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Artificial intelligence (AI) is amongst the most rapidly growing technologies in orthopedic surgery. With the exponential growth in healthcare data, computing power, and complex predictive algorithms, this technology is poised to aid providers in data processing and clinical decision support throughout the continuum of orthopedic care. Understanding the utility and limitations of this technology is vital to practicing orthopedic surgeons, as these applications will become more common place in everyday practice. AI has already demonstrated its utility in shoulder and elbow surgery for imaging-based diagnosis, predictive modeling of clinical outcomes, implant identification, and automated image segmentation. The future integration of AI and robotic surgery represents the largest potential application of AI in shoulder and elbow surgery with the potential for significant clinical and financial impact. This editorial's purpose is to summarize common AI terms, provide a framework to understand and interpret AI model results, and discuss current applications and future directions within shoulder and elbow surgery. [ABSTRACT FROM AUTHOR]

After the popularity of reverse total shoulder arthroplasty (rTSA) in Europe, the United States Food and Drug Administration (FDA) cleared the Delta rTSA system (DePuy Inc., Warsaw, IN, USA) for use in late 2003. The original FDA approved indications for rTSA in the United States were limited to a "Grossly rotator cuff deficient joint with severe arthropathy or a previous failed joint replacement with a grossly rotator cuff deficient joint." Surgeons began to use rTSA for many off-label indications: osteoarthritis (OA) without rotator cuff tear (RCT), massive RCT without OA, proximal humerus fractures (PHFx), inflammatory arthritis (IA), and chronic glenohumeral joint dislocation (GHJD). Since 2006, The FDA has approved PHFx as an indication for some but not all reverse implants. The purpose of this study is to evaluate the trends in off-label rTSA use in the American Academy of Orthopaedic Surgeons Shoulder and Elbow Registry (AAOS-SER). All rTSA procedures reported to the AAOS-SER from January 2015 to March 2021 were analyzed. Diagnoses associated with the use of rTSA including RCT arthropathy, OA without RCT, RCT without OA, PHFx, IA, and GHJD were evaluated, and trends were assessed over the data collection period. At the time of data analysis the AAOS-SER contained 3850 cases of rTSA. Only 24.4% of rTSA surgeries were performed for original on-label use (RCT arthropathy). Off-label use of rTSA was seen in 75.6% of cases. When reviewing those rTSA done off-label, the majority (41.4%) were done for OA without RCT. Other off-label rTSA use included 15.1% for RCT without OA, 13% potentially off-label for PHFx, 4.6% for IA, and 1.6% for GHJD. Proportionally, off-label use is increasing over time while on-label use is decreasing. In the AAOS-SER, the majority of rTSA were performed for indications originally considered off-label by the FDA-a trend increasing over time. Some implant manufacturers have expanded indications for rTSA without providing clinical data to support changing FDA approved indications for use. The incremental expansion of indications for use without supportive data, a practice known as predicate creep, is occurring with rTSA. Performing rTSA for off-label indications may create liability risk for surgeons and implant manufacturers. Device manufacturers should formally expand indications of use for rTSA with the FDA to be consistent with published literature and trends. [ABSTRACT FROM AUTHOR]

Recent work has shown inpatient length of stay (LOS) following shoulder arthroplasty to hold the second strongest association with overall cost (after implant cost itself). In particular, a preoperative understanding for the patients at risk of extended inpatient stays (≥3 days) can allow for counseling, optimization, and anticipating postoperative adverse events. A multicenter retrospective review was performed of 5410 anatomic (52%) and reverse (48%) total shoulder arthroplasties done at 2 large, tertiary referral health systems. The primary outcome was extended inpatient LOS of at least 3 days, and over 40 preoperative sociodemographic and comorbidity factors were tested for their predictive ability in a multivariable logistic regression model based on the patient cohort from institution 1 (derivation, N = 1773). External validation was performed using the patient cohort from institution 2 (validation, N = 3637), including area under the receiver operator characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive values. A total of 814 patients, including 318 patients (18%) in the derivation cohort and 496 patients (14%) in the validation cohort, experienced an extended inpatient LOS of at least 3 days. Four hundred forty-five (55%) were discharged to a skilled nursing or rehabilitation facility. Following parameter selection, a multivariable logistic regression model based on the derivation cohort (institution 1) demonstrated excellent preliminary accuracy (AUC: 0.826), with minimal decrease in accuracy under external validation when tested against the patients from institution 2 (AUC: 0.816). The predictive model was composed of only preoperative factors, in descending predictive importance as follows: age, marital status, fracture case, ASA (American Society of Anesthesiologists) score, paralysis, electrolyte disorder, body mass index, gender, neurologic disease, coagulation deficiency, diabetes, chronic pulmonary disease, peripheral vascular disease, alcohol dependence, psychoses, smoking status, and revision case. A freely-available, preoperative online clinical decision tool for extended inpatient LOS (≥ 3 days) after shoulder arthroplasty reaches excellent predictive accuracy under external validation. As a result, this tool merits consideration for clinical implementation, as many risk factors are potentially modifiable as part of a preoperative optimization strategy. [ABSTRACT FROM AUTHOR]

Total shoulder arthroplasty (TSA) has become the gold-standard treatment to relieve joint pain and disability in patients with glenohumeral osteoarthritis who do not respond to conservative treatment. An adverse reaction to metal debris released due to fretting corrosion has been a major concern in total hip arthroplasty. To date, it is unclear how frequently implant corrosion occurs in TSA and whether it is a cause of implant failure. This study aimed to characterize and quantify corrosion and fretting damage in a single anatomic TSA design and to compare the outcomes to the established outcomes of total hip arthroplasty. We analyzed 21 surgically retrieved anatomic TSAs of the same design (Tornier Aequalis Pressfit). The retrieved components were microscopically examined for taper corrosion, and taper damage was scored. Head and stem taper damage was quantitatively measured with a non-contact optical coordinate-measuring machine. In selected cases, damage was further characterized at high magnifications using scanning electron microscopy. Energy-dispersive x-ray spectroscopy and metallographic evaluations were performed to determine underlying alloy microstructure and composition. Comparisons between groups with different damage features were performed with independent-samples t tests; Mann-Whitney tests and multivariate linear regression were conducted to correlate damage with patient factors. The level of statistical significance was set at P <.05. The average material loss for head and stem tapers was 0.007 mm3 and 0.001 mm3, respectively. Material loss was not correlated with sex, age, previous implant, or time in situ (P >.05). We observed greater volume loss in head tapers compared with stem tapers (P =.002). Implants with evidence of column damage had larger volumetric material loss than those without such evidence (P =.003). Column damage aligned with segregation bands within the alloy (preferential corrosion sites). The average angular mismatch was 0.03° (standard deviation, 0.0668°), with negative values indicating distal engagement and positive values indicating proximal engagement. Implants with proximal engagement were significantly more likely to have column damage than those with distal engagement (P =.030). This study has shown not only that the metal components of TSA implants can corrode but also that the risk of corrosion can be reduced by (1) eliminating preferential corrosion sites and (2) ensuring distal engagement to prevent fluid infiltration into the modular junction. [ABSTRACT FROM AUTHOR]

Unexpected positive cultures (UPCs) are very commonly found during shoulder arthroplasty when surgeons send intraoperative cultures to rule out periprosthetic joint infection (PJI) without clinical or radiographic signs of infection. Cutibacterium acnes is thought to be the most common bacteria cultured in this setting; however, the implications of an unexpected positive result are neither well defined nor agreed upon within the literature. The current review evaluates the incidence of UPCs and C acnes in reverse total arthroplasty; the clinical significance, if any, of these cultures; and various prognostic factors that may affect UPC incidence or recovery following PJI. A systematic review was performed with PRISMA guidelines using PubMed, CINAHL, and Scopus databases. Inclusion criteria included studies published from January 1, 2000, to May 20, 2021, that specifically reported on UPCs, native or revision shoulder surgery, and any study that directly addressed one of our 6 proposed clinical questions. Two independent investigators initially screened 267 articles for further evaluation. Data on study design, UPC rate/speciation, UPC risk factors, and UPC outcomes were analyzed and described. A total of 22 studies met the inclusion criteria for this study. There was a pooled rate of 27.5% (653/2373) deep UPC specimen positivity, and C acnes represented 76.4% (499/653) of these positive specimens. Inanimate specimen positivity was reported at a pooled rate of 20.1% (29/144) across 3 studies. Male patients were more likely to have a UPC; however, the significance of prior surgery, surgical approach, and type of surgery conflicted across multiple articles. Patient-reported outcomes and reoperation rates did not differ between positive-UPC and negative-UPC patients. The utilization of antibiotics and treatment regimen varied across studies; however, the reinfection rates following surgery did not statistically differ based on the inclusion of antibiotics. UPCs are a frequent finding during shoulder surgery and C acnes represents the highest percentage of cultured bacteria. Various preoperative risk factors, surgical techniques, and postoperative treatment regimens did not significantly affect the incidence of UPCs as well as the clinical outcomes for UPC vs. non-UPC patients. A standardized protocol for treatment and follow-up would decrease physician uncertainty when faced with a UPC from shoulder surgery. Given the results of this review, shoulder surgeons can consider not drastically altering the postoperative clinical course in the setting of UPC with no other evidence of PJI. [ABSTRACT FROM AUTHOR]

Glenoid bone loss in anatomic total shoulder arthroplasty (aTSA) remains a controversial and challenging clinical problem. Previous studies have shown high rates of glenoid loosening for aTSA in shoulders with retroversion, posterior bone loss, and posterior humeral head subluxation. This study is the first to present minimum 2-year follow-up data of an all-polyethylene, biconvex augmented anatomic glenoid component for correction of glenoid retroversion and posterior humeral head subluxation. This study is a multicenter, retrospective review of prospectively collected data on consecutive patients from 7 global clinical sites. All patients underwent aTSA using the biconvex posterior augmented glenoid (PAG). Inclusion criteria were preoperative computed tomographic (CT) scan, minimum 2 years since surgery, preoperative and minimum 2-year postoperative range of motion examination, and patient-reported outcome measures (PROMs). Glenoid classification, glenoid retroversion, and posterior humeral head subluxation were measured from preoperative CT and radiography and postoperative radiography. Statistical comparisons between pre- and postoperative values were performed with a paired t test. Eighty-six of 110 consecutive patients during the study period (78% follow-up) met the inclusion criteria and were included in our analysis. Mean follow-up was 35 ± 10 months, with a mean age of 68 ± 8 years (range 48-85). Range of motion statistically improved in all planes from pre- to postoperation. Mean visual analog scale score improved from 5.2 preoperation to 0.7 postoperation, Single Assessment Numeric Evaluation score from 43.2 to 89.5, Constant score from 41.8 to 76.9, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score from 49.8 to 86.7 (all P <.0001). Mean glenoid retroversion improved from 19.3° to 7.4° (P <.0001). Posterior subluxation improved from 69.1% to 53.5% and posterior decentering improved from 5.8% to –3.0% (P <.0001). There was 1 patient with both a prosthetic joint infection and radiographic glenoid loosening that required revision. Seventy-nine of 86 patients had a Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up. This study shows that at minimum 2-year follow-up, a posterior-augmented all-polyethylene glenoid can correct glenoid retroversion and posterior humeral head subluxation. Clinically, there was significant improvement in both range of motion and PROMs. [ABSTRACT FROM AUTHOR]

As bundled payment models continue to spread, understanding the primary drivers of cost excess helps providers avoid penalties and ensure equal health care access. Recent work has shown discharge to rehabilitation and skilled nursing facilities (SNFs) to be a primary cost driver in total joint arthroplasty, and an accurate preoperative risk calculator for shoulder arthroplasty would not only help counsel patients in clinic during shared decision-making conversations but also identify high-risk individuals who may benefit from preoperative optimization and discharge planning. Anatomic and reverse total shoulder arthroplasty cohorts from 2 geographically diverse, high-volume centers were reviewed, including 1773 cases from institution 1 (56% anatomic) and 3637 from institution 2 (50% anatomic). The predictive ability of a variety of candidate variables for discharge to SNF/rehabilitation was tested, including case type, sociodemographic factors, and the 30 Elixhauser comorbidities. Variables surviving parameter selection were incorporated into a multivariable logistic regression model built from institution 1's cohort, with accuracy then validated using institution 2's cohort. A total of 485 (9%) shoulder arthroplasties overall were discharged to post-acute care (anatomic: 6%, reverse: 14%, P <.0001), and these patients had significantly higher rates of unplanned 90-day readmission (5% vs. 3%, P =.0492). Cases performed for preoperative fracture were more likely to require post-acute care (13% vs. 3%, P <.0001), whereas revision cases were not (10% vs. 10%, P =.8015). A multivariable logistic regression model derived from the institution 1 cohort demonstrated excellent preliminary accuracy (area under the receiver operating characteristic curve [AUC]: 0.87), requiring only 11 preoperative variables (in order of importance): age, marital status, fracture, neurologic disease, paralysis, American Society of Anesthesiologists physical status, gender, electrolyte disorder, chronic pulmonary disease, diabetes, and coagulation deficiency. This model performed exceptionally well during external validation using the institution 2 cohort (AUC: 0.84), and to facilitate convenient use was incorporated into a freely available, online prediction tool. A model built using the combined cohort demonstrated even higher accuracy (AUC: 0.89). This validated preoperative clinical decision tool reaches excellent predictive accuracy for discharge to SNF/rehabilitation following shoulder arthroplasty, providing a vital tool for both patient counseling and preoperative discharge planning. Further, model parameters should form the basis for reimbursement legislation adjusting for patient comorbidities, ensuring no disparities in access arise for at-risk populations. [ABSTRACT FROM AUTHOR]

As of January 1, 2021, total shoulder arthroplasty was removed from the Medicare inpatient-only list, reflecting a growing belief in the potential merits of same-day discharge regardless of insurance type. It is yet unknown whether Medicare populations, which frequently have more severe comorbidity burdens, would experience higher complication rates relative to privately insured patients, who are often younger with fewer comorbidities. Given the limited number of true outpatient cohorts available to study, discharge at least by postoperative day 1 may serve as a useful proxy for true same-day discharge, and we hypothesized that these Medicare patients would have increased 90-day readmission rates compared with their privately insured counterparts. Data on 4723 total shoulder arthroplasties (anatomic in 2459 and reverse in 2264) from 2 large, geographically diverse health systems in patients having either Medicare or private insurance were collected. The unplanned 90-day readmission rate was the primary outcome, and patients were stratified into those who were discharged at least by postoperative day 1 (short inpatient stay) and those who were not. Patients with private insurance (n = 1845) were directly compared with those with Medicare (n = 2878), whereas cohorts of workers' compensation (n = 198) and Medicaid (n = 58) patients were analyzed separately. Forty preoperative variables were examined to compare overall health burden, with the χ2 and Wilcoxon rank sum tests used to test for statistical significance. Medicare patients undergoing short-stay shoulder arthroplasty were not significantly more likely than those with private insurance to experience an unplanned 90-day readmission (3.6% vs. 2.5%, P =.14). This similarity existed despite a substantially worse comorbidity burden in the Medicare population (P <.05 for 26 of 40 factors). Furthermore, a short inpatient stay did not result in an increased 90-day readmission rate in either Medicare patients (3.6% vs. 3.4%, P =.77) or their privately insured counterparts (2.5% vs. 2.4%, P =.92). Notably, when the analysis was restricted to a single insurance type, readmission rates were significantly higher for reverse shoulder arthroplasty compared with total shoulder arthroplasty (P <.001 for both), but when the analysis was restricted to a single procedure (anatomic or reverse), readmission rates were similar between Medicare and privately insured patients, whether undergoing a short or extended length of stay. Despite a substantially more severe comorbidity profile, Medicare patients undergoing short-stay shoulder arthroplasty did not experience a significantly higher rate of unplanned 90-day readmission relative to privately insured patients. A higher incidence of reverse shoulder arthroplasty in Medicare patients does increase their overall readmission rate, but a similar increase also appears in privately-insured patients undergoing a reverse indicating that Medicare populations may be similarly appropriate for accelerated-care pathways. [ABSTRACT FROM AUTHOR]

Malnutrition is associated with poor postoperative outcomes after knee, hip, and spine surgery. However, whether albumin labs should be part of the routine preoperative workup for shoulder arthroplasty remains understudied. This study investigated the role of preoperative albumin levels in predicting common postoperative adverse outcomes in patients undergoing shoulder arthroplasty. All shoulder arthroplasty cases performed at 2 tertiary referral centers between July 2013 and May 2019 (institution 1) and between June 2007 and Feb 2020 (institution 2) were reviewed. A total of 421 primary and 71 revision elective shoulder arthroplasty cases had preoperative albumin levels recorded. Common demographic variables and relevant Elixhauser comorbidities were pulled. Outcomes gathered included extended (>3 days) postoperative inpatient length of stay (eLOS), 90-day readmission, and discharge to rehab or skilled nursing facility (SNF). The prevalence of malnutrition (albumin <3.5 g/dL) was higher in the revision group compared with the primary group (36.6% vs. 19.5%, P =.001). Reverse shoulder arthroplasty (P =.013) and increasing American Society of Anesthesiologists score (P =.016) were identified as independent risk factors for malnutrition in the primary group. In the revision group, liver disease was associated with malnutrition (P =.046). Malnourished primary shoulder arthroplasty patients had an increased incidence of eLOS (26.8% vs. 13.6%, P =.003) and discharge to rehab/SNF (18.3% vs. 10.3%, P =.045). On univariable analysis, low albumin had an odds ratio (OR) of 2.34 for eLOS (P =.004), which retained significance in a multivariable model including age, American Society of Anesthesiologists score, sex, and body mass index (OR 2.11, P =.03). On univariable analysis, low albumin had an OR of 1.94 for discharge to SNF/rehab (P =.048), but this did not reach significance in the multivariable model. Among revisions, malnourished patients had an increased incidence of eLOS (30.8% vs. 6.7%, P =.014) and discharge to rehab/SNF (26.9% vs. 4.4%, P =.010). In both the primary and revision groups, there was no difference in 90-day readmission rate between patients with low or normal albumin. Malnutrition is more prevalent among revision shoulder arthroplasty patients compared with those undergoing a primary procedure. Primary shoulder arthroplasty patients with low preoperative albumin levels have an increased risk of eLOS and may have an increased need for postacute care. Low albumin was not associated with a risk of 90-day readmissions. Albumin level merits further investigation in large, prospective cohorts to clearly define its role in preoperative risk stratification. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the cost-effectiveness of the most commonly used type of antimicrobial silver-impregnated occlusive dressing (Aquacel Ag, ConvaTec, Oklahoma City, OK, USA) for prosthetic shoulder infection (PSI) prevention after shoulder arthroplasty. Data regarding the cost of silver-impregnated occlusive dressing, cost to treat a PSI and initial infection rates after shoulder arthroplasty were calculated from available literature. Using a break-even economic analysis, we developed an equation that incorporated these variables to determine the absolute risk reduction (ARR) in infection rate required to make the use of this dressing cost-effective. To provide a widely applicable and reusable model, multiple simulations were performed at varying unit costs, infection rates, and PSI-related care costs. At a dressing cost of $34.00 and presuming a cost of $50,230 for treating a PSI, these dressings are considered cost-effective if their use prevents at least 1 infection in 1471 TSA (ARR of 0.068% from the initial infection rate of 0.7%). The cost-effectiveness of this dressing was maintained through a realistic range of dressing and PSI treatment costs, while initial infection rate was found not to influence cost-effectiveness. Antimicrobial silver-impregnated occlusive dressings represent a cost-effective infection prevention strategy after shoulder arthroplasty. The presented model serves as a useful resource to aid in weighing the economic effects of implementing any potential prophylactic measures aimed at minimizing infections after shoulder arthroplasty. Level IV; Economic Decision Analysis [ABSTRACT FROM AUTHOR]

Background: The goals of this study were to determine the incidence in the United States of preoperative three-dimensional imaging prior to anatomic total shoulder arthroplasty for osteoarthritis and to determine if preoperative imaging is associated with decreased complication rates. Methods: Using a Medicare insurance database, we identified all patients who underwent computed tomography (n = 9380) and/or magnetic resonance imaging (n = 15,653) prior to anatomic total shoulder arthroplasty for a diagnosis of osteoarthritis from 2005 to 2014. The incidence of imaging over time was analyzed and complication rates compared between patients with imaging to matched controls. Results: The incidence of preoperative three-dimensional imaging significantly increased over time, with computed tomography increasing more than magnetic resonance imaging. Compared to controls, patients with preoperative computed tomography imaging had significantly lower revision rates at two years (odds ratio 0.72 (0.64–0.82), p = 0.008). There were no other significant differences in the other complications studied. Conclusions: The use of preoperative three-dimensional imaging for anatomic total shoulder arthroplasty for a diagnosis of osteoarthritis has increased dramatically, with the use of computed tomography increasing the most. Patients who underwent preoperative computed tomography imaging experienced lower revision rates at two years postoperatively compared to matched controls without such imaging. Level of evidence: Level III, retrospective comparative study. [ABSTRACT FROM AUTHOR]

Variations in glenoid morphology affect surgical treatment and outcome of advanced glenohumeral osteoarthritis (OA). The purpose of this study was to assess the inter- and intraobserver reliability of the modified Walch classification using 3-dimensional (3D) computed tomography (CT) imaging in a multicenter research group. Deidentified preoperative CTs of patients with primary glenohumeral OA undergoing anatomic or reverse total shoulder arthroplasty (TSA) were reviewed with 3D imaging software by 23 experienced shoulder surgeons across 19 institutions. CTs were separated into 2 groups for review: group 1 (96 cases involving all modified Walch classification categories evaluated by 12 readers) and group 2 (98 cases involving posterior glenoid deformity categories [B2, B3, C1, C2] evaluated by 11 readers other than the first 12). Each case group was reviewed by the same set of readers 4 different times (with and without the glenoid vault model present), blindly and in random order. Inter- and intraobserver reliabilities were calculated to assess agreement (slight, fair, moderate, substantial, almost perfect) within groups and by modified Walch classification categories. Interobserver reliability showed fair to moderate agreement for both groups. Group 1 had a kappa of 0.43 (95% confidence interval [CI]: 0.38, 0.48) with the glenoid vault model absent and 0.41 (95% CI: 0.37, 0.46) with it present. Group 2 had a kappa of 0.38 (95% CI: 0.33, 0.43) with the glenoid vault model absent and 0.37 (95% CI: 0.32, 0.43) with it present. Intraobserver reliability showed substantial agreement for group 1 with (0.63, range 0.47-0.71) and without (0.61, range 0.52-0.69) the glenoid vault model present. For group 2, intraobserver reliability showed moderate agreement with the glenoid vault model absent (0.51, range 0.30-0.72), which improved to substantial agreement with the glenoid vault model present (0.61, range 0.34-0.87). Inter- and intraobserver reliability of the modified Walch classification were fair to moderate and moderate to substantial, respectively, using standardized 3D CT imaging analysis in a large multicenter study. The findings potentially suggest that cases with a spectrum of posterior glenoid bone loss and/or dysplasia can be harder to distinguish by modified Walch type because of a lack of defined thresholds, and the glenoid vault model may be beneficial in determining Walch type in certain scenarios. The ability to reproducibly separate patients into groups based on preoperative pathology, including Walch type, is important for future studies to accurately evaluate postoperative outcomes in TSA patient cohorts. [ABSTRACT FROM AUTHOR]

Shoulder periprosthetic joint infection (PJI) is a significant complication after arthroplasty with high morbidity. An evidence-based algorithm for the treatment of shoulder PJI is lacking in current practice. The purpose of this systematic review and meta-analysis was to understand and compare the role of single- and 2-stage shoulder arthroplasty revision for PJI. A comprehensive literature review was performed to identify all studies related to shoulder arthroplasty for PJI in PubMed, Scopus, and EMBASE. Inclusion criteria for this systematic review were studies that reported on single- or 2-stage revision, with infection eradication and a minimum follow-up of 12 months and a minimum of 5 patients for analysis. A random-effects meta-analysis was performed, and heterogeneity was assessed with Cochrane Q and I2. A total of 13 studies reporting on single-stage revision and 30 studies reporting on 2-stage revision were included in final analysis. The majority of positive cultures from single-stage revision for PJI resulted in Cutibacterium acnes with 113 of 232 (48.7%) reported cases compared with 190 of 566 (33.7%) reported cases for 2-stage revision. However, there was a lower percentage of methicillin-resistant Staphylococcus aureus positive cultures, with 2.5% for single-stage compared with 9.7% for 2-stage revision. The overall pooled random-effect reinfection incidence was 0.05 (95% confidence interval: 0.02-0.08), with moderate heterogeneity (I2 = 34%, P =.02). The reinfection rate was 6.3% for single-stage and 10.1% for 2-stage revision, but this was not significant (Q = 0.9 and P =.40). Based on a systematic review with meta-analysis, single-stage revision for shoulder PJI is an effective treatment. Indeed, our analysis showed single-stage to be more effective than 2-stage, but this is likely confounded by a treatment bias given the higher propensity of virulent and drug-resistant bacteria treated with 2-stage in the published literature. This implies that shoulder surgeons treating PJI can be reassured of a low recurrence rate (6.3%) when using single-stage treatment for C acnes or other sensitive, low-virulence organisms. [ABSTRACT FROM AUTHOR]

Anatomic total shoulder arthroplasty is the gold standard shoulder replacement procedure for patients with an intact rotator cuff and sufficient glenoid bone to accommodate prosthetic glenoid implant and offers reliable patient satisfaction, excellent implant longevity, and a low incidence of complications. Disparity exists in the literature regarding rehabilitation strategies following anatomic total shoulder arthroplasty. This article presents a consensus statement from experts in the field on rehabilitation following anatomic total shoulder arthroplasty. The goal of this consensus statement is to provide a current evidence–based foundation to inform the rehabilitation process after anatomic total shoulder arthroplasty. These guidelines apply to anatomic total shoulder arthroplasty (replacement of the humeral head and glenoid), hemiarthroplasty (replacing only the humeral head), and hemiarthroplasty with glenoid reaming or resurfacing. The consensus statement integrates an extensive literature review, as well as survey results of the practice patterns of members of the American Society of Shoulder and Elbow Therapists and the American Shoulder and Elbow Surgeons. Three stages of recovery are proposed, which initially protect and then gradually load soft tissue affected by the surgical procedure, such as the subscapularis, for optimal patient outcomes. The proposed guidelines should be used in collaboration with surgeon preferences and patient-specific factors. [ABSTRACT FROM AUTHOR]

There is no current standard by which culture specimens from revision shoulder arthroplasty should be handled, processed, cultured, and reported. Due to the relatively low numbers of cases multicenter study may provide information to form consensus recommendations. However, assimilation of multicenter data requires comparable methodologies. The objective of this study was to document and evaluate the extent of variability between surgeons and institutions. An 11-question survey was sent to 20 shoulder surgeons as part of the American Shoulder and Elbow Surgeons Periprosthetic Joint Infection Multicenter Workgroup. Questions addressed how samples are handled in the operating room by surgeons, processing of tissue samples and explants by laboratories, number of media, culture incubation durations, and culture reporting. Common practices regarding specimen handling and processing were identified including prolonged culture incubation times >13 days (94% of participants). However, substantial variation in handling of tissue and explant specimens, number and type of media used, and reporting of results were identified. The majority of surgeons reported using a sterile instrument to harvest each individual tissue specimen (10/17, 59%), more so than using any available instrument (4/17, 24%) or washing and re-using the same instrument (3/17, 18%). Half of the institutions require a time limit by which samples must be processed in the laboratory (8/16, 50%). Nine institutions (9/16, 56%) report cultures in a semiquantitative manner, while 7 (44%) report cultures in a binary fashion. Five institutions reported having performed a negative control study, and the rate of positive cultures ranged between 0% and 17%. The majority of positive cultures from the negative controls contained Cutibacterium (92%). Specimen handling, processing, culturing, and reporting varies widely between institutions. Due to the risk of false positives as demonstrated by negative control studies, surgeons should be cognizant of potential sources of contamination at the specimen handling level in the operating room and specimen processing level in the laboratory. Given the challenges in interpretation of positive cultures in revision shoulder arthroplasty, further studies are needed to determine whether assimilation of data across institutions is acceptable or whether a standard culturing methodology across institutions is necessary. Level of Evidence: V [ABSTRACT FROM AUTHOR]

The utility of next-generation sequencing (NGS) in differentiating between active infection and contaminant or baseline flora remains unclear. The purpose of this study is to compare NGS with culture-based methods in primary shoulder arthroplasty. A prospective series of primary shoulder arthroplasty patients with no history of infection or antibiotic use within 60 days of surgery was enrolled. All patients received standard perioperative antibiotics. After skin incision, a 10 × 3-mm sample of the medial skin edge was excised. A 2 × 2-cm synovial tissue biopsy was taken from the rotator interval after subscapularis takedown. Each sample set was halved and sent for NGS and standard cultures. Samples from 25 patients were analyzed. Standard aerobic/anaerobic cultures were positive in 10 skin samples (40%, 95% confidence interval [CI] 20%-60%) and 3 deep tissue samples (12%, 90% CI 1%-23%]). NGS detected ≥1 bacterial species in 17 of the skin samples (68%, 95% CI 49%-87%) and 7 deep tissue samples (28%, 95% CI 9%-47%). There was a significant difference (P <.03) in the mean number of bacterial species detected with NGS between the positive standard culture (1.6 species) and the negative standard culture groups (5.7 species). NGS identified bacteria at higher rates in skin and deep tissue samples than standard culture did in native, uninfected patients undergoing primary procedures. Further research is needed to determine which NGS results are clinically relevant and which are false positives before NGS can be reliably used in orthopedic cases. [ABSTRACT FROM AUTHOR]

The Second International Consensus Meeting on Orthopedic Infections was held in Philadelphia, Pennsylvania, in July 2018. Over 800 international experts from all 9 subspecialties of orthopedic surgery and allied fields of infectious disease, microbiology, and epidemiology were assembled to form a consensus workgroup. The following proceedings on the prevention of periprosthetic shoulder infection come from 16 questions evaluated by delegates from the shoulder section. [ABSTRACT FROM AUTHOR]

Background The in vivo effects of metal hypersensitivity remain a topic of much debate. At the core of this debate is the possible, although still hotly contested, link between metal hypersensitivity and poorly functioning or failing implants. There are multiple studies on this topic in the hip and knee arthroplasty literature, but the applicability of this experience to shoulder arthroplasty remains unclear. Although how often metal hypersensitivity affects shoulder arthroplasty patients remains uncertain, a multitude of case reports have implicated metallic implants as a source of local and systemic allergic reactions. We recommend a cautious approach to patients with a history of metal hypersensitivity, including a careful evaluation of suspected metal hypersensitivities in all patients undergoing shoulder arthroplasty. If available, we recommend a metallic implant with low to no nickel content in patients with metal hypersensitivity. Given the large and increasing, number of total shoulder arthroplasty procedures and the high percentage of the population having a known or suspected metal hypersensitivity, this review is intended to guide and educate the shoulder surgeon in the evaluation and treatment of this patient population and to point out the areas where evidence-based recommendations are lacking. [ABSTRACT FROM AUTHOR]