Two-year clinical outcomes and complication rates in anatomic and reverse shoulder arthroplasty implanted with Exactech GPS intraoperative navigation.

INTRODUCTION: We compared the 2-year clinical outcomes of both anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) using intraoperative navigation compared to traditional positioning techniques. We also examined the effect of glenoid implant retroversion on clinical outcomes. HYPOTHESIS: In both ATSA and RTSA, computer navigation would be associated with equal or better outcomes with fewer complications. Final glenoid version and degree of correction would not show outcome differences. MATERIAL AND METHODS: A total of 216 ATSAs and 533 RTSAs were performed using preoperative planning and intraoperative navigation with a minimum of 2-year follow-up. Matched cohorts (2:1) for age, gender, and follow-up for cases without intraoperative navigation were compared using all standard shoulder arthroplasty clinical outcome metrics. Two subanalyses were performed on navigated cases comparing glenoids positioned greater or less than 10° of retroversion and glenoids corrected more or less than 15°. RESULTS: For ASTA, no statistical differences were found between the navigated and non-navigated cohorts for postoperative complications, glenoid implant loosening, or revision rate. No significant differences were seen in any of the ATSA outcome metrics besides higher internal and external rotation in the navigated cohort. For RTSA, the navigated cohort showed an ARR of 1.7% (95% CI 0%, 3.4%) for postoperative complications and 0.7% (95% CI 0.1%, 1.2%) for dislocations. No difference was found in the revision rate, glenoid implant loosening, acromial stress fracture rates, or scapular notching. Navigated RTSA patients demonstrated significant improvements over non-navigated patients in internal rotation, external rotation, maximum lifting weight, the Simple Shoulder Test (SST), Constant, and Shoulder Arthroplasty Smart (SAS) scores. For the navigated subcohorts, ATSA cases with a higher degree of final retroversion showed significant improvement in pain, Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), SST, University of California-Los Angeles shoulder score (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. No significant differences were found in the RTSA subcohort. Higher degrees of version correction showed improvement in external rotation, SST, and Constant scores for ATSA and forward elevation, internal rotation, pain, SST, Constant, ASES, UCLA, SPADI, and SAS scores for RTSA. CONCLUSION: The use of intraoperative navigation shoulder arthroplasty is safe, produces at least equally good outcomes at 2 years as standard instrumentation does without any increased risk of complications. The effect of final implant position above or below 10° of glenoid retroversion and correction more or less than 15° does not negatively impact outcomes.

Inhibition of HIV Replication by Apolipoprotein A-I Binding Protein Targeting the Lipid Rafts.

Apolipoprotein A-I binding protein (AIBP) is a protein involved in regulation of lipid rafts and cholesterol efflux. AIBP has been suggested to function as a protective factor under several sets of pathological conditions associated with increased abundance of lipid rafts, such as atherosclerosis and acute lung injury. Here, we show that exogenously added AIBP reduced the abundance of lipid rafts and inhibited HIV replication in vitro as well as in HIV-infected humanized mice, whereas knockdown of endogenous AIBP increased HIV replication. Endogenous AIBP was much more abundant in activated T cells than in monocyte-derived macrophages (MDMs), and exogenous AIBP was much less effective in T cells than in MDMs. AIBP inhibited virus-cell fusion, specifically targeting cells with lipid rafts mobilized by cell activation or Nef-containing exosomes. MDM-HIV fusion was sensitive to AIBP only in the presence of Nef provided by the virus or exosomes. Peripheral blood mononuclear cells from donors with the HLA-B*35 genotype, associated with rapid progression of HIV disease, bound less AIBP than cells from donors with other HLA genotypes and were not protected by AIBP from rapid HIV-1 replication. These results provide the first evidence for the role of Nef exosomes in regulating HIV-cell fusion by modifying lipid rafts and suggest that AIBP is an innate factor that restricts HIV replication by targeting lipid rafts.IMPORTANCE Apolipoprotein A-I binding protein (AIBP) is a recently identified innate anti-inflammatory factor. Here, we show that AIBP inhibited HIV replication by targeting lipid rafts and reducing virus-cell fusion. Importantly, AIBP selectively reduced levels of rafts on cells stimulated by an inflammatory stimulus or treated with extracellular vesicles containing HIV-1 protein Nef without affecting rafts on nonactivated cells. Accordingly, fusion of monocyte-derived macrophages with HIV was sensitive to AIBP only in the presence of Nef. Silencing of endogenous AIBP significantly upregulated HIV-1 replication. Interestingly, HIV-1 replication in cells from donors with the HLA-B*35 genotype, associated with rapid progression of HIV disease, was not inhibited by AIBP. These results suggest that AIBP is an innate anti-HIV factor that targets virus-cell fusion.

T cells with high PD-1 expression are associated with lower HIV-specific immune responses despite long-term antiretroviral therapy.

OBJECTIVE: We evaluated frequencies of T cells with high PD-1 expression (PD-1) before and after long-term effective antiretroviral therapy (ART), and determined if frequencies on-ART correlated positively with measures of HIV persistence and negatively with HIV-specific responses. METHODS: We enrolled individuals who started ART during chronic infection and had durable suppression of viremia for at least 4 years (N = 99). We assessed PD-1 T-cell frequencies at timepoints pre-ART and on-ART using flow cytometry, and evaluated how frequencies on-ART are associated with measures of HIV persistence, HIV-specific immune responses, and immune activation levels. RESULTS: Pre-ART, PD-1 CD4 T cells correlated positively with viremia and negatively with CD4 T-cell count. At year 1 on-ART, %PD-1 CD4 T cells decreased but then remained stable at 4 and 6-15 years on-ART, whereas %PD-1 CD8 T cells on-ART remained similar to pre-ART. PD-1 CD4 T cells correlated positively with HIV DNA pre-ART and on-ART, and with CD4 T-cell activation on-ART. PD-1 CD4 T cells negatively correlated with HIV Gag-specific and Env-specific T-cell responses but not with CMV-specific or EBV-specific responses. PD-1 CD8 T cells trended towards a negative correlation with responses to Gag and Env, but not to CMV and EBV. CONCLUSION: PD-1 T cells persist in blood despite prolonged suppression on ART, correlate with HIV DNA levels, and are associated with lower HIV-specific T-cell responses but not CMV-specific or EBV-specific responses, suggesting that these cells are HIV-specific. The findings support evaluating PD-1 blockade strategies for their effect on HIV persistence and HIV-specific immunity.

Effect of Tuberosity Healing on Clinical Outcomes in Elderly Patients Treated With a Reverse Shoulder Arthroplasty for 3- and 4-Part Proximal Humerus Fractures.

OBJECTIVES: To evaluate tuberosity union rate and clinical outcome after 3- and 4-part proximal humerus fractures in the elderly. DESIGN: Retrospective, multicenter database cohort study. SETTING: Level I and Level II trauma centers. PATIENTS: Fifty-five patients older than 65 years had insertion of reverse shoulder arthroplasty (RTSA) for OTA/AO 11-B and 11-C proximal humerus fractures. INTERVENTION: Treatment with RTSA using a dedicated low profile onlay fracture stem using variable tuberosity fixation. MAIN OUTCOME MEASURES: Constant score, the American Shoulder and Elbow Surgeons score, Shoulder Pain and Disability Index score, University of California at Los Angeles score, Simple Shoulder Test score, visual analog pain score, shoulder function score, active range of motion, external rotation (ER)-specific tasks and position, rate of greater tuberosity healing, effect of tuberosity healing on overall clinical metrics, incidence of humeral lucency, and scapular notching. RESULTS: Eighty-three percent of the greater tuberosities that were repaired united. Greater tuberosity union resulted in greater active ER (P = 0.0415). There was a statistically significant difference in the ability to do ER-type activities between the 2 cohorts reflected in the ability to position one's hand behind their head with the elbow forward (P = 0.002) and comb their hair (P < 0.001). CONCLUSION: The use of a low profile onlay fracture stem in RTSA for acute 3- and 4-part proximal humerus fractures in the elderly can result in a high tuberosity union rate. Greater tuberosity healing significantly influences ER and ER-type activities that are not apparent by analysis of the overall metrics studied. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Identification of Novel Protein Expression Changes Following Cisplatin Treatment and Application to Combination Therapy.

Determining the effect of chemotherapeutic treatment on changes in protein expression can provide important targets for overcoming resistance. Due to challenges in simultaneously measuring large numbers of proteins, a paucity of data exists on global changes. To overcome these challenges, we utilized microwestern arrays that allowed us to measure the abundance and modification state of hundreds of cell signaling and transcription factor proteins in cells following drug exposure. HapMap lymphoblastoid cell lines (LCLs) were exposed to cisplatin, a chemotherapeutic agent commonly used to treat testicular, head and neck, non-small cell lung, and gynecological cancers. We evaluated the expression of 259 proteins following 2, 6, and 12 h of cisplatin treatment in two LCLs with discordant sensitivity to cisplatin. Of these 259 proteins, 66 displayed significantly different protein expression changes (p < 0.05). Fifteen of these proteins were evaluated in a second pair of LCLs with discordant sensitivities to cisplatin; six demonstrated significant differences in expression. We then evaluated a subset of 63 proteins in a second set of LCLs with discordant sensitivity, and 40% of those that were significant in the first pair were also significant in the second part with concordant directionality (p < 0.05). We functionally validated one of the top proteins identified, PDK1, and demonstrated a synergistic relationship between cisplatin and a PDK1 inhibitor in multiple lung cancer lines. This study highlights the potential for identifying novel targets through an understanding of cellular changes in protein expression and modification following drug treatments.

IFITM1 targets HIV-1 latently infected cells for antibody-dependent cytolysis.

HIV-1 persistence in latent reservoirs during antiretroviral therapy (ART) is the main obstacle to virus eradication. To date, there is no marker that adequately identifies latently infected CD4+ T cells in vivo. Using a well-established ex vivo model, we generated latently infected CD4+ T cells and identified interferon-induced transmembrane protein 1 (IFITM1), a transmembrane antiviral factor, as being overexpressed in latently infected cells. By targeting IFITM1, we showed the efficient and specific killing of a latently infected cell line and CD4+ T cells from ART-suppressed patients through antibody-dependent cytolysis. We hypothesize that IFITM1 could mark natural reservoirs, identifying an immune target for killing of latently infected cells. These novel insights could be explored to develop clinical therapeutic approaches to effectively eradicate HIV-1.

Microwestern Arrays for Systems-Level Analysis of SH2 Domain-Containing Proteins.

The Microwestern Array (MWA) method combines the scalability and miniaturization afforded by the Reverse Phase Lysate Array (RPLA) approach with the electrophoretic separation characteristic of the Western blot. This technology emulates the creation of an array of small Western blots on a single sheet of nitrocellulose allowing for the sensitive and quantitative measurement of hundreds of proteins from hundreds of cell lysates with minimal cost and maximal accuracy, precision, and reproducibility. The MWA is a versatile technology that can be easily configured for purposes such as antibody screening, cell signaling network inference, protein modification/phenotype regression analysis, and genomic/proteomic relationships. Accordingly, configurations for the MWA can be optimized for maximal numbers of proteins analyzed from small numbers of cell lysates, for small numbers of antibodies against large numbers of cell lysates, or for maximal resolution of protein size achieved by increased electrophoretic separation distance. For example, on a single gel, 6 samples can be printed 96 times if a few samples need to be assayed with a large number of antibodies. Alternatively, up to 100 samples can be assayed with four antibodies on a single gel. Intermediate configurations are also discussed.The efficiency of the MWA is orders of magnitude greater in reagents, labor, and time required per data point relative to the standard Western blotting method and orders of magnitude more sensitive than standard mass spectrometry methods. The MWA is therefore a very attractive approach for capturing global changes in protein abundances and modifications including tyrosine phosphorylation and SH2 domain binding sites.

Reverse total shoulder arthroplasty with structural bone grafting of large glenoid defects.

BACKGROUND: Large glenoid defects pose difficulties in shoulder arthroplasty. Structural grafts consisting of a humeral head autograft, iliac crest, and allograft have been described. Few series describe grafts used with reverse total shoulder arthroplasty (RTSA). METHODS: We retrospectively reviewed patients who had undergone primary or revision RTSA. We identified 44 patients (20 men and 24 women; mean age, 69 years) as having a bulk structural graft to the glenoid behind the baseplate. The grafts consisted of a humeral head autograft in 29, iliac crest autograft in 1, or femoral head allograft in 14. Range of motion data, American Shoulder and Elbow Surgeons score, simple shoulder test, shoulder pain and disability index, and Constant scores were obtained from preoperative and the latest follow-up visits. Radiographs were reviewed from the initial postoperative visit and the latest follow-up. The grafting cohort was compared with an age- and sex-matched cohort of RTSA patients without glenoid grafting. RESULTS: Improvements were seen in the functional outcome scores at the latest follow-up. No significant differences were found in the preoperative or postoperative data between allografts and autografts. Postoperative scores for the bone graft cohort were significantly lower than those in the cohort without grafting. Complete or partial incorporation was shown radiographically in 81% of grafts. Six baseplates were considered loose. Complications included 2 infections, 1 dislocation, 1 humeral loosening, and 2 instances of clinical aseptic baseplate loosening. Six patients showed mild scapular notching. CONCLUSIONS: The use of bulk structural grafts is a promising treatment option. Allografts may yield equally acceptable results compared with autografts.

Distribution of Glenoid Implant Options for Correcting Deformities Using a Preoperative Planning Tool.

Preoperative planning tools in shoulder arthroplasty are a recently developing technology with the advantage of being able to clearly assess patient anatomy and deformities before entering the OR. Addressing retroverted glenoids remains one of the most difficult aspects of primary shoulder arthroplasty. In this study, five surgeons were provided with a preoperative planning tool with posterior augmented glenoid implant options (0°, 8°, and 16°) to treat 10 cadaveric cases with a range of versions from 7.8° anteversion to 25.1° retroversion. Surgeons were able to remove less bone using 8° augmented implants over standard non-augmented implants (2.8° reamed vs. 6.4° reamed) and were able to correct each case on average within ± 1.8° of neutral version. Slight glenoid vault perforation was observed in 18% of the plans. Eight degrees posterior augmented implants were used in scans averaging 9.0° retroversion, and 16° posterior augmented implants were used in scans averaging 20.6° retroversion. Results were then compared to 14 preoperative CT scans provided by one of the surgeons in which both 8° and 16° posterior augmented glenoid implants were used in actual patients, showing 8° posterior augmented implants were used in cases averaging 12.3° retroversion, and 16° posterior augmented implants were used in cases averaging 20.7° retroversion. The study shows that surgeons can effectively and predictably use a preoperative planning tool to correct glenoid abnormalities using augmented implant solutions while minimizing both scapular bone removal and vault perforation and maximizing version correction.

Evaluation of Preoperative Implant Placement in Total Shoulder Arthroplasty.

INTRODUCTION: New technology to assist with glenoid placement in shoulder arthroplasty has evolved to include preoperative planning tools and intraoperative guides. These tools provide surgeons with a more complete understanding of glenoid anatomy prior to surgery. However, there have been no studies identifying the information that most influences surgical decision making. Further, there have been few studies that quantify intraoperative identification of scapular landmarks required to execute a preoperative plan. The purpose of this study is to examine the variables that are considered when making a preoperative plan in shoulder arthroplasty. METHODS: The first part of this study was a cadaveric lab in which three surgeons identified the neutral axis in surgical simulation. The second part of the study utilized a preliminary software tool in which surgeons were able to place glenoid implants in a set of CT reconstructions utilizing standard pegged glenoid components. In the third part of the study, surgeons utilized a novel planning software that included the ability to view the 3D reconstructed glenoid in all planes simultaneously and place either standard or augmented glenoid implants. The results of these three studies were compared. RESULTS: The center of the glenoid identified in the cadaver lab was 1.69 mm ± 1.58 mm anterior and 1.99 mm ± 2.49 mm superior to center. The identified neutral axis was tilted 14.2° ± 9.2° superior to the Friedman axis with 11.8° ± 7.9° of retroversion relative to that axis. Using the novel preoperative planning tool, the surgeons placed implants less than 0.5 mm from the center of the glenoid (AP = -0.07 mm ± 0.42 mm, SI = 0.44 mm ± 0.82 mm) with an average retroversion of less than 1° (-0.96° ± 3.04°). CONCLUSION: There was a discernible difference between the neutral axis identified in the cadaveric simulation (aver age of 14.2° superior and 11.8° retroverted) and the implant orientation planned using preoperative software (average of 3.26° superior and 0.96° retroverted). Based on the variability of position and orientation seen cadaverically, it is concluded that additional intraoperative guidance is needed alongside a preoperative plan in order to execute ideal placement of the glenoid component.

Bone Grafting the Glenoid Versus Use of Augmented Glenoid Baseplates with Reverse Shoulder Arthroplasty.

BACKGROUND: Large glenoid defects are a difficult reconstructive problem for surgeons performing reverse shoulder arthroplasty (rTSA). Options to address glenoid defects include eccentric reaming, bone grafting, and augmented glenoid baseplates. Augmented glenoid baseplates may provide a simpler, cost-effective, bone-preserving option compared to other techniques. No studies report the use of augmented baseplates to correct glenoid deformity in rTSA relative to the use of glenoid bone graft. MATERIALS AND METHODS: We retrospectively reviewed 80 patients that received a primary rTSA and received either a structural bone graft or an augmented glenoid baseplate to address a significant glenoid defect. There were 39 patients in the augmented baseplate cohort and 41 patients in the bone graft cohort. The augmented baseplate cohort contained 24 8° posterior augment implants and 15 10° superior augment baseplates. The bone graft cohort consisted of 36 autograft humeral heads and 5 allograft femoral heads. The average follow-up for rTSA patients with an augmented baseplate was 28.3 ± 5.7 months, and the average follow-up for rTSA patients with glenoid bone graft was 34.1 ± 15.0 months. Each patient was scored preoperatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI metrics. Range of motion data was obtained as well. RESULTS: All patients demonstrated significant improvements in pain, ROM, and functional scores following treatment with rTSA using either augmented baseplates or glenoid bone graft to correct glenoid defects. The database contained no complications for the augmented glenoid baseplate cohort, and six complications (14.6%) for the glenoid bone graft cohort (including two glenoid loosenings and graft failures). Additionally, the augmented baseplate cohort showed a lower scapular notching rate of 10% as compared to the bone graft cohort which had a notching rate of 18.5%. DISCUSSION: The results of this study suggest that either augmented glenoid baseplates or glenoid bone graft can be used to address large glenoid defects during rTSA with significant improvement in outcomes. Augmented glenoid baseplates may achieve a lower complication and scapular notching rate, but additional and longer-term clinical follow-up is required to confirm these results.

The DIONESUS algorithm provides scalable and accurate reconstruction of dynamic phosphoproteomic networks to reveal new drug targets.

Many drug candidates fail in clinical trials due to an incomplete understanding of how small-molecule perturbations affect cell phenotype. Cellular responses can be non-intuitive due to systems-level properties such as redundant pathways caused by co-activation of multiple receptor tyrosine kinases. We therefore created a scalable algorithm, DIONESUS, based on partial least squares regression with variable selection to reconstruct a cellular signaling network in a human carcinoma cell line driven by EGFR overexpression. We perturbed the cells with 26 diverse growth factors and/or small molecules chosen to activate or inhibit specific subsets of receptor tyrosine kinases. We then quantified the abundance of 60 phosphosites at four time points using a modified microwestern array, a high-confidence assay of protein abundance and modification. DIONESUS, after being validated using three in silico networks, was applied to connect perturbations, phosphorylation, and cell phenotype from the high-confidence, microwestern dataset. We identified enhancement of STAT1 activity as a potential strategy to treat EGFR-hyperactive cancers and PTEN as a target of the antioxidant, N-acetylcysteine. Quantification of the relationship between drug dosage and cell viability in a panel of triple-negative breast cancer cell lines validated proposed therapeutic strategies.

Mapping glucose-mediated gut-to-brain signalling pathways in humans.

OBJECTIVES: Previous fMRI studies have demonstrated that glucose decreases the hypothalamic BOLD response in humans. However, the mechanisms underlying the CNS response to glucose have not been defined. We recently demonstrated that the slowing of gastric emptying by glucose is dependent on activation of the gut peptide cholecystokinin (CCK1) receptor. Using physiological functional magnetic resonance imaging this study aimed to determine the whole brain response to glucose, and whether CCK plays a central role. EXPERIMENTAL DESIGN: Changes in blood oxygenation level-dependent (BOLD) signal were monitored using fMRI in 12 healthy subjects following intragastric infusion (250ml) of: 1M glucose+predosing with dexloxiglumide (CCK1 receptor antagonist), 1M glucose+placebo, or 0.9% saline (control)+placebo, in a single-blind, randomised fashion. Gallbladder volume, blood glucose, insulin, and GLP-1 and CCK concentrations were determined. Hunger, fullness and nausea scores were also recorded. PRINCIPAL OBSERVATIONS: Intragastric glucose elevated plasma glucose, insulin, and GLP-1, and reduced gall bladder volume (an in vivo assay for CCK secretion). Glucose decreased BOLD signal, relative to saline, in the brainstem and hypothalamus as well as the cerebellum, right occipital cortex, putamen and thalamus. The timing of the BOLD signal decrease was negatively correlated with the rise in blood glucose and insulin levels. The glucose+dex arm highlighted a CCK1-receptor dependent increase in BOLD signal only in the motor cortex. CONCLUSIONS: Glucose induces site-specific differences in BOLD response in the human brain; the brainstem and hypothalamus show a CCK1 receptor-independent reduction which is likely to be mediated by a circulatory effect of glucose and insulin, whereas the motor cortex shows an early dexloxiglumide-reversible increase in signal, suggesting a CCK1 receptor-dependent neural pathway.

Enhanced prediction of Src homology 2 (SH2) domain binding potentials using a fluorescence polarization-derived c-Met, c-Kit, ErbB, and androgen receptor interactome.

Many human diseases are associated with aberrant regulation of phosphoprotein signaling networks. Src homology 2 (SH2) domains represent the major class of protein domains in metazoans that interact with proteins phosphorylated on the amino acid residue tyrosine. Although current SH2 domain prediction algorithms perform well at predicting the sequences of phosphorylated peptides that are likely to result in the highest possible interaction affinity in the context of random peptide library screens, these algorithms do poorly at predicting the interaction potential of SH2 domains with physiologically derived protein sequences. We employed a high throughput interaction assay system to empirically determine the affinity between 93 human SH2 domains and phosphopeptides abstracted from several receptor tyrosine kinases and signaling proteins. The resulting interaction experiments revealed over 1000 novel peptide-protein interactions and provided a glimpse into the common and specific interaction potentials of c-Met, c-Kit, GAB1, and the human androgen receptor. We used these data to build a permutation-based logistic regression classifier that performed considerably better than existing algorithms for predicting the interaction potential of several SH2 domains.

Scapular notching in reverse shoulder arthroplasty: validation of a computer impingement model.

PURPOSE: The purpose of this study is to validate a reverse shoulder computer impingement model and quantify the impact of implant position on scapular impingement by comparing it to that of a radiographic analysis of 256 patients who received the same prosthesis and were followed postoperatively for an average of 22.2 months. METHODS: A geometric computer analysis quantified anterior and posterior scapular impingement as the humerus was internally and externally rotated at varying levels of abduction and adduction relative to a fixed scapula at defined glenoid implant positions. These impingement results were compared to radiographic study of 256 patients who were analyzed for notching, glenoid baseplate position, and glenosphere overhang. RESULTS: The computer model predicted no impingement at 0° humeral abduction in the scapular plane for the 38 mm, 42 mm, and 46 mm devices when the glenoid baseplate cage peg is positioned 18.6 mm, 20.4 mm, and 22.7 mm from the inferior glenoid rim (of the reamed glenoid) or when glenosphere overhang of 4.6 mm, 4.7 mm, and 4.5 mm was obtained with each size glenosphere, respectively. When compared to the radiographic analysis, the computer model correctly predicted impingement based upon glenoid base- plate position in 18 of 26 patients with scapular notching and based upon glenosphere overhang in 15 of 26 patients with scapular notching. CONCLUSIONS: Reverse shoulder implant positioning plays an important role in scapular notching. The results of this study demonstrate that the computer impingement model can effectively predict impingement based upon implant positioning in a majority of patients who developed scapular notching clinically. This computer analysis provides guidance to surgeons on implant positions that reduce scapular notching, a well-documented complication of reverse shoulder arthroplasty.

Addressing glenoid erosion in anatomic total shoulder arthroplasty.

Glenoid wear is common in the setting of shoulder arthritis. Severe glenoid erosion presents a serious challenge to the surgeon performing a shoulder arthroplasty. This paper presents the various classification schemes for glenoid erosion. The results of the six main treatment options for shoulder arthroplasty with an eroded glenoid are reviewed. The six treatment options include: 1. eccentric reaming, 2. bone grafting, 3. use of inset glenoid, 4. use of an augmented (asymmetric) glenoid component, 5. hemiarthroplasty, and 6. reverse shoulder arthroplasty. A treatment algorithm is proposed based on the amount of glenoid erosion. Severe glenoid wear resulting in the need for shoulder replacement surgery is a challenge; however, new tools for dealing with this complicated entity are rapidly evolving, including the use of augmented anatomic glenoid components and reverse shoulder arthroplasty with augmented baseplates.

Hemiarthroplasty for proximal humeral fractures. Indications, pitfalls, and technique.

Complex displaced proximal humerus fractures are frequently treated with a fracture prosthesis. This paper outlines the indications, introduces various fracture prostheses, describes the surgical technique, and rehabilitation for treatment of proximal humerus fractures with a fracture prosthesis hemiarthroplasty. Outcomes are noted to be improved when near anatomic humeral head height, and retroversion is obtained using a small body proximal humeral replacing implant designed for fracture treatment. The use of a common platform stem allows for relatively easy conversion to a reverse shoulder arthroplasty if tuberosity nonunion should occur.