Does Adding Hydrogen Peroxide to Chlorhexidine Gluconate Increase the Effectiveness of Skin Preparation in Reducing Cutaneous Cutibacterium Levels? A Randomized Controlled Trial.

INTRODUCTION: Shoulder periprosthetic joint infection (PJI) is most commonly caused by Cutibacterium. Effective removal of these bacteria from the skin is difficult because Cutibacterium live protected in the dermal sebaceous glands beneath the skin surface to which surgical preparation solutions, such as chlorhexidine gluconate (CHG), are applied. There is conflicting evidence on the additional benefit of using hydrogen peroxide (H2O2) as an adjunct to CHG in eliminating Cutibacterium from the skin. A previous study demonstrated that after CHG skin preparation, repopulation of Cutibacterium from sebaceous glands onto the skin surface occurs in 90% of shoulders by 60 minutes after application. The objective of this randomized controlled study was to determine the effectiveness of adding H2O2 to CHG in reducing skin Cutibacterium. METHODS: Eighteen male volunteers (36 shoulders) were recruited for this study. The two shoulders of each volunteer were randomized to receive the control preparation ("CHG-only" - 2% CHG in 70% isopropyl alcohol [ISA] alone) or the study preparation ("H2O2+CHG" - 3% H2O2 followed by 2% CHG in 70% ISA). Skin swabs were taken from each shoulder prior to skin preparation and again at 60 minutes after preparation. Swabs were cultured for Cutibacterium and observed for 14 days. Cutibacterium skin load was reported using a semi-quantitative system based on the number of quadrants growing on the culture plate. RESULTS: Prior to skin preparation, 100% of the CHG-only shoulders and 100% of the H2O2+CHG shoulders had positive skin surface cultures for Cutibacterium. Repopulation of Cutibacterium on the skin at 60 minutes occurred in 78% of CHG-only and 78% of H2O2+CHG shoulders (p=1.00). Reduction of Cutibacterium skin levels occurred in 56% of CHG-only and 61% of H2O2+CHG shoulders (p=0.735). Cutibacterium levels were significantly decreased from before skin preparation to 60 minutes after preparation in both the CHG-only (2.1 ± 0.8 to 1.3 ± 0.9, p=0.003) and the H2O2+CHG groups (2.2 ± 0.7 to 1.4 ± 0.9, p<0.001). Substantial skin surface levels of Cutibacterium were present at 60 minutes after both preparations. CONCLUSIONS: In this randomized controlled study, there was no additional benefit of using hydrogen peroxide as an adjunct to chlorhexidine gluconate skin preparation in the reduction of cutaneous Cutibacterium levels. Neither preparation was able to eliminate repopulation of Cutibacterium on the skin surface from the dermal sebaceous glands.

2023 Neer Award for Basic Science: Genetics of Cutibacterium acnes in Revision Shoulder Arthroplasty: A Large-Scale Bacterial Whole-Genome Sequencing Study.

BACKGROUND: Cutibacterium acnes is the bacterium most commonly responsible for shoulder periprosthetic joint infection (PJI) and is often cultured from samples obtained at the time of revision for failed shoulder arthroplasty. We sought to determine whether these bacteria originate from the patient or from exogenous sources. We also sought to identify which C. acnes genetic traits were associated with the development of shoulder PJI. METHODS: We performed bacterial whole-genome sequencing of C. acnes from a single-institution repository of cultures obtained before or during primary and revision shoulder arthroplasty and correlated the molecular epidemiology and genetic content of strains with clinical features of infection. RESULTS: A total of 341 isolates collected over a four-year period from 88 patients were sequenced. C. acnes cultured from surgical specimens demonstrated significant similarity to the strains colonizing the skin of the same patient (p<0.001). Infrequently, there was evidence of strains shared across unrelated patients, suggesting that exogenous sources of C. acnes culture-positivity were uncommon. Phylotypes IB and II were modestly associated with clinical features of PJI, but all phylotypes appeared inherently capable of causing disease. Chronic shoulder PJI was associated with the absence of common C. acnes genes involved in bacterial quorum-sensing (luxS, tqsA). CONCLUSION: C. acnes strains cultured from deep intraoperative sources during revision shoulder arthroplasty demonstrate strong genetic similarity to the strains colonizing a patient's skin. Some phylotypes of C. acnes commonly colonizing human skin are modestly more virulent than others, but all phylotypes have a capacity for PJI. C. acnes cultured from cases of PJI commonly demonstrated genetic hallmarks associated with adaptation from acute to chronic phases of infection. This is the strongest evidence to date supporting the role of the patient's own, cutaneous C. acnes strains in the pathogenesis of shoulder arthroplasty infection. Our findings support the importance of further research focused on perioperative decolonization and management of endogenous bacteria that are likely to be introduced into the arthroplasty wound at the time of skin incision.

Anatomic Total Shoulder: Predictors of Excellent Outcomes at Five Years after Arthroplasty.

PURPOSE: The objectives of this study were to: report minimum 5-year outcomes in patients undergoing TSA and determine characteristics predictive of patients achieving an excellent functional outcome. METHODS: Pre-operative demographic variables and Simple Shoulder Test (SST) scores were obtained pre-operatively and at a minimum of five years after surgery. A final SST ≥ 10 and percentage of maximal possible improvement (% MPI) of ≥ 66.7% were determined to be the thresholds for excellent outcomes. Univariate and multivariate analysis were performed to identify factors associated with excellent five year clinical outcomes. RESULTS: Of 233 eligible patients, 188 (81%) had adequate follow-up for inclusion in this study. Mean SST scores improved from 3.4 ± 2.4 to 9.7 ± 2.2 (p < 0.001). Male sex was an independent predictor of both SST ≥ 10 (OR 3.46, 95% CI 1.70-7.31; p < 0.001) and %MPI ≥ 66.7 (OR 2.27, 95% CI 1.11-4.81, p = 0.027). Workers' Compensation insurance was predictive of not obtaining SST ≥ 10 (OR 0.12, 95% 0.02-0.60; p = 0.016) or %MPI ≥ 66.7 (OR 0.16, 95% CI 0.03-0.77, p = 0.025). MCID was passed by the vast majority (95%) of patients undergoing TSA and did not necessarily indicate an excellent, satisfactory outcome. CONCLUSION: Male sex and commercial insurance coverage were significantly associated with these excellent outcomes, while Workers' Compensation insurance was associated with failure to achieve this result. Thresholds for excellent outcomes, such as final SST ≥ 10 and %MPI ≥ 66.7, may be useful in identifying the characteristics of patients who benefit most from TSA.

Anatomic shoulder arthroplasty: the correlation between patient resilience, mental health, and outcome.

BACKGROUND: Recovery from anatomic shoulder arthroplasty may be enhanced in patients with good mental health and the resilience to participate in the prescribed postoperative rehabilitation program. To test this concept, we utilized validated and reliable scales in determining whether resilience and mental health are associated with the outcome of anatomic arthroplasty. METHODS: Three hundred ninety-nine patients (195 ream and run [RnR] and 204 anatomic total shoulder arthroplasty [aTSA]) were surveyed at a mean follow-up of 6.3 ± 3.3 years. Preoperative variables included age, sex, body mass index, history of prior shoulder surgery, diabetes, visual analog scale for pain, Simple Shoulder Test (SST) scores, and Veteran's RAND 12 Mental Component Score (VR-12 MCS). Outcomes collected included the SST, American Shoulder and Elbow Surgeons (ASES) score, revision rate, and patient satisfaction. Resilience was documented using the Connor-Davidson Resilience Scale 10 (CD-RISC 10) at latest follow-up. Univariable and multivariable regression analyses were used to identify factors significantly associated with follow-up postoperative SST, ASES, and satisfaction. RESULTS: In the univariable analysis, CD-RISC 10 was positively correlated with postoperative SST, ASES, and satisfaction after both RnR and aTSA. The mean CD-RISC 10 scores were higher in the RnR cohort (34.3 ± 4.8 vs. 32.5 ± 6.2 for aTSA, P < .001). Male sex and lower preoperative visual analog scale for pain were correlated with higher ASES after RnR; VR-12 MCS was positively correlated with all outcomes except SST after RnR. In the multivariable linear regression analysis, CD-RISC 10 was independently associated with postoperative SST, ASES and satisfaction scores in aTSA patients. In the RnR cohort, CD-RISC 10 was only correlated with satisfaction. VR-12 MCS was correlated with ASES and satisfaction after RnR. DISCUSSION: In this study of anatomic arthroplasties, increased resilience and better mental health were correlated with better outcomes. RnR patients had higher resilience than aTSA patients. Greater resilience was associated with better outcomes after aTSA. Better mental health was associated with superior outcomes after the ream and run procedure.

Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty.

BACKGROUND: Disabling cuff tear arthropathy (CTA) is commonly managed with reverse shoulder arthroplasty (RSA). However, for patients with CTA having preserved active elevation, cuff tear arthropathy hemiarthroplasty (CTAH) may offer a cost-effective alternative that avoids the complications unique to RSA. We sought to determine the characteristics and outcomes of a series of patients with CTA managed with these procedures. MATERIALS AND METHODS: We retrospectively reviewed 103 patients with CTA treated with shoulder arthroplasty, the type of which was determined by the patient's ability to actively elevate the arm. Outcome measures included the change in the Simple Shoulder Test (SST), the percent maximum improvement in SST (%MPI), and the percentage of patients exceeding the minimal clinically important difference for the change in SST and %MPI. Postoperative x-rays were evaluated to assess the positions of the center of rotation and the greater tuberosity for each implant. RESULTS: Forty-four percent of the 103 patients were managed with CTAH while 56% were managed with RSA. Both arthroplasties resulted in clinically significant improvement. Patients having RSA improved from a mean preoperative SST score of 1.7 (interquartile range [IQR], 0.0-3.0) to a postoperative score of 6.3 (IQR, 2.3-10.0) (P < .01). Patients having CTAH improved from a preoperative SST score of 3.1 (IQR, 1.0-4.0) to a postoperative score of 7.6 (IQR, 5.0-10.) (P < .001). These improvements exceeded the minimal clinically important difference. Instability accounted for most of the RSA complications; however, it did not account for any CTAH complications. The postoperative position of the center of rotation and greater tuberosity on anteroposterior radiographs did not correlate with the clinical outcomes for either procedure. CONCLUSION: For 103 patients with CTA, clinically significant improvement was achieved with appropriately indicated CTAH and RSA. In view of the lower cost of the CTAH implant, it may provide a cost-effective alternative to RSA for patients with retained active elevation.

Minimum 10-year follow-up of anatomic total shoulder arthroplasty and ream-and-run arthroplasty for primary glenohumeral osteoarthritis.

BACKGROUND: Reports on long term outcomes and failures of shoulder arthroplasty are uncommon. The purpose of this study is to present minimum 10-year outcomes in consecutive patients undergoing ream-and-run and anatomic total shoulder arthroplasty (TSA) for primary glenohumeral arthritis. METHODS: This study analyzed consecutive patients who had undergone a ream-and-run or TSA with minimum 10-year follow-up. Pain scores and Simple Shoulder Test (SST) values were obtained preoperatively and at a minimum of 10 years postoperatively via e-mail or mail-in response. Percentage of maximum possible improvement (%MPI) was also calculated. RESULTS: Of 127 eligible patients, 63 (50%) responded to a 10-year survey. This included 34 patients undergoing ream-and-run arthroplasty and 29 patients undergoing TSA. The ream-and-run patients were significantly younger than the TSA patients (60 ± 7 vs. 68 ± 8, P < .001), predominantly male (97% vs. 41%, P < .001), and had a lower American Society of Anesthesiologists classification (P = .018). In the ream-and-run group, the mean pain score improved from a preoperative value of 6.5 ± 1.9 to 0.9 ± 1.3 (P < .001), and the mean SST score improved from 5.4 ± 2.4 to 10.3 ± 2.1 at 10-year follow-up (P < .001). Twenty-eight (82%) achieved an SST improvement above the minimally clinically important difference (MCID) of 2.6. Four patients (12%) underwent single-stage exchange to another hemiarthroplasty, whereas 1 (3%) required manipulation under anesthesia. In the TSA group, the pain score improved from a preoperative value of 6.6 ± 2.2 to 1.2 ± 2.3 (P < .001), and the SST score improved from 3.8 ± 2.6 to 8.9 ± 2.6 at 10-year follow-up (P < .001). Of the 29 patients who underwent a TSA, 27 (93%) achieved an SST improvement above the MCID of 1.6. No patient in the TSA group required reoperation. CONCLUSION: Although the characteristics of the patients differ between the 2 groups, excellent functional results can be obtained with the ream-and-run arthroplasty and TSA for glenohumeral osteoarthritis.

Dynamics of Cutibacterium repopulation onto the skin surface of the shoulder after chlorhexidine application.

PURPOSE: The objective of this study was to characterize the temporal dynamics of Cutibacterium repopulation of the skin surface after application of chlorhexidine to the shoulder. METHODS: Ten shoulders in five male subjects were used. A skin swab was taken prior to (0 minutes) and then at three, 30, 60, 120, and 240 minutes after skin preparation with 2% chlorhexidine gluconate and 70% isopropyl alcohol. Semi-quantitative bacterial load was measured for each timepoint. RESULTS: From zero minutes (pre-treatment) to three minutes, chlorhexidine-isopropyl alcohol reduced the skin bacterial load in eight out of ten shoulders. Of these eight shoulders, four (50%) had growth by 30 minutes, seven (88%) had growth by 60 minutes, and all eight (100%) had growth by 240 minutes. Compared to the three minutes after chlorhexidine application, bacterial load had significantly increased by 60 minutes but were still significantly lower than the pre-prep bacterial load (0 minutes). CONCLUSION: Following standard surgical skin preparation with chlorhexidine-isopropyl alcohol, the surface of the shoulder is repopulated with Cutibacterium within one hour, presumably from reservoirs in sebaceous glands not penetrated by topical antiseptic agents. Since these dermal glands are transected by skin incision for shoulder arthroplasty, this study suggests that they may be sources of wound contamination during surgery in spite of skin preparation with chlorhexidine.

Factors associated with success of ream-and-run arthroplasty at a minimum of 5 years.

BACKGROUND: Ream-and-run arthroplasty offers improvements in shoulder pain and function for patients with primary glenohumeral arthritis who wish to avoid limitations associated with a polyethylene glenoid component. Longer-term clinical outcome assessments of the ream-and-run procedure are sparse in the literature. This study aimed to present minimum 5-year functional outcomes in a large cohort following ream-and-run arthroplasty to determine factors associated with clinical success and reoperation. METHODS: Patients who underwent ream-and-run surgery with a minimum of 5 years of follow-up were identified through a retrospective review of a prospectively maintained database from a single academic institution. To assess clinical outcomes, the Simple Shoulder Test (SST) was administered and assessed to determine achievement of the minimal clinically important difference, as well as the necessity for open revision surgery. Factors associated with P < .1 on univariate analysis were included in multivariate analysis. RESULTS: Of 228 patients who consented to undergo long-term follow-up, 201 (88%) were included in our analysis (mean follow-up period, 7.6 ± 2.1 years). The average age was 59.4 ± 8.8 years, and 93% of patients were men. The majority of patients had a diagnosis of osteoarthritis (79%) or capsulorrhaphy arthropathy (10%). SST scores improved from a mean of 4.9 ± 2.5 preoperatively to a mean of 10.2 ± 2.6 at latest follow-up. The minimal clinically important difference in the SST score of 2.6 was reached by 165 patients (82%). Male sex (P = .020), nondiabetic status (P = .080), and lower preoperative SST score (P < .001) were included in a multivariate analysis. Male sex (P = .010) and lower preoperative SST score (P < .001) were associated with clinically important improvements in SST scores on multivariate analysis. Open revision surgery was required in 22 patients (11%). Younger age (P < .001), female sex (P = .055), and higher preoperative pain score (P = .023) were included in a multivariate analysis. Only younger age was predictive of open revision surgery (P = .003). CONCLUSIONS: Ream-and-run arthroplasty can provide significant and clinically important improvements in clinical outcomes at minimum 5-year follow-up. Successful clinical outcomes were significantly associated with male sex and lower preoperative SST scores. Reoperation was more common in younger patients.

Predictors of success following single-stage revision shoulder arthroplasty: results at a mean of five year follow-up in one hundred and twelve patients.

PURPOSE: The objective was to determine factors associated with a successful outcome at a minimum of two years after revision of a failed shoulder arthroplasty. METHODS: We conducted a retrospective study of revision shoulder arthroplasties performed over a ten year period and collected patient-reported outcome data and re-revision data. A successful outcome was defined by improvement greater than the minimal clinically important difference (MCID) for the Simple Shoulder Test (SST). RESULTS: One hundred twelve patients with average follow-up of five years were included. Improvement of VAS pain scores (6.6 ± 2.3 to 2.9 ± 2.6) and SST scores (2.7 ± 2.6 to 6.6 ± 3.3) were significant (p < 0.001). Males were more likely to have a successful outcome than females (p = 0.01). CONCLUSION: Two-thirds of patients experienced clinically significant improvement at a minimum of two years after revision shoulder arthroplasty. Male sex was the strongest independent predictor of a successful outcome.

Revision of total shoulder arthroplasty to hemiarthroplasty: results at mean 5-year follow-up.

BACKGROUND: Although there is a trend to manage failed anatomic total shoulder arthroplasties (aTSA) with revision to a reverse total shoulder arthroplasty, such revisions can be complicated by difficulties in baseplate fixation, instability, and acromial stress fractures. Some cases of failed aTSA may be safely revised to a hemiarthroplasty (HA). The objectives of this study were to report patient-reported outcomes after conversion from aTSA to HA and assess patient and shoulder characteristics associated with a successful outcome. METHODS: Patients who underwent revision from aTSA to HA between 2009 and 2018 were contacted. Patient demographics, surgical history, intraoperative findings, and microbiology results were collected. Patient-reported outcomes were collected with minimum 2-year follow-up. Preoperative radiographic characteristics were reviewed for component positioning and component loosening. Patients with a clinically significant improvement exceeding the minimal clinically important difference (MCID) of the Simple Shoulder Test (SST) were compared with those patients who did not improve past the MCID. RESULTS: Twenty-nine patients underwent conversion from aTSA to HA with a mean follow-up of 4.5 ± 1.8 years. Intraoperative glenoid or humeral component loosening was found in all 29 patients. Pain improved in 25 of 30 patients (87%), and mean pain scores improved from 6.2 ± 2.3 to 3.1 ± 2.4 (P < .001). SST scores improved from 4.1 ± 3.1 to 7.3 ± 3.2 (P < .001), and 18 of 29 patients (62%) had improvement above the SST MCID threshold of 2.4. The mean American Shoulder and Elbow Surgeons score at the latest follow-up was 64 ± 19, and the Single Assessment Numeric Evaluation score was 65 ± 23. Twenty-two of 29 (76%) patients were satisfied with the procedure. Four patients (14%) required conversion to total shoulder arthroplasty-2 to anatomic and 2 to reverse. An additional 3 patients (10%) had a revision HA performed. No significant differences in patient or shoulder characteristics were found in those patients who improved greater than the MCID of the SST compared patients who improved less than the MCID of the SST. Fifty-nine percent of patients had ≥2 positive cultures with the same bacteria, and 82% of these were with Cutibacterium. Seven of 8 patients (88%) with a loose humeral component had ≥2 positive cultures with the same bacteria. DISCUSSION: Component loosening is a common failure mode after aTSA. Revision to HA can improve pain and patient-reported outcomes in most patients.

Drivers of inpatient hospitalization costs, joint-specific patient-reported outcomes, and health-related quality of life in shoulder arthroplasty for cuff tear arthropathy.

BACKGROUND: Cuff tear arthropathy (CTA) can be successfully treated with various types of shoulder arthroplasty. While reverse total shoulder arthroplasty (RSA) is commonly used to treat CTA, CTA hemiarthroplasty (CTA-H, hemiarthroplasty with an extended humeral articular surface) can also be effective in patients with preserved glenohumeral elevation and an intact coracoacromial (CA) arch. As the value of arthroplasty is being increasingly scrutinized, cost containment has become a priority. The objective of this study was to assess hospitalization costs and improvements in joint-specific measures and health-related quality of life for these two types of shoulder arthroplasty in the management of CTA. METHODS: Seventy-two patients (39 CTA-H and 33 RSA) were treated during the study time period using different selection criteria for each of the two procedures: CTA-H was selected in patients with retained active elevation, an intact CA arch, and an intact subscapularis, while RSA was selected in patients with pseudoparalysis or glenohumeral instability. The Simple Shoulder Test (SST) was used as a joint-specific patient-reported outcome measure. Improvement in quality-adjusted life years was measured using the Short Form 36. Costs associated with inpatient care were collected from hospital financial records. Univariate and multivariate analyses focused on determining predictors of hospitalization costs and improvements in patient-reported outcomes. RESULTS: Significant improvements in SST and Short Form 36 physical component scores were seen in both groups. Inpatient hospitalization costs were significantly higher in the RSA group than that in the CTA-H group ($15,074 ± $1614 vs. $10,389 ± $1948, P < .001), driven primarily by supplies including the cost of the prosthesis ($9005 ± $2521 vs. $4715 ± $2091, P < .001). The diagnosis of diabetes was an independent predictor of higher inpatient hospitalization costs for both groups. There were no independent predictors for quality-adjusted life year improvements. SST improvement in the CTA-H group was significantly higher in patients with lower preoperative SST scores. CONCLUSION: Using a standard algorithm of CTA-H for shoulders with retained active elevation and an intact CA arch and RSA for poor active elevation or glenohumeral instability, both procedures led to significant improvements in health-related quality of life and joint-specific measures. Costs were significantly lower for patients meeting the selection criteria for CTA-H. Further value analytics are needed to compare the relative cost effectiveness of RSA and CTA-H for patients with CTA having retained active elevation, intact CA arch, and intact subscapularis.

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.

The minimal clinically important differences of the Simple Shoulder Test are different for different arthroplasty types.

BACKGROUND: Preoperative and postoperative patient self-reported measures are the key to understanding the benefit of shoulder arthroplasty for patients with different diagnoses and having different surgical approaches. The minimal clinically important difference (MCID) for patient-reported outcomes such as the Simple Shoulder Test (SST) is often used to document the amount of improvement that is of importance to the patient; however, the MCID may differ for different types of shoulder arthroplasty. The objective of this study was to report the MCID of the SST and the MCID of the percentage of maximal possible improvement (%MPI) for 5 different arthroplasty types. METHODS: Eight hundred eighty-seven patients undergoing shoulder arthroplasty with preoperative SST scores, 2-year postoperative SST scores, and patient satisfaction were included. The sample comprised 368 patients undergoing anatomic total shoulder arthroplasty (aTSA), 330 patients undergoing ream-and-run arthroplasty (R&R), 80 patients undergoing reverse total shoulder arthroplasty (rTSA), 53 patients undergoing cuff tear arthropathy arthroplasty, and 56 patients undergoing hemiarthroplasty. For each type of arthroplasty, the anchor-based method was used for calculating the MCID for both absolute SST scores and %MPI. RESULTS: Significant improvements in SST values were seen for all arthroplasty types. The MCID for SST change was 2.3 overall but ranged from 1.6 for aTSA, to 2.6 for R&R, to 3.7 for rTSA. The MCID for %MPI was 32% overall but ranged from 22% for aTSA to 42% for hemiarthroplasty. The percentage of patients exceeding the MCID threshold was highest for aTSA at 96% and lowest for hemiarthroplasty at 61%. CONCLUSION: The same MCID value may not be appropriate for different types of shoulder arthroplasty. This study reports MCID thresholds that can be used when assessing the effectiveness for each of the common types of 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.

Factors associated with failure of surgical revision and IV antibiotics to resolve Cutibacterium periprosthetic infection of the shoulder.

PURPOSE: Cutibacterium is the most common organism causing shoulder periprosthetic infection (PJI). While most shoulder PJIs are well treated by prosthesis exchange and antibiotics, in some cases this treatment fails to resolve the infection. The factors associated with these failures have not been previously identified. The aim of this study was to identify the characteristics of patients with failure of treatment for PJI. METHODS: Thirty-five patients suspected of having Cutibacterium PJI had revision arthroplasty with single-stage implant exchange followed by intravenous antibiotics. The characteristics of those with ≥ two positive cultures at revision surgery were compared to those who did not. The characteristics of those patients having a re-revision with ≥ two positive deep cultures (documented treatment failures) were compared to those who did not. RESULTS: The 17 patients that had ≥ two positive cultures at their index revision were more likely to be male, to have had ream and run procedures, and to have higher loads of Cutibacterium on pre-operative cultures of their unprepared skin. The five patients that had documented treatment failure had higher loads of Cutibacterium on their skin and in deep cultures obtained at their index revision. CONCLUSION: Patients harboring high loads of Cutibacterium on their unprepared skin prior to revision and high loads of Cutibacterium on deep cultures at the time of their index revision are at increased risk for failure of implant exchange and antibiotics to resolve a Cutibacterium PJI.

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.

Oral and IV Antibiotic Administration After Single-Stage Revision Shoulder Arthroplasty: Study of Survivorship and Patient-Reported Outcomes in Patients without Clear Preoperative or Intraoperative Infection.

BACKGROUND: Following revision shoulder arthroplasty, postoperative antibiotics are selected before the results of intraoperative cultures become available. We determined infection-free survival, revision-free survival, complications, and patient-reported outcomes for patients selected to receive oral or intravenous (IV) antibiotics after revision arthroplasty. METHODS: This study included 92 patients who had revision shoulder arthroplasty. IV antibiotics were administered if the surgeon had a high index of suspicion for infection, and oral antibiotics were given if there was a low suspicion. Antibiotic therapy was modified based on intraoperative culture results. Patient-reported outcomes and adverse events were documented at a mean of 4.1 years. RESULTS: In selecting antibiotic therapy, surgeons correctly predicted the presence or absence of multiple positive cultures of specimens from the revision surgery in 72% of the 92 cases. Subsequent re-revision surgery was required in 17 (18%) of the patients; 8 of these 17 patients had ≥2 positive cultures at re-revision. Patients who initially received IV antibiotics and those who initially received oral antibiotics had similar revision-free (p = 0.202) and infection-free (p = 0.155) survivorship. Patients requiring a change from oral to IV antibiotics based on positive cultures had similar survivorship compared with those initially treated with IV antibiotics. The IV and oral antibiotic groups had similar postoperative Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES), and satisfaction scores. Patients receiving IV antibiotics had a higher rate of antibiotic-related adverse events. CONCLUSIONS: Post-revision antibiotic therapy was associated with an infection-free survival rate of 91% at a mean of >4 years of follow-up. Infection-free survival, revision-free survival, and patient-reported outcomes were similar in high-risk patients placed on IV antibiotics and low-risk patients placed on oral antibiotics. Further study is needed to define the indications for IV or oral antibiotics after revision arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Arthroscopic management of glenohumeral arthritis in the young patient does not negatively impact the outcome of subsequent anatomic shoulder arthroplasty.

PURPOSE: The objective of this study was to determine the impact of prior arthroscopic management of glenohumeral arthritis in the young patient on results of subsequent anatomic shoulder arthroplasty. METHODS: Forty-three patients that had a total shoulder or ream-and-run arthroplasty with a history of arthroscopic management were matched to 86 patients without prior surgery. Each case was matched to two cases without prior arthroscopic surgery with similar age, sex, Walch classification, and type of arthroplasty. RESULTS: Forty-three patients with a history of arthroscopic management were matched to 86 patients without prior surgery. The mean two year SST scores (10.3 vs. 9.9, p = 0.334), % MPI (75.4 vs. 73.0%, p = 0.687), two year SANE scores (79.6 vs. 79.8, p = 0.953), and % of patients to exceed SST score MCID (89 vs. 91%, p = 0.860) and SANE score MCID (86 vs. 75%, p = 0.180) were statistically similar in patients with prior arthroscopic debridement compared with those without prior arthroscopic debridement. The rate of MUA (9 vs. 6%, p = 0.480) and open revision (9 vs. 8%, p = 1.000) were statistically similar between groups. CONCLUSION: Arthroscopic management of glenohumeral arthritis in patients aged 65 years and younger prior to anatomic shoulder arthroplasty was not associated with inferior outcomes for either total shoulder arthroplasty or ream-and-run arthroplasty.

Drivers of lower inpatient hospital costs and greater improvements in health-related quality of life for patients undergoing total shoulder and ream-and-run arthroplasty.

BACKGROUND: With increasing emphasis on value-based care and the heavy demands on the US health care budget, surgeons must be cognizant of factors that drive cost and quality of patient care. Our objective was to determine patient-level drivers of lower costs and improved health-related quality of life (HRQoL) in 2 anatomic shoulder arthroplasty procedures: total shoulder arthroplasty (TSA) and ream-and-run arthroplasty. METHODS: This study included 222 TSAs and 211 ream-and-run arthroplasties. Simple Shoulder Test, Single Assessment Numeric Evaluation, and Short Form 36 scores were collected preoperatively and 2 years postoperatively. Quality-adjusted life-years (QALYs) were calculated as a measure of HRQoL. Univariate and multivariate analyses determined factors significantly associated with decreased hospitalization costs and improved HRQoL. RESULTS: In the TSA group, female sex, lower American Society of Anesthesiologists class, diagnosis other than capsulorrhaphy arthropathy, lower pain score, and higher Single Assessment Numeric Evaluation score were associated with decreased total hospitalization costs; in addition, female sex was an independent predictor of lower total costs. Insurance other than workers' compensation, a diagnosis of chondrolysis, and higher optimism led to greater QALY gains, but a diagnosis of capsulorrhaphy arthropathy was the only independent predictor of greater QALY gains. In the ream-and-run arthroplasty group, older age, lower body mass index (BMI), lower American Society of Anesthesiologists class, insurance other than Medicaid, diagnosis other than capsulorrhaphy arthropathy, no history of surgery, higher preoperative Simple Shoulder Test score, and higher preoperative Short Form 36 Physical Component Summary score were associated with lower total costs; moreover, lower BMI was an independent predictor of lower costs. Higher preoperative optimism was an independent predictor of greater QALY gains. CONCLUSIONS: Identifying factors associated with decreased costs and increased quality is becoming increasingly important in value-based care. This study identified fixed (sex and diagnosis) and modifiable (BMI) factors that drive decreased hospitalization costs and increased HRQoL improvements in shoulder arthroplasty patients. Higher preoperative patient optimism is a consistent predictor of improved HRQoL for both TSA patients and ream-and-run arthroplasty patients, and further study on optimizing the influence of patient expectations and optimism may be warranted.

Randomized controlled trial of chlorhexidine wash versus benzoyl peroxide soap for home surgical preparation: neither is effective in removing Cutibacterium from the skin of shoulder arthroplasty patients.

INTRODUCTION: Home chlorhexidine washes prior to shoulder surgery are commonly used in an attempt to reduce the skin bacterial load. However, recent studies have suggested that this agent is relatively ineffective against Cutibacterium acne. Benzoyl peroxide soap is a treatment for acne, but evidence regarding its effectiveness as prophylaxis in shoulder surgery is lacking. Therefore, the objective of this study was to compare the effectiveness of home chlorhexidine washes with benzoyl peroxide soap (BPO) in patients undergoing shoulder arthroplasty surgery in reducing Cutibacterium levels on the skin surface and in the dermis. METHODS: Fifty male patients planning to undergo shoulder arthroplasty were consented to be randomized into treatment with 4% chlorhexidine solution (CHG) and 10% benzoyl peroxide soap (BPO) used to wash the operative shoulder the night prior and morning of surgery. Skin swabs prior to incision and dermal wound swabs after incision were obtained, and the bacterial load was reported in a semiquantitative manner as the Specimen Cutibacterium Value (SpCuV). The two groups were compared with regards to the percent positivity of the skin surface and incised dermal edge as well as the bacterial load at each site. RESULTS: Skin surface swabs were positive in 100% of patients using CHG and 100% of patients using BPO soap. The Cutibacterium load (SpCuV) on the skin surface was similar between the two groups (CHG 1.6 ± 1.1 vs. BPO 1.5 ± 1.4, p = 0.681). The percentages of dermal cultures that were positive were not significantly different between the two groups (CHG 61% vs BPO 46%, p = 0.369). The Cutibacterium load (SpCuV) on the incised dermal edge was similar between the two groups (CHG 0.8 ± 1.0 vs. BPO 0.8 ± 1.4, p = 0.991). DISCUSSION: Neither BPO soap nor chlorhexidine washes prior to shoulder surgery were effective in eliminating Cutibacterium from the skin surface or the incised dermal edge. Further study of means of reducing the Cutibacterium load of the skin at the time of shoulder arthroplasty is warranted.