UNASSIGNED: Stemless humeral components are being clinically investigated for reverse shoulder arthroplasty (RSA) procedures. There is, however, a paucity of basic science literature on the surgical parameters that influence the success of these procedures. Therefore, this cadaveric biomechanical study evaluated the neck shaft angle (NSA) of implantation on the survivability and performance of stemless RSA humeral components during cyclical loading.
UNASSIGNED: Twelve paired cadaveric humeri were implanted with stemless RSA humeral components at NSAs of 135° and 145°. Implant-bone motion at the periphery of the implant was measured with 3 optical machine vision USB3 cameras outfitted with c-mount premium lenses and quantified with ProAnalyst software. A custom 3-dimensional loading apparatus was used to cyclically apply 3 loading directions representative of physiological states at 5 progressively increasing loading magnitudes. Stemless 135° and 145° implants were compared based on the maximum implant-bone relative distraction detected, as well as the survivorship of the implants throughout the loading protocol.
UNASSIGNED: Primary fixation and implant biomechanical survivorship were substantially better in the 145° NSA implants. The 135° NSA implants elicited significantly higher implant-bone distractions during cyclical loading (P = .001), and implant survivorship was considerably lower in the 135° NSA specimens when compared to the 145° NSA specimens (135° NSA: 0%, 145° NSA: 50%) (P < .001).
UNASSIGNED: NSA is a modifiable parameter that influences time-zero implant stability, as well as the early survivorship of the stemless RSA humeral components tested in this study. NSA resections of 145° appear to promote better stability than those utilizing 135° NSAs during early postoperative eccentric loads. Further studies are required to assess if other stemless reversed humeral implant designs have improved time-zero fixation at higher NSAs.

Reverse total shoulder arthroplasty (rTSA) is increasingly being used as a reliable option for various shoulder disorders with deteriorated rotator cuff and glenohumeral joints. The stemless humerus component for shoulder arthroplasties is evolving with theoretical advantages, such as preservation of the humeral bone stock and decreased risk of periprosthetic fractures, as well as clinical research demonstrating less intraoperative blood loss, reduced surgical time, a lower rate of intraoperative fractures, and improved center of rotation restoration. In particular, for anatomical total shoulder arthroplasty (aTSA), the utilization of stemless humeral implants is gaining consensus in younger patients. The current systematic review of 14 clinical studies (637 shoulders) demonstrated the clinical outcomes of stemless rTSA. Regarding shoulder function, the mean Constant-Murley Score (CS) improved from 28.3 preoperatively to 62.8 postoperatively. The pooled overall complication and revision rates were 14.3% and 6.3%, respectively. In addition, recent studies have shown satisfactory outcomes with stemless rTSA relative to stemmed rTSA. Therefore, shoulder surgeons may consider adopting stemless rTSA, especially in patients with sufficient bone quality. However, further long-term studies comparing survivorship between stemless and stemmed rTSA are required to determine the gold standard for selecting stemless rTSA.

UNASSIGNED: Improvements in pain control after shoulder arthroplasty with a reduction in narcotic use continues to be an important postoperative goal. With the increased utilization of stemless anatomic total shoulder arthroplasty (aTSA), it is relevant to compare between stemmed and stemless arthroplasty to assess if there is any association between this implant design change and early postoperative pain.
UNASSIGNED: Patients from a multicenter, prospectively-maintained database who had undergone a stemless aTSA with a minimum of two year clinical follow-up were retrospectively identified. Patients who underwent aTSA with a short stem were identified in the same registry, and matched to the stemless aTSA patients by age, sex and preoperative pain score. The primary study outcome was the Visual Analog Scale pain score. Secondary pain outcomes were the American Shoulder and Elbow Surgeons shoulder pain subscore, Western Ontario Osteoarthritis of the Shoulder physical symptoms subscore, and the Single Assessment Numeric Evaluation score. Finally, the percentage of patients who could sleep on the affected shoulder was assessed for each group. These pain-related clinical outcomes were assessed and compared preoperatively, and postoperatively at 9 weeks, 26 weeks, one year and two years. For all statistical comparisons, P > .05 was considered significant.
UNASSIGNED: 124 patients were included in the study; 62 in each group. At 9 weeks after surgery, statistically significantly improved pain control was reported by patients undergoing stemless aTSA, as assessed by the Visual Analog Scale (stemless: 1.5, stemmed: 2.5, P = .001), American Shoulder and Elbow Surgeons pain subscore (stemless: 42.4, stemmed: 37.3, P < .001), Western Ontario Osteoarthritis of the Shoulder Physical Symptoms (stemless: 80.3, stemmed: 73.1, P = .006) and Single Assessment Numeric Evaluation (stemless: 58.1, stemmed: 47.4, P = .011). Patients who underwent a stemless aTSA were significantly more likely to be able to sleep on the affected shoulder at 9 weeks (29% vs. 11%, odds ratio 3.2, 95% confidence interval 1.2-8.4, P = .014). By 26 weeks postoperatively, there were no differences in all pain-specific outcomes. At two years postoperatively, patient-reported outcomes, range of motion, and strength measures were all similar between the two cohorts.
UNASSIGNED: Stemless aTSA provides earlier improvement in postoperative shoulder pain compared to matched patients undergoing short-stem aTSA. Additionally, earlier return to sleeping on the affected shoulder was reported in the stemless aTSA group. The majority of these differences dissipate by 26 weeks postoperatively and there were no differences in pain, patient-reported outcomes, range of motion or strength measures between stemless and short-stem aTSA at 2 years postoperatively.

The primary aim of this study was to assess the medium-term outcomes of the Global Icon stemless shoulder replacement in patients who have undergone primary total shoulder arthroplasty (TSA) for glenohumeral joint osteoarthritis. A retrospective review of patients who had undergone a TSA using the Global Icon stemless shoulder system was performed. The Western Ontario Osteoarthritis Shoulder (WOOS) Index and Oxford Shoulder Score (OSS) were evaluated pre-operatively and at 12 to 24 months post-operatively. Radiological outcomes, operation time, and post-operative complications were reported. Primary analysis for the WOOS Index and OSS focused on detecting within-group treatment effects at 24 months using a repeated measures ANOVA. Thirty patients were included in the study. Post-surgery, there was a significant improvement at 24 months on the OSS (ES = 0.932, CI: 41.7 to 47.7, p < 0.001) and the WOOS Index (ES = 0.906, CI: 71.9 to 99.8, p < 0.001). Radiographs revealed that no component loosened, migrated, or subsided. The median operative time was 75.5 (IQR: 12.25, range: 18 to 105) min. No implant-related complications were reported. The Global Icon stemless replacements have excellent clinical outcomes in this cohort at 12- and 24-month follow-up with no implant-related complications.

UNASSIGNED: Stemless total shoulder arthroplasty (TSA) continues to grow in popularity as an evolution of stemmed humeral implants. Proposed advantages include bone preservation and ease of potential revision. However, absence of a stem may necessitate a change in subscapularis takedown approach. Specifically, there is theoretical concern about violation of supportive bone with lesser tuberosity osteotomy when using a stemless device. Therefore, the goal of this study was to identify if surgeons change their subscapularis takedown preference when performing stemless vs. stemmed TSA.
UNASSIGNED: Data from a consecutive series of patients who underwent stemmed and stemless TSA at an academic institution were collected. The subscapularis management technique was documented. Subscapularis takedown techniques were divided into 2 groups: soft-tissue approach (subscapularis tenotomy or peel) and bony approach (lesser tuberosity osteotomy). Historical preference for each surgeon was determined by evaluating techniques employed using stemmed TSA. A Cramers V analysis was run to determine the strength of association between this historical preference and subscapularis management technique used for stemless TSA.
UNASSIGNED: One hundred and fifty-four patients were included in this analysis. There were 72 and 82 stemmed and stemless arthroplasty cases performed, respectively. Of the 154 patients, 50.6% were women. The average age of patients was 64.2 years. Four surgeons were included in this study. In all, there were 79 and 75 bony and soft-tissue subscapularis techniques, respectively. The historical preference for 3 of the surgeons was a subscapularis bony approach, and the historical preference for one of the surgeons was a soft-tissue approach. A Cramer\'s V analysis was used to measure the relative strength of association between patient factors, historical subscapularis management preference, and subscapularis takedown approach in stemless TSA. Our analysis yielded a value of 0.65 (P < .01), indicating a redundant association between subscapularis management approach used between stemmed and stemless implant per surgeon.
UNASSIGNED: In determining subscapularis tendon management strategy, in surgeons who performed stemmed TSA before stemless TSA, the subscapularis takedown approach used for stemless TSA is strongly associated with surgeon\'s historical preference for stemmed TSA. Future research will be needed to determine the clinical ramifications of this finding.

UNASSIGNED: Methods to determine whether a stemless humeral component is appropriate for anatomic total shoulder arthroplasty are varied and often subjective. Objective preoperative data regarding metaphyseal bone quality may help guide surgical decision-making. This study sought to evaluate preoperative proximal humeral bone quality and determine whether it is predictive of intraoperative conversion to a stemmed humeral component.
UNASSIGNED: Consecutive patients who underwent primary anatomic total shoulder arthroplasty from a single-surgeon practice were enrolled. All patients received a preoperative computed tomography (CT) scan for surgical templating purposes. The exclusion criteria were lack of a preoperative CT scan, preoperative plan for a stemmed component, and intraoperative conversion to a stem for a reason other than bone quality (ie, fracture). Preoperative CT scans were analyzed with an automated templating software. Cortical index and thickness were calculated, and bone density of the proximal diaphysis, cancellous metaphysis, and cortical metaphysis was obtained by averaging Hounsfield units (HU) across anatomically defined regions using a previously validated technique. The decision to convert to a stemmed humeral component was made intraoperatively based on a lack of stability of the trial stemless component. Bone quality measurements were compared between stemless and stemmed groups. An exact logistic regression was used incorporating gender and age.
UNASSIGNED: A total of 79 patients who underwent primary anatomic total shoulder arthroplasty were included in this study. Of these patients, 6 underwent intraoperative conversion to a stemmed humeral component (7.6%). There was no significant difference between cohorts in terms of cortical index and bone density within the proximal diaphysis and cortical metaphysis. On univariate analysis, cortical thickness, metaphyseal cancellous bone density, and gender were significantly different between groups. Patients receiving a stem had significantly lower metaphyseal cancellous bone density than those receiving stemless components (5.5 ± 11.2 HU vs. 47.6 ± 29.4 HU, P<.001). All patients converted to stems were female individuals (P = .01) and had metaphyseal cancellous bone density less than 20 HU (P<.001).
UNASSIGNED: Metaphyseal cancellous bone density can be calculated on preoperative CT scans and is associated with intraoperative conversion to a stemmed humeral component in anatomic shoulder arthroplasty. A threshold of 20 HU can be used to predict which patients are more likely to require stemmed components.

Stemless anatomic total shoulder arthroplasty (aTSA) is a promising option for the treatment of degenerative disease in patients. This novel technique avoids the stem-related complications associated with the traditional stemmed aTSA. Stemless aTSA offers additional benefits such as decreased operative time, preservation of bone stock, improved radiographic outcomes, and easier revision. Moreover, loading of the metaphyseal region rather than the diaphysial region with traditional stemmed implants can decrease stress shielding. When compared to stemmed-implants, stemless aTSA has demonstrated similar outcomes and complication rates. The purpose of this article is to analyze published outcomes and complications following the utilization of stemless aTSA. Additionally, key aspects of the surgical technique that may promote optimal results in stemless aTSA implantation are presented.

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UNASSIGNED: This study aims to evaluate restoration of anatomy following Total Shoulder Arthroplasty (TSA) with the Mathys Affinis Short prosthesis.
UNASSIGNED: Over the last decade stemless shoulder arthroplasty has increased in popularity. One of the reported advantages of the stemless designs is the ability to restore anatomy following surgery. However, very few studies have evaluated restoration of anatomy following stemless shoulder arthroplasty.
UNASSIGNED: The study included all patients who had undergone TSA using the Affinis Short (Mathys Ltd, Bettlach, Switzerland) prosthesis for primary osteoarthritis between 2010 and 2016. The mean follow up was 42.8 months (range 9.4 to 83.4 months). Pre and post-operative radiographs were assessed for Centre of Rotation (COR), Humeral Head Height (HHH), Humeral Head Diameter (HHD), Humeral Height (HH) and, Neck Shaft Angle (NSA) using the best fit circle method on PACS software. Measurements were scored and compared to assess the accuracy of the implant in restoring the native geometry, including the intraobserver variability. The same data was collected by another experienced observer to measure the interobserver variability.
UNASSIGNED: The deviation of COR of the prosthesis from the anatomical centre was less than 3 mm in 58 cases (85%). Humeral head height and humeral head diameter showed a variation of less than 3 mm in 66 cases (97%) and 43 cases (63%) respectively. Humeral height followed a similar trend, with 62 cases (91.2%) showing a difference of less than 5 mm. The neck shaft angle showed a variation of more than 8 degrees in 38 cases (55%), and 29 cases (42.6%) had a postoperative angle of less than 130 degrees.
UNASSIGNED: Overall, stemless total shoulder arthroplasty with the Affinis Short prosthesis allows excellent restoration of anatomy confirmed by most of the measured radiographic parameters. The variability in neck shaft angle might be due to differing surgical techniques, with some surgeons preferring a slightly vertical neck cut to protect the rotator cuff insertion.

UNASSIGNED: The purpose was to report mid-term to long-term clinical outcomes in a multicentre series of patients who received stemless total shoulder arthroplasty (TSA). The hypothesis was that stemless TSA would be a safe and effective treatment with satisfactory clinical outcomes.
UNASSIGNED: Authors retrospectively reviewed records of 62 stemless TSAs implanted between March 2013 and December 2014. Six were excluded because they had fractures or muscular impairment, which left 56: primary osteoarthritis (n = 49), rheumatoid arthritis (n = 4), avascular necrosis (n = 1), or glenoid dysplasia (n = 2). Outcomes were absolute Constant Score (CS), age-/sex-adjusted CS, and the American Shoulder and Elbow Surgeons (ASES) score. Proportions of patients that achieved substantial clinical benefits for absolute CS and ASES scores were determined.
UNASSIGNED: Of the 56 patients, 8 (14%) died (unrelated to TSA), 5 (9%) were lost to follow-up, and 2 (4%) refused participation. One patient was reoperated for infection with implant removal (excluded from analysis), and one for periprosthetic fracture without implant removal. At 7.6 ± 0.5 years (range 6.8-9.3), the remaining 40 patients, aged 71.0 ± 8.5 years, achieved net improvements of 40.7 ± 15.8 (CS), 62%±23% (age-/sex-adjusted CS), and 59.7 ± 16.4 (ASES). Of patients with complete absolute CS (n = 37) and ASES score (n = 28), respectively, 33 (89%) and 27 (96%) achieved substantial clinical benefits.
UNASSIGNED: Stemless TSA yields improvements in functional outcomes at mid-term to long-term that exceed the substantial clinical benefits of the absolute CS and ASES score at a mean follow-up of 7.6 years. Although the findings of this study revealed low complications and revision rates, more studies are needed to confirm long-term benefits of stemless TSA.
UNASSIGNED: IV, case series.