Biomechanics of anatomic and reverse shoulder arthroplasty

Effect of Antifibrotic Medications on Development of Postoperative Adhesive Capsulitis and Need for Manipulation Under Anesthesia Following Total Shoulder Arthroplasty

BACKGROUND

The local inflammatory response after total shoulder arthroplasty leads to increased scar formation and, potentially, adhesive capsulitis. Recent research has evaluated the use of antifibrotic medications to decrease rates of postoperative adhesive capsulitis (AC).

METHODS

PearlDiver database was used to analyze patients from 2010 to 2022 who underwent total shoulder arthroplasty, identified by Common Procedural Terminology codes. Medication usage was determined using National Drug Codes. Patients who developed ipsilateral AC within 6 months after surgery or underwent a manipulation under anesthesia (MUA) within 12 months of diagnosis of AC were identified. Logistic regression analysis was used to evaluate patient characteristics and drug class usage that increased odds for postoperative AC within 12 months and for MUA within 6 months of diagnosis of AC.

RESULTS

Overall, 1.3% (993/79,010) of patients developed postoperative AC within 6 months of surgery. Of those who developed AC, 7.2% (71/993) underwent MUA within 12 months of diagnosis. Medication use with any of the drug classes had no markedly decreased odds for the development of AC or subsequent MUA. Male sex, increasing age, and diagnosis of depression all markedly decreased the odds of developing AC ((odds ratio) OR = 0.42, P = 0.001; OR = 0.95, P < 0.001; OR = 0.59, P = 0.04, respectively) and subsequent need for MUA (OR = 0.68, P ≤ 0.001; OR = 0.96, P < 0.001; OR = 0.87, P = 0.04, respectively).

CONCLUSION

Patients on an antifibrotic medication had no difference in the odds of being diagnosed with AC within 6 months of surgery and for MUA within 12 months of diagnosis of AC. Male sex, increasing age, and presence of depression markedly decreased the odds.

Instability and the Anatomic Total Shoulder Arthroplasty

Instability of the anatomic total shoulder arthroplasty is a challenging problem. With an incidence of 1% to 5% reported in the literature, it is critical for shoulder surgeons to understand and be capable of addressing this complication. Etiology is multifactorial and related to soft-tissue imbalance, osseous pathology, implant malposition, or more commonly, a combination of these various causes. Historically, high rates of failure have been reported after revision procedures, prompting a movement toward the more inherently stable reverse shoulder arthroplasty as a reliable form of management. However, this may not be the ideal solution for all patients, particularly the young and active population. Consequently, the purpose of this article was to provide a review of the literature on the management of postoperative instability and intraoperative strategies to prevent this complication during the index procedure.

Context-Aware Dual-Task Deep Network for Concurrent Bone Segmentation and Clinical Assessment to Enhance Shoulder Arthroplasty Preoperative planning

Goal: Effective preoperative planning for shoulder joint replacement requires accurate glenohumeral joint (GH) digital surfaces and reliable clinical staging. Methods: xCEL-UNet was designed as a dual-task deep network for humerus and scapula bone reconstruction in CT scans, and assessment of three GH joint clinical conditions, namely osteophyte size (OS), joint space reduction (JS), and humeroscapular alignment (HSA). Results: Trained on a dataset of 571 patients, the model optimized segmentation and classification through transfer learning. It achieved median root mean squared errors of 0.31 and 0.24 mm, and Hausdorff distances of 2.35 and 3.28 mm for the humerus and scapula, respectively. Classification accuracy was 91 for OS, 93 for JS, and 85% for HSA. GradCAM-based activation maps validated the network's interpretability. Conclusions: this framework delivers accurate 3D bone surface reconstructions and dependable clinical assessments of the GH joint, offering robust support for therapeutic decision-making in shoulder arthroplasty.

Short humeral stem in total shoulder arthroplasty does not jeopardize primary implant stability

Background

The trend of the modern humeral components in total shoulder arthroplasty is toward shorter and shorter humeral stems. However, the question remains whether short uncemented stems can provide the same implant stability as long stems. This study aimed to evaluate and compare the torsional primary stability and the pull-out extraction force of both a long and a short version of the same stem.

Materials and methods

Ten humeral components (five long stems and five short stems) were press-fitted into ten synthetic composite humeri. A torsional load was applied to generate the most critical loading condition. The specimens were loaded with 100 cycles between 2 Nm and 10 Nm, at 1 Hz. A 3D Digital Image Correlation system was used to measure the relative displacement between the prosthesis and the host bone during the test. After completing the torsional test, the pull-out force was measured. Differences between the long and short stem on the biomechanical parameters (permanent migrations, inducible micromotion, and extraction force) were tested with the nonparametric Mann-Whitney test (P < .05).

Results

The main rotational inducible micromotion was around the craniocaudal axis. No significant differences were found between the rotational permanent migrations of the long and short stem around the craniocaudal (P = .421), anteroposterior (P = .841), and mediolateral axes (P = .452). No significant differences were found between the rotational inducible micromotions of the long and short stem around the craniocaudal (P = .222), anteroposterior (P = .420), and mediolateral axes (P = .655). No significant differences were found between the permanent translations of the long and short stem along the craniocaudal (P = .341), anteroposterior (P = .420), and mediolateral (P = .429) directions. No significant differences were found between the translations of the long and short stem in terms of inducible translation in the craniocaudal (P = .547), anteroposterior (P = .999), and mediolateral axes (P = .285). Similar extraction force (P = .35) was found.

Discussion and Conclusion

No statistically significant difference was found between the long-stem and short-stem implants. These results show that short uncemented stems can provide adequate primary mechanical stability. As the long-stem version of this stem is already clinically used, the present findings suggest that the short version can be reasonably expected to deliver similar outcomes in terms of implant stability.

The effect of reverse shoulder arthroplasty design and surgical indications on deltoid and rotator cuff muscle length

BACKGROUND

Advancements in surgical planning, technique, and prosthesis design have improved adaptation to patient anatomy in reverse total shoulder arthroplasty (rTSA). Postoperative changes in deltoid and rotator cuff muscle length are important and may vary based on preoperative indications and prosthesis selection. The purpose of this study is to demonstrate the changes in deltoid and rotator cuff muscle length for planned rTSA using the spectrum of prosthesis configurations in both glenohumeral arthritis (GHOA) and rotator cuff tear arthropathy (RCA).

METHODS

Ten shoulder arthroplasty surgeons used preoperative planning software to plan rTSA cases for 20 subjects (10 GHOA, 10 RCA) following surgical guidelines. Each surgeon planned each case using 3 prosthesis configurations: (1) 8-mm lateralized glenosphere and 135° neck-shaft angle (135 + 8), (2) 4-mm lateralized glenosphere and 145° neck-shaft angle (145 + 4), and (3) 0-mm lateralized glenosphere and 155° neck-shaft angle (155 + 0). Pre- and postoperative deltoid and rotator cuff muscle lengths and percentage-change were calculated and compared between prosthesis configurations within each indication. Different muscle lines of action were included representing the deltoid, subscapularis, infraspinatus, and teres minor.

RESULTS

Preoperatively, the RCA cohort had significantly shorter muscle lines of action in the posterior, lateral, and anterior deltoid (P < .001), a longer inferior subscapularis (P = .022), and a longer teres minor (P = .001) than the GHOA cohort. ANOVA and post-hoc analysis showed that postplanning lengths of each deltoid action line were greater in the 155 + 0 configuration compared to the 135 + 8 configuration in the RCA cohort (P < .001, P = .003, P = .032, respectively), and postplanning lengths of the anterior and middle deltoid action lines were also greater for the same comparison in the GHOA cohort (P = .004 and P = .017, respectively). There were no significant differences in postplanning deltoid lengths between the 135 + 8 and 145 + 4 configurations in either diagnosis cohort (P > .05). All postplanning rotator cuff muscle lengths (subscapularis, infraspinatus, and teres minor) differed significantly (P < .001) between all prosthesis configurations in both diagnosis cohorts, with the 135 + 8 configuration resulting in the longest lengths and the 155 + 0 configuration resulting in the shortest lengths.

CONCLUSION

Automated preoperative planning software calculates the lengths of muscle action lines, which vary between GHOA and RCA diagnoses. Varying rTSA implant geometries result in predictable differences in deltoid lengthening and rotator cuff shortening. Shoulder prostheses with a more lateralized center of rotation show greater rotator cuff muscle length and similar deltoid muscle length when compared to medialized designs with similar deltoid lengthening. Surgeons can use this software to understand the impact of implant geometry on muscle length.

Surgical decisions on implant-related parameters can enhance knowledge transfer for glenoid bone grafting in primary reverse shoulder arthroplasty: a scoping review of heterogeneity sources

Purpose

The purpose of the present scoping review is to identify sources of heterogeneity in reporting domains that have the potential to improve surgical decision-making in reverse shoulder arthroplasty associated with glenoid bone grafting.

Methods

A scoping review was conducted according to the JBI and PRISMA ScR guidelines. Articles covering glenoid bone grafting at the time of reverse shoulder replacement, published between 2012 and 2022 in MEDLINE, Scopus, Epistemonikos, Web of Science, and Cochrane Database of Systematic Reviews, were searched. Reporting of core outcome measures, as well as prosthesis-related variables, rehabilitation protocols, radiographic evaluation methods, and bone graft incorporation assessments, were collected.

Results

For the final analysis, a total of 14 articles were considered. There were 649 operated shoulders with a mean patient age of 72 years, ranging from 48 to 85 years. Analysis of preoperative ranges of motion and patient-reported outcome measures revealed increased heterogeneity in patient selection between studies. Reporting of implant-related parameters was the most inconsistent. Rehabilitation protocols were scarcely reported. Assessment of graft incorporation and radiographic evaluation of choice revealed that there is no consistent method or measurement and the clinical relevance of radiolucent lines at the graft-glenoid bone interface is unclear.

Conclusion

Addressing implant-related reporting gaps has the highest potential to improve surgical decision-making and provide orthopedic surgeons with a more comprehensive understanding of published results on glenoid bone grafting at the time of primary reverse shoulder arthroplasty.

Research advances and trends in anatomy from 2013 to 2023: A visual analysis based on CiteSpace and VOSviewer

As the cornerstone of medicine, the development of anatomy is related to many disciplines and fields and has received extensive attention from researchers. How to integrate and grasp the cutting-edge information in this field quickly is a challenge for researchers, so the aim of this study is to analyze research in anatomy using CiteSpace and VOSviewer in order to identify research hotspots and future directions. To offer a fresh viewpoint for assessing the academic influences of researchers, nations, or institutions on anatomy, and to examine the development of hotspots in anatomical study and to forecast future trends. A total of 4637 anatomy-related publications from 2013 to 2023 were collected from Web of Science Core Collection databases. Their temporal distribution, spatial distribution, cited authors, co-cited journals, keywords, and disciplinary connections in the literature were analyzed using CiteSpace and VOSviewer, and a knowledge graph was constructed. The temporal distribution shows a general fluctuation in the amount of literature published from 2013 to 2023. In spatial distribution, the total number of published articles was highest in the United States, the United Kingdom, and China, the United States leading. Tubbs, Rhoton, Iwanaga, and LaPrade are important authors in anatomy. Clinical Anatomy, Surgical and Radiologic Anatomy, and Journal of Anatomy were the most highly cited journals. Analysis of keywords and citation emergence showed that the research hotspots and trends in anatomy focused mainly on anatomy education, digital technology, and surgical management. At the same time, anatomy showed a trend toward multidisciplinary crossover, developing closer relationships with molecular biology, immunology, and clinical medicine. Current research in anatomy focuses on innovative reform of the educational model and the application and promotion of digital technology. Also, multidisciplinary cross-fertilization is an inevitable trend for the future development of anatomy.

Conjoint tendon lengthening improves internal rotation following reverse total shoulder arthroplasty: a cadaveric study

BACKGROUND

Reverse shoulder arthroplasty (RSA) is a common procedure for treating a variety of shoulder pathologies. However, many patients struggle with postoperative internal rotation (IR) deficits, which often hinder their activities of daily living. The conjoint tendon provides an anatomic barrier that can impede the postoperative IR of the shoulder, and this study aims to evaluate the effect of a conjoint tendon lengthening on the glenohumeral range of motion (ROM) following RSA.

METHODS

This study used ten fresh-frozen cadaver specimens of the upper extremity. An RSA was implanted using a standard deltopectoral approach, and the ROM was assessed postimplantation. Following this, the conjoint tendon was identified and lengthened using a tendon sheath z-plasty, and the ROM was rerecorded. Statistical significance for the ROM gains after conjoint tendon lengthening was determined with a significance level of P < .05.

RESULTS

Following the lengthening of the conjoint tendon, there were statistically significant improvements in all ROMs (P < .05). Subjects demonstrated a notable gain in IR to the back by 10.3 cm (P < .01), and all ROMs increased by at least 10°, except for forward flexion, which increased by 6° (P < .001).

CONCLUSIONS

This study suggests that lengthening the conjoint tendon improves postoperative ROM of the glenohumeral joint after RSA, offering a potential solution to considerable IR deficits that are commonly encountered post-RSA. Subsequent clinical and biomechanical studies should assess the stability of the shoulder joint following conjoint tendon lengthening.

Does preoperative forward elevation weakness affect clinical outcomes in anatomic or reverse total shoulder arthroplasty patients with glenohumeral osteoarthritis and intact rotator cuff?

BACKGROUND

This study sought to determine if preoperative forward elevation (FE) weakness affects outcomes of anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) for patients with rotator cuff-intact glenohumeral osteoarthritis (RCI-GHOA).

METHODS

A retrospective review of a single institution's prospectively collected shoulder arthroplasty database was performed between 2007 and 2020, including 333 aTSAs and 155 rTSAs for primary RCI-GHOA with a minimum 2-year follow-up. Defining preoperative weakness as FE strength ≤4.9 lb (2.2 kg), three cohorts were matched 1:1:1 by age, sex, and follow-up: weak (n=82) to normal aTSAs, weak (n=44) to normal rTSAs, and weak aTSAs (n=61) to weak rTSAs. Compared outcomes included range of motion, outcome scores, and complication and revision rates at latest follow-up.

RESULTS

Weak aTSAs and weak rTSAs achieved similar postoperative outcome measures to normal aTSAs and normal rTSAs, respectively (P>0.05). Compared to weak rTSAs, weak aTSAs achieved superior postoperative passive (P=0.006) and active external rotation (ER) (P=0.014) but less favorable postoperative Shoulder Pain and Disability Index (P=0.032), American Shoulder and Elbow Surgeons (P=0.024), and University of California, Los Angeles scores (P=0.008). Weak aTSAs achieved the minimal clinically important difference and substantial clinical benefit at a lower rate for abduction (P=0.045 and P=0.003) and FE (P=0.011 and P=0.001). Weak aTSAs had a higher revision rate (P=0.025) but a similar complication rate (P=0.291) compared to weak rTSAs.

CONCLUSIONS

Patients with RCI-GHOA and preoperative FE weakness obtain postoperative outcomes similar to patients with normal preoperative strength after either aTSA or rTSA. Preoperatively, weak aTSAs achieved greater ER but lower rates of clinically relevant improvement in overhead motion compared to weak rTSAs. Level of evidence: III.

Reverse shoulder arthroplasty design-inlay vs. onlay: does it really make a difference?

BACKGROUND

The design of reverse shoulder arthroplasty (RSA) implants has evolved significantly over the past 50 years. Today there are many options available that differ in design of the glenoid and humeral components, fixation methods, sizes, and modularity. With respect to the humeral component, the literature has generally focused on the differences between inlay and onlay designs and the potential impact on outcomes. However, inlay and onlay design represents only one factor of many.

METHODS

It is our hypothesis that separating onlay and inlay designs into 2 distinct entities is an oversimplification as there can be a wide overlap of the 2 designs, depending on surgical technique and the implant selected. As such, the differences between inlay and onlay designs should be measured in absolute terms-meaning combined distalization and lateralization.

RESULTS

By reviewing the many factors that can contribute to the glenosphere-humerus relationship, the role of inlay and onlay humeral designs as an important distinguishing feature is shown to be limited. Preliminary studies suggest that the amount of distalization and lateralization of the construct may be the most accurate method of describing the differences in the constructs.

CONCLUSIONS

Inlay and onlay humeral component design represents only one factor of many that may impact outcomes. A more accurate method of defining specific design and technique factors in RSA is the degree of lateralization and distalization.

Automatic quantification of scapular and glenoid morphology from CT scans using deep learning

OBJECTIVES

To develop and validate an open-source deep learning model for automatically quantifying scapular and glenoid morphology using CT images of normal subjects and patients with glenohumeral osteoarthritis.

MATERIALS AND METHODS

First, we used deep learning to segment the scapula from CT images and then to identify the location of 13 landmarks on the scapula, 9 of them to establish a coordinate system unaffected by osteoarthritis-related changes, and the remaining 4 landmarks on the glenoid cavity to determine the glenoid size and orientation in this scapular coordinate system. The glenoid version, glenoid inclination, critical shoulder angle, glenopolar angle, glenoid height, and glenoid width were subsequently measured in this coordinate system. A 5-fold cross-validation was performed to evaluate the performance of this approach on 60 normal/non-osteoarthritic and 56 pathological/osteoarthritic scapulae.

RESULTS

The Dice similarity coefficient between manual and automatic scapular segmentations exceeded 0.97 in both normal and pathological cases. The average error in automatic scapular and glenoid landmark positioning ranged between 1 and 2.5 mm and was comparable between the automatic method and human raters. The automatic method provided acceptable estimates of glenoid version (R2 = 0.95), glenoid inclination (R2 = 0.93), critical shoulder angle (R2 = 0.95), glenopolar angle (R2 = 0.90), glenoid height (R2 = 0.88) and width (R2 = 0.94). However, a significant difference was found for glenoid inclination between manual and automatic measurements (p < 0.001).

CONCLUSIONS

This open-source deep learning model enables the automatic quantification of scapular and glenoid morphology from CT scans of patients with glenohumeral osteoarthritis, with sufficient accuracy for clinical use.

Does forearm referencing using a retroversion guide achieve the targeted retroversion of the humeral component in reverse shoulder arthroplasty?

BACKGROUND

Component positioning affects clinical outcomes of reverse shoulder arthroplasty, which necessitates an implantation technique that is reproducible, consistent, and reliable. This study aims to assess the accuracy and precision of positioning the humeral component in planned retroversion using a forearm referencing guide.

METHODS

Computed tomography scans of 54 patients (27 males and 27 females) who underwent primary reverse shoulder arthroplasty for osteoarthritis or cuff tear arthropathy were evaluated. A standardized surgical technique was used to place the humeral stem in 15° of retroversion. Version was assessed intraoperatively visualizing the retroversion guide from above and referencing the forearm axis. Metal subtraction techniques from postoperative computed tomography images allowed for the generation of 3D models of the humerus and for evaluation of the humeral component position. Anatomical humeral plane and implant planes were defined and the retroversion 3D angle between identified planes was recorded for each patient. Accuracy and precision were assessed. A subgroup analysis evaluated differences between male and female patients.

RESULTS

The humeral retroversion angle ranged from 0.9° to 22.8°. The majority (81%) of the measurements were less than 15°. Mean retroversion angle (±SD) was 9.9° ± 5.8° (95% CI 8.4°-11.5°) with a mean percent error with respect to 15° of -34% ± 38 (95% CI -23 to -44). In the male subgroup (n = 27, range 3.8°-22.5°), the mean retroversion angle was 11.9° ± 5.4° (95% CI 9.8°-14.1°) with a mean percent error with respect to 15° of -21% ± 36 (95% CI -6 to -35). In the female subgroup (n = 27, range 0.9°-22.8°), mean retroversion angle was 8.0° ± 5.5° (95% CI 5.8°-10.1°) and the mean percent error with respect to 15° was -47% ± 36 (95% CI -32 to -61). The differences between the 2 gender groups were statistically significant (P = .006).

CONCLUSION

Referencing the forearm using an extramedullary forearm referencing system to position the humeral stem in a desired retroversion is neither accurate nor precise. There is a nonnegligible tendency to achieve a lower retroversion than planned, and the error is more marked in females.

Does glenoid version and its correction affect outcomes in anatomic shoulder arthroplasty? A systematic review

BACKGROUND

Correction of glenoid retroversion is commonly performed in anatomic total shoulder arthroplasty (TSA) to increase component contact area and decrease eccentric loading of the glenoid component. Despite demonstrated biomechanical advantages, limited information exists on the clinical benefit of correcting glenoid retroversion. The purpose of this systematic review is to critically evaluate the existing literature on the effect of preoperative and postoperative glenoid retroversion on clinical functional and radiologic outcomes in patients who underwent anatomic TSA.

METHODS

A systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses using PubMed, Embase, and Cochrane Library evaluating the impact of glenoid retroversion on clinical and radiologic outcomes of TSA. English-language studies of level I through IV evidence were included. Blinded reviewers conducted multiple screens and methodological quality was appraised using the Modified Coleman Methodology Score.

RESULTS

Sixteen studies, including 3 level III and 13 level IV studies (1211 shoulders), satisfied all inclusion criteria. To address glenoid retroversion, 9 studies used corrective reaming techniques, and 4 studies used posteriorly augmented glenoids. Two studies used noncorrective reaming techniques. Mean preoperative retroversion ranged from 12.7° to 24° across studies. Eleven studies analyzed the effect of glenoid retroversion on clinical outcomes, including patient-reported outcome scores (PROs), range of motion (ROM), or clinical failure or revision rates. Most studies (8 of 11) did not report any significant association of pre- or postoperative glenoid retroversion on any clinical outcome. Of the 3 studies that reported significant effects, 1 study reported a negative association between preoperative glenoid retroversion and PROs, 1 study reported inferior postoperative abduction in patients with postoperative glenoid retroversion greater than 15°, and 1 study found an increased clinical failure rate in patients with higher postoperative retroversion. Ten studies reported radiographic results (medial calcar resorption, Central Peg Lucency [CPL] grade, Lazarus lucency grade) at follow-up. Only 1 study reported a significant effect of pre- and postoperative retroversion greater than 15° on CPL grade.

CONCLUSION

There is currently insufficient evidence that pre- or postoperative glenoid version influences postoperative outcomes independent of other morphologic factors such as joint line medialization. Given that noncorrective reaming demonstrated favorable postoperative outcomes, and postoperative glenoid version was not significantly and consistently found to impact outcomes, there is inconclusive evidence that correcting glenoid retroversion is routinely required.

Radiologic, clinical, and patient-reported outcomes in stemless reverse shoulder arthroplasty at a mean of 46 months

BACKGROUND

The humeral stem can be a cause of problems in shoulder arthroplasty, for example, loss of bone stock, intraoperative and postoperative periprosthetic fractures, or postoperative infections involving the medullary canal. Therefore, stemless reverse shoulder arthroplasty (slRSA) has gained popularity, particularly in terms of preserving bone stock. However, there are limited data available on the midterm outcomes of slRSA. The objective of this study was to evaluate the clinical, radiologic, and patient-reported outcomes of slRSA at a minimum follow-up period of 2 years.

METHODS

Data on all stemless reverse shoulder prostheses implanted between January 2016 and October 2020 were collected. Patients were followed up at 6 weeks and 6, 12, and 24 months postoperatively. Clinical and radiologic data as well as patient-reported outcome measures were assessed with validated questionnaires (University of California at Los Angeles Shoulder Score [UCLA], American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], Quick Disabilities of the Arm, Shoulder, and Hand questionnaire [Quick-DASH], visual analog scale [VAS] for pain, Subjective Shoulder Value [SSV], and Constant-Murley score [CS]). All patients had a minimum follow-up of 2 years.

RESULTS

During the observation period, 26 shoulders in 25 patients fulfilled the inclusion criteria. The mean follow-up was 46.8 months (range 25-66). The mean age was 70.1 years (range 59.9-86.4). At the most recent follow-up, a significant improvement was noted in the ASES score (55.9 ± 19.9 vs. 85.6 ± 10.7, P < .001), SSV (44.3 ± 18.7 vs. 85.3 ± 10.4, P < .001), Quick-DASH score (40.6 ± 22.0 vs. 17.8 ± 13.9, P < .001), VAS pain score (4.6 ± 3.2 vs. 0.9 ± 1.2, P < .001), and range of motion in flexion (66 ± 53 vs. 154 ± 22, P < .001) as well as in the absolute (44.1 ± 18.7 vs. 83.1 ± 10.1, P < .001) and relative CS (62.1 ± 27.8 vs. 111.9 ± 13.3, P < .001). Scapular notching was observed in 16% of cases, and radiolucent lines were detected in 28% of cases without symptoms of implant loosening. No revision was necessitated by any causes related to the stemless humeral component. Hence, implant survivorship was 100%.

CONCLUSIONS

With an ASES score showing a 30-point improvement and thus exceeding the minimal clinically important difference of 21 points and no revisions due to the stemless component, these results indicate that slRSA is a viable option, providing good to excellent midterm outcomes that are comparable to those of stemmed reverse shoulder prostheses, with the added advantage of bone stock preservation.

Imaging in shoulder arthroplasty: Current applications and future perspectives

Shoulder arthroplasty has become a standard surgical procedure for treating a variety of complex shoulder disorders, including those with degenerative and traumatic aetiologies. The ever-improving success rates of shoulder arthroplasty could be attributed to advancements in endoprosthesis design, improvements in the biomechanics of endoprosthetic components, and improvements in surgical techniques. It improves patient outcomes and helps restore shoulder joint function and mobility. Imaging plays a vital role by enabling surgeons to plan arthroplasty procedures, help guide endoprosthesis placement, and monitor postoperative outcomes. In addition, imaging plays a role in assessing the residual bone stock and status of rotator cuff integrity and in correcting the placement of prosthetic components to restore shoulder mobility. CT-guided navigation aids surgeons by helping them choose appropriate components for implants and ensuring that implants are placed optimally during surgery. It can lead to better surgical results with reduced patient morbidity and a longer duration of prosthetic stability. After surgery, it is crucial to use imaging techniques to detect issues such as periprosthetic loosening, infections, or fractures to start effective management strategies to enhance patient recovery. This article aims to provide orthopaedic surgeons and radiologists with knowledge on the imaging methods used in shoulder arthroplasty and their role in presurgical planning, intraoperative guidance and postoperative assessment. In this study, we aimed to investigate the rationale behind utilising various types of shoulder replacements: total shoulder replacement (TSA), reverse total shoulder arthroplasty (RTSA), and hemiarthroplasty; methods, their respective advantages and limitations; and outcomes. Our objective is to comprehensively analyse the procedures mentioned above and highlight their unique features and benefits to facilitate a better understanding of these approaches. Additionally, we will discuss how these imaging techniques help identify issues such as loose components, fractures around the implant site, joint instability and infections.

Modification of Humeral Component Results in Increased Impingement Free Range of Motion in a Reverse Shoulder Arthroplasty Model

Introduction

Shoulder arthroplasties have been demonstrated to provide reliable pain relief as well as functional benefits. The advent of the reverse shoulder arthroplasty allowed for expanded indications for shoulder replacement. Several studies comparing the outcomes of anatomic and reverse total shoulder arthroplasties have demonstrated decreased range of motion in the reverse arthroplasty cohort, especially in internal rotation. The authors hypothesized that slight modifications to the humeral component of a reverse shoulder arthroplasty could result in increased impingement free range of motion without significant sacrifices to stability.

Methods

A reverse shoulder arthroplasty model was fashioned to mimic a setting of anterior mechanical impingement after replacement. Sequential resections were taken from the anterior aspect of the polyethylene up to a resection of 10 mm. A solid modeling software was utilized to compare the experimental group to the control group with regard to impingement free motion. Finite element analysis was subsequently utilized to assess stability of the construct in comparison to the nonmodified polyethylene.

Results

Impingement free internal rotation increased minimally at 3 mm of resection but considerably at each further increase in resection. A resection of 10 mm resulted roughly 30% improvement in impingement free internal rotation. Instability in this model increased with modifications beyond 7 mm.

Conclusion

Slight alterations to the geometry of the humeral tray and polyethene components can result in improvements in impingement-free internal rotation without substantial increased instability in this model. Further work is needed to determine in vivo implications of modifications to the humeral tray and polyethylene.

Does matching glenosphere size to patient height improve outcomes following reverse total shoulder arthroplasty?

Introduction

Optimal biomechanics in reverse total shoulder arthroplasty (rTSA) are still a topic of debate. Although larger glenospheres have been linked with a theoretical improvement in the range of movement, results from clinical studies are mixed. We hypothesised that matching glenosphere diameter to patient height would result in greater improvements in post-operative range of motion (ROM) and patient-reported outcomes (PROMs).

Methods

An international database of rTSAs was analysed. After exclusions, 3318 rTSA patients were classified as short (<158 cm), average (158-173 cm) or tall(>173 cm). Outcomes were stratified for glenosphere size (small≤38 mm, large≥40 mm). Results were compared preoperatively and at 2 years.

Results

In short patients glenosphere diameter had no statistically significant impact on the degree of post-operative improvement for any ROM or PROM. Average height patients treated with small glenospheres had significantly more improvement in internal rotation (1.3 vs 1.0, p = 0.01), VAS pain (5.3 vs 4.8, p = 0.002), American Shoulder and Elbow Surgeons (47.8 vs 45.2, p = 0.03) and Shoulder Arthroplasty Smart (30.9 vs 28.2, p = 0.01) but significantly less improvement in constant score (31.7 vs 35.3, p = 0.009). Tall patients treated with small glenospheres had significantly more improvement in external rotation (21.2 vs 16.4, p = 0.01) and VAS pain scores (4.7 vs 4.3, p = 0.04).

Conclusions

While most significant differences favoured small glenospheres, the magnitude of these differences was small. Overall, patients of all heights can expect similar clinical improvements irrespective of glenosphere size.

Can Distalisation and Lateralisation Shoulder Angles in Reverse Arthroplasty Interfere with the Functional Results in Patients with Rotator Cuff Arthropathy?

Objective:  To evaluate the influence of radiographic values on clinical and functional results in patients treated with reverse arthroplasty for rotator cuff arthropathy (RCA) using a lateralized design. Methods:  A retrospective analysis was performed. Patient demographics were recorded, as well as preoperative and postoperative range of motion. Function was calculated using the Constant-Murley score both before and after the procedure. Pre and postoperative anteroposterior and axial radiographs of the affected shoulder were analysed. In the preoperative images, the following was calculated: acromiohumeral distance (AHD) and lateral humeral offset (LHO). Postoperative measurements included: AHD, LHO, distalization shoulder angle (DSA) and lateralisation shoulder angle (LSA). Linear regression and quadratic regression analysis was performed to determine their degree of association with final functional outcomes. By applying a quadratic regression analysis and ROC curves, the cut-off values were determined with respect to the above-mentioned angles and the positive predictive value was calculated. Results:  The greater anterior elevation (AE) ranges were found with DSA between 40-45° and LSA among 80°- 90°, while better ABD was observed with LSA of 90-100°. Preoperative AHD was correlated to RE (r s :0.47; p:0.049). Postoperative AHD was found to be in a directly proportional relationship with AE (r s :0.49; p:0.03). Postoperative ABD showed an inverse linear regression with preoperative AHD (r s : -0.44, p:0.047). LSA and DSA were inversely related. Conclusion:  We found that a DSA between 40-45° and a LSA of 80-100° could lead to better range of motion regarding AE and ABD in patients with rotator cuff arthropathy treated with RSA.

Influence of Lateralization and Distalization on Joint Function after Primary Reverse Total Shoulder Arthroplasty

The purpose of this study was to investigate how lateralization shoulder angle (LSA) and distalization shoulder angle (DSA) are related to clinical and kinematic outcomes after reverse total shoulder arthroplasty. Thirty-three patients were evaluated at least six months postoperatively. The Single Assessment Numeric Evaluation (SANE), Constant Murley Score (CMS), Simple Shoulder Test (SST), and Visual Analogue Scale (VAS) were used. Shoulder kinematics was evaluated with a stereophotogrammetric system. LSA and DSA inter-rater reliability was analysed through the interclass correlation coefficient (ICC). Stepwise forward linear regression analysis was conducted between LSA and DSA with clinical scales and kinematic measures, between which a correlation analysis was conducted. The inter-rater reliability for LSA (mean ICC = 0.93) and DSA (mean ICC = 0.97) results were good to excellent. Greater LSA values were associated with higher peaks of internal rotation (p = 0.012, R2 = 0.188) and range of motion (ROM) (p = 0.037, R2 = 0.133). SANE (p = 0.009), CMS (p = 0.031), and SST (0.026) were positively correlated to external rotation, while VAS (p = 0.020) was negatively related. Abduction peaks were positively related to CMS (p = 0.011) and SANE (p = 0.037), as well as abduction ROM (SANE, p = 0.031; CMS, p = 0.014).

Clinical outcomes of anatomical versus reverse total shoulder arthroplasty in patients with primary osteoarthritis, an intact rotator cuff, and limited forward elevation

Aims

Both anatomical and reverse total shoulder arthroplasty (aTSA and rTSA) provide functional improvements. A reported benefit of aTSA is better range of motion (ROM). However, it is not clear which procedure provides better outcomes in patients with limited foward elevation (FE). The aim of this study was to compare the outcome of aTSA and rTSA in patients with glenohumeral osteoarthritis (OA), an intact rotator cuff, and limited FE.

Methods

This was a retrospective review of a single institution's prospectively collected shoulder arthroplasty database for TSAs undertaken between 2007 and 2020. A total of 344 aTSAs and 163 rTSAs, which were performed in patients with OA and an intact rotator cuff with a minimum follow-up of two years, were included. Using the definition of preoperative stiffness as passive FE ≤ 105°, three cohorts were matched 1:1 by age, sex, and follow-up: stiff aTSAs (85) to non-stiff aTSAs (85); stiff rTSAs (74) to non-stiff rTSAs (74); and stiff rTSAs (64) to stiff aTSAs (64). We the compared ROMs, outcome scores, and complication and revision rates.

Results

Compared with non-stiff aTSAs, stiff aTSAs had poorer passive FE and active external rotation (ER), whereas there were no significant postoperative differences between stiff rTSAs and non-stiff rTSAs. There were no significant differences in preoperative function when comparing stiff aTSAs with stiff rTSAs. However, stiff rTSAs had significantly greater postoperative active and passive FE (p = 0.001 and 0.004, respectively), and active abduction (p = 0.001) compared with stiff aTSAs. The outcome scores were significantly more favourable in stiff rTSAs for the Shoulder Pain and Disability Index, Simple Shoulder Test, American Shoulder and Elbow Surgeons score, University of California, Los Angeles score, and the Constant score, compared with stiff aTSAs. When comparing the proportion of stiff aTSAs versus stiff rTSAs that exceeded the minimal clinically important difference and substantial clinical benefit, stiff rTSAs achieved both at greater rates for all measurements except active ER. The complication rate did not significantly differ between stiff aTSAs and stiff rTSAs, but there was a significantly higher rate of revision surgery in stiff aTSAs (p = 0.007).

Conclusion

Postoperative overhead ROM, outcome scores, and rates of revision surgery favour the use of a rTSA rather than aTSA in patients with glenohumeral OA, an intact rotator cuff and limited FE, with similar rotational ROM in these two groups.

Arthroscopic Lysis of Adhesions for Stiffness After Surgical Management of Proximal Humerus Fractures Leads to Satisfactory Outcomes in Most Patients

Purpose

To report patient-reported outcomes (PROs), range of motion (ROM), and satisfaction, in patients who underwent arthroscopic lysis of adhesions for stiffness after open reduction with internal fixation (ORIF) or reverse shoulder arthroplasty (RSA) for fracture.

Methods

A retrospective review was performed to identify patients with stiffness who underwent arthroscopic lysis of adhesions following ORIF or RSA for proximal humerus fracture at a single institution between 2012 and 2021 with minimum 1-year follow-up. PROs including visual analog scale for pain (VAS), American Shoulder and Elbow Surgeons (ASES), and Subjective Shoulder Value (SSV), as well as active ROM including forward flexion (FF), external rotation (ER), internal rotation (IR), were collected pre- and postoperatively. Attempted nonoperative treatment before arthroscopic lysis of adhesions was documented. Complications and satisfaction were also recorded.

Results

A total of 21 patients met the study criteria (4 RSA, 17 ORIF), with an average age of 66.7 ± 8 years. The study sample comprised mostly of female patients (90%). The mean time from the index surgery to arthroscopy was 9 months, and mean follow-up post-lysis was 17 months. Patients with ORIF reported significant pain relief (VAS, Δ -3.2) and improvement in range of motion (FF, Δ 36°; ER, Δ 20°; IR Δ 3 spinal levels) and PROs (ASES, Δ 34.7; SSV Δ 44.8) (P < .01) after lysis. Patients with RSA had significant improvement in ASES (Δ 21.8; P = .04), SSV (Δ 8.8; P = .04), and FF (Δ 38; P = .02) but did not have significant improvement in VAS (Δ -2; P = .2), ER (Δ 0°; P = 1.0), and IR (Δ 1 spinal level; P = .2). Satisfaction was 100% in the RSA cohort and 82% in the ORIF cohort. No complications were observed.

Conclusions

Arthroscopic lysis of adhesions for stiffness after surgical management of proximal humerus fracture leads to satisfactory outcomes in most patients. Post-ORIF, patients may achieve improvement in PROs and global ROM, whereas post-RSA, patients may achieve improvement in PROs and FF but do not necessarily improve in rotational ROM.

Level of Evidence

Level IV, therapeutic case series.

Identifying the patient harms to include in an in silico clinical trial

BACKGROUND AND OBJECTIVE

Clinical trials represent a crucial step in the development and approval of medical devices. These trials involve evaluating the safety and efficacy of the device in a controlled setting with human subjects. However, traditional clinical trials can be expensive, time-consuming, and ethically challenging. Augmenting clinical trials with data from computer simulations, so called in silico clinical trials (ISCT), has the potential to address these challenges while satisfying regulatory requirements. However, determination of the patient harms in scope of an ISCT is necessary to ensure all harms are sufficiently addressed while maximizing the utility of the ISCT. This topic is currently lacking guidance. The objective of this work is to propose a general method to determine which patient harms should be included in an ISCT for a regulatory submission.

METHODS

The proposed method considers the risk associated with the harm, the impact of the device on the likelihood of occurrence of the harm and the technical feasibility of evaluating the harm via ISCT. Consideration of the risk associated with the harm provides maximum clinical impact of the ISCT, in terms of focusing on those failure modes which are most relevant to the patient population. Consideration of the impact of the device on a particular harm, and the technical feasibility of modeling a particular harm supports that the technical effort is devoted to a problem that (1) is relevant to the device in question, and (2) can be solved with contemporary modeling techniques.

RESULTS AND CONCLUSIONS

As a case study, the proposed method is applied to a total shoulder replacement humeral system. With this framework, it is hoped that a consistent approach to scoping an ISCT can be adopted, supporting investment in ISCT by the industry, enabling consistent review of the ISCT approach across device disciplines by regulators, and providing maximum impact of modeling technologies in support of devices to improve patient outcomes.

Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study

Objective

The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA).

Methods

In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0°, +10°, +20°) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and posteroinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths.

Results

All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05).

Conclusion

Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM.

Level of Evidence

Basic Science Study; Computer Modeling.

Reconstruction with a double-constrained implant design after complex shoulder extra-articular resection

BACKGROUND

Approximately, one-third of patients with tumors of proximal humerus will require an extra-articular resection to achieve oncologic margins. This procedure yields poor functional outcomes with a considerable rate of revisions. Unconstrained implants are prone to instability hindering also function of the elbow and hand, whereas constrained shoulder reconstructions suffer from early aseptic loosening of the glenoid component due to bone overload. The purpose of this study was to develop a constrained implant suitable for extra-articular resection with loss of function in deltoid and rotator cuff, which would provide both stability and passive motion, whilst also decreasing the risk of aseptic loosening of the glenoid component.

METHODS

In cooperation with Czech Technical University in Prague, we devised an implant consisting of two constrained joints in series connected by a dumbbell piece. The biomechanical analysis showed a reduction of load transfer to the glenoid component with a torque of 8.6 Nm capable of generating an 865-N pulling force on bone screw to just 0.07 Nm, hence shielding the glenoid component from undesired forces and decreasing the risk of aseptic loosening. Three patients with extra-articular resection with a total loss of function of both rotator cuff and deltoid muscle received this type of reconstruction. The average follow-up was 16 months.

RESULTS

The surgical technique is straightforward. The surgery took 175 min on average with average blood loss of 516 ml. There were no surgical- or implant-related complications. All three patients were pain-free and had a stable shoulder joint after the reconstruction. All had fully functional elbow, wrist, and hand joints. The average Musculoskeletal Tumor Society (MSTS) score was 21/30 (70%). All patients were pleased with the results.

CONCLUSION

The presented innovative implant design has demonstrated to be a promising alternative for reconstruction in these challenging cases.

Secondary Rotator Cuff Insufficiency After Anatomic Total Shoulder Arthroplasty

» Secondary rotator cuff insufficiency is a challenging complication after anatomic total shoulder arthroplasty.» Acute tears may be amenable to open or arthroscopic repair in some instances.» Chronic attritional tears are best managed with revision to reverse shoulder arthroplasty, especially in the elderly.» Increased glenoid inclination, larger critical shoulder angle, oversized humeral components, thicker glenoid components, and rotator cuff muscle fatty infiltration have all shown to contribute to tear risk.

Navigation in reverse shoulder arthroplasty: how the lateralization of glenosphere can affect the clinical outcome

INTRODUCTION

One of the main causes of RSA failure is attributable to the malpositioning of the glenoid component. Initial experiences with computer-assisted surgery have shown promising results in increasing the accuracy and repeatability of placement of the glenoid component and screws. The aim of this study was to evaluate the functional clinical results, in terms of joint mobility and pain, by correlating them with intraoperative data regarding the positioning of the glenoid component. The hypothesis was that the lateralization more than 25 mm of the glenosphere can led to better stability of the prosthesis but should pay in term of a reduced range of movement and increased pain.

MATERIALS AND METHODS

50 patients were enrolled between October 2018 and May 2022; they underwent RSA implantation assisted by GPS navigation system. Active ROM, ASES score and VAS pain scale were recorded before surgery. Preoperative data about glenoid inclination and version were collected by pre-op X-Rays an CT. Intraoperative data-inclination, version, medialization and lateralization of the glenoid component-were recorded using computer-assisted surgery. 46 patients had been further clinically and radiographically re-evaluated at 3-months, 6-months, 1-year, and 2-years follow-up.

RESULTS

We found a statistically significant correlation between anteposition and glenosphere lateralization value (DM - 6.057 mm; p = 0.043). Furthermore a statistically significant correlation has been shown between abduction movement and the lateralization value (DM - 7.723 mm; p = 0.015). No other statistically significant associations were found when comparing the values of glenoid inclination and version with the range of motion achieved by the patients after reverse shoulder arthroplasty.

CONCLUSION

We observed that the patients with the best anteposition and abduction results had a glenosphere lateralization between 18 and 22 mm. When increasing the lateralization above 22 mm or reducing it below 18 mm, on the other hand, both movements considered decreased their range.

LEVEL OF EVIDENCE

Level IV; Case Series; Treatment Study.

Best-Fit Circle for the Replication of Humeral Head Anatomy in Total Shoulder Arthroplasty

Background

Anatomic restoration of the humeral head is critical for successful shoulder replacement. Accurate measurements of the humeral head are essential for anatomic substitution.

Purpose

To evaluate whether a best-fit circle of the humeral head, as determined from different projections of plain radiographs, can predict the humeral head implant size for either the left or right shoulder.

Study Design

Descriptive laboratory study.

Methods

Bilateral shoulder radiographs of 200 patients without arthropathy or other abnormal findings of the humeral head were evaluated. The best-fit circle was obtained based on 3 points: the medial and lateral endpoints of the anatomic neck and the lateral cortex below the greater tuberosity. This circle was drawn on 5 different radiographic projections (shoulder anteroposterior [AP], glenoid AP, outlet, axillary, and 30° caudal tilt) of the left and right shoulders of each patient, and the radius of each circle was measured. Agreement in the best-fit circle radius between the left and right shoulders was statistically analyzed using the intraclass correlation coefficient (ICC). There were 2 independent blinded observers who performed each measurement twice to evaluate inter- and intraobserver reliability.

Results

Overall agreement in the radius between the right and left shoulders was excellent (all ICCs ≥0.990). The ICCs according to the radiographic view were 0.990 (95% CI, 0.986-0.993) for shoulder AP, 0.992 (95% CI, 0.989-0.995) for glenoid AP, 0.996 (95% CI, 0.994-0.997) for outlet, 0.994 (95% CI, 0.991-0.996) for axillary, and 0.993 (95% CI, 0.990-0.995) for 30° caudal tilt. Interobserver ICCs demonstrated a high level of precision: 0.987 (95% CI, 0.978-0.993) for shoulder AP, 0.986 (95% CI, 0.974-0.992) for glenoid AP, 0.974 (95% CI, 0.954-0.985) for outlet, 0.991 (95% CI, 0.984-0.995) for axillary, and 0.987 (95% CI, 0.977-0.993) for 30° caudal tilt. Intraobserver ICCs demonstrated excellent test-retest reliability: 0.983 (95% CI, 0.970-0.991) for shoulder AP, 0.989 (95% CI, 0.980-0.994) for glenoid AP, 0.987 (95% CI, 0.978-0.993) for outlet, 0.985 (95% CI, 0.973-0.991) for axillary, and 0.970 (95% CI, 0.947-0.983) for 30° caudal tilt.

Conclusion

The best-fit circle to calculate the ideal size of a humeral head implant was able to be determined from different projections of plain radiographs.

Clinical Relevance

Anatomic restoration of a deformed humeral head can be achieved using the best-fit circle of the contralateral humeral head as obtained from plain radiographs. This method can facilitate preoperative planning and postoperative evaluation in the anatomic restoration of the shoulder to avoid the problems of overstuffing.

Age- and sex-specific normative values of bone mineral density in the adult glenoid

The objective of this study was to determine the normative bone mineral density (BMD) of cortical and trabecular bone regions in the adult glenoid and its dependence on the subject's age and sex. We analyzed computed tomography (CT) scans of 441 shoulders (310 males, 18-69 years) without any signs of glenohumeral joint pathology. Glenoid BMD was automatically quantified in six volumes of interest (VOIs): cortical bone (CO), subchondral cortical plate (SC), subchondral trabecular bone (ST), and three adjacent layers of trabecular bone (T1, T2, and T3). BMD was measured in Hounsfield unit (HU). We evaluated the association between glenoid BMD and sex and age with the Student's t test and Pearson's correlation coefficient (r), respectively. The lambda-mu-sigma method was used to determine age- and sex-specific normative values of glenoid BMD in cortical (CO and SC) and trabecular (ST, T1, T2, and T3) bone. Glenoid BMD was higher in males than females, in most age groups and most VOIs. Before 40 years old, the effect of age on BMD was very weak in both males and females. After 40 years old, BMD declined over time in all VOIs. This BMD decline with age was greater in females (cortical: r = -0.45, trabecular: r = -0.41) than in males (cortical: r = -0.30; trabecular: r = -0.32). These normative glenoid BMD values could prove clinically relevant in the diagnosis and management of patients with various shoulder disorders, in particular glenohumeral osteoarthritis and shoulder arthroplasty or shoulder instability, as well as in related research.

Shoulder Proprioception Following Reverse Total Shoulder Arthroplasty for Unreconstructable Upper Third Fractures of the Humerus: 2-Year Outcomes

Background

Proximal humerus fractures may be comminuted in the elderly or after injury with high-energy mechanisms. Reverse total shoulder arthroplasty that may affect shoulder proprioception (rTSA) has also begun to play a part in treating acute proximal humeral fractures. In this study, the authors aimed to evaluate joint position sense (JPS) after rTSA.

Methods

Humac Norm II isokinetic device was used to evaluate the joint position sense. A joint angle was determined and the ability of the patient to create the same value of the angle by the active movement was evaluated. The difference between the pre-determined angle and the patient's measured angle was recorded. For proprioceptive sense, the initial position was 0° and the determination position was 30°, 60°, and 90° for flexion and abduction, and 15° and 30° for internal rotation and external rotation.

Results

While both the mean Constant and ADLEIR scores did not differ between non-operated and operated sides, the mean proprioception differences in all flexion (30°, 60°, and 90°), abduction (30°, 60°, and 90°), internal rotation (15° and 30°), and external rotation (15° and 30°) were significantly higher in the operated side than that in non-operated side (p < 0.01 for each pairwise comparison).

Conclusion

Reverse total shoulder arthroplasty (rTSA) treatment, which has increasingly become a surgical option in un-reconstructable proximal humeral fractures has significant adverse effects on proprioception on the operated side and may pose a risk for long-term instability, premature loosening, and prosthesis mechanical complications, in this context, well-designed prospective controlled studies are required.

Difference analysis of the glenoid centerline between 3D preoperative planning and 3D printed prosthesis manipulation in total shoulder arthroplasty

INTRODUCTION

Excessive version and inclination of the glenoid component during total shoulder arthroplasty can lead to glenohumeral instability, early loosening, and even failure. The orientation and position of the central pin determine the version and inclination of the glenoid component. The purpose of this study was to compare the differences in centerline position and orientation obtained using "3D preoperative planning based on the best-fit method for glenoid elements" and the surgeon's manipulation.

MATERIALS AND METHODS

Twenty-nine CT images of glenohumeral osteoarthritis of the shoulder were reconstructed into a 3D model, and a 3D printer was used to create an in vitro model for the surgeon to drill the center pin. The 3D shoulder model was also used for 3D preoperative planning (3DPP) using the best-fit method for glenoid elements. The in vitro model was scanned and the version, inclination and center position were measured to compare with the 3DPP results.

RESULTS

The respective mean inclinations (versions) of the surgeon and 3DPP were -2.63° ± 6.60 (2.87° ± 5.97) and -1.96° ± 4.24 (-3.21° ± 4.00), respectively. There was no significant difference in the inclination and version of the surgeon and 3DPP. For surgeons, the probability of the inclination and version being greater than 10° was 13.8% (4/29) and 10.3% (3/29), respectively. Compared to the 3DPP results, the surgeon's center position was shifted down an average of 1.63 mm. There was a significant difference in the center position of the surgeon and 3DPP (p < 0.05).

CONCLUSION

The central pin drilled by surgeons using general instruments was significantly lower than those defined using 3D preoperative planning and standard central definitions. 3D preoperative planning prevents the version and inclination of the centerline from exceeding safe values (± 10°).

Inlay versus onlay humeral design for reverse shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

Since the introduction of the Grammont-style reverse total shoulder arthroplasty, the humeral stem design has been modified with improved clinical outcomes. Two distinct humeral designs have been used extensively: the inlay design, in which the humeral tray is seated within the metaphysis, and the onlay design, in which the humeral tray sits on the metaphysis at the level of the humeral neck cut. The purpose of this systematic review was to determine whether there are differences in clinical outcomes and complication rates between these designs.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used to perform this systematic review. A search of MEDLINE, PubMed, and Embase was performed to identify all studies comparing the clinical results of both humeral designs. Primary outcomes included patient-reported outcome measures, shoulder range of motion, and incidence of complications.

RESULTS

From the 156 identified publications, 12 studies were included in the final review. A total of 1447 patients were included, with a minimum follow-up period of 12 months. At final follow-up, both implants demonstrated significant improvements in comparison to preoperative baseline. On comparison of the inlay vs. onlay groups, the American Shoulder and Elbow Surgeons score was higher in the inlay group (mean difference, 2.53 [95% confidence interval, 0.27-4.78]; P = .03). Postoperative motion, even if statistically greater in the onlay group (differences of 5° in forward flexion [P < .001], 3° in abduction [P = .003], and 4° in external rotation [P < .001]), was not clinically different. On comparison of complications, the inlay group showed more instances of scapular notching (93 of 322 patients vs. 70 of 415 patients; odds ratio, 0.35; P < .001) but fewer scapular spine fractures (26 of 727 patients vs. 21 of 559 patients, P = .09).

DISCUSSION

Inlay and onlay humeral tray designs in reverse total shoulder arthroplasty demonstrate similar clinical improvements postoperatively. Onlay implants have a low rate of scapular notching but a higher rate of scapular spine fracture. Understanding the strengths and weaknesses of the 2 humeral tray designs is important to provide surgeons with options to tailor surgical plans for high-risk patients.

Pathogenesis, Evaluation, and Management of Osteolysis After Total Shoulder Arthroplasty

Radiographic osteolysis after total shoulder arthroplasty (TSA) remains a challenging clinical entity, as it may not initially manifest clinically apparent symptoms but can lead to clinically important complications, such as aseptic loosening. A thorough consideration of medical history and physical examination is essential to rule out other causes of symptomatic TSA—namely, periprosthetic joint infection—as symptoms often progress to vague pain or discomfort due to subtle component loosening. Once confirmed, nonoperative treatment of osteolysis should first be pursued given the potential to avoid surgery-associated risks. If needed, the current surgical options include glenoid polyethylene revision and conversion to reverse shoulder arthroplasty. The current article provides a comprehensive review of the evaluation and management of osteolysis after TSA through an evidence-based discussion of current concepts.

Reverse shoulder arthroplasty vs. hemiarthroplasty for the treatment of osteoporotic proximal humeral fractures in elderly patients: A systematic review and meta‑analysis update

The present meta-analysis was conducted to compare the safety and effectiveness of reverse shoulder arthroplasty (RSA) and hemiarthroplasty (HA) in the treatment of osteoporotic proximal humeral fractures in elderly patients. The Embase, Pubmed Central, Cumulative Index to Nursing and Allied Health Literature, ProQuest Dissertations and Theses, Cochrane Library and Chinese Biomedical databases were searched between January 2009 and January 2022 to identify relevant studies. According to the search strategy, a total of 210 associated studies were retrieved and 16 were finally included. Review Manager 5.4 software was used for the data analysis. This study indicated that patients in the RSA group had significantly improved treatment outcomes compared with patients in the HA group, as assessed by Constant-Murley Shoulder Outcome Score (95% CI, 1.69-3.76; P<0.001), American Shoulder and Elbow Surgeons score (95% CI, 11.81-24.88; P<0.001) and shoulder range of motion (ROM; 95% CI, 3.41-9.07; P<0.001). However, the HA group was superior to the RSA group in terms of the Oxford Shoulder score (95% CI, 2.89-11.11; P<0.001). There was no significant statistical difference between the two groups in terms of the Disabilities of the Arm, Shoulder and Hand score and complications. Overall, for the treatment of osteoporotic proximal humeral fractures in the elderly, the RSA group had improved postoperative ROM and functional scores compared with the HA group, without significant difference in the incidence of complications. However, HA remains a safe and reliable treatment option.

Does Humeral Component Version Affect Range of Motion and Clinical Outcomes in Reverse Total Shoulder Arthroplasty? A Systematic Review

BACKGROUND

Prosthesis selection, design, and placement in reverse total shoulder arthroplasty (RTSA) affect post-operative results. The aim of this systematic review was to evaluate the influence of the humeral stem version and prosthesis design (inlay vs. onlay) on shoulder function following RTSA.

METHODS

A systematic review of the literature on post-operative range of motion (ROM) and functional scores following RTSA with specifically known humeral stem implantations was performed using MEDLINE, Pubmed, and Embase databases, and the Cochrane Library. Functional scores included were Constant scores (CSs) and/or American Shoulder and Elbow Surgeons (ASES) scores. The patients were organised into three separate groups based on the implanted version of their humeral stem: (1) less than 20° of retroversion, (2) 20° of retroversion, and (3) greater than 20° of retroversion.

RESULTS

Data from 14 studies and a total of 1221 shoulders were eligible for analysis. Patients with a humeral stem implanted at 20° of retroversion had similar post-operative mean ASES (75.8 points) and absolute CS (68.1 points) compared to the group with humeral stems implanted at less than 20° of retroversion (76 points and 62.5 points; p = 0.956 and p = 0.153) and those implanted at more than 20° of retroversion (73.3 points; p = 0.682). Subjects with humeral stem retroversion at greater than 20° tended towards greater active forward elevation and external rotation compared with the group at 20° of retroversion (p = 0.462) and those with less than 20° of retroversion (p = 0.192). Patients with an onlay-type RTSA showed statistically significantly higher mean post-operative internal rotation compared to patients with inlay-type RTSA designs (p = 0.048). Other functional scores and forward elevation results favoured the onlay-types, but greater external rotation was seen in inlay-type RTSA designs (p = 0.382).

CONCLUSIONS

Humeral stem implantation in RTSA at 20° of retroversion and greater appears to be associated with higher post-operative outcome scores and a greater range of motion when compared with a retroversion of less than 20°. Within these studies, onlay-type RTSA designs were associated with greater forward elevation but less external rotation when compared to inlay-type designs. However, none of the differences in outcome scores and range of motion between the humeral version groups were statistically significant.