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.

BACKGROUND: The utilization of stemless anatomic total shoulder arthroplasty is on the rise. Epiphyseal fixation leads to radiological bone remodeling, which has been reported to exceed 40% in certain studies series. The aim of this study was to present the clinical and radiological outcomes of a stemless implant with asymmetric central epiphyseal fixation at an average follow-up of 31 months.
METHODS: This retrospective multicenter study examined prospective data of patients undergoing total anatomic arthroplasty with ISA Stemless implant and followed up at least 2 years. Clinical assessment included preoperative and final follow-up measurements of active range of motion (ROM), Constant score, and Subjective Shoulder Value (SSV). Anatomical epiphyseal reconstruction and bone remodeling at the 2-year follow-up were assessed by standardized Computed Tomography Scanner (CT scan). Statistical analysis employed unpaired Student\'s t-test or chi-squared test depending on the variable type, conducted using EasyMedStat software (version 3.22; www.easymedstat.com).
RESULTS: Fifty patients (mean age 68 years, 62% females) were enrolled, with an average follow-up of 31 months (24-44). Primary osteoarthritis (68%) with type A glenoid (78%) was the prevailing indication. The mean Constant score and SSV improved significantly from 38 ± 11 to 76 ± 11 (p<0.001) and from 31% ± 16 to 88% ± 15 (p<0.001) respectively at the last follow-up. Forward elevation, external rotation and internal rotation ROM increased by 39° ± 42, 28° ± 21 and 3,2 ± 2,5 points respectively, surpassing the Minimally Clinically Important Difference (MCID) after total shoulder arthroplasty. No revisions were necessary. CT scans identified 30% osteolysis in the posterior-medial calcar region, devoid of clinical repercussions. No risk factors were associated with bone osteolysis.
CONCLUSIONS: At an average follow-up of 31 months, ISA Stemless implant provided favorable clinical results. CT analysis revealed osteolysis-like remodeling in the posterior-medial zone of the calcar (30%), without decline in clinical outcomes and revisions. Long-term follow-up studies are mandated to evaluate whether osteolysis is associated with negative consequences.

BACKGROUND: Reverse shoulder arthroplasty (RSA) is a well-recognized treatment for many shoulder conditions, including rotator cuff arthropathy, primary glenohumeral joint arthritis, and rheumatoid arthritis, and can be used in both trauma and revision settings. Over the past 10 years, its popularity in New Zealand has been increasing, with a 6%-7% annual growth rate during this period. Stemless RSA designs have the following proposed advantages: They can preserve humeral bone stock, they can limit periprosthetic fractures, and they can be indicated in patients with abnormal diaphyseal humeral anatomy. To date, only 1 study has evaluated the outcomes of the Lima SMR Stemless implant. We present our data with an aim to report how the stemless reverse arthroplasty compares to a conventional stemmed implant.
METHODS: We performed a retrospective review of a consecutive series of patients treated at a single institution between 2015 and 2020. The endpoint was defined as final follow-up at a minimum of 2 years. Patients were excluded from the final analysis if they underwent revision. Thirty-three patients were identified as having undergone stemless RSA. Thirty patients had patient-reported outcome measures and radiographs at a minimum of 2 years\' follow-up. Three patients had undergone revision within 2 years. The same sample size of stemmed RSAs (n = 33) was selected for comparison.
RESULTS: A total of 60 patients were included in the final analysis, of whom 30 underwent stemless RSA and 30 underwent stemmed RSA. The demographic characteristics of the 2 groups were comparable except age at operation, which showed a statistically significant difference (P = .001): 77 years (stemmed) vs. 65 years (stemless). The mean Oxford Shoulder Score was 40.1 in the stemless group vs. 40 in the stemmed group. The mean American Shoulder and Elbow Surgeons score was 72.9 in the stemless group vs. 79 in the stemmed group. Patient-reported outcome measures, pain scores, and satisfaction ratings were not statistically significantly different between the 2 groups. In terms of radiographic data, subsidence was observed in 2 patients in the stemless RSA group but the patients had no clinical symptoms. Also in the stemless RSA group, 1 patient had an acromial stress fracture and 1 patient had a superficial wound infection successfully treated with oral antibiotics. In terms of revisions in the stemless RSA group, 1 patient underwent revision owing to chronic infection, 1 underwent revision as a result of a periprosthetic fracture after a fall, and 1 underwent revision for gross instability.
CONCLUSIONS: The early results of sRSA are promising, and the stemless implant shows similar outcomes to a conventional stemmed implant.

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.

OBJECTIVE: Periprosthetic fractures around a stemless implant often involve lesser and greater tuberosities with a well-fixed implant in the metaphysis. This exposes the surgeon to unique questions and challenges as no surgical option (open reduction and internal fixation or revision to a stem) appears satisfactory to address them. Purpose of this study was to evaluate the clinical outcomes after non-operative management of periprosthetic fractures after stemless shoulder arthroplasty.
METHODS: A retrospective multicenter study was conducted to identify all patients who had sustained non-operative management of a periprosthetic fracture after a stemless shoulder. Exclusion criteria were as follows: (1) intraoperative fractures and (2) implant loosening. Primary outcomes included mean Constant score and mean active range of motion. Secondary outcomes were VAS, radiological analysis, and complications.
RESULTS: Nine patients were included. One was excluded due to the loss of follow-up at three months. Mean age was 79 years. At the last follow-up, no significant difference was observed between the Constant score, VAS, or the range of motion before fracture and at the last follow-up. Fracture healing did not result in any change in angulation in the frontal plane in seven cases and was responsible for a varus malunion in two cases of anatomic arthroplasty. No change in lateralization or distalization was reported. No cases of implant loosening after fracture have been observed.
CONCLUSIONS: Conservative management seems to be appropriate in cases of minimally displaced fractures without implant loosening.

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.

BACKGROUND: Stemless anatomic humeral components are commonly used and are an accepted alternative to traditional stemmed implants in patients with good bone quality. Presently, little literature exists on the design and implantation parameters that influence primary time-zero fixation of stemless reverse humeral implants. Accordingly, this finite element analysis study assessed the surgical implantation variable of neck-shaft angle, and its effect on the primary time-zero fixation of reversed stemless humeral implants.
METHODS: Eight computed tomography-derived humeral finite element models were used to examine a generic stemless humeral implant at varying neck-shaft angles of 130°, 135°, 140°, 145°, and 150°. Four loading scenarios (30° shoulder abduction with neutral forearm rotation, 30° shoulder abduction with forearm supination, a head-height lifting motion, and a single-handed steering motion) were employed. Implantation inclinations were compared based on the maximum bone-implant interface distraction detected after loading.
RESULTS: The implant-bone distraction was greatest in the 130° neck-shaft angle implantation cases. All implant loading scenarios elicited significantly lower micromotion magnitudes when neck-shaft angle was increased (P = .0001). With every 5° increase in neck-shaft angle, there was an average 17% reduction in bone-implant distraction.
CONCLUSIONS: The neck-shaft angle of implantation for a stemless reverse humeral component is a modifiable parameter that appears to influence time-zero implant stability. Lower, more varus, neck-shaft angles increase bone-implant distractions with simulated activities of daily living. It is therefore suggested that humeral head osteotomies at a higher neck-shaft angle may be beneficial to maximize stemless humeral component stability.