Posterior Shoulder Instability Part II - Glenoid Bone-Grafting, Glenoid Osteotomy, and Rehabilitation/Return to Play - An International Expert Delphi Consensus Statement.

PURPOSE: The purpose of this study was to establish consensus statements on glenoid bone-grafting, glenoid osteotomy, rehabilitation, return to play, and follow-up for posterior shoulder instability. METHODS: A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating based on their level of expertise in the field. Experts were assigned to one of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80-89% agreement, whereas strong consensus was defined as 90-99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: All of the statements relating to rehabilitation, return to play, and follow-up achieved consensus. There was unanimous consensus that the following criteria should be considered: restoration of strength, range of motion, proprioception, and sport-specific skills, with a lack of symptoms. There is no minimum time point required to return to play. Collision athletes and military athletes may take longer to return because of their higher risk for recurrent instability, and more caution should be exercised in clearing them to return to play, with elite athletes potentially having different considerations in returning to play. The relative indications for revision surgery are symptomatic apprehension, multiple recurrent instability episodes, further intra-articular pathologies, hardware failure, and pain. CONCLUSION: The study group achieved strong or unanimous consensus on 59% of statements. Unanimous consensus was reached regarding the criteria for return to play, collision/elite athletes having different considerations in return to play, indications for revision surgery, and imaging only required as routine for those with glenoid bone-grafting/osteotomies at subsequent follow-ups. There was no consensus on optimal fixation method for a glenoid bone-block, the relative indications for glenoid osteotomy, whether fluoroscopy is required or if the labrum should be concomitantly repaired. LEVEL OF EVIDENCE: Level V Expert Opinion.

Posterior Shoulder Instability, Part I-Diagnosis, Nonoperative Management, and Labral Repair for Posterior Shoulder Instability-An International Expert Delphi Consensus Statement.

PURPOSE: To establish consensus statements on the diagnosis, nonoperative management, and labral repair for posterior shoulder instability. METHODS: A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating on the basis of their level of expertise in the field. Experts were assigned to 1 of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80% to 89% agreement, whereas strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: Unanimous agreement was reached on the indications for nonoperative management and labral repair, which include whether patients had primary or recurrent instability, with symptoms/functional limitations, and whether there was other underlying pathology, or patient's preference to avoid or delay surgery. In addition, there was unanimous agreement that recurrence rates can be diminished by attention to detail, appropriate indication and assessment of risk factors, recognition of abnormalities in glenohumeral morphology, careful capsulolabral debridement and reattachment, small anchors with inferior placement and multiple fixation points that create a bumper with the labrum, treatment of concomitant pathologies, and a well-defined rehabilitation protocol with strict postoperative immobilization. CONCLUSIONS: The study group achieved strong or unanimous consensus on 63% of statements related to the diagnosis, nonoperative treatment, and labrum repair for posterior shoulder instability. The statements that achieved unanimous consensus were the relative indications for nonoperative management, and the relative indications for labral repair, as well as the steps to minimize complications for labral repair. There was no consensus on whether an arthrogram is needed when performing advanced imaging, the role of corticosteroids/orthobiologics in nonoperative management, whether a posteroinferior portal is required. LEVEL OF EVIDENCE: Level V, expert opinion.

Glenohumeral morphological predictors of recurrent shoulder instability following arthroscopic Bankart repair.

PURPOSE: The purpose of this study was to evaluate glenohumeral morphological features on a magnetic resonance arthrogram (MRA) to determine risk factors for recurrence of anterior shoulder instability following arthroscopic Bankart repair (ABR). METHODS: A retrospective review of patients who underwent ABR between 2012 and 2017 was performed to identify patients who had recurrence of instability following stabilisation (Group 1). These were pair-matched in a 2:1 ratio for age, gender and sport with a control (Group 2) who underwent ABR without recurrence. Preoperative MRAs were evaluated for risk factors for recurrence, with glenoid bone loss and Hill-Sachs lesions also measured. Multilinear and multilogistic regression models were used to evaluate factors affecting recurrence. RESULTS: Overall, 72 patients were included in this study, including 48 patients without recurrence and 24 patients with recurrent instability. There was a significant difference between the two groups in mean glenoid bone loss (Group 1: 7.3% vs. Group 2: 5.7%, p < 0.0001) and the rate of off-track Hill-Sachs lesions (Group 1: 20.8% vs. Group 2: 0%, p = 0.0003). Of the variables analysed in logistic regression, increased glenoid anteversion (p = 0.02), acromioclavicular (AC) degeneration (p = 0.03) and increased Hill-Sachs width were associated with increased risk of failure. Increased chondral version (p = 0.01) and humeral head diameter in the anteriorposterior view were found to be protective and associated with a greater likelihood of success. CONCLUSION: Glenoid anteversion was a risk factor for recurrent instability, whereas increased chondral version and humeral head diameter were associated with higher rates of success following ABR. Glenoid bone loss, presence of an off-track Hill-Sachs lesion, increased Hill-Sachs width and AC degeneration were also associated with failure. These findings should be used by surgeons to stratify risk for recurrence following ABR. LEVEL OF EVIDENCE: Level III.

Radiographic comparison of eccentric stemmed vs. concentric stemless prosthetic humeral head positioning after anatomic total shoulder arthroplasty.

INTRODUCTION: Maintaining premorbid proximal humeral positioning is an essential consideration of anatomic total shoulder arthroplasty (aTSA), as malposition of the prosthetic humeral head can result in poor clinical outcomes. Stemless aTSA prosthetic heads are usually concentric, while stemmed aTSA prosthetic heads are typically eccentric in nature. Therefore, the purpose of this study was to compare the ability to restore native humeral head position between stemmed (eccentric) vs. stemless (concentric) aTSA. MATERIALS AND METHODS: Postoperative anteroposterior radiographs of 52 stemmed and 46 stemless aTSAs were analyzed. A best-fit circle was created using previously published and validated techniques to represent the premorbid humeral head position and axis of rotation. This circle was juxtaposed with another circle following the arc of the implant head. Next, the offset in center of rotation (COR), radius of curvature (RoC), and humeral head height above the greater tuberosity (HHH) were measured. Additionally, based on prior studies, an offset of >3 mm at any point between the implant head surface and premorbid best-fit circle was considered significant and further classified as overstuffed or understuffed. RESULTS: RoC deviation was significantly greater in the stemmed cohort than the stemless cohort (1.19 ± 1.37 mm vs. 0.65 ± 1.17 mm, P = .025). There was no statistically significant difference in deviation from premorbid humeral head between the stemmed and stemless cohorts for COR (3.20 ± 2.28 mm vs. 3.23 ± 2.09 mm, P = .800) or HHH (1.12 ± 3.27 mm vs. 0.92 ± 2.70 mm, P = .677). When comparing overstuffed implants to appropriately placed implants, there was a significant difference in overall COR deviation in stemmed implants (3.93 ± 2.51 mm vs. 1.92 ± 1.05 mm, P < .001). Superoinferior COR deviation (stemmed: 2.38 ± 3.01 mm vs. -0.61 ± 1.59 mm, P < .001; stemless: 2.70 ± 1.75 mm vs. -0.16 ± 1.87 mm, P < .001), mediolateral COR deviation (stemmed: 0.79 ± 2.65 mm vs. -0.62 ± 1.27 mm, P = .020; stemless: 0.40 ± 1.41 mm vs. -1.13 ± 1.96 mm, P = .020), and HHH (stemmed: 3.61 ± 2.73 mm vs. 0.50 ± 1.31 mm, P < .001; stemless: 3.98 ± 1.18 mm vs. 0.53 ± 1.41 mm, P < .001) were significantly different between overstuffed implants and appropriate implants in both the stemmed and stemless cohorts. DISCUSSION: Stemless and stemmed aTSA implants have similar rates of reproducing satisfactory postoperative humeral head COR with both producing COR deviation most commonly in the superomedial direction. Deviation in HHH contributes to overstuffing in both stemmed and stemless implants, COR deviation contributes to overstuffing in stemmed implants, while RoC (humeral head size) is not associated with overstuffing. Based on this study, it appears that neither eccentric nor concentric prosthetic heads are superior in recreating premorbid humeral head position.

Defining Pseudoparalysis & Pseudoparesis - A Consensus Study.

PURPOSE: The purpose of this study was to establish consensus statements via a modified Delphi process on the definition of shoulder pseudoparalysis and pseudoparesis. METHODS: A consensus process on the definition of a diagnosis of pseudoparalysis utilizing a modified Delphi technique was conducted, and 26 shoulder/sports surgeons from 11 countries, selected based on their level of expertise in the field, participated in these consensus statements. Consensus was defined as achieving 80-89% agreement, whereas strong consensus was defined as 90-99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: Three statements regarding the diagnosis of pseudoparalysis reached strong (>89%) consensus: passive range of motion (ROM) should be unaffected, the passive range of abduction should not be considered and diagnosis should be excluded if lidocaine injection produces a substantial improvement in range of motion. Additionally, consensus (>79%) was reached that the active range of external rotation should not be considered for diagnosis, pain as a cause of restricted motion must be excluded, and that distinctions between restricted active flexion and external rotation should be made by ROM rather than tear characteristics. No consensus could be reached on statements regarding the size, number of tendons or chronicity of cuff tears. Nor was there agreement on the active range of flexion permitted or on the difference between pseudoparalysis and pseudoparesis. CONCLUSION: A modified Delphi process was utilized to establish consensus on the definition of shoulder pseudoparalysis and pseudoparesis. Unfortunately, almost half of the statements did not reach consensus, and agreement could not be reached across all domains for a unifying definition for the diagnosis of pseudoparalysis in the setting of RCTs. Furthermore, it was not agreed how or whether pseudoparalysis should be differentiated from pseudoparesis. Based on the lack of a consensus for these terms, studies should report explicitly how these terms are defined when they are used.

Optimal combination of arthroplasty type, fixation method and postoperative rehabilitation protocol for complex proximal humerus fractures in the elderly: A network meta-analysis.

PURPOSE: The purpose of this study was to define the optimal combination of surgical technique and postoperative rehabilitation protocol for elderly patients undergoing either hemiarthroplasty (HA) or reverse total shoulder arthroplasty (rTSA) for acute proximal humerus fracture (PHF) by performing a network meta-analysis of the comparative studies in the literature. METHODS: A systematic review of the literature using PRISMA guidelines of MEDLINE, EMBASE, and Cochrane Library was screened from 2007-2023. Inclusion criteria were level I-IV studies utilizing primary HA and/or rTSA published in a peer-reviewed journal, that specified whether humeral stems were cemented or noncemented, specified postoperative rehabilitation protocol, reported results of HA and/or rTSA performed for PHF. Early range of motion (ROM) was defined as the initiation of active ROM at ≤3 weeks after surgery. Level of evidence was evaluated based on the criteria by the Oxford Centre for Evidence-Based Medicine. Clinical outcomes were compared using a frequentist approach to network meta-analysis with a random-effects model that was performed using the netmeta package version 0.9-6 in R. RESULTS: A total of 28 studies (1,119 patients) were included with an average age of 74±3.7 and mean follow-up of 32±11.1 months. In the early ROM cohort (Early), the mean time to active ROM was 2.4±0.76 weeks compared to 5.9±1.04 weeks in the delayed ROM cohort (Delayed). Overall, rTSA-Pressfit-Early resulted in statistically superior outcomes including postoperative forward elevation (126±27.5), abduction (116±30.6), internal rotation (5.27±0.74, corresponding to L3-L1), ASES score (71.8±17), tuberosity union (89%), and lowest tuberosity nonunion rate (9.6%) in patients ≥65 years old with acute PHF undergoing shoulder arthroplasty (all p≤0.05). In total there were 277 (14.5%) complications across the cohorts, of which 89/277 (34%) were in the HA-Cement-Delayed cohort. HA-Cement-Delayed resulted in 2-times higher odds of experiencing a complication when compared to rTSA-Cement-Delayed (p=0.005). Conversely, rTSA-Cement-Early cohort followed by rTSA-Pressfit-Early resulted in a total complication rate of 4.7% and 5.4% (OR, 0.30; p=0.01 & OR, 0.42; p=0.05), respectively. The total rate of scapular notching was higher in the cemented rTSA subgroups (16.5%) versus (8.91%) in the press fit rTSA subgroups (p=0.02). CONCLUSION: Our study demonstrates that patients ≥65 years of age, who sustain a 3-or 4-part PHF achieve the most benefit in terms of range of motion, postoperative functional outcomes, tuberosity union, and overall complication rate when undergoing rTSA with a noncemented stem and early postoperative range of motion when compared to the mainstream preference-rTSA-Cement-Delayed.

Complications following arthroscopic Bankart repair: a systematic review.

BACKGROUND: Complications are rare after arthroscopic Bankart repair, and as a result, there is a lack of guidance over rates of complications that can be used to consent patients. The purpose of this study is to systematically review the literature to assess the complications after arthroscopic Bankart repair, other than recurrent instability. METHODS: A literature search of MEDLINE, Embase, and the Cochrane Library was performed based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Clinical studies reporting on the complications after arthroscopic Bankart repair were included. RESULTS: A total of 194 studies were included in the analysis, with 13,979 patients and 14,019 shoulders undergoing arthroscopic Bankart repair. The overall complication rate was 0.67%, with frozen shoulder being the most common complication occurring in 0.32%. Persistent pain occurred in 0.17%. The rates of nerve, hardware, and wound complications were 0.07%, 0.05%, and 0.03%, respectively. CONCLUSION: The arthroscopic Bankart repair has a very low rate of complications. Frozen shoulder and persistent pain are the most frequently encountered complications.

Risk factors for intracellular fatty accumulation in rotator cuff muscle: a histologic analysis.

BACKGROUND: Fatty accumulation in rotator cuff muscles has been associated with shoulder dysfunction, risk of repair failure, and poor postoperative outcomes. This study sought to assess risk factors associated with true fatty accumulation based on histologic analysis and determine whether preoperative function directly correlated with this fatty rotator cuff accumulation. METHODS: Supraspinatus muscle biopsy specimens obtained prospectively from patients undergoing arthroscopic rotator cuff repair were stained with LipidTOX to quantify lipid accumulation. Two-step cluster analysis with Goutallier classification was used to define the fatty and non-fatty rotator cuff groups. We further performed a receiver operating characteristic curve analysis to confirm the group cutoff values. RESULTS: In total, 51 patients (aged 60.1 ± 10.5 years) were included. There were 19 high-grade partial tears, 10 small tears, 7 medium tears, 10 large tears, and 5 massive tears. Both cluster and receiver operating characteristic curve analyses yielded a cutoff value of 30% LipidTOX/4',6-diamidino-2-phenylindole (DAPI) separating the fatty vs. non-fatty groups. In the univariate analysis, patients with fatty rotator cuffs were aged 63.2 years on average compared with 59.7 years in the non-fatty group (P = .038). Female patients made up 57.1% of the fatty cohort, which was statistically higher than the non-fatty group (P = .042). Massive and large tears were more likely to occur in the fatty group (P = .005). In the multivariate analysis, full tendon tears had the largest predictive status of falling into the fatty group (odds ratio, 15.4; P = .008), followed by female sex (odds ratio, 4.9; P = .036). Patients in the fatty group had significantly higher American Shoulder and Elbow Surgeons scores (P = .048) and lower visual analog scale scores (P = .002). DISCUSSION AND CONCLUSION: This prospective histologic assessment revealed that full-thickness rotator cuff tears and female sex were the largest risk factors for intracellular lipid accumulation. Although tear size correlated with fatty accumulation, the sex disparity is a noteworthy finding that warrants further research.

Clinical Outcomes in Prospective versus Retrospective Studies on Arthroscopic Bankart Repair: A Systematic Review.

BACKGROUND: The majority of the current literature on arthroscopic Bankart repair is retrospective and discrepancies exist regarding clinical outcomes including recurrent instability and return to play amongst studies of different levels of evidence. PURPOSE: The purpose of this study is to perform a systematic review of the literature to compare the outcomes of prospective and retrospective studies on arthroscopic Bankart repair. METHODS: A search was performed using the PubMed/Medline database for all studies that reported clinical outcomes on Bankart repair for anterior shoulder instability. The search term "Bankart repair" with all results being analyzed via strict inclusion and exclusion criteria. Three independent investigators extracted data and scored each included study based on the 10 criteria of the Modified Coleman Methodology Score (CMS) out of 100. A chi-square test was performed to assess if recurrent instability, revision, return to play, and complications are independent of prospective and retrospective studies. RESULTS: One hundred ninety-three studies were included in the analysis with 53 prospective studies and 140 retrospective in design. Encompassing a total of 13,979 patients and 14,019 surgical procedures for Bankart repair for shoulder instability. The rate of re-dislocation in the prospective studies was 8.0% vs. 5.9% in retrospective (p < 0.001). The rate of recurrent subluxation in the prospective studies was 3.4% vs. 2.4% in retrospective (p = 0.004). The rate of revision was higher in retrospective studies at 4.9% vs. 3.9% in prospective studies (p = 0.013) There was no significant difference in terms of overall rate to return to play in prospective and retrospective studies was 90% and 91%, respectively (p=0.548). The overall rate of complications in the prospective cohort was 0.27% and 0.78% in the retrospective studies (p = 0.002). CONCLUSION: The overall rates of recurrent dislocations, subluxations are higher in prospective studies compared to retrospective studies. However, rates of revision were reportedly higher in retrospective studies. Complications after arthroscopic Bankart repair are rare in both prospective and retrospective studies, and there was no difference in rates of return to play.

Outcomes and Complications of Revision Reverse Shoulder Arthroplasty Following Failed Primary Anatomical Shoulder Arthroplasty or Hemiarthroplasty: A Systematic Review.

BACKGROUND: The purpose of this study is to systematically review the evidence in the literature to ascertain the functional outcomes, range of motion (ROM) and complication and reoperation rates following revision reverse shoulder arthroplasty (RSA) for a failed primary total shoulder arthroplasty (TSA) or hemiarthroplasty (HA). METHODS: Two independent reviewers performed the literature search based on PRISMA guidelines, utilizing the EMBASE, MEDLINE, and The Cochrane Library Databases. Studies were included if they reported clinical outcomes for revision RSA for a failed primary TSA or HA. RESULTS: Our review found 23 studies including 1,041 shoulders (627 TSA, 414 HA) meeting our inclusion criteria. The majority of patients were female (66.1%), with an average age of 69.0 years (range 39-93) with a mean follow-up of 46.3 months. ASES and VAS pain scores improved from 32.6 to 61.9 and 6.7 to 2.7, respectively. ROM results including forward flexion, abduction and external rotation that improved from 59.4° to 107.7°, 50.7° to 104.4°, and 19.8° to 26.3° respectively. Only one out of the ten studies reporting internal rotation found a statistically significant difference with mean internal rotation improving from S1-S3 preoperatively to L4-L5 postoperatively for patients undergoing HA. The overall complication rate and reoperation rate were 23.4% and 12.5% respectively. The most common complications were glenoid component loosening (6.0%), fracture (periprosthetic, intraoperative, or other scapula fractures) (n=4.7%), and infection (n=3.3%). CONCLUSION: Revision RSA for a failed primary TSA and HA has been shown to result in excellent functional outcomes and improved ROM suggesting patients who have failed TSA or HA may benefit from a revision RSA.

Artificial intelligence in shoulder and elbow surgery: overview of current and future applications.

Artificial intelligence (AI) is amongst the most rapidly growing technologies in orthopedic surgery. With the exponential growth in healthcare data, computing power, and complex predictive algorithms, this technology is poised to aid providers in data processing and clinical decision support throughout the continuum of orthopedic care. Understanding the utility and limitations of this technology is vital to practicing orthopedic surgeons, as these applications will become more common place in everyday practice. AI has already demonstrated its utility in shoulder and elbow surgery for imaging-based diagnosis, predictive modeling of clinical outcomes, implant identification, and automated image segmentation. The future integration of AI and robotic surgery represents the largest potential application of AI in shoulder and elbow surgery with the potential for significant clinical and financial impact. This editorial's purpose is to summarize common AI terms, provide a framework to understand and interpret AI model results, and discuss current applications and future directions within shoulder and elbow surgery.

Glenohumeral arthrodesis outcomes and complications: a systematic review.

BACKGROUND: The purpose of this study was to systematically review the evidence in the literature to determine the clinical outcomes following glenohumeral arthrodesis. METHODS: Two independent reviewers performed a literature search in the PubMed database based on Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies were included if they reported on outcomes following shoulder arthrodesis from the years of 2000-2022. Functional outcomes that were collected included the Subjective Shoulder Value, American Shoulder and Elbow Surgeons shoulder index score, visual analog scale pain score, and Oxford Shoulder Score. Range-of-motion data were also collected. RESULTS: This review included 17 studies, with a total of 316 patients, that met the inclusion criteria. The majority of the patients were male (67.4%), and the average age was 38.4 years (range, 7-82 years). The overall fusion rate was 88.7%, and the time to fusion was on average, 3.9 months (range, 2-8 months). Shoulder arthrodesis resulted in improvement in each of the functional outcomes assessed: Subjective Shoulder Value (preoperatively, 18.8; postoperatively, 43.9; and percent change, 132.8%), American Shoulder and Elbow Surgeons shoulder index score (postoperatively, 62.1), visual analog scale pain score (preoperatively, 8.5; postoperatively, 3.03; and percent change, 62.4%), and Oxford Shoulder Score (preoperatively, 9.4; postoperatively, 30.9; and percent change, 328.7%). The abduction, forward flexion, external rotation, and internal rotation range-of-motion measurements postoperatively were 57°, 64°, 3°, and 48°, respectively. Complications were reported in 33.6% of patients, with fractures (20.9%) and infections (18.6%) being the most common sources of complication. CONCLUSION: Shoulder arthrodesis provides improvement in functional outcomes for end-stage glenohumeral injuries; however, it is also associated with high rates of complications.

Utility of Superior Augments in Reverse Shoulder Arthroplasty (Exactech, Equinoxe GPS) without Significant Glenoid Deformity.

INTRODUCTION: Superior augment use may help avoid superior tilt while minimizing removal of inferior glenoid bone. Therefore, our goal is to compare superior augments versus no augment baseplates in RSA for patients with rotator cuff dysfunction and no significant superior glenoid erosion. METHODS: A multicenter retrospective analysis of 145 patients who underwent RSA with intraoperative navigation (Exactech, Equinoxe GPS) and three-year follow-up (mean 32-month follow-up, range 20 to 61 months) who had preoperative superior inclination less than 10 degrees and retroversion less than 15 degrees. Patient demographics, radiographic measurements, surgical characteristics, patient-reported outcomes at preoperative and postoperative visit closest to three years, and adverse events at final follow-up were obtained. Operative time, planned inclination, and planned version of the baseplate were obtained. Chi-square test used to compare categorical variables and student t-test used to compare augment and no augment cohorts. RESULTS: The study population consisted of 54 superior augment patients and 91 no augment patients. The augment cohort had lower BMI (27.2 vs. 29.4, p-0.023), higher native superior inclination (5.9 vs. 1.4 degrees, p<0.001). No difference between the augment and no augment cohorts was found regarding age (p=0.643), gender (p=0.314), medical comorbidities (p>0.05), surgical indication (p=0.082), and native glenoid version (p=0.564). The augment cohort had higher internal rotation score (4.6 vs. 3.9, p=0.023), all remaining ROM and PROs preoperatively were not significantly different. At final follow-up, active ROM in all planes was not different between the cohorts. Regarding PROs, the postoperative SAS score was significantly higher (78.0 vs. 73.6, p=0.042), and ASES score trended towards higher (83.6 vs. 77.5, p=0.063) in the augment cohort. The augment cohort had significantly lower proportion of patients planned to have superior baseplate tilt (1.9% vs. 14.3%, p=0.012), and had greater mean inclination correction (6.3 vs. 1.3 degrees, p<0.001), compared to no augment cohort. Adverse events were rare, and there was no significant difference found between the augment and no augment cohorts (5.6% vs. 3.3%, p=0.509). DISCUSSION: Superior augmented baseplate in RSA with minimal superior glenoid erosion is associated with similar ROM and adverse events with somewhat improved postoperative PROs compared to non-augmented baseplates at 3-year follow-up. Additionally, superior augments resulted in a greater proportion of baseplates planned to avoid superior tilt, and trended toward shorter operative times. Further investigation of long-term glenoid baseplate loosening is imperative to fully understand the cost-effectiveness of superior augments in the setting of minimal glenoid deformity.

Outcomes of Arthroscopic Stabilization for Posterior Shoulder Instability - A Systematic Review.

BACKGROUND: Posterior shoulder instability makes up approximately 10% of all shoulder instability cases and its diagnosis and treatment is less well understood. Recently, however, there has been increased recognition of posterior instability and posterior stabilization. The purpose of this study was to systematically review the literature to ascertain the outcomes on arthroscopic stabilization of posterior shoulder instability. METHODS: Two independent reviewers conducted a systematic literature search based on PRISMA guidelines, utilizing the MEDLINE database. Studies were eligible for inclusion if they reported postoperative outcomes for posterior shoulder instability following arthroscopic stabilization. RESULTS: A total of 48 studies met inclusion criteria for review including 2307 shoulders. Majority of patients were male (83.3%), with an average age of 26.1 years and a mean follow-up of 46.8 months. The functional outcome score primarily utilized for postoperative assessment was ASES with an average of 84.77. Overall, 90.9% of patients reported being satisfied with their arthroscopic stabilization. Recurrent instability occurred in 7.4% of patients. The total revision rate was 5.2%. 16.6% of patients reported residual pain postoperatively. The rate of return to play was 86.4% with 68.0% of patients returning to play at the same or higher level of play. CONCLUSION: Arthroscopic stabilization of posterior shoulder instability resulted in good outcomes with high patient satisfaction and low rates of recurrent instability, revisions, and residual pain.

Technological innovations in shoulder replacement: current concepts and the future of robotics in total shoulder arthroplasty.

BACKGROUND: Total shoulder arthroplasty (TSA) has been rapidly evolving over the last several decades, with innovative technological strategies being investigated and developed in order to achieve optimal component precision and joint alignment and stability, preserve implant longevity, and improve patient outcomes. Future advancements such as robotic-assisted surgeries, augmented reality, artificial intelligence, patient-specific instrumentation (PSI) and other peri- and preoperative planning tools will continue to revolutionize TSA. Robotic-assisted arthroplasty is a novel and increasingly popular alternative to the conventional arthroplasty procedure in the hip and knee but has not yet been investigated in the shoulder. Therefore, the purpose of this study was to conduct a narrative review of the literature on the evolution and projected trends of technological advances and robotic assistance in total shoulder arthroplasty. METHODS: A narrative synthesis method was employed for this review, rather than a meta-analysis or systematic review of the literature. This decision was based on 2 primary factors: (1) the lack of eligible, peer-reviewed studies with high-quality level of evidence available for review on robotic-assisted shoulder arthroplasty, and (2) a narrative review allows for a broader scope of content analysis, including a comprehensive review of all technological advances-including robotics-within the field of TSA. A general literature search was performed using PubMed, Embase, and Cochrane Library databases. These databases were queried by 2 independent reviewers from database inception through November 11, 2022, for all articles investigating the role of robotics and technology assistance in total shoulder arthroplasty. Inclusion criteria included studies describing "shoulder arthroplasty" and "robotics." RESULTS: After exclusion criteria were applied, 4 studies on robotic-assisted TSA were described in the review. Given the novelty of this technology and limited data on robotics in TSA, these studies consisted of a literature review, nonvalidated experimental biomechanical studies in sawbones models, and preclinical proof-of-concept cadaveric studies using prototype robotic technology primarily in conjunction with PSI. The remaining studies described the technological advancements in TSA, including PSI, computer-assisted navigation, artificial intelligence, machine learning, and virtual, augmented, and mixed reality. Although not yet commercially available, robotic-assisted TSA confers the theoretical advantages of precise humeral head cuts for restoration of proximal humerus anatomy, more accurate glenoid preparation, and improved soft-tissue assessment in limited early studies. CONCLUSION: The evidence for the use of robotics in total hip arthroplasty and total knee arthroplasty demonstrates improved component accuracy, more precise radiographic measurements, and improved early/mid-term patient-reported and functional outcomes. Although no such data currently exist for shoulder arthroplasty given that the technology has not yet been commercialized, the lessons learned from robotic hip and knee surgery in conjunction with its rapid adoption suggests robotic-assisted TSA is on the horizon of innovation. By achieving a better understanding of the past, present, and future innovations in TSA through this narrative review, orthopedic surgeons can be better prepared for future applications.

Impact of reverse shoulder arthroplasty design and patient shoulder size on moment arms and muscle fiber lengths in shoulder abductors.

BACKGROUND: Reverse shoulder arthroplasty (RSA) increases the moment arm of the deltoid; however, there is limited knowledge on the accompanying changes in muscle architecture that play a role in muscle force production. The purpose of this study was to use a geometric shoulder model to evaluate the anterior deltoid, middle deltoid, and supraspinatus regarding (1) the differences in moment arms and muscle-tendon lengths in small, medium, and large native shoulders and (2) the impact of 3 RSA designs on moment arms, muscle fiber lengths, and force-length (F-L) curves. METHODS: A geometric model of the native glenohumeral joint was developed, validated, and adjusted to represent small, medium, and large shoulders. Moment arms, muscle-tendon lengths, and normalized muscle fiber lengths were assessed for the supraspinatus, anterior deltoid, and middle deltoid from 0° to 90° of abduction. RSA designs were modeled and virtually implanted, including a lateralized glenosphere with an inlay 135° humeral component (lateral glenoid-medial humerus [LGMH]), a medialized glenosphere with an onlay 145° humeral component (medial glenoid-lateral humerus [MGLH]), and a medialized glenosphere with an inlay 155° humeral component (medial glenoid-medial humerus [MGMH]). Descriptive statistics were used to compare moment arms and normalized muscle fiber lengths. RESULTS: As shoulder size increased, the moment arms and muscle-tendon lengths for the anterior deltoid, middle deltoid, and supraspinatus increased. All RSA designs achieved greater moment arms for the anterior and middle deltoid, with the MGLH design achieving the largest increase. The resting normalized muscle fiber length of the anterior and middle deltoid was substantially increased in the MGLH (1.29) and MGMH (1.24) designs, shifting the operating ranges of these muscles to the descending portions of their F-L curves, whereas the LGMH design maintained a resting deltoid fiber length (1.14) and operating range similar to the native shoulder. All RSA designs demonstrated a decrease in the native supraspinatus moment arm in early abduction, with the largest decrease in the MGLH design (-59%) and minimal decrease in the LGMH design (-14%). The supraspinatus operated on the ascending limb of its F-L curve in the native shoulder and remained on this portion of the F-L curve for all RSA designs. CONCLUSION: Although the MGLH design maximizes the abduction moment arm for the anterior and middle deltoid, overlengthening of the muscle may compromise deltoid muscle force production by forcing the muscle to operate on the descending portion of its F-L curve. In contrast, the LGMH design increases the abduction moment arm for the anterior and middle deltoid more modestly while allowing the muscle to operate near the plateau of its F-L curve and maximizing its force-producing potential.

Outcomes after bilateral shoulder arthroplasty: a systematic review.

The purpose of this systematic review was to report outcomes after bilateral shoulder arthroplasty including bilateral total shoulder arthroplasty (TSA), bilateral reverse shoulder arthroplasty (RSA), and ipsilateral TSA with contralateral RSA (TSA/RSA). Two reviewers independently performed a PRISMA-guided systematic search using MEDLINE/PubMed, Embase, and Cochrane Database of Systematic Reviews up to May 11, 2021. The databases were queried using the following search terms: (["bilateral" OR "contralateral"] AND "shoulder" AND ["arthroplast∗" OR "replacement"]). A total of 486 titles/abstracts were screened for eligibility and 19 studies were included in the final analysis. Risk of bias was assessed using Methodological Index for Nonrandomized Studies and Modified Coleman Methodology scores. Analysis compared overall results for bilateral shoulder arthroplasty and sub-group analyses compared TSA (all shoulders from bilateral TSA patients and the TSA shoulder in TSA/RSA patients) to RSA (all shoulders from bilateral RSA patients and the RSA shoulder in TSA/RSA patients), first shoulder arthroplasty to second contralateral shoulder arthroplasty, and interval between arthroplasty (IBA) <20 months to IBA ≥20 months. Nineteen studies analyzed bilateral TSA (n = 3), bilateral RSA (n = 7), and TSA/RSA (n = 8). The mean Methodological Index for Nonrandomized Studies was 18 and mean Modified Coleman Methodology Score was 74, with 63.2% of studies demonstrating level III evidence. A total of 2729 patients (30.4% male; mean age 72.2 years, mean follow-up 47.3 months, mean IBA 20 months) were analyzed. Postoperative forward flexion (142.0° vs. 129.6°), external rotation (ER) (42.5° vs. 25.6°), and internal rotation (60% reaching T12-T8 vs 85.7% reaching L3-L1) were higher for TSA when compared to RSA. Patient reported outcome measures such as Constant-Murley (73.2 vs. 59.2), American Shoulder and Elbow Surgeons (87.9 vs. 77.7), and Single Assessment Numeric Evaluation (SANE) (86.9 vs. 67.8) were higher for TSA when compared to RSA. Patients with IBA ≥20 months demonstrated greater ER and patient satisfaction than patients with IBA <20 months. Postoperative complication rates were 15.1% for TSA and 10.6% for RSA, while reoperation and revision rates were 13.7% for TSA and 7.1% for RSA. Bilateral shoulder arthroplasty results in improvements in motion, strength, pain, function, and high satisfaction. Bilateral TSA is associated with greater improvement in motion and function than bilateral RSA but higher complication, reoperation, and revision rates. IBA ≥20 months is associated with greater ER and satisfaction than IBA <20 months.

Subscapularis repair for reverse shoulder arthroplasty: a systematic review and meta-analysis.

BACKGROUND: The purpose of this study is to perform a systematic review of the literature evaluating the importance of subscapularis repair in patients who underwent reverse shoulder arthroplasty (RSA). METHODS: A systematic search of articles in PubMed, EMBASE, and the Cochrane Library databases was carried out according to the PRISMA guidelines. Cohort studies comparing RSA with subscapularis repair vs. RSA without subscapularis repair were included. All statistical analysis was performed using Review Manager. A P value of <.05 was considered to be statistically significant. RESULTS: Seventeen studies with 2620 patients were included. Subscapularis repair resulted in less instability compared to without subscapularis repair (0.8% vs. 4.2%, P = .04), and there were no significant differences in rate of instability with lateralization (0.6% vs. 1.6%, P = .40), revision rates (2.6% vs. 3.9%, P = .62), and complication rates (7.7% vs. 4.9%, P = .21). Subscapularis repair had improved American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (83.6 vs. 80.2, P = .02) and Constant scores (72.6 vs. 68.9, P < .01) but there was not a significant difference in visual analog scale pain scores (1.2 vs. 1.6, P = .11). Subscapularis repair had a significant difference in forward flexion (140° vs. 137°, P = .04) and internal rotation score (5.5 vs. 4.6, P = .001); however, there was no significant difference in external rotation (35° vs. 35°, P = .80) and abduction (117° vs. 123°, P = .13). CONCLUSION: This study found that RSA with subscapularis repair demonstrated a reduction in the occurrence of implant instability with medialized implants. However, subscapularis repair did not yield improvements in revision rates, complications, or instability with lateralized implants. Additionally, other outcome measures such as ASES, Constant score, and range of motion exhibited statistically significant improvements with subscapularis repair but did not surpass clinically significant thresholds.

Association between radiographic soft-tissue thickness and increased length of stay, operative time, and infection rate after reverse shoulder arthroplasty.

BACKGROUND: Reverse shoulder arthroplasty (RSA) is a widely performed surgical procedure to address various shoulder pathologies. Several studies have suggested that radiographic soft-tissue thickness may play a role in predicting complications after orthopedic surgery, but there have been limited studies determining the use of radiographic soft-tissue thickness in RSA. The purpose of this study was to evaluate whether radiographic soft-tissue thickness could predict clinical outcomes after RSA and compare the predictive capabilities against body mass index (BMI). We hypothesized that increased radiographic shoulder soft-tissue thickness would be a strong predictor of operative time, length of stay (LOS), and infection in elective RSA. MATERIAL AND METHODS: A retrospective review of patients undergoing RSA at an academic institution was conducted. Preoperative radiographic images were evaluated including measurements of the radius from the humeral head center to the skin (HS), deltoid radius-to-humeral head radius ratio (DHR), deltoid size, and subcutaneous tissue size. Different correlation coefficients were used to analyze various types of relationships, and the strength of these associations was classified based on predefined boundaries. Subsequently, multivariable linear and logistic regressions were performed to determine whether HS, DHR, deltoid size, and subcutaneous tissue size could predict LOS, operative time, or infection while controlling for patient factors. RESULTS: HS was the most influential factor in predicting both operative time and LOS after RSA, with strong associations indicated by standardized ß coefficients of 0.234 for operative time and 0.432 for LOS. Subcutaneous tissue size, deltoid size, and DHR also showed stronger predictive values than BMI for both outcomes. In terms of prosthetic joint infection, HS, deltoid size, and DHR were significant predictors, with HS demonstrating the highest predictive power (Nagelkerke R2 = 0.44), whereas BMI did not show a statistically significant association with infection. Low event counts resulted in wide confidence intervals for odds ratios in the infection analysis. CONCLUSION: Greater shoulder soft-tissue thickness as measured with concentric circles on radiographs is a strong predictor of operative time, LOS, and postoperative infection in elective primary RSA patients.

A validated preoperative risk prediction tool for extended inpatient length of stay following anatomic or reverse total shoulder arthroplasty.

BACKGROUND: Recent work has shown inpatient length of stay (LOS) following shoulder arthroplasty to hold the second strongest association with overall cost (after implant cost itself). In particular, a preoperative understanding for the patients at risk of extended inpatient stays (≥3 days) can allow for counseling, optimization, and anticipating postoperative adverse events. METHODS: A multicenter retrospective review was performed of 5410 anatomic (52%) and reverse (48%) total shoulder arthroplasties done at 2 large, tertiary referral health systems. The primary outcome was extended inpatient LOS of at least 3 days, and over 40 preoperative sociodemographic and comorbidity factors were tested for their predictive ability in a multivariable logistic regression model based on the patient cohort from institution 1 (derivation, N = 1773). External validation was performed using the patient cohort from institution 2 (validation, N = 3637), including area under the receiver operator characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive values. RESULTS: A total of 814 patients, including 318 patients (18%) in the derivation cohort and 496 patients (14%) in the validation cohort, experienced an extended inpatient LOS of at least 3 days. Four hundred forty-five (55%) were discharged to a skilled nursing or rehabilitation facility. Following parameter selection, a multivariable logistic regression model based on the derivation cohort (institution 1) demonstrated excellent preliminary accuracy (AUC: 0.826), with minimal decrease in accuracy under external validation when tested against the patients from institution 2 (AUC: 0.816). The predictive model was composed of only preoperative factors, in descending predictive importance as follows: age, marital status, fracture case, ASA (American Society of Anesthesiologists) score, paralysis, electrolyte disorder, body mass index, gender, neurologic disease, coagulation deficiency, diabetes, chronic pulmonary disease, peripheral vascular disease, alcohol dependence, psychoses, smoking status, and revision case. CONCLUSION: A freely-available, preoperative online clinical decision tool for extended inpatient LOS (≥ 3 days) after shoulder arthroplasty reaches excellent predictive accuracy under external validation. As a result, this tool merits consideration for clinical implementation, as many risk factors are potentially modifiable as part of a preoperative optimization strategy.