Outcomes of Augmented versus Standard Baseplates in Reverse Shoulder Arthroplasty.

Background: Glenoid bone loss presents a complex challenge in the management of patients with glenohumeral osteoarthritis (GHOA) undergoing Reverse Shoulder Arthroplasty (RSA). Eccentric reaming and bone grafting have been utilized to address this issue but are associated with their own set of challenges. This study explores the effectiveness of augmented glenoid baseplate RSA in addressing glenoid bone loss.

Two-year minimum survivorship and radiographic analysis of a pressfit short humeral stem for total shoulder arthroplasty.

Background: Newer generation humeral stem designs in total shoulder arthroplasty (TSA) are trending towards shorter lengths and uncemented fixation. The goal of this study is to report a 2-yr minimum clinical and radiographic outcomes of an uncemented short-stem press-fit humeral stem in anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA).

Methods: A retrospective multicenter database review was performed of all patients who received an uncemented short-length press-fit humeral stem (Equinoxe Preserve humeral stem, Exactech, Inc.

Initial clinical experience with a predictive clinical decision support tool for anatomic and reverse total shoulder arthroplasty.

Purpose: Clinical decision support tools (CDSTs) are software that generate patient-specific assessments that can be used to better inform healthcare provider decision making. Machine learning (ML)-based CDSTs have recently been developed for anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty to facilitate more data-driven, evidence-based decision making. Using this shoulder CDST as an example, this external validation study provides an overview of how ML-based algorithms are developed and discusses the limitations of these tools.

Impact of accumulating risk factors on the acromial and scapular fracture rate after reverse total shoulder arthroplasty with a medialized glenoid-lateralized humerus onlay prosthesis.

Background: Identifying risk factors for acromial and scapular fractures improves our understanding about which variables are relevant to these fracture complications; however, these data are difficult to integrate into clinical practice because the majority of reverse total shoulder arthroplasty (rTSA) patients have ≥1 risk factor. The goal of this study was to better facilitate preoperative identification of patients at risk of acromial and scapular fractures and quantify the impact of accumulating risk factors on the incidence of fracture.

Methods: We retrospectively analyzed 9079 rTSA patients from a multicenter database of rTSA procedures performed with a single medialized glenoid-lateralized humerus onlay rTSA prosthesis to quantify the rate of acromial and scapular fractures.

Longitudinal analysis of shoulder arthroplasty utilization, clinical outcomes, and value: a comparative assessment of changes in improvement over 15 years with a single platform shoulder prosthesis.

Background: The goal of this longitudinal analysis of anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) utilization from 2007 to 2021 is to quantify changes in clinical outcomes, cost, and value, resulting from the introduction and adoption of new shoulder arthroplasty (SA) technologies.

Methods: We analyzed an international database of a single SA prosthesis (Equinoxe; Exactech, Inc.; Gainesville, FL, USA) for all clinical sites that have continuously enrolled cases from 2007 to 2021 to compare changes in primary aTSA and primary rTSA utilization and outcomes across 3, 5-year cohorts based upon the date of implantation.

Augmented baseplates yield optimum outcomes when compared with bone graft augmentation for managing glenoid deformity during reverse total shoulder arthroplasty: a retrospective comparative study.

Purpose: The purpose of this study was to compare the outcomes of primary reverse total shoulder arthroplasty (rTSA) using glenoid bone grafting (BG rTSA) with primary rTSA using augmented glenoid baseplates (Aug rTSA) with a minimum 2-year follow-up.

Methods: A total of 520 primary rTSA patients treated with 8° posterior glenoid augments (n = 246), 10° superior glenoid augments (n = 97), or combined 10° superior/8° posterior glenoid augments (n = 177) were compared with 47 patients undergoing glenoid bone grafting for glenoid bone insufficiency. The mean follow-up was 37.

Using machine learning to predict internal rotation after anatomic and reverse total shoulder arthroplasty.

Background: Improvement in internal rotation (IR) after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty is difficult to predict, with rTSA patients experiencing greater variability and more limited IR improvements than aTSA patients. The purpose of this study is to quantify and compare the IR score for aTSA and rTSA patients and create supervised machine learning that predicts IR after aTSA and rTSA at multiple postoperative time points.

Methods: Clinical data from 2270 aTSA and 4198 rTSA patients were analyzed using 3 supervised machine learning techniques to create predictive models for internal rotation as measured by the IR score at 6 postoperative time points.

Equal care for all? Do surgical outcomes in shoulder arthroplasty depend on insurance type?

Background: Although it has been shown that Medicare populations have a higher overall rate of complications than those with private insurances for large cohort total joint studies, there is limited information comparing patient-reported outcomes (PROs) among private insurance patients. The purpose of this study was to determine the impact of non-Medicaid insurance type on outcomes after shoulder arthroplasty.

Methods: This retrospective case-controlled study included 203 patients who underwent shoulder arthroplasty from 2012 to 2017 by a single surgeon.

Development and validation of a predictive model for outcomes in shoulder arthroplasty: a multicenter analysis of nearly 2000 patients.

Background: Guiding expectations following shoulder arthroplasty is important in improving patient satisfaction. The purpose of this study was to develop a predictive model to calculate 2-year American Shoulder and Elbow Surgeons (ASES) scores in shoulder arthroplasty patients from a comprehensive set of preoperative patient factors and types of arthroplasty performed.

Methods: This retrospective multicenter study included 1947 shoulder arthroplasties performed from 2010 to 2015 at 3 high-volume centers.

Risk factors for complications and revision surgery after anatomic and reverse total shoulder arthroplasty.

Background: Complications and revisions following anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty have deleterious effects on patient function and satisfaction. The purpose of this study is to evaluate patient-specific, implant-specific and technique-specific risk factors for intraoperative complications, postoperative complications, and the occurrence of revisions after aTSA and rTSA.

Methods: A total of 2964 aTSA and 5616 rTSA patients were enrolled in an international database of primary shoulder arthroplasty.

Validation of a machine learning-derived clinical metric to quantify outcomes after total shoulder arthroplasty.

Background: We propose a new clinical assessment tool constructed using machine learning, called the Shoulder Arthroplasty Smart (SAS) score to quantify outcomes following total shoulder arthroplasty (TSA).

Methods: Clinical data from 3667 TSA patients with 8104 postoperative follow-up reports were used to quantify the psychometric properties of validity, responsiveness, and clinical interpretability for the proposed SAS score and each of the Simple Shoulder Test (SST), Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), University of California Los Angeles (UCLA), and Shoulder Pain and Disability Index (SPADI) scores.

Results: Convergent construct validity was demonstrated, with all 6 outcome measures being moderately to highly correlated preoperatively and highly correlated postoperatively when quantifying TSA outcomes.

Preoperative external rotation deficit does not predict poor outcomes or lack of improvement after reverse total shoulder arthroplasty.

Introduction: The purpose was to compare postoperative outcomes and functional improvement between patients with preoperative aER deficits vs. preserved aER function.

Results: There were 115 patients in the <0° aER group and 314 in the ≥30° aER group.

Using machine learning to predict clinical outcomes after shoulder arthroplasty with a minimal feature set.

Background: A machine learning analysis was conducted on 5774 shoulder arthroplasty patients to create predictive models for multiple clinical outcome measures after anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA). The goal of this study was to compare the accuracy associated with a full-feature set predictive model (ie, full model, comprising 291 parameters) and a minimal-feature set model (ie, abbreviated model, comprising 19 input parameters) to predict clinical outcomes to assess the efficacy of using a minimal feature set of inputs as a shoulder arthroplasty clinical decision-support tool.

Methods: Clinical data from 2153 primary aTSA patients and 3621 primary rTSA patients were analyzed using the XGBoost machine learning technique to create and test predictive models for multiple outcome measures at different postoperative time points via the full and abbreviated models.

The influence of preoperative external rotation weakness or stiffness on reverse total shoulder arthroplasty.

Background: Some reverse total shoulder arthroplasty (rTSA) patients may have limited preoperative external rotation (ER) because of stiffness or weakness. Currently it is not known if this affects their clinical outcome or if their ER will improve after surgery.

Methods: A multicenter shoulder arthroplasty database was queried to analyze patients undergoing a primary rTSA using a single prosthesis design featuring a medial glenoid-lateral humerus.

What Is the Accuracy of Three Different Machine Learning Techniques to Predict Clinical Outcomes After Shoulder Arthroplasty?

Background: Machine learning techniques can identify complex relationships in large healthcare datasets and build prediction models that better inform physicians in ways that can assist in patient treatment decision-making. In the domain of shoulder arthroplasty, machine learning appears to have the potential to anticipate patients' results after surgery, but this has not been well explored.

Questions/purposes: (1) What is the accuracy of machine learning to predict the American Shoulder and Elbow Surgery (ASES), University of California Los Angeles (UCLA), Constant, global shoulder function, and VAS pain scores, as well as active abduction, forward flexion, and external rotation at 1 year, 2 to 3 years, 3 to 5 years, and more than 5 years after anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA)? (2) What is the accuracy of machine learning to identify whether a patient will achieve clinical improvement that exceeds the minimum clinically important difference (MCID) threshold for each outcome measure? (3) What is the accuracy of machine learning to identify whether a patient will achieve clinical improvement that exceeds the substantial clinical benefit threshold for each outcome measure?

Methods: A machine learning analysis was conducted on a database of 7811 patients undergoing shoulder arthroplasty of one prosthesis design to create predictive models for multiple clinical outcome measures.

Patient-reported outcomes of reverse total shoulder arthroplasty: a comparative risk factor analysis of improved versus unimproved cases.

Background: The purpose of this study was to compare characteristics of patients who reported to be subjectively unimproved vs. improved after reverse total shoulder arthroplasty.

Methods: Data were derived from a prospective registry of patients who underwent reverse total shoulder arthroplasty with a minimum 2-year follow-up.

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.

Subscapularis-Sparing Approaches to Total Shoulder Arthroplasty: Ready for Prime Time?

To minimize the risk of subscapularis failure after shoulder replacement, a method of preserving the subscapularis while allowing access to the glenohumeral joint was developed. Only the inferior 30% to 50% of the subscapularis tendon is detached from the humerus, leaving the superior aspect attached to the lesser tuberosity. This subscapularis-sparing, minimally invasive approach to the glenohumeral joint was evaluated in 43 subjects with a minimum 2-year follow-up and subscapularis strength equal to the opposite side.

Isolated Rhabdomyolysis of the Infraspinatus Muscle Following the CrossFit "Sissy Test": A Report of Two Cases.

Case: Following the completion of a CrossFit-style challenge (the "Sissy Test"), 2 patients presented with severe pain and swelling over the posterior aspect of the scapula. Magnetic resonance imaging demonstrated isolated edema of the infraspinatus muscle in both patients; the compartments were compressible. Neurovascular checks and observation of range of motion were performed.

Local injection of liposomal bupivacaine combined with intravenous dexamethasone reduces postoperative pain and hospital stay after shoulder arthroplasty.

Background: Alternative techniques have been developed to address pain after shoulder arthroplasty and are well documented. We evaluated the effect of adding intraoperative liposomal bupivacaine and intravenous dexamethasone during shoulder arthroplasty.

Methods: We retrospectively reviewed 2 consecutive cohorts undergoing elective shoulder arthroplasty.

Stemless and Short Stem Humeral Components in Shoulder Arthroplasty.

Humeral-sided arthroplasty design evolution continues to be supported by the published literature in the transition away from traditional stemmed devices. Early studies have shown not only absence of failure with these newer shorter and stemless designs but also equivalence in terms of early outcomes compared to traditional stemmed devices with the benefits of shorter operative time, less blood loss, easier revision, and the potential to reduce stress shielding and periprosthetic fractures. We will review the literature available on the different designs of both short stem and stemless humeral devices.

Impact of Posterior Wear on Muscle Length with Reverse Shoulder Arthroplasty.

The use of reverse total shoulder arthroplasty (rTSA) in patients with posterior glenoid wear can be challenging. Implanting a baseplate in the correct version may require significant eccentric reaming, which further medializes the joint line and results in greater rotator cuff muscle shortening. To restore the joint line, bone graft may be required, though it is associated with additional risks.

Optimizing Deltoid Efficiency with Reverse Shoulder Arthroplasty Using a Novel Inset Center of Rotation Glenosphere Design.

Introduction: Paul Grammont's hemispherical gleno sphere concept medializes the center of rotation (CoR) to the glenoid face to increase deltoid abductor moment arms and improve muscle efficiency. Reducing glenosphere thickness to less than half its spherical radius further medializes the CoR and offers the potential for even greater improvements in efficiency. To that end, this study quantifies deltoid abducttor moment arms for six different rTSA prostheses during scapular abduction from 0° to 140°.