Use of computed tomography for shoulder arthroplasty: A systematic review.

Introduction: The prevalence of total shoulder arthroplasties is on the rise annually. Improvements in implant quality, construct stability, and surgical techniques have notably enhanced post-operative results, prompting an expansion of indications for shoulder arthroplasty. Despite its high success rate, opportunities for enhancement remain, especially in preoperative planning and intraoperative execution. Advanced imaging technologies offer significant potential in optimizing implant placement, thus improving the longevity of the procedure. To our knowledge, a comprehensive review examining the impact of advanced imaging on shoulder arthroplasty has yet to be conducted. This systematic review aims to investigate the benefits of advanced imaging technologies in this context, focusing on their application in preoperative planning, osteoarthritis assessment, intraoperative adjustments, patient-specific instrumentation, and navigational aids. Methods: This review utilized a comprehensive search of PubMed to identify relevant studies published from 2000 to 2024, focusing on the application of various imaging techniques in shoulder arthroplasty. The search was conducted by two authors and centered on plain radiography, CT scans, and MRI. The selection criteria included availability of full-text articles, English language, direct comparison of imaging techniques, and a focus on patient outcomes, including discussions on broader applications such as intraoperative navigation and patient-specific instrumentation development. Results: Enhanced imaging techniques, particularly CT scans and MRIs, have been shown to significantly improve outcomes in shoulder arthroplasty. While plain radiographs remain standard, CT scans provide superior bony detail, crucial for evaluating glenoid wear and determining augmentation needs. Preoperative CT imaging has been demonstrated to enhance implant placement accuracy. Moreover, intraoperative technologies based on CT imaging, such as patient-specific instrumentation and navigation systems, contribute to better surgical results. Conclusion: The benefits of CT imaging in shoulder arthroplasty significantly outweigh the associated costs. Current literature strongly supports the adoption of CT imaging in these procedures, particularly when used alongside modern operative technologies.

Outcomes of patients undergoing anatomical total shoulder arthroplasty with augmented glenoid components - a systematic review.

Background: Glenoid loosening is an issue in anatomic total shoulder arthroplasty (a-TSA). This has been attributed to abnormal glenoid anatomy, common among these patients. Different alternatives have been proposed to tackle glenoid bone loss and restore joint alignment with augmented glenoid implants being increasingly used to deal with this problem. This systematic review aims to evaluate the clinical and radiological outcomes of patients undergoing augmented glenoid a-TSAs. Our hypothesis was that augmented glenoid components will lead to good patient outcomes with a low incidence of complications and revision procedures. Methods: MEDLINE, EMBASE, CENTRAL and CINHAL were searched from inception to February 2022 for information pertaining to outcomes of patients undergoing a-TSA with augmented glenoid implants. Results: Eighteen studies reported on outcomes of 814 a-TSA (800 participants) with a mean follow-up of 3.7 years. Most studies (67%) were Type IV level of evidence. Almost 70% of participants underwent an a-TSA secondary to primary glenohumeral osteoarthritis. Most glenoids were type B2 (73%). Augmented glenoids material was mostly all-polyethylene (81%) with full wedge (45%) and stepped components (38%) designs being the most common. Most studies reported good clinical outcomes. 17 patients (4%) underwent a revision surgery. Conclusions: Our review found that patients undergoing a-TSA with augmented glenoid components report good outcomes at short-to-mid-term follow-up. Further research is warranted to determine if such outcomes remain similar in long term. Level of evidence: Level III, Systematic Review of Therapeutic Studies.

Finding the Truth: Cadaver and CT scan Study of Differences in Glenoid Width Size in the Indian Population.

Introduction: Glenoid mass issues have been extensively published in the recent literature. The controversy arose from our need to compare and obtain the appropriate implant size for reverse shoulder arthroplasty patients. Some well-known authors and surgeons say that Indian patients have a smaller glenoid than their Western friends and patients. Therefore, we decided to examine the glenoid size obtained on a computed tomography (CT) scan and the size obtained on a cadaver, preferably the same cadaver in tertiary care medical school. Necessary permissions were obtained from the relatives of the cadaver, the ethical board, the anatomy department, and the radiology department. Materials and Methods: We evaluated 3D CT scans of 100 patients from our medical college during the global pandemic. Of these, we evaluated only 12 patients whose families agreed to postmortem studies and CT scans. Our research focuses on the shoulder of non-orthopedic diseases conducted at KCGMCH and measured the glenoid height, width, and version using a commercially available computer. Results: The mean age of the patients was 38.5 (range 19-59). The mean glenoid height was 33.8 ± 3.2 mm, maximum glenoid width was 24.3 ± 2.2 mm. The mean glenoid version is 3.48 ± 4 retrospectively. The glenoid width appears to be 23-25 mm on CT scan film, which is similar to cadaver studies. Conclusion: The findings from the cadaver study indicate that the average glenoid size is smaller in the Indian demographic when compared to CT scans. Glenoid width is less in one subset of the population, especially female patients than of the average population than Westerners. However, our studies are limited by the small size of the population and a larger study is recommended in our institution in the future. A better understanding of this glenoid size could help us design a smaller glenoid plate plan, especially for patients in the Indian subcontinent.

Complications after Reverse Total Shoulder Arthroplasty in the Korean Population: A Single Center Study of 299 Cases.

BACKGROUND: Knowledge regarding differences in the order of frequency of complications after reverse total shoulder arthroplasty (RTSA) between Asian and Western populations is limited. We therefore asked for (1) What is the order of frequency of complications after primary RTSA in the Korean population? (2) What are the rates of complication, reoperation, and revision, and clinical outcomes after index surgery? METHODS: We retrospectively reviewed the 299 consecutive cases who underwent primary RTSA with more than 1 year of follow-up over a period of 12 years. The mean age of the patients was 73.4 years (range, 58-88 years) and the mean follow-up period was 3.8 years (range, 1-11.5 years). Evaluation of the clinical outcomes, complications, and reinterventions was performed at the final follow-up. RESULTS: The mean VAS pain score, UCLA score, ASES score, and SSV improved from 6.7, 10.2, 30.7, and 27.7% before RTSA to 1.4, 26.4, 80.5, 77.2% after RTSA, respectively (P < .001). Overall, 45 complications (15.1%) were observed in 44 patients. The order of frequency of complications was as follows: 16 cases of scapular stress fracture (5.4%), 9 intraoperative or postoperative periprosthetic fracture (3.0%), 6 brachial plexus injury (2.0%), 4 instability (1.3%), 2 glenoid loosening (0.7%), 2 glenoid disassembly (0.7%), 2 periprosthetic joint infection (0.7%), 1 glenoid fixation failure (0.3%), 1 humeral stem fixation failure (0.3%), 1 hematoma (0.3%), and 1 complex regional pain syndrome (0.3%). Reintervention was performed in 15 cases (5.0%) including reoperation (8 cases; 2.7%) and revision surgery (7 cases; 2.3%). CONCLUSION: At a mean follow-up period of 3.8 years, primary RTSA showed satisfactory clinical outcomes with a complication rate of 15.1%, a reoperation rate of 2.7%, and a revision rate of 2.3%. Scapular stress fracture appears to be the most common complication after RTSA in the Korean population.

Modified notching classification in inverted-bearing and conventional-bearing reverse total shoulder arthroplasty.

BACKGROUND: Scapular notching is a common complication of reverse total shoulder arthroplasty (RTSA). Although the notching rate has reduced significantly thanks to modifications to the surgical technique and humeral and glenoid components, uncontrollable polyethylene (PE)-induced osteolysis can still occur. In contrast to conventional-bearing (CB-RTSA), inverted-bearing RTSA (IB-RTSA) systems, with PE glenospheres and metal or ceramic humeral liners, avoid PE abrasion through scapulohumeral contact. If present, the resulting notch has a different size and configuration than with CB-RTSA. Thus, a modified notching classification seems reasonable. Even in CB-RTSA, the early stages of notching show a different configuration than implied by the established Nerot-Sirveaux classification; therefore, a modification of the classification system is recommended. METHODS: In a prospective multicentre study, 250 cases underwent IB-RTSA. Of these, 39 died, and 28 were lost to follow-up for other reasons, leaving 183 shoulders for the final follow-up examination at a mean of 120.7 months (range 84.1-172.4 months). In the CB-RTSA group, we retrospectively evaluated radiographs of 59 consecutive patients with a follow-up ranging from 2 to 7 years. We analysed the appearance, evolution over time, and location of bone loss on the scapular neck according to the modified Nerot-Sirveaux classification. RESULTS: In IB-RTSA, notching resulted in a new morphological configuration: In contrast to the Nerot-Sirveaux classification, notching began far from the baseplate as an impression or abrasion of the humeral component in the inferior scapular rim. Due to simultaneous mechanical ablation, the defect gradually enlarged, but usually did not contact the baseplate or extend beyond the inferior peg. No signs of PE-induced osteolysis were found. The notching rate reached 19% after 2 years and approached 36% after 10 years. Most shoulders had grade 0 notching (64%), followed by grade 1 (29%); extensive erosion (grade 4) was not observed. In the CB-RTSA group, a small bony impression or erosion without signs of PE-induced osteolysis was observed medial to the scapular neck, without contact with the metaglene in the early phase, which was similar to the impression of the humeral component in IB-RTSA. The notching rate was 86% for CB-RTSA. CONCLUSIONS: A new classification was developed for IB-RTSA, which corresponds to the pathophysiological processes and is compatible with the existing Nerot-Sirveaux classification. Bone erosion in CB-RTSA is not adequately represented by the established classification in the early stages. For this reason, a supplement to the existing classification is presented. LEVEL OF EVIDENCE: Level 4, Case Series, Treatment Study.

A reduced scapulo-humeral angle contributes to the development of scapular notching in reverse total shoulder arthroplasty.

PURPOSE: Scapular Notching (SN) is one of the most common postoperative complications for a patient after Reverse Total Shoulder Arthroplasty (RTSA). Despite employing various strategies to mitigate SN risk, the overall incidence remains far from zero. This article introduces a new risk factor, the scapulo-humeral angle (SHA), as a key element influencing the risk for SN. METHODS: A retrospective analysis was conducted on all patients who underwent RTSA for rotator cuff arthropathy at the study centre. The preoperative SHA was measured, and the presence of SN was investigated and graded using the Nerot classification at the latest follow-up. RESULTS: 42 patients were included. 12 presented SN (incidence 28.5%). A statistically significant Pearson coefficient correlation between pre-operative SHA and the incidence of SN was observed (r= -0.6954; 95% C.I. -0,8250 to -0,4963; p < 0.0001). A statistically significant Pearson coefficient correlation was also found between the degree of SN and the pre-operative SHA (r= -0,7045; 95% C.I. -0,8306 to -0,5096; P value (two-tailed) < 0,0001, alpha 0.05). CONCLUSIONS: The primary finding is a statistically significant correlation between a reduced preoperative SHA and an increased incidence of postoperative SN. The secondary finding is that a smaller preoperative SHA is associated with a more severe degree of SN A SHA cut-off of 50° distinguished patients at high risk of SN from those at low risk. All patients with an SHA below 50° developed SN (10/10), whereas only 6.25% of patients with an SHA exceeding 50° experienced SN (2/32).

Outcomes of revision versus re-revision reverse total shoulder arthroplasty: A case-control-matched cohort study.

Background: The increasing incidence of reverse total shoulder arthroplasties (RTSA) has led to an increase in revision surgery. We aimed to compare patients undergoing re-revision RTSA to a matched cohort undergoing first-revision RTSA. Methods: A retrospective review of all revision RTSAs was performed at a single institution. Sixteen shoulders that underwent re-revision RTSA were matched 1:3 to shoulders that underwent revision RTSA with a minimum two-year follow-up. Outcome scores including the American Shoulder and Elbow Surgeons Shoulder Score (ASES), Short-Form 12 (SF-12), Shoulder Pain and Disability Index (SPADI), and Simple Shoulder Test (SST) scores, range of motion (ROM), and improvement from preoperative to postoperative outcomes after re-revision RTSA were assessed. Additionally, postoperative outcomes after re-revision RTSA were compared to patients that underwent first revision RTSA and subsequently compared to the minimal clinically important difference (MCID) values for the outcome scores and ROM measurements assessed. Results: Sixteen shoulders that underwent re-revision RTSA and 78 revision RTSAs met the final inclusion criteria to be included in this study. Significant improvement from preoperative to postoperative re-revision RTSA was seen in the ASES score (p = 0.046), SPADI score (p = 0.044), SST (p = 0.008), abduction (p = 0.016), and elevation (p = 0.025), but not the SF-12 score (p = 0.396), external rotation (p = 0.449), or internal rotation (p = 0.451). Outcomes after revision RTSA were found to be superior to outcomes after re-revision RTSA for all outcome scores (ASES p = 0.029, SF-12 p = 0.018, SPADI p = 0.003) except the SST score (p = 0.080) and all ROM measures (p > 0.05 for all). Internal rotation was equivalent postoperatively between both groups. From preoperative to postoperative re-revision RTSA, the mean improvement exceeded the MCID for the SST score, abduction, forward elevation, and external rotation. When comparing postoperative revision RTSA to postoperative re-revision RTSA, the mean difference between revision and re-revision RTSA exceeded the MCID for the SPADI score and external rotation. The complication rate was 19% in shoulders undergoing first revision and 41% in shoulders undergoing re-revision RTSA. Conclusion: Patients undergoing re-revision RTSA receive improvement in clinical outcomes, but do not achieve outcomes comparable to those achieved after first revision RTSA.

Trend shift in proximal humeral fracture treatment: a detailed review of national shoulder arthroplasty data.

Background/aim: This study aimed to scrutinize nationwide utilization trends of shoulder arthroplasty for proximal humerus fractures (PHFs) using a comprehensive national surgical database. Materials and methods: A retrospective study was conducted with 4181 patients who underwent shoulder arthroplasty due to PHF between 2016 and 2022 using national health records. They are grouped as hemiarthroplasty (HA), anatomical total shoulder arthroplasty (TSA), and reverse shoulder arthroplasty (RSA). The patients' demographic data, length of hospital stay, revision histories, transfusion rates, mortality data, trends in arthroplasty methods over the years, the distribution of cases by hospital characteristics and geographical regions were analyzed. Results: Treatment with HA was administered to 22.1% of patients, TSA to 30.2%, and RSA to 47.7%. The lowest revision rate was observed after HA (4.3%), while higher rates were recorded after TSA (7.9%) and RSA (7.4%) (p = 0.019). It was observed that there was a significant increasing trend in RSA rates and a decreasing trend in HA and TSA rates over time (p < 0.001). Conclusion: From 2016 to 2022, there appears to have been a significant increase in the utilization of RSA for the arthroplasty treatment of proximal humeral fractures in Türkiye, and it is used more frequently than HA. However, revision rates after RSA are still higher than those after HA. Level of evidence: Level III, retrospective cohort study.

Use of pre-operative 3D planning software for revision shoulder arthroplasty: clinical experience data from a survey in a real-world setting.

Background: Preoperative 3D planning is routinely used in primary shoulder arthroplasty, while specific challenges in the revision setting make such approaches more cumbersome and less accessible. Recently, an established preoperative planning software (Blueprint; Stryker, Tornier SAS, Montbonnot-Saint-Martin, France) was expanded to offer a capability for planning of revision and complex primary shoulder arthroplasty cases. The aim of this study was to survey experienced surgeons on their perception of the new software feature for preoperative 3D planning in the setting of revision shoulder arthroplasty. Methods: An observational survey was conducted from January 2022 to October 2022 among orthopedic surgeons performing revision shoulder arthroplasty cases. The survey was part of the Early Product Surveillance program, with the primary goal of obtaining observational data from surgical experience in a real-world setting. A two-staged survey process was applied with separate questionnaires to seek voluntary feedback on the preoperative planning phase as well as on the intraoperative evaluation of the software planning features in revision shoulder arthroplasty. Results: Twenty-five fellowship-trained orthopedic surgeons from the USA and Canada participated in the survey and reported their feedback on 34 revision shoulder arthroplasty cases that were preoperatively planned with the use of Blueprint revision planning software. The surgeons were largely in favor of the revision software planning features and confirmed perceived benefits of its use in the preoperative planning stage of revision shoulder arthroplasty cases. Reported benefits in the preoperative planning phase included increased efficiency and improved ease of creating an appropriate surgical plan as well as increased confidence to execute revision shoulder arthroplasty cases. Surgeons also noted improvements in translation of preoperative planning to intraoperative execution of revision cases, including more appropriate implant selection and improved accuracy of implant placement. Conclusion: The feedback from fellowship-trained shoulder arthroplasty surgeons on the use of the new software feature for preoperative 3D planning of revision shoulder arthroplasty is largely favorable. Further research should be conducted to investigate whether these surgeon-perceived benefits can lead to improved clinical outcomes for patients.

Anatomic restoration of lateral humeral offset and humeral retroversion optimizes functional outcomes following reverse total shoulder arthroplasty.

Cadaveric and computer simulations suggest lateral humeral offset (LHO) and humeral retroversion (HR) are associated with strength and range of motion (ROM) after reverse total shoulder arthroplasty (rTSA), butin vivodata is lacking. This study aimed to evaluate the effects of implant parameters (i.e. LHO and HR) on strength and ROM. LHO and HR were measured using pre-operative and post-operative computed tomography (CT) scans. Postoperative strength was measured across three planes of motion using a Biodex isokinetic dynamometer. Postoperative active and passive ROM during forward elevation, external rotation (ER), and internal rotation (IR) were assessed using a goniometer or spinal level. 30 rTSA patients (14 M, 16F, age: 71.8 ± 6.7yrs) participated with an average postoperative follow-up of 2.4 ± 1.1 years. Regarding strength, higher post-op LHO values were predictive of greater postoperative strength across all movements. However, lateralization of the implant beyond pre-op values (i.e. post-op LHO > pre-op LHO) was associated with poorer strength performance across all ranges of motion. Similar to strength outcomes, greater deviations from pre-op LHO was predictive of poorer IR ROM. Lastly, patients with minimal deviations in HR (post-op HR within 10° of pre-op HR) and minimal deviations in LHO (post-op LHO ≤ pre-op LHO) displayed the greatest postoperative ER ROM. Anatomic restoration of LHO combined with anatomic restoration of HR may be ideal for maximizing strength and ROM following rTSA. Overlateralization beyond anatomic may have negative consequences. Optimal implant lateralization and version may need to be individualized based on preoperative values.

ChatGPT is capable of providing satisfactory responses to frequently asked questions regarding total shoulder arthroplasty.

Background: The rising prominence of artificial intelligence in healthcare has revolutionized patient access to medical information. This cross-sectional study sought to assess if ChatGPT could satisfactorily address common patient questions about total shoulder arthroplasty (TSA). Methods: Ten commonly encountered questions in TSA practice were selected and posed to ChatGPT. Each response was assessed for accuracy and clarity using the Mika et al. scoring system, which ranges from "excellent response not requiring clarification" to "unsatisfactory response requiring substantial clarification," and a modified DISCERN score. The readability was further evaluated using the Flesch Reading Ease Score and the Flesch-Kincaid Grade Level. Results: The mean Mika et al. score was 2.93, corresponding to an overall subjective rating of "satisfactory but requiring moderate clarification." The mean DISCERN score was 46.60, which is considered "fair." The readability analysis suggested that the responses were at a college-graduate level, higher than the recommended level for patient educational materials. Discussion: Our results suggest that ChatGPT has the potential to supplement the collaborative decision-making process between patients and experienced orthopedic surgeons for TSA-related inquiries. Ultimately, while tools like ChatGPT can enhance traditional patient education methods, they should not replace direct consultations with medical professionals.

A machine learning analysis of patient and imaging factors associated with achieving clinically substantial outcome improvements following total shoulder arthroplasty: Implications for selecting anatomic or reverse prostheses.

Background: Indications for reverse total shoulder arthroplasty(rTSA) continue to expand making it challenging to predict whether patients will benefit more from anatomic TSA(aTSA) or rTSA. The purpose of this study was to determine which factors differ between aTSA and rTSA patients that achieve meaningful outcomes and may influence surgical indication. Methods: Random Forest dimensionality reduction was applied to reduce 23 features into a model optimizing substantial clinical benefit (SCB) prediction of the American Shoulder and Elbow Surgeon score using 1117 consecutive patients with 2-year follow up. Features were compared between aTSA patients stratified by SCB achievement and subsequently with rTSA SCB achievers. Results: Eight combined features optimized prediction (accuracy = 87.1%, kappa = 0.73): (1) age, (2) body mass index (BMI), (3) sex, (4) history of rheumatic disease, (5) humeral head subluxation (HH) on computed tomography (CT), (6) HH-acromion distance on X-ray, (7) glenoid retroversion on CT, and (8) Walch classification on CT. A higher proportion of males (65.6% vs. 54.9%, p = 0.022), Walch B-C glenoid morphologies (49.5% vs. 37.9%, p < 0.001), and greater BMI (30.1 vs. 26.5 kg/m2, p = 0.038) were observed in aTSA nonachievers compared with aTSA achievers, while aTSA nonachievers were statistically similar to rTSA achievers. Discussion: Patients with glenohumeral osteoarthritis and intact rotator cuffs that have a BMI > 30 kg/m2 and exhibit Walch B-C glenoids may be less likely to achieve the SCB following aTSA and should be considered for rTSA.

Survivorship analysis of CAD-CAM total shoulder replacement.

Background: Glenoid bone loss represents a challenge in shoulder arthroplasty and often precludes standard implants. The CAD-CAM total shoulder replacement (TSR) is an option in these cases. This study aimed to assess survivorship and long-term patient outcomes of the CAD-CAM TSR. Methods: Fifty-eight patients that underwent a CAD-CAM TSR by three surgeons at a single tertiary referral centre between 2009 and 2017 were reviewed. The mean follow-up was 70 months (28-130). Data was collected on survivorship, range of movement, Oxford shoulder score (OSS, 0-48), subjective shoulder value (SSV, 0-100%), pain score (0-10), and overall patient satisfaction. Results: CAD-CAM TSR was undertaken as a primary procedure in 28% (n = 16) for end-stage arthritis with severe glenoid bone loss, and as a revision procedure in 72% (n = 42). Of the total, 17% (n = 10) required component revision at a mean of 24 months (4x prosthesis loosening, 3x infection, 3x periprosthetic fracture). Forward elevation improved from 45° ± 27° to 59° ± 29° (P = 0.0056), abduction from 43° ± 29° to 55° ± 26° (P = 0.034) and external rotation from 8° ± 11° to 16° ± 14° (P = 0.031). OSS improved from 15 ± 8 to 29 ± 9 (P = 0.0009), SSV from 18 ± 16 to 62 ± 23 (P < 0.0001), and pain score from 8 ± 2 to 2 ± 2 (P < 0.0001). 88% of patients would undergo the procedure again. Conclusion: CAD-CAM TSR is reserved for complex cases involving severe glenoid bone loss, offering significant improvements in pain and function with overall positive patient satisfaction.

Do modifiable patient factors increase the risk of postoperative complications after total joint arthroplasty?

INTRODUCTION: Numerous studies demonstrate that modifiable lifestyle risk factors can influence patient outcomes including survivability, quality of life, and postoperative complications following orthopaedic surgery. The purpose of this study was to determine the impact of modifiable lifestyle risk factors on postoperative medical and surgical complications following a total joint arthroplasty (TJA) in a large national healthcare system. METHODS: A retrospective chart review of a large national health system database was performed to identify patients who underwent TJA between 2017 and 2021. TJA included total knee arthroplasty, total hip arthroplasty, and total shoulder arthroplasty. Modifiable lifestyle risk factors were defined as tobacco use, narcotic drug abuse, hypertension, and diabetes mellitus. Postoperative medical complications and postoperative surgical complications were collected. Logistic regression and odds ratio point estimate analysis were conducted to assess for associations between postoperative complications and modifiable lifestyle risk factors. RESULTS: Of the 16,940 patients identified, the mean age was 71 years, mean BMI was 29.7 kg/m2, and 62% were women. We found that 3.5% had used narcotics, 8.7% were past or current smokers, 24% had diabetes, and 61% had hypertension; in addition, 5.4% experienced postoperative medical complications and 6.4% experienced postoperative surgical complications. Patients who used narcotics were 90% more likely to have postoperative complications (p < 0.0001) and 105% more likely to experience prosthetic complications (p < 0.0001). Similarly, patients with tobacco use were 65% more likely to have postoperative complications (p < 0.0001) and 27% more likely to experience prosthetic complications. CONCLUSIONS: Our results demonstrate critical rates of increased postoperative medical and surgical complications after TJA for patients with narcotic abuse, tobacco use, or diabetes mellitus. Furthermore, adopting preoperative interventions and optimization programs informed by our findings on specific modifiable risk factors could aid orthopaedic surgeons in optimizing patient health. LEVEL OF EVIDENCE: III; Retrospective study.

Reverse Allograft Prosthetic-Composite Versus Endoprosthesis Reconstruction for Massive Proximal Humerus Bone Loss: A Systematic Review and Meta-analysis of Outcomes and Complications.

Background: This systematic review and meta-analysis sought to compare the clinical outcomes after proximal humerus reconstruction with a reverse allograft-prosthetic composite (APC) versus reverse endoprosthesis. Methods: Per PRISMA guidelines, we queried PubMed/MEDLINE, Embase, Web of Science, and Cochrane databases to identify articles reporting clinical outcomes of reverse APC or reverse endoprosthesis reconstruction of the proximal humerus for massive bone loss secondary to tumor, fracture, or failed arthroplasty. We compared postoperative range of motion, outcome scores, and the incidence of complications and revision surgery. Results: Of 259 unique articles, 18 articles were included (267 APC, 260 endoprosthesis). There were no significant differences between the APC and endoprosthesis cohort for postoperative forward elevation (P = .231), external rotation (P = .634), ASES score (P = .420), Constant score (P = .414), MSTS (P = .815), SST (P = .367), or VAS (P = .714). Rate of complications was 15% (31/213) in the APC cohort and 19% (27/144) in the endoprosthesis cohort. The rate of revision surgery was 12% after APC cohort and 7% after endoprosthesis. APC-specific complications included a 10% APC nonunion/malunion/resorption rate and 6% APC fracture/fragmentation rate. Discussion: Reverse APC and endoprosthesis are reasonable options for proximal humerus reconstruction. APC carries additional risks for complications, warranting evaluation of patients' healing capacity and surgeon experience. Level of Evidence: Level IV; Systematic Review. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-024-01248-7.

An in vitro study of glenoid implant peripheral peg interface mechanics during eccentric loading and lift-off.

Glenoid implants used in anatomic total shoulder arthroplasties typically incorporate peripheral pegs as a design feature to support eccentric loads. These peripheral pegs and the implant-cement-bone interface undergo substantial cyclic tensile-compressive loads during normal activity. Therefore, these pegs are of interest in translating the micromechanics of local implant fixation failure to the biomechanics of gross anatomic failure of the glenoid implant after total shoulder arthroplasty. This study used an in vitro peg-cement-bone construct which incorporated bone tissue acquired from osteoarthritic patients undergoing total shoulder arthroplasty. Strain distributions in the peripheral peg-cement-bone interfaces were analyzed under loading conditions emulating glenoid implant edge displacements. It was found that tensile strains in the interfaces were highest near the backside-peg junction and were greater in magnitude than compressive strains. Notably, strains near the peg's fixation channels were relatively low. These results suggest that cracks may initiate around the peg near the backside and travel downward to cause broader fixation failure.

Predicting Unplanned Return to Operating Room Following Primary Total Shoulder Arthroplasty: Insights from Fair and Explainable Ensemble Machine Learning.

Reoperation is the most significant complication following any surgical procedure. Developing machine learning methods that predict the need for reoperation will allow for improved shared surgical decision making and patient-specific and preoperative optimisation. Yet, no precise machine learning models have been published to perform well in predicting the need for reoperation within 30 days following primary total shoulder arthroplasty (TSA). This study aimed to build, train, and evaluate a fair (unbiased) and explainable ensemble machine learning method that predicts return to the operating room following primary TSA with an accuracy of 0.852 and AUC of 0.91.