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.

Outcomes of Eyes Lost to Follow-up After Treatment With Intraocular or Periocular Steroid Injections.

Purpose: To evaluate the visual, intraocular pressure (IOP), and anatomic outcomes of eyes with loss to follow-up (LTFU) after intravitreal or periocular steroid injections. Methods: Patients receiving intraocular or periocular steroid injections and with LTFU for at least 180 days were included in this retrospective cohort study. Charts were reviewed for the visual acuity (VA), IOP, and central foveal thickness at the visit before LTFU, the first return visit, and 3, 6, and 12 months after return. Results: Fifty-three eyes of 47 patients were identified. The mean (±SD) age was 62.3 ± 14.9 years, the mean LTFU time was 295 ± 181.2 days (range, 182-1101), and the mean follow-up after return was 354 ± 339.3 days (range, 32-1141). The overall mean number of steroid injections was 5.2 ± 3.9 (range, 1-18). Compared with the mean logMAR VA at the visit before LTFU (0.59 [Snellen 20/77]), the mean VA remained stable at all timepoints after return as follows: return visit (0.62 [20/83]; P = .6), month 3 (0.55 [20/70]; P = .6), month 6 (0.55 [20/70]; P = .5), month 12 (0.64 [20/87]; P = .6), and final visit (0.69 [20/97]; P = .2). At the first return visit, 8 (15%) of 53 patients had an IOP of 21 mm Hg or higher (range, 21-31); 2 required treatment with a new antihypertensive medication (latanoprost and timolol, respectively). Conclusions: Patients with LTFU after receiving steroid injections maintained their VA. No patient required incisional glaucoma surgery. Compared with other etiologies, eyes with diabetic macular edema had a greater increase in IOP.

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: 399 patients (195 ream and run (RnR) and 204 anatomic total shoulder (aTSA)) were surveyed at a mean follow-up of 6.3 ± 3.3 years. Preoperative variables included age, sex, body mass index (BMI), history of prior shoulder surgery, diabetes, visual analog scale for pain (VAS), 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 Score (ASES), 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. Mean CD RISC-10 scores were higher in the RnR cohort (34.3 ± 4.8 vs. 32.5 ± 6.2 for aTSA, p<0.001). Male sex and lower preoperative VAS 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 anatomic total shoulder arthroplasty. Better mental health was associated with superior outcomes after the ream and run procedure.

Generation of a humanized mAce2 and a conditional hACE2 mouse models permissive to SARS-COV-2 infection.

The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) remains a public health concern and a subject of active research effort. Development of pre-clinical animal models is critical to study viral-host interaction, tissue tropism, disease mechanisms, therapeutic approaches, and long-term sequelae of infection. Here, we report two mouse models for studying SARS-CoV-2: A knock-in mAce2F83Y,H353K mouse that expresses a mouse-human hybrid form of the angiotensin-converting enzyme 2 (ACE2) receptor under the endogenous mouse Ace2 promoter, and a Rosa26 conditional knock-in mouse carrying the human ACE2 allele (Rosa26hACE2). Although the mAce2F83Y,H353K mice were susceptible to intranasal inoculation with SARS-CoV-2, they did not show gross phenotypic abnormalities. Next, we generated a Rosa26hACE2;CMV-Cre mouse line that ubiquitously expresses the human ACE2 receptor. By day 3 post infection with SARS-CoV-2, Rosa26hACE2;CMV-Cre mice showed significant weight loss, a variable degree of alveolar wall thickening and reduced survival rates. Viral load measurements confirmed inoculation in lung and brain tissues of infected Rosa26hACE2;CMV-Cre mice. The phenotypic spectrum displayed by our different mouse models translates to the broad range of clinical symptoms seen in the human patients and can serve as a resource for the community to model and explore both treatment strategies and long-term consequences of SARS-CoV-2 infection.

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.

Enhanced durability and evolution of retreatment criteria of intravitreal antivascular endothelial growth factor agents for diabetic macular edema.

PURPOSE OF REVIEW: The increasing prevalence of diabetic macular edema (DME) necessitates an updated review of treatment modalities. While the shift from laser to anti-vascular endothelial growth factor (anti-VEGF) therapy has transformed patient outcomes, benefits of these agents are not fully realized in real-world implementation relative to the setting of controlled clinical trials. This review outlines the evolution of intravitreal anti-VEGF treatment extension protocols for DME that reflect efforts to address treatment adherence challenges while optimizing visual outcomes. RECENT FINDINGS: Recent studies highlight the efficacy of extended-interval dosing with anti-VEGF agents in managing DME. Trials such as RISE/RIDE, VISTA/VIVID, and LUCIDATE have established the foundation of these regimens by demonstrating sustained visual gains with continuous treatment. However, newer trials including PROTOCOL T, KESTREL/KITE, YOSEMITE/RHINE, and PHOTON have furthered this concept, revealing that less frequent dosing of various anti-VEGF agents can maintain similar visual acuity and anatomical outcomes to traditional monthly injections. SUMMARY: The reviewed findings suggest a paradigm shift in DME treatment toward less frequent anti-VEGF injections. This has significant implications for clinical practice, potentially leading to greater adherence to treatment regimens and sustained visual function in patients, while minimizing treatment burden and healthcare costs. Further investigation into the long-term effects of extended dosing intervals is required.

Conversion to faricimab after prior anti-vascular endothelial growth factor therapy for persistent diabetic macular oedema.

BACKGROUND: To assess the anatomical and functional outcomes in eyes with persistent diabetic macular oedema (pDME) on chronic anti-vascular endothelial growth factor therapy switched to intravitreal faricimab. METHODS: Patients with pDME on chronic anti-vascular endothelial growth factor therapy that were switched to faricimab and received at least three injections at our institution between April 2022 and May 2023 were included in this study. Patients were excluded if they had complete response to previous treatment but were switched to extend treatment intervals if they had steroid or laser treatment for DME within 6 months prior to switch. Clinical and imaging data were extracted from the electronic medical record. Central foveal thickness (CFT) and Snellen visual acuity (VA) were obtained before and after three intravitreal faricimab injections. Generalised estimating equations were used to analyse the change in CFT and VA. RESULT: During the study period, 69 eyes of 53 patients met inclusion criteria. The mean age was 68.6±9.0 years. The mean number of injections prior to switch was 18.1±16.0. Pre-switch mean logarithm of the minimal angle of resolution VA was 0.40±0.30 (Snellen equivalent 20/50) and 0.38±0.27 (Snellen equivalent 20/48) after three faricimab injections (p=0.397). Mean CFT improved from 380±155 microns to 323±147 microns (p<0.001). No ophthalmic or systemic adverse events occurred during the study period. CONCLUSIONS: Intravitreal faricimab can improve anatomic outcomes while maintaining visual acuity in eyes with pDME previously treated with anti-VEGF therapy.

Risk of Endophthalmitis Based on Cumulative Number of Anti-VEGF Intravitreal Injections.

PURPOSE: To determine the risk of endophthalmitis in eyes undergoing intravitreal injections (IVIs) of anti-VEGF based on cumulative number of injections per eye. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients from a single center undergoing IVIs of ranibizumab, aflibercept, or bevacizumab. METHODS: Eyes were divided into quartiles based on injection number causative of endophthalmitis between January 1, 2011, and June 1, 2022. MAIN OUTCOME MEASURES: Interquartile clinical outcomes and cumulative risk of endophthalmitis per injection and per eye. RESULTS: A total of 43 393 eyes received 652 421 anti-VEGF injections resulting in 231 endophthalmitis cases (0.035% per injection, 1 in 2857), of which 215 were included. The cumulative endophthalmitis risk increased from 0.0018% (1 in 55 556) after 1 injection to 0.013% (1 in 7692) after 11 injections (0.0012 percentage point change), versus 0.014% (1 in 7143) after 12 injections to 0.025% (1 in 4000) after 35 injections (0.00049 percentage point change), versus 0.025% (1 in 4000) after 36 injections to 0.031% (1 in 3226) after 66 injections (0.00017 percentage point change), versus 0.031% (1 in 3226) after 63 injections to 0.033% (1 in 3030) after 126 injections (0.000042 percentage point change) (P < 0.001). Likewise, the cumulative endophthalmitis risk per eye increased from 0.028% (1 in 3571) to 0.20% (1 in 500) between injections 1 and 11 (0.018 percentage point change), versus 0.21% (1 in 476) to 0.38% (1 in 263) between injections 12 and 35 (0.0075 percentage point change), versus 0.38% (1 in 263) to 0.46% (1 in 217) between injections 36 and 66 (0.0026 percentage point change), versus 0.46% (1 in 217) to 0.50% (1 in 200) between injections 67 and 126 (0.00063 percentage point change) (P < 0.001). CONCLUSIONS: The cumulative endophthalmitis risk per injection and per eye increased with greater number of injections received but appeared to do so at a higher rate during earlier injections and at a lower rate further into the treatment course. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

OCT-Based Description of Spontaneous Reattachment of Macula-Off Tractional Retinal Detachment With Significant Vision Improvement.

Purpose: To describe the clinical course and optical coherence tomography (OCT) features of patients with spontaneous reattachment of macula-off tractional retinal detachments (TRDs). Methods: Findings on clinical examination and OCT were evaluated. Results: Four eyes of 4 patients with a history of macula-off TRD secondary to diabetic retinopathy (n = 3) or sickle cell retinopathy (n = 1) were included. OCT confirmed spontaneous resolution of the macular RD without complete posterior vitreous separation in all eyes. The median (interquartile range [IQR]) time from TRD diagnosis to OCT-confirmed foveal reattachment was 6 months (10.25; range, 1-12 months). The median logMAR visual acuity (VA) at the time of macula-off TRD was 0.544 (IQR, 0.452; Snellen 20/70), which improved to 0.350 (IQR, 0.156; Snellen 20/45), with reattachment characterized by OCT (P = .068). Conclusions: Nonsurgical spontaneous retinal reattachment and significant VA improvement can occur in eyes with a TRD, albeit rarely. In these cases, no OCT evidence of posterior vitreous separation was found, suggesting that some relaxation of the contractile fibrovascular membranes occurred.

Machine-Learning Based Risk Assessment for Cancer Therapy-Related Cardiac Adverse Events Among Breast Cancer Patients.

The study aims to develop machine-learning models to predict cardiac adverse events in female breast cancer patients who receive adjuvant therapy. We selected breast cancer patients from a retrospective dataset of the Taipei Medical University Clinical Research Database and Taiwan Cancer Registry between January 2004 and December 2020. Patients were monitored at the date of prescribed chemo- and/or -target therapies until cardiac adverse events occurred during a year. Variables were used, including demographics, comorbidities, medications, and lab values. Logistics regression (LR) and artificial neural network (ANN) were used. The performance of the algorithms was measured by the area under the receiver operating characteristic curve (AUC). In total, 1321 patients (an equal 15039 visits) were included. The best performance of the artificial neural network (ANN) model was achieved with the AUC, precision, recall, and F1-score of 0.89, 0.14, 0.82, and 0.2, respectively. The most important features were a pre-existing cardiac disease, tumor size, estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), cancer stage, and age at index date. Further research is necessary to determine the feasibility of applying the algorithm in the clinical setting and explore whether this tool could improve care and outcomes.

In Situ Electrochemistry of Formate on Cu Thin Films Using ATR-FTIR Spectroscopy and X-ray Photoelectron Spectroscopy.

Formate (HCOO-) is the most dominant intermediate identified during carbon dioxide electrochemical reduction (CO2ER). While previous studies showed that copper (Cu)-based materials that include Cu(0), Cu2O, and CuO are ideal catalysts for CO2ER, challenges to scalability stem from low selectivity and undesirable products in the -1.0-1.0 V range. There are few studies on the binding mechanism of intermediates and products for these systems as well as on changes to surface sites upon applying potential. Here, we use an in situ approach to study the redox surface chemistry of formate on Cu thin films deposited on Si wafers using a VeeMAX III spectroelectrochemical (SEC) cell compatible with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Spectra for surface species were collected in real time as a function of applied potential during cyclic voltammetry (CV) experiments. Results showed the reproducibility of CV curves on freshly prepared Cu/Si wafers with relatively high signal-to-noise ATR-FTIR absorbance features of surface species during these electrochemical experiments. The oxidation reaction of HCOO- to bicarbonate (HCO3-) was observed using ATR-FTIR at a voltage of 0.27 V. Samples were then subjected to reduction in the CV, and the aqueous phase products below the detection limit of the SEC-ATR-FTIR were identified using ion chromatography (IC). We report the formation of glycolate (H3C2O3-) and glyoxylate (HC2O3-) with trace amounts of oxalate (C2O42-), indicating that C-C coupling reactions proceed in these systems. Changes to the oxidation state of surface Cu were measured using X-ray photoelectron spectroscopy, which showed a reduction in Cu(0) and an increase in Cu(OH)2, indicating surface oxidation.

Surgical Management of Full-Thickness Macular Holes in Macular Telangiectasia Type 2: A Global Multicenter Study.

PURPOSE: To report on macular hole repair in macular telangiectasia type 2 (MacTel2). DESIGN: Global, multicenter, retrospective case series. PARTICIPANTS: Patients undergoing surgery for MacTel2-associated full-thickness macular hole (MTMH). METHODS: Standardized data collection sheet distributed to all surgeons. MAIN OUTCOME MEASURES: Anatomic closure and visual outcomes of MTMH. RESULTS: Sixty-three surgeries in 47 patients with MTMH were included from 30 surgeons. Mean age was 68.1 years, with 62% female, 72% White, 21% East or South Asian, 2% African American, and 2% Hispanic or Latino. Procedures included 34 internal limiting membrane (ILM) peeling alone, 22 ILM flaps, 5 autologous retinal transplantations (ARTs), 1 retinotomy, and 1 subretinal bleb. For ILM peeling, preoperative visual acuity (VA) was 0.667 ± 0.423 logarithm of the minimum angle of resolution (logMAR). Minimum hole diameter (MHD) was 305.5 ± 159.4 µm (range, 34-573 µm). Sixteen of 34 ILM peels (47%) resulted in MTMH closure. At postoperative month 6, VA was stable at 0.602 ± 0.516 logMAR (P = 0.65). VA improved by at least 2 lines in 43% and at least 4 lines in 24%. For ILM flaps, preoperative VA was 0.878 ± 0.552 logMAR. MHD was 440.8 ± 175.5 µm (range, 97-697 µm), which was significantly larger than for ILM peels (P < 0.01). Twenty of 22 ILM flaps (90%) resulted in MTMH closure, which was significantly higher than for ILM peels (P < 0.01). At postoperative month 6, VA improved to 0.555 ± 0.405 logMAR (P < 0.05). VA improved by at least 2 lines in 56% and at least 4 lines in 28%. For ARTs, preoperative VA was 1.460 ± 0.391 logMAR. MHD was 390.2 ± 203.7 µm (range, 132-687 µm). All 5 ARTs (100%) resulted in MTMH closure. At postoperative month 6, VA was stable at 1.000 ± 0.246 logMAR (P = 0.08). Visual acuity improved at least 2 lines in 25%. CONCLUSIONS: Surgical closure of macular holes improved VA in 57% of MTMHs. Internal limiting membrane flaps achieved better anatomic and functional outcomes than ILM peeling alone. Autologous retinal transplantation may be an option for refractory MTMHs. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

IMPACT OF FOVEAL STATUS AND TIMING OF SURGERY ON VISUAL OUTCOME IN RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To investigate the impact of surgical timing on visual acuity outcomes in retinal detachments based on the preoperative foveal status. METHODS: A retrospective multicenter cohort study was conducted. Cases were stratified into fovea-on, fovea-split, and fovea-off groups. Days to surgery was defined as the time between the preoperative examination and surgery. The main outcome measure was the final postoperative visual acuity. RESULTS: 1,675 cases were studied. More than 80% of fovea-on/fovea-split and fovea-off cases had surgery within 1 and 3 days, respectively. The mean final postoperative visual acuity did not differ significantly between the fovea-on and fovea-split groups (Snellen equivalent [SE] 20/33 ± 20/49 and 20/32 ± 20/39, P = 1.000) and did not change significantly based on days to surgery in either group. The mean final postoperative visual acuity was lowest in the fovea-off group (Snellen equivalent = 20/56 ± 20/76, P < 0.001) and was significantly lower in cases where surgery was performed after two or more days when compared with cases performed within 1 day (Snellen equivalent 20/74 ± 20/89 vs. 20/46 ± 20/63, P < 0.001). CONCLUSION: Fovea-on and fovea-split retinal detachments demonstrated comparable visual outcomes. Fovea-off RDs demonstrated worse visual outcomes, which declined further when surgery was delayed by two or more days.

CHARACTERISTICS OF PARTICIPANTS IN DIABETIC RETINOPATHY CLINICAL RESEARCH CLINICAL TRIALS WHO WERE LOST TO FOLLOW-UP.

PURPOSE: Our study describes the racial/ethnic composition and the broad health status/severity of disease of the cohorts of Diabetic Retinopathy Clinical Research clinical trials and compares the rates of noncompletion of the trial with the first data report (lost to follow-up). METHODS: This study is a retrospective cohort study of participants in Diabetic Retinopathy Clinical Research Retina Network clinical trials who met our inclusion criteria. The primary outcome was the lost to follow-up rates and their associated risk factors. RESULTS: Eight clinical trials with 3,492 participants met our inclusion criteria. Participants who were lost to follow-up were more likely to be younger, Hispanic or Black, had Type 1 diabetes mellitus, had worse baseline best-corrected visual acuity, had higher hemoglobin A1c, had higher blood pressure, and had proliferative diabetic retinopathy (PDR) (Diabetic Retinopathy Severity Score >66). CONCLUSION: Participants who were lost to follow-up during Diabetic Retinopathy Clinical Research clinical trials tended to be younger, Hispanic or Black, and had worse diabetes and hypertension. This study highlights the importance of ensuring that a representative population is maintained through the end of the study period.

How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability.

BACKGROUND: Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs. METHODS: Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 µm was defined as failure. RESULTS: Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-µm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 µm; 2PL: 78 ± 32 µm; 2PNL: 79 ± 8 µm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-µm threshold (1P: 88 ± 22 µm; 2PL: 132 ± 26 µm; 2PNL: 107 ± 39 µm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-µm threshold whereas the 1-piece design did not (1P: 133 ± 35 µm; 2PL: 183 ± 21 µm; 2PNL: 166 ± 39 µm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041). DISCUSSION: The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

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.

Infection in Shoulder Arthroplasty: Prevention, Diagnosis, and Treatment.

Prosthetic joint infection is a devastating complication following shoulder arthroplasty that can lead to pain, poor function, and poor quality of life. With the increasing number of shoulder arthroplasties performed annually, recognition of prosthetic infection and treatment is necessary. The skin surrounding the shoulder has a unique microbiome, and Cutibacterium acnes is the most commonly encountered bacteria causing prosthetic joint infection. C acnes is a low-virulence organism that resides in the subcutaneous layer of the skin. As a result, the clinical presentation is typically less obvious than prosthetic infections seen in other joints such as the hip and knee. Therefore, diagnosis is not always straightforward, and optimal treatment strategy is unclear. Guidance on prevention, diagnosis, and treatment of shoulder prosthetic joint infection with special emphasis on the consensus definition established at the 2018 International Consensus Meeting is provided.