The Use of Tumor Prostheses for Primary or Revision Reverse Total Shoulder Arthroplasty With Proximal Humeral Bone Loss

Background During shoulder arthroplasty with substantial bone and soft tissue loss, reverse shoulder arthroplasty (RSA) with a tumor prosthesis may restore function, reduce pain, and improve implant fixation. Methods Thirteen adult patients undergoing RSA using a tumor prosthesis system were retrospectively reviewed. Preoperative visual analog score (VAS), single assessment numeric evaluation (SANE), American Shoulder and Elbow Surgeons (ASES) score, simple shoulder test (SST), and forward flexion were compared to latest follow up. Postoperative radiographs and complications were recorded. Results Mean age at surgery was 68.4 years. Eight patients had undergone at least 1 prior operation on the indicated shoulder. Six patients required wide excision of proximal humerus tumor. At mean of 34 months postoperatively, significant improvements were noted in VAS ( P = .03) and ASES score ( P = .04). Active forward elevation was 81.1 degrees. For all patients, postoperative radiographs demonstrated satisfactory alignment. Complications occurred in 38% of patients, with 31% requiring reoperation. Conclusion In cases of failed shoulder arthroplasty with excessive bone and soft tissue loss or substantial tumor burden, RSA with a tumor prosthesis can reduce pain levels and improve functional outcomes. However, forward elevation remains limited, and postoperative complications are a concern.

Scapular Notching Following Ipsilateral Traumatic Clavicle Fracture in Reverse Total Shoulder Arthroplasty: A Case Report

Introduction Reverse total shoulder arthroplasty (RTSA) procedures are becoming increasingly more common. While the main complications are known, the management of clavicle fractures in patients with an ipsilateral RTSA is not well described. There are three case studies that document clavicular stress fractures following RTSA with an atraumatic etiology, and to our knowledge, no studies have described a traumatic clavicular fracture following RTSA. Case We describe the case of a 75-year-old woman with a traumatic clavicle fracture five years after RTSA for rotator cuff tear arthropathy. With minimal pain and subjective symptoms initially, the patient wished to pursue non-operative treatment. However, she eventually developed a painful non-union and pseudoparalysis of the shoulder with serial radiographs demonstrating progressive superior scapular tilting and scapular notching. Subsequent open reduction internal fixation of her clavicle fracture significantly improved her pain and function. Conclusion We report a traumatic clavicle fracture in the setting of RTSA that not only failed to heal but also resulted in scapular notching and shoulder pseudoparalysis that was improved with surgical stabilization of the fracture. It is possible that the setting of a semi-constrained RTSA, the resulting biomechanical imbalance may predispose to impaired fracture healing and non-union of the clavicle fracture.

Development of a Machine Learning Algorithm for Prediction of Complications and Unplanned Readmission Following Reverse Total Shoulder Arthroplasty

Background Reverse total shoulder arthroplasty (rTSA) offers tremendous promise for the treatment of complex pathologies beyond the scope of anatomic total shoulder arthroplasty but is associated with a higher rate of major postoperative complications. We aimed to design and validate a machine learning (ML) model to predict major postoperative complications or readmission following rTSA. Methods We retrospectively reviewed California's Office of Statewide Health Planning and Development database for patients who underwent rTSA between 2015 and 2017. We implemented logistic regression (LR), extreme gradient boosting (XGBoost), gradient boosting machines, adaptive boosting, and random forest classifiers in Python and trained these models using 64 binary, continuous, and discrete variables to predict the occurrence of at least one major postoperative complication or readmission following primary rTSA. Models were validated using the standard metrics of area under the receiver operating characteristic (AUROC) curve, area under the precision–recall curve (AUPRC), and Brier scores. The key factors for the top-performing model were determined. Results Of 2799 rTSAs performed during the study period, 152 patients (5%) had at least 1 major postoperative complication or 30-day readmission. XGBoost had the highest AUROC and AUPRC of 0.681 and 0.129, respectively. The key predictive features in this model were patients with a history of implant complications, protein-calorie malnutrition, and a higher number of comorbidities. Conclusion Our study reports an ML model for the prediction of major complications or 30-day readmission following rTSA. XGBoost outperformed traditional LR models and also identified key predictive features of complications and readmission.

Tomographic Analysis of Positioning of Reverse Baseplates Positioning

Objective To verify whether reverse baseplate positioning without the support of intraoperative three-dimensional technology is within the acceptable parameters in the literature and whether glenoid bone deformity (GBD) compromises this positioning. Methods Sixty-nine reverse shoulder arthroplasties were evaluated with volumetric computed tomography (CT). Two radiologists performed blinded CT scan analysis and evaluated baseplate position within 2mm of the inferior glenoid; the inclination and version of the baseplate in relation to the Friedman line; and upper and lower screw and baseplate metallic peg end point positionings. The patients were divided according to the presence of GBD for statistical analyses. Results The two radiologists concurred reasonably in their interpretations of the following analyzed parameters: baseplate position within 2mm of the inferior glenoid rim (97.1% and 95.7%), baseplate inclination (82.6% and 81.2%), baseplate version (69.6% and 56.5%), the upper screw reaching the base of the coracoid process (71% and 79.7%), the inferior screw remaining inside the scapula (88.4% and 84.1%), and the metallic peg of the baseplate considered intraosseous (88.4% and 72.5%). Conclusion Reverse baseplate positioning without intraoperative three-dimensional technology is within the acceptable parameters of the literature, except for baseplate version and upper screw position. GBD did not interfere with baseplate positioning in reverse shoulder arthroplasty.

Does Preservation of Coracoacromial Ligament Reduce the Acromial Stress Pathology Following Reverse Total Shoulder Arthroplasty?

Introduction Acromial pathologies (AP), such as acromial stress reaction (ASR), acromial stress occult fracture (ASOF), and acromial stress fracture (ASF), are known as complications that deteriorate the clinical score and patient satisfaction after reverse total shoulder arthroplasty (RSA). Several factors that increase stress on the acromion have been reported as risk factors for AP, but this is also unclear. Thecoracoacromial ligament (CAL) is a structure that distributes the stress loading on such an acromion, although its importance has been mentioned, there is a lack of research. Therefore, we investigated the incidence of AP according to the preservation of the CAL and whether it is a risk factor. Methods The study was retrospectively conducted on patients who underwent RSA from 2016 and 2018. Patients with CAL transection was classified into group 1 and CAL preservation was classified into group 2. ASR and ASOF were identified through symptoms and ultrasound, and ASF identified through simple radiograph or computed tomography. The incidence of AP in each group was checked and compared. Results Of the total of 265 patients. Among 197 cases of group 1, 21 cases of ASR(10.7%), 28 cases of ASOF (14.2%),10 cases of ASF (5.1%), and 59 cases of total AP (29.4%). Among 68 cases in group 2, 2 cases (2.9%) of ASR, 6 cases of ASOF(8.8%), 1 case of ASF (1.5%), and 9 cases of total AP (13.2%). It was confirmed that ASR and ASOP were significantly decreased in the group preserving CAL. (P = .008) Conclusion In the case of preservation of CAL during surgery, it was confirmed that the incidence of ASR, ASOF was reduced. Therefore, preservation of CAL can be regarded as a modifiable risk factor that can reduce the risk of AP by distributing the stress applied to acromion after RSA surgery.

Outpatient Shoulder Arthroplasty—A Systematic Review

Objective Recent reports have shown that outpatient shoulder arthroplasty (SA) may be a safe alternative to inpatient management in appropriately selected patients. The purpose was to review the literature reporting on outpatient SA. Methods A systematic review of publications on outpatient SA was performed. Included publications discussed patients who were discharged on the same calendar day or within 23 hours from surgery. Articles were categorized by discussions on complications, readmissions, and safety, patient selection, pain management strategies, cost effectiveness, and patient and surgeon satisfaction. Results Twenty-six articles were included. Patients undergoing outpatient SA were younger and with a lower BMI than those undergoing inpatient SA. Larger database studies reported more medical complications for patients undergoing inpatient compared to outpatient SA. Articles on pain management strategies discussed both single shot and continuous interscalene blocks with similar outcomes. Both patients and surgeons reported high levels of satisfaction following outpatient SA, and cost analysis studies demonstrated significant cost savings for outpatient SA. Conclusion In appropriately selected patients, outpatient SA can be a safe, cost-saving alternative to inpatient care and may lead to high satisfaction of both patients and physicians, though further studies are needed to clarify appropriate utilization of outpatient SA.

Maximizing Muscle Function in Cuff-Deficient Shoulders: A Rehabilitation Proposal for Reverse Arthroplasty

Purpose The purpose of this review is to describe the role of altered joint biomechanics in reverse shoulder arthroplasty and to propose a rehabilitation protocol for a cuff-deficient glenohumeral joint based on the current evidence. Methods and Materials: The proposed rehabilitation incorporates the principles of pertinent muscle loading while considering risk factors and surgical complications. Results In light of altered function of shoulder muscles in reverse arthroplasty, scapular plane abduction should be more often utilized as it better activates deltoid, teres minor, upper trapezius, and serratus anterior. Given the absence of supraspinatus and infraspinatus and reduction of external rotation moment arm of the deltoid in reverse arthroplasty, significant recovery of external rotation may not occur, although an intact teres minor may assist external rotation in the elevated position. Conclusion Improving the efficiency of deltoid function before and after reverse shoulder arthroplasty is a key factor in the rehabilitation of the cuff deficient shoulders. Performing exercises in scapular plane and higher abduction angles activates deltoid and other important muscles more efficiently and optimizes surgical outcomes.

Reverse Total Shoulder Arthroplasty Baseplate Stability in Superior Bone Loss With Augmented Implant

Background Glenoid bone loss is commonly encountered in cases of rotator cuff tear arthropathy and can create challenges during reverse shoulder arthroplasty. In this study, we sought to investigate the biomechanical properties of a new treatment option for superior glenoid defect, an augmented reverse total shoulder baseplate. Methods Three conditions were examined: non-augmented baseplate without defect, non-augmented baseplate with defect, and augmented baseplate with defect. The augmented baseplates included a 30-degree half wedge which also matched the created superior defect. The samples were cyclically loaded at a 60° simulated abduction angle to mimic baseplate loosening. The migration and micromotion of the baseplate were measured on the superior edge using a 3D Digital Image Correlation System. Results The migration measured in the augmented baseplate showed no significant difference when compared to the no defect or defect cases. In terms of micromotion, the augmented baseplate showed values that were between the micromotions reported for the no defect and defect conditions, but not by a statistically significant amount. Conclusion This study provides biomechanical evidence that augmented baseplates can reduce the amount of micromotion experienced by the RSA construct in the presence of significant superior glenoid bone deficiency, but do not fully restore stability to that of a full contact non-augmented baseplate.

Racial and Gender Shoulder Arthroplasty Utilization Disparities of High- and Low-Volume Centers in New York State

Introduction The literature has consistently demonstrated utilization disparities in joint replacement procedures, though no studies have evaluated disparities in total shoulder arthroplasty with regard to operative volume. Methods We queried the New York (NY) Statewide Planning and Research Cooperative System (SPARCS) database for 32 410 total shoulder arthroplasties performed between 2009 and 2017. Patients were identified using Clinical Classifications Software code 154 for Non-Hip/Knee Arthroplasty and All Patient Refined-Diagnosis Related Group code 322 for Shoulder. Racial groups included Hispanic, non-Hispanic white, non-Hispanic black, and Other. High-volume centers were facilities that performed 2 standard deviations above the mean annual procedures. Utilization rates were calculated by dividing total shoulder arthroplasties per group by the 2010 NY Census population of that group. The Fisher exact test was used to determine significance. Results Total shoulder arthroplasty utilization increased from 43/100 000 to 73/100 000, two-thirds of which was driven by an increase in white resident utilization. More White residents per 100 000 underwent shoulder arthroplasty than Black, Hispanic, and Other residents per 100 000 residents of their respective race. White residents were 90% more likely than Hispanic residents to undergo total shoulder arthroplasty at high-volume centers ( P = .04). There were no differences in utilization rate regarding operative volume comparing Black or Other residents to White residents. More females underwent total shoulder arthroplasty than males, though there was no difference in utilization rate regarding operative volume. Conclusion Though total shoulder arthroplasty utilization nearly doubled, disparities persisted across gender and minority groups particularly in Hispanic utilization as White residents were 90% more likely than Hispanic residents to undergo shoulder arthroplasty at high-volume centers.

Stemless Total Shoulder: A Review of Biomechanical Fixation and Recent Results

Introduction: Anatomic total shoulder arthroplasty is the replacement of the humeral head and glenoid surfaces with the goal of replicating normal anatomy. It is commonly utilized for patients with osteoarthritis, rheumatoid arthritis, and osteonecrosis, who have decreased range of motion (ROM), persistent pain, and loss of strength. Total shoulder Arthroplasty (TSA) is the third most common joint replacement in the United States. The incidence of TSA has been increasing, some data suggest that by the year 2025, TSA incidence may rise to 439,206 operations per year. In recent years, stemless total shoulder implants have become available. Results: These implants preserve bone stock while decreasing complications such as osteolysis, stress shielding and periprosthetic fracture. Stemless implants improve anatomic reconstruction and biomechanical function of the shoulder joint. Conclusion: Increasing amounts of data suggest stemless TSA to be a safe and effective technology that will become more common in the coming year.