reports and a review of the literature.

BACKGROUND: Despite some studies on Gram-negative bacteria as difficult to treat pathogens in periprosthetic joint infections, there are no detailed analyses on Serratia periprosthetic joint infections. As such, we present two cases of Serratia periprosthetic joint infections and summarize all known cases to date in the course of a PRISMA criteria-based systematic review. CASE PRESENTATION: Case 1: a 72-year-old Caucasian female with Parkinson's disease and treated breast cancer developed periprosthetic joint infection caused by Serratia marcescens and Bacillus cereus, following multiple prior revisions for recurrent dislocations of her total hip arthroplasty. Two-stage exchange was performed, and the patient remained free of Serratia periprosthetic joint infection recurrence at 3 years. Case 2: an 82-year-old Caucasian female with diabetes and chronic obstructive pulmonary disease presented with a chronic parapatellar knee fistula after undergoing multiple failed infection treatments at external clinics. After performing two-stage exchange and gastrocnemius flap plastic for combined Serratia marcescens and Proteus mirabilis periprosthetic joint infection, the patient was released without any signs of infection, but was subsequently lost to follow-up. REVIEW: a total of 12 additional Serratia periprosthetic joint infections were identified. Merged with our two cases, the mean age of 14 patients was 66 years and 75% were males. Mean length of antibiotic therapy was 10 weeks with ciprofloxacin most commonly used (50%). Mean follow-up was 23 months. There was a total of four reinfections (29%), including one case of Serratia reinfection (7%). CONCLUSIONS: Serratia is a rare cause of periprosthetic joint infection affecting elderly with secondary diseases. While the overall reinfection rate was high, the risk of Serratia periprosthetic joint infection persistence was low. Treatment failure in patients may be attributable to the host, rather than the Serratia periprosthetic joint infection itself, thus challenging current concepts on Gram-negatives as a uniform class of difficult-to-treat pathogens. LEVEL OF EVIDENCE: Therapeutic level IV.

Surgical Treatment of Shoulder Infection Following Rotator Cuff Repair.

Background: Deep infection after rotator cuff repair (RCR) can cause significant morbidity and healthcare burden. Outcomes of surgical treatment of infection following RCR are limited. This study aimed to assess the clinical course and outcomes related to surgical management of deep infection following RCR. Methods: Patients treated with debridement for infection after RCR at a single institution were included. Postoperative deep infection included the following criteria: persistent drainage more than five days from index surgery, development of a sinus tract to the joint, ≥ 2 positive cultures at the time of revision surgery with the same bacteria, or presence of purulence. Functional outcomes (ASES, SANE, SF-12) were assessed at a minimum of 1-year post-debridement. Results: Twenty-three patients were included and analyzed at mean six years post-debridement. All were free of infection at the final follow-up. The average age was 55 years; fifteen (65.2%) had infection after primary RCR and eight (34.8%) after revision RCR. Twelve (52.2%) patients required a repeat debridement prior to eradicating infection for an average of 1.9 surgeries before clearance of infection. Statistically significant predictors of need for a repeat debridement included initial open RCR (P = .02), open debridement (P = .002) and infection requiring IV antibiotics (P = .014). Postoperative ASES, SANE, SF-12M, SF-12P, and satisfaction scores were 71.7±25.7, 67.0±28.1, 55.5±6.5, 38.4±14.3 and 3.7±1.3, respectively. Conclusion: Deep infection after RCR can be treated with open or arthroscopic debridement. However, more than 50% of patients may require multiple debridements. Final functional results after infection control following RCR are satisfactory. However, chronic infection predicts worse functional outcomes.

Corynebacterium periprosthetic joint infection: a systematic review of 52 cases at 2.5 years follow-up.

INTRODUCTION: While large progress has been achieved in identifying and treating the most common pathogens involved in periprosthetic joint infections (PJI), there remains limited knowledge on atypical pathogens such as Corynebacterium. For that reason, we analyzed infection and diagnostical characteristics, as well as treatment outcome in Corynebacterium PJI. METHODS: A systematic review was performed based on a structured PubMed and Cochrane Library analysis using the PRISMA algorithm. The search was performed by 2 independent reviewers, and articles from 1960 to 2022 considered eligible for inclusion. Out of 370 search results, 12 studies were included for study synthesis. RESULTS: In total, 52 cases of Corynebacterium PJI were identified (31 knees, 16 hips, 4 elbows, 1 shoulder). Mean age was 65 years, with 53% females, and a mean Charlson Comorbidity Index of 3.9. The most common species was Corynebacterium striatum in 37 cases (71%). Most patients were treated with two-stage exchange (40%), isolated irrigation and debridement (21%), and resection arthroplasty (19%). Mean duration of antibiotic treatment was 8.5 weeks. At a mean follow-up of 2.5 years, there were 18 reinfections (33%), and 39% were for Corynebacterium. Initial infection by Corynebacterium striatum species was predictive of reoperation (p = 0.035) and reinfection (p = 0.07). CONCLUSION: Corynebacterium PJI affects multimorbid and elderly patients, with one in three developing a reinfection at short term. Importantly, the relative majority of reinfections was for persistent Corynebacterium PJI.

Shoulder periprosthetic joint infection is associated with increased mortality.

BACKGROUND: Periprosthetic joint infections (PJIs) are a catastrophic complication after shoulder arthroplasty and may be associated with an increased mortality risk, as seen in hip and knee arthroplasty. Shoulder PJI organisms differ from hip and knee infections, as lower-virulence organisms, such as Cutibacterium acnes, are more commonly encountered. This study evaluated the association between shoulder PJI and mortality. METHODS: We retrospectively identified 411 patients who underwent revision shoulder arthroplasty from 2007 to 2020 at a single institution. 2018 International Consensus Meeting on Musculoskeletal Infection criteria were used to categorize each case as definite, probable, possible, or unlikely PJI. Mortality rate was assessed by performing chart reviews and an obituary search. Revision cases were grouped into a septic cohort (definite and probable PJI) and an aseptic cohort (possible and unlikely PJI). Kaplan-Meier analyses were performed to compare survival between septic and aseptic groups. The log-rank test was used to compare cumulative survival distributions and survival rates at 90 days, 6 months, 1 year, 2 years, and 5 years. Demographic information, Charlson Comorbidity Index (CCI), and culture data were collected. PJI organisms were categorized as virulent or nonvirulent per an infectious disease specialist, and predictors of mortality were determined by performing stepwise logistic regression analyses. RESULTS: The overall mortality rate was significantly greater (P < .001) in the septic group (20.5%) than in the aseptic group (6.6%). When evaluating time from revision surgery to death, patients with PJI had significantly greater mortality compared with those undergoing aseptic revision at 2 years (7.7% vs. 2.1%, P = .01) and 5 years (17% vs. 5.1%, P < .001). Body mass index, CCI, race, sex, and age were not significantly different between groups. Groups differed in utilization of 2-staged procedures (65% septic, 9% aseptic, P < .001). Multivariate regression analysis found that the variables most associated with mortality were septic revision, 2-staged procedures, and CCI. In the septic group, patients with C acnes PJI had a significantly lower mortality rate when compared to PJI from any other offending organism (3.1% vs. 48.4%, P = .001). CONCLUSION: Revision shoulder arthroplasty in the setting of PJI not only carries severe functional consequences for patients but is also associated with an increased mortality risk. Furthermore, C acnes infections are associated with a more favorable survival profile than PJI resulting from other organisms. Continued efforts to decrease shoulder arthroplasty infection rates are warranted and may influence long-term survival.

Two-stage shoulder arthroplasty after deep infection of the shoulder caused by arthroplasty, osteosynthesis or other surgical procedures: microbial spectrum, complications and functional outcome after at least 1 year follow-up.

PURPOSE: Infection represents probably the most challenging complication in shoulder arthroplasty and all other surgical procedures of the shoulder. A deep infection of the shoulder is often combined with a destruction of the joint and a loss of function. In many cases the arthroplasty is the last resort for these patients to obtain a satisfactory function. The objective of this study was to determine outcome data on microbiota and clinical results of a two-stage shoulder arthroplasty procedure after deep infection of the shoulder. METHODS: Twenty-six patients with a deep shoulder infection after arthroplasty, osteosynthesis, or rotator-cuff repair were included, while two patients had an empyema without prior surgery. All underwent initial surgical debridement with implantation of an antibiotic-loaded spacer, followed by postoperative systemic antibiotics. The patients obtained definitive shoulder arthroplasty in a second surgery. None of the patients had to undergo more than two surgeries before the arthroplasty. The follow-up analysis including microbiota results, complication rates, and functional outcomes could be determined after at least 1 year in 60% of patients (n = 16). RESULTS: The most frequently detected microorganisms were S. epidermidis (31%, n = 10) and Cutibacterium acnes (19%, n = 6). In 28% (n = 9) of cases multi-drug resistant bacteria were detected and in 35% (n = 8) of cases more than one microorganism was found. The overall revision rate was 42%, 11 of 26 patients, in the first 8 weeks after arthroplasty. Reasons for revision were joint dislocations in 23% (n = 6), 15% (n = 4) postoperative hematomas, one (4%) re-infection and one (4%) periprosthetic fracture. At follow-up after 19.3 ± 5.5 months postoperatively, a mean abduction of 113.4°, anteversion of 122.8° and external rotation of 14° was found, with an average age and gender-adjusted Constant Score of the affected shoulder of 63. The subjects' pain and impairment in normal life measured by a questionnaire with school grades were significantly reduced (p < 0.05) as compared to prior shoulder arthroplasty. CONCLUSION: The most relevant bacteria in the study cohort were Staphylococcus subspecies and to a lower extent Cutibacterium acnes. A high number of multi-drug resistant and mixed microbiota spectra were detected, defining a need to adapt therapeutic regimen targeting these microbiotas. The two-stage shoulder arthroplasty after a deep infection resulted in excellent infection control with however high early postoperative rates for joint dislocation (23%) and hematomas (15%). At follow-up a stable joint was achieved with a sufficient functional outcome and satisfying outcome for activities of daily living and pain. CLINICAL TRIAL: Trial registration number: DRKS00016927, date of registration: 2019/03/19.

The role of serum D-Dimer for the diagnosis of periprosthetic shoulder infection.

INTRODUCTION: D-Dimer was recently identified as an additional biomarker in the diagnosis of hip and knee periprosthetic joint infection (PJI). Currently, there is only one study in literature dealing with the role of D-Dimer in the diagnosis of shoulder PJI. The purpose of this study was, therefore, to validate the sensitivity and specificity of D-Dimer in detecting shoulder PJI. MATERIALS AND METHODS: All patients, who underwent septic or aseptic revision shoulder arthroplasty in our institution between November 2018 und March 2021, were analyzed. Our cohort consisted of 30 patients, of that 14 (47%) had a shoulder PJI according the last proposed criteria of the International Consensus Meeting. The diagnostic validity of serum D-Dimer regarding the detection of PJI was analyzed. RESULTS: The mean D-Dimer level was significantly higher for the patients with shoulder PJI compared to patients with aseptic failure (1.44 ± 1 mg/l vs. 0.76 ± 0.6 mg/l, p = 0.025). Coagulase-negative staphylococci were the most commonly isolated pathogens, in 9/14 patients (64%), followed by Cutibacterium acnes in 5/14 patients (36%). According to the ROC analysis, a serum D-Dimer threshold of 0.75 mg/l had a sensitivity of 86% and a specificity of 56% for detection of a shoulder PJI. The area under curve was 0.74. A serum C-reactive protein (CRP) cutoff of 10 mg/l showed a sensitivity of 69% and a specificity of 88%. When both serum D-Dimer and CRP above the thresholds of 0.75 mg/l and 10 mg/l, respectively, were used to identify a PJI the sensitivity and specificity were 57% and 100%, respectively. CONCLUSIONS: Serum D-Dimer showed a good sensitivity but a poor specificity for the diagnosis of shoulder PJI. Combination D-Dimer and CRP led to improvement of the specificity, however, at the cost of sensitivity. Thus, combination of both methods may be used as a confirmatory test in the diagnosis of shoulder PJI but not to rule out infection. LEVEL OF EVIDENCE: Diagnostic level II.

What is the concordance rate of preoperative synovial fluid aspiration and intraoperative biopsy in detecting periprosthetic joint infection of the shoulder?

BACKGROUND: The accuracy of preoperative synovial fluid culture for microbe detection in shoulder periprosthetic joint infection (PJI) is poorly described. To evaluate the utility of preoperative culture data for early pathogen identification for shoulder PJI, we determined the concordance between preoperative synovial fluid culture results and intraoperative tissue culture results. METHODS: Fifty patients who met the 2014 Musculoskeletal Infection Society criteria for shoulder PJI between January 2016 and December 2019 were retrospectively reviewed for clinical and demographic data. This cohort of patients was divided into 2 groups based on the concordance between preoperative and intraoperative culture results. The pathogens identified on preoperative and intraoperative cultures were classified as high-virulence or low-virulence. Student's t tests and Mann-Whitney U tests were used as appropriate for continuous variables, and χ2 and Fisher's exact tests were used as appropriate for categorical variables. RESULTS: Concordance between preoperative aspiration and intraoperative tissue culture was identified in 28 of 50 patients (56%). Preoperative cultures positive for Gram-positive species were more likely to be concordant than discordant (P = .015). Preoperative cultures positive for Cutibacterium acnes were more likely to be concordant with intraoperative cultures (P = .022). There were more patients with polymicrobial infection in the discordant group compared with the concordant group (P < .001). No statistically significant correlation between the preoperative serum C-reactive protein level and the intraoperative category of bacteria was reported. Staphylococcus aureus and coagulase-negative Staphylococci were associated with high specificity and negative predictive value. Preoperative cultures positive for C. acnes demonstrated sensitivity, specificity, positive predictive value, and negative predictive value lower than 0.8. Gram-negative pathogens demonstrated the highest sensitivity (1) and specificity (1), whereas polymicrobial infections exhibited the lowest sensitivity and positive predictive value. CONCLUSION: Preoperative synovial fluid aspiration for shoulder PJI poorly predicts intraoperative culture results, with a discordance of 44%. More favorable concordance was observed for monomicrobial preoperative cultures, particularly for Gram-negative organisms and methicillin-sensitive S. aureus. The overall high rate of discordance between preoperative and intraoperative culture may prompt surgeons to base medical and surgical management on patient history and other factors and avoid relying solely on preoperative synovial fluid culture data.

Manual wheelchair use leads to a series of failed shoulder replacements: A case report and literature review.

Manual wheelchair users place high stress on their shoulders. We describe a 69-year-old male who developed end-stage shoulder osteoarthritis from chronic manual wheelchair (MW) use. Three prosthetic total shoulder replacements failed, reflecting his refusal to transition to an electric wheelchair. MW use must be avoided in some of these patients.

Culturing explants for Cutibacterium at revision shoulder arthroplasty: an analysis of explant and tissue samples at corresponding anatomic sites.

BACKGROUND: Culturing of deep tissues obtained at revision arthroplasty for Cutibacterium is a key component of diagnosing a periprosthetic infection. The value of culturing explanted components has not been well described. This study sought to answer the following questions: (1) How does the culture positivity of explant cultures compare with that of deep tissue cultures? (2) How often are explant cultures positive when tissue cultures are not, and vice versa? (3) How does the bacterial density in explant cultures compare with that in tissue cultures? METHODS: A total of 106 anatomic arthroplasties revised over a 7-year period were included. Explant (humeral head, humeral stem, and glenoid) and tissue (collar membrane, humeral canal tissue, and periglenoid tissue) specimens were sent for semiquantitative Cutibacterium culture. We compared culture positivity and bacterial density when cultures of an explant and tissue adjacent to the implant were both available. RESULTS: Explants had positive cultures at a higher rate than adjacent tissue specimens for most anatomic sites. Of the shoulders that had Cutibacterium growth, a higher proportion of explants were culture positive when tissue samples were negative (23%-43%) than vice versa (0%-21%). The Cutibacterium density was higher in explants than in tissues. Considering only the results of tissue samples, 16% of the shoulders met our threshold for infection treatment (≥2 positive cultures); however, with the inclusion of the results for explant cultures, additional 14% of cases-a total of 30%-met the criteria for infection treatment. CONCLUSIONS: In this group of patients, culturing explants in addition to tissue cultures increased the sensitivity for detecting Cutibacterium in revision shoulder arthroplasty.

What do positive and negative Cutibacterium culture results in periprosthetic shoulder infection mean? A multi-institutional control study.

BACKGROUND: Deep tissue culture specimens obtained at the time of revision shoulder arthroplasty are commonly positive for Cutibacterium. Clinical interpretation of positive cultures can be difficult. This was a multi-institutional study evaluating the accuracy of cultures for Cutibacterium using positive control (PC) and negative control (NC) samples. The relationship between time to culture positivity and strength of culture positivity was also studied. METHODS: Eleven different institutions were each sent 12 blinded samples (10 PC and 2 NC samples). The 10 PC samples included 2 sets of 5 different dilutions of a Cutibacterium isolate from a failed total shoulder arthroplasty with a probable periprosthetic infection. At each institution, the samples were handled as if they were received from the operating room. Specimen growth, time to culture positivity, and strength of culture positivity (based on semiquantitative assessment) were reported. RESULTS: A total of 110 PC samples and 22 NC samples were tested. One hundred percent of specimens at the 4 highest dilutions were positive for Cutibacterium. At the lowest dilution, 91% of samples showed positive findings. Cutibacterium grew in 14% of NC samples. Cutibacterium grew in PC samples at an average of 4.0 ± 1.3 days, and all of these samples showed growth within 7 days. The time to positivity was significantly shorter (P < .001) and the strength of positivity was significantly higher (P < .001) in true-positive cultures compared with false-positive cultures. CONCLUSIONS: This multi-institutional study suggests that different institutions may report highly consistent rates of culture positivity for revision shoulder arthroplasty samples with higher bacterial loads. In contrast, with lower bacterial loads, the results are somewhat less consistent. Clinicians should consider using a shorter time to positivity and a higher strength of positivity as adjuncts in determining whether a tissue culture sample is a true positive.

The role of serum C-reactive protein in the diagnosis of periprosthetic shoulder infection.

INTRODUCTION: There is a paucity of literature regarding serum C-reactive protein (CRP) in the evaluation of a shoulder periprosthetic joint infection (PJI). The purpose of the current study was to establish cutoff values for diagnosing shoulder PJI and evaluate the influence of the type of infecting microorganism and the classification subgroups according to last proposed International Consensus Meeting (ICM) criteria on the CRP level. MATERIALS AND METHODS: A retrospective analysis of all 136 patients, who underwent septic or aseptic revision shoulder arthroplasty in our institution between January 2010 and December 2019, was performed. Shoulder PJI was defined according to the last proposed definition criteria of the ICM. Serum CRP levels were compared between infected and non-infected cases, between infection subgroups, as well as between different species of infecting microorganisms. A receiver-operating characteristic (ROC) analysis was performed to display sensitivity and specificity of serum CRP level for shoulder PJI. RESULTS: A total of 52 patients (38%) were classified as infected, 18 meeting the criteria for definitive infection, 26 for probable infection and 8 for possible infection. According to the ROC curve, an optimized serum CRP threshold of 7.2 mg/l had a sensitivity of 69% and specificity of 74% (area under curve = 0.72). Patients with definitive infection group demonstrated significantly higher median serum CRP levels (24.3 mg/l), when compared to probable, possible infection groups and PJI unlikely group (8 mg/l, 8.3 mg/l, 3.6 mg/l, respectively, p < 0.05). The most common isolated microorganism was Cutibacterium acnes in 25 patients (48%) followed by coagulase-negative staphylococci (CNS) in 20 patients (39%). Patients with a PJI caused by high-virulent microorganisms had a significantly higher median serum CRP level compared to patients with PJI caused by low-virulent microorganisms (48 mg/l vs. 11.3 mg/l, p = 0.04). CONCLUSIONS: Serum CRP showed a low sensitivity and specificity for the diagnosis of shoulder PJI, even applying cutoffs optimized by receiver-operating curve analysis. Low-virulent microorganisms and patients with probable and possible infections are associated with lower CRP levels compared to patients with definitive infection and infections caused by high-virulent microorganisms. LEVEL OF EVIDENCE: Diagnostic Level III.

Efficacy of antimicrobial washes before shoulder surgery against Cutibacterium: a systematic review and meta-analysis.

Background: Cutibacterium acnes is a commensal intradermal microorganism that is commonly isolated at revision shoulder arthroplasty. Standard practice chlorhexidine gluconate (CHG) skin preparation agents have limited effectiveness at eradicating C. acnes in the dermis. Benzoyl peroxide (BPO) has demonstrated effectiveness against C. acnes. This meta-analysis compares the efficacy of at-home shoulder decolonization before surgery using CHG vs. BPO to reduce shoulder C. acnes burden. Methods: This was a Preferred Reporting Items for Systematic Reviews and Meta-Analyses systematic review. PubMed and MEDLINE databases were searched for studies evaluating the effects of CHG and BPO in reducing C. acnes at the shoulder. Trial results were extracted and pooled using a random effects model, separating data from randomized controlled trials (RCTs) and non-RCTs. Methodologic quality of studies was assessed using the Cochrane Risk of Bias Assessment Tools. Results: Ten studies (589 patients) were included. RCTs showed that both BPO and CHG led to significant reductions in culture positivity compared with negative controls (risk ratio [RR] with 95% confidence interval [CI] = 0.20 [0.13, 0.30], P < .0001 and 0.46 [0.37, 0.57], P < .0001, respectively). Non-RCT data demonstrated similar results comparing BPO and CHG to the control (RR with 95% CI = 0.34 [0.21, 0.57], P < .0001 and 0.31 [0.20, 0.49], P < .0001, respectively). Comparing BPO and CHG, RCT data showed a significant reduction in culture positivity with BPO (RR with 95% CI = 0.46 [0.27, 0.77], P < .009). Of RCTs, 5 were low and one was of moderate risk of bias. Of non-RCTs, 3 had low risk of bias, whereas one had moderate risk of bias. Conclusion: This review demonstrated that preoperative CHG and BPO can reduce C. acnes at the shoulder. However, BPO exhibits greater efficacy than CHG, potentially because of the compound's ability to penetrate the dermis. BPO is a simple and economical agent that may reduce joint exposure to C. acnes in shoulder surgery.

Cutibacterium recovered from deep specimens at the time of revision shoulder arthroplasty samples has increased biofilm-forming capacity and hemolytic activity compared with Cutibacterium skin isolates from normal subjects.

BACKGROUND: Biofilm formation and hemolytic activity are factors that may correlate with the virulence of Cutibacterium. We sought to compare the prevalence of these potential markers of pathogenicity between Cutibacterium recovered from deep specimens obtained at the time of surgical revision for failed shoulder arthroplasty and Cutibacterium recovered from skin samples from normal subjects. METHODS: We compared 42 deep-tissue or explant isolates with 43 control Cutibacterium samples obtained from skin isolates from normal subjects. Subtyping information was available for all isolates. Biofilm-forming capacity was measured by inoculating a normalized amount of each isolate onto a 96-well plate. Planktonic bacteria were removed, the remaining adherent bacteria were stained with crystal violet, the crystal violet was re-solubilized in ethyl alcohol, and biofilm-forming capacity was quantitated by optical density (OD). Hemolytic activity was measured by plating a normalized amount of isolate onto agar plates. The area of the colony and the surrounding area of blood lysis were measured and reported as minimal, moderate, or severe hemolysis. RESULTS: Biofilm-forming capacity was significantly higher in the tissue and explant samples compared with the control skin samples (OD of 0.34 ± 0.30 for deep tissue vs. 0.20 ± 0.28 for skin, P = .002). Hemolytic activity was also significantly higher in the tissue and explant samples than in the control skin samples (P < .0001). Samples with hemolytic activity had significantly higher biofilm-forming capacity compared with samples without hemolytic activity (OD of 0.27 ± 0.29 vs. 0.12 ± 0.15, P = .015). No difference in biofilm-forming capacity or hemolytic activity was found between subtypes. CONCLUSIONS: Cutibacterium obtained from deep specimens at the time of revision shoulder arthroplasty has higher biofilm-forming capacity and hemolytic activity than Cutibacterium recovered from the skin of normal subjects. These data add support for the view that Cutibacterium harvested from deep tissues may have clinically significant virulence characteristics. The lack of correlation between these clinically relevant phenotypes and subtypes indicates that additional study is needed to identify genotypic markers that better correlate with biofilm and hemolytic activity.

Two-Stage Exchange Arthroplasty for Periprosthetic Shoulder Infection Is Associated with High Rate of Failure to Reimplant and Mortality.

BACKGROUND: Patients with a periprosthetic joint infection (PJI) of the shoulder, who fail to undergo reimplantation in an attempted two-stage exchange seem to be neglected in the current literature. The aim of this study was to assess the clinical course of patients after the first stage in the process of an attempted two-stage exchange for shoulder PJI. METHODS: After a retrospective review of our institutional database between 2008 and 2018, 49 patients, who were treated with an intended two-stage exchange for shoulder PJI, were identified. Patients' demographics, laboratory and health status parameters, along with records of clinical outcome were collected. The primary outcome measurements analyzed were infection eradication, successful reimplantation, and patient survival. RESULTS: Reimplantation was completed in only 35 (71%) of 49 cases and eradication of infection was achieved in 85.7% of patients with successful reimplantation after a mean follow-up duration of 5.1 years (1.1 to 10.2 years). Reasons for failure to reimplant were premature death in 36%, high general morbidity in 29%, satisfaction with the current status in 21%, or severe infection with poor bone and soft tissues in 14% of the patients. Of the 14 cases without reimplantation, eradication rate of infection was 57% after a mean follow-up of 5 years (2.6 to 11 years). The overall mortality rate of the entire cohort was 25% at the latest follow-up and 10% within ninety days after implant removal. Patients who deceased or did not undergo reimplantation during the follow-up were significantly older and had a significantly higher Charlson comorbidity index (CCI). CONCLUSIONS: While the two-stage exchange arthroplasty can lead to high rates of infection eradication, a considerable subset of patients never undergoes the second stage for a variety of reasons. Shoulder PJI and its treatment are associated with a high risk of mortality, especially in patients with older age and higher CCI.

Management of periprosthetic infection after reverse shoulder arthroplasty.

BACKGROUND: Periprosthetic shoulder infection (PSI) remains a devastating complication after reverse shoulder arthroplasty (RSA). Currently, scientific data related to the management of PSI are limited, and the optimal strategy and related clinical outcomes remain unclear. Guidelines from the Infectious Diseases Society of America for the management of periprosthetic joint infection are mainly based on data from patients after hip and knee arthroplasty. The aim of this study was to evaluate whether these guidelines are also valid for patients with PSI after RSA. In addition, the functional outcome according to the surgical intervention was assessed. METHODS: An RSA database was retrospectively reviewed to identify infections after primary and revision RSAs, diagnosed between 2004 and 2018. Data collected included age, sex, indication for RSA, causative pathogen, surgical and antimicrobial treatment, functional outcome, and recurrence. RESULTS: Thirty-six patients with a PSI were identified. Surgical treatment was subdivided into débridement and implant retention (DAIR) (n = 6, 17%); 1-stage revision (n = 1, 3%); 2-stage revision (n = 16, 44%); multiple-stage revision (>2 stages) (n = 7, 19%); definitive spacer implantation (n = 2, 6%); and resection arthroplasty (n = 4, 11%). The most common causative pathogens were Staphylococcus epidermidis (n = 11, 31%) and Cutibacterium acnes (n = 9, 25%). Recurrence was diagnosed in 4 patients (11%), all of whom were initially treated with a DAIR approach. The median follow-up period was 36 months (range, 24-132 months). CONCLUSION: PSI is typically caused by low-virulence pathogens, which often are diagnosed with a delay, resulting in chronic infection at the time of surgery. Our results indicate that treatment of patients with chronic PSI with DAIR has a high recurrence rate. In addition, implant exchange (ie, 1- and 2-stage exchange) does not compromise the functional result as compared with implant retention. Thus, patients with chronic PSI should be treated with implant exchange. Future research should further clarify which surgical strategy (ie, 1-stage vs. 2-stage exchange) has a better outcome overall.