Operative Treatment of Acromial and Scapular Spine Fracture Nonunions Complicating Reverse Total Shoulder Arthroplasty.

BACKGROUND: Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describe our evolution of fixation techniques. METHODS: Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD=15.1) years. Fixation strategies included single (n=11) and double plate fixation (n=11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables. RESULTS: Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but one fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2° to 91.3° pre- and postoperatively, respectively). CONCLUSIONS: ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with one of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.

Identification of ChatGPT-Generated Abstracts Within Shoulder and Elbow Surgery Poses a Challenge for Reviewers.

PURPOSE: To evaluate the extent to which experienced reviewers can accurately discern between AI-generated and original research abstracts published in the field of shoulder and elbow surgery and compare this to the performance of an AI-detection tool. METHODS: Twenty-five shoulder and elbow-related articles published in high-impact journals in 2023 were randomly selected. ChatGPT was prompted with only the abstract title to create an AI-generated version of each abstract. The resulting 50 abstracts were randomly distributed to and evaluated by 8 blinded peer reviewers with at least 5 years of experience. Reviewers were tasked with distinguishing between original and AI-generated text. A Likert scale assessed reviewer confidence for each interpretation and the primary reason guiding assessment of generated text was collected. AI output detector (0-100%) and plagiarism (0-100%) scores were evaluated using GPTZero. RESULTS: Reviewers correctly identified 62% of AI-generated abstracts and misclassified 38% of original abstracts as being AI-generated. GPTZero reported a significantly higher probability of AI output among generated abstracts (median 56%, IQR 51-77%) compared to original abstracts (median 10%, IQR 4-37%; p < 0.01). Generated abstracts scored significantly lower on the plagiarism detector (median 7%, IQR 5-14%) relative to original abstracts (median 82%, IQR 72-92%; p < 0.01). Correct identification of AI-generated abstracts was predominately attributed to the presence of unrealistic data/values. The primary reason for misidentifying original abstracts as AI was attributed to writing style. CONCLUSIONS: Experienced reviewers faced difficulties in distinguishing between human and AI-generated research content within shoulder and elbow surgery. The presence of unrealistic data facilitated correct identification of AI abstracts, whereas misidentification of original abstracts was often ascribed to writing style.

The Relationship Between Design-Based Lateralization, Humeral bearing design, Polyethylene Angle, and Patient-Related Factors on Surgical Complications after Reverse Shoulder Arthroplasty: A Machine Learning Analysis.

INTRODUCTION: Technological advancements in implant design and surgical technique have focused on diminishing complications and optimizing performance of reverse shoulder arthroplasty (RSA). Despite this, there remains a paucity of literature correlating prosthetic features and clinical outcomes. This investigation utilized a machine learning approach to evaluate the effect of select implant design features and patient-related factors on surgical complications after RSA. METHODS: Over a 16-year period (2004 - 2020), all primary RSA performed at a single institution for elective and traumatic indications with a minimum follow-up of 2 years were identified. Parameters related to implant design evaluated in this study included inlay vs onlay humeral bearing design, glenoid lateralization (medialized or lateralized), humeral lateralization (medialized, minimally lateralized, or lateralized), global lateralization (medialized, minimally lateralized, lateralized, highly lateralized, or very highly lateralized), stem to metallic bearing neck shaft angle (NSA), and polyethylene NSA. Machine learning models predicting surgical complications were constructed for each patient and Shapley additive explanation (SHAP) values were calculated to quantify feature importance. RESULTS: A total of 3,837 RSAs were identified, of which 472 (12.3%) experienced a surgical complication. Those experiencing a surgical complication were more likely to be current smokers (Odds ratio [OR] = 1.71; P = .003), have prior surgery (OR = 1.60; P < .001), have an underlying diagnosis of sequalae of instability (OR = 4.59; P < .001) or non-union (OR = 3.09; P < .001), and required longer OR times (98 vs. 86 minutes; P < .001). Notable implant design features at an increased odds for complications included an inlay humeral component (OR = 1.67; P < .001), medialized glenoid (OR = 1.43; P = .001), medialized humerus (OR = 1.48; P = .004), a minimally lateralized global construct (OR = 1.51; P < .001), and glenohumeral constructs consisting of a medialized glenoid and minimally lateralized humerus (OR = 1.59; P < .001), and a lateralized glenoid and medialized humerus (OR = 2.68; P < .001). Based on patient- and implant-specific features, the machine learning model predicted complications after RSA with an area under the receiver operating characteristic curve (AUC ROC) of 0.61. CONCLUSIONS: This study demonstrated that patient-specific risk factors had a more substantial effect than implant design configurations on the predictive ability of a machine learning model on surgical complications after RSA. However, certain implant features appeared to be associated with a higher odd of surgical complications.

Supracondylar Ostectomy and Shortening (S.O.S) for Distal Humerus Nonunions.

INTRODUCTION: Many distal humerus nonunions are associated with bone loss and rigid internal fixation is difficult to obtain, especially for low transcondylar nonunions and those with severe intraarticular comminution. The purpose of this study was to analyze the results of a strategy to address this challenge utilizing internal fixation using the Supracondylar Ostectomy + Shortening (i.e. S.O.S.) procedure for distal humerus nonunions. The goals of this procedure are to (1) optimize bony contact and compression through re-shaping the nonunited fragments at the supracondylar level with selective humeral metaphyseal shortening, (2) maximize fixation using parallel-plating, and (3) provide biologic and structural augmentation with bone graft. MATERIALS AND METHODS: Between 1995 and 2019, 28 distal humerus nonunions underwent internal fixation using the S.O.S. procedure at a single Institution. There were 14 males and 14 females with mean age of 47 (range 14-78) years at the time of the S.O.S procedure and an average of 1.7 prior surgeries. Medical records and radiographs were reviewed to determine rates of union, reoperations, complications, and Mayo Elbow Performance Scores (MEPS). Patients were also prospectively contacted to update their MEPS and gather additional information on complications and reoperations. Mean clinical exam follow-up was 17 months, mean clinical contact follow-up was 19 months, and mean radiographic follow-up was 32 months. RESULTS: Four patients did not have adequate follow-up to determine union. Of the remaining 24 elbows, 22 achieved union. Two elbows developed collapse of the articular surface and were converted to a total elbow arthroplasty (TEA). There were complications in 10 elbows: contracture (5), superficial infection (2), ulnar neuropathy (1), deep infection (1), and hematoma (1). Twelve elbows underwent reoperation: 4 for contracture release, 3 for hardware removal, 2 for total elbow arthroplasty, 1 for bone grafting, 1 for hematoma evacuation, and 1 for ulnar nerve neurolysis. Compared to preoperative data, there was a significant improvement in postoperative flexion, extension and pronation (p<0.01). The mean range of motion was 21° of extension, 119° of flexion, 79° of pronation, and 77° of supination. The mean MEPS was 80 points (range, 25 to 100 points) and 19 elbows (76%) rated as excellent or good. DISCUSSION: Stable fixation and high union rates are possible in distal humerus nonunions with bone loss using a technique that combines supracondylar humeral shortening, parallel plating, and bone grafting. Secondary procedures are commonly needed to restore function in this challenging patient population.

Comparison of reconstructive techniques for nonprimary malignancies in the proximal humerus.

BACKGROUND: Endoprostheses (EPC) are often utilized for reconstruction of the proximal humerus with either hemiarthroplasty (HA) or reverse arthroplasty (RA) constructs. RA constructs have improved outcomes in patients with primary lesions, but no studies have compared techniques in metastatic disease. The aim of this study is to compare functional outcomes and complications between HA and RA constructs in patients undergoing endoprosthetic reconstruction for proximal humerus metastases. METHODS: We retrospectively reviewed our institutional arthroplasty database to identify 66 (56% male; 38 HA and 28 RA) patients with a proximal humerus reconstruction for a non-primary malignancy. The majority (88%) presented with pathologic fracture, and the most common diagnosis was renal cell carcinoma (48%). RESULTSS: Patients with RA reconstructions had better postoperative forward elevation (74° vs. 32°, p < 0.01) and higher functional outcome scores. HA patients had more complications (odds ratio 13, p < 0.01), with instability being the most common complication. CONCLUSIONS: Patients with nonprimary malignancies of the proximal humerus had improved functional outcomes and fewer complications after undergoing reconstruction with a reverse EPC compared to a HA EPC. Preference for reverse EPC should be given in patients with good prognosis and ability to complete postoperative rehabilitation.

After Primary Shoulder Arthroplasty Appropriate Vancomycin Antibiotic Prophylaxis Does Not Lead to Increased Infectious Complications When Compared to Cefazolin.

INTRODUCTION: In primary shoulder arthroplasty (SA), intravenous (IV) cefazolin has demonstrated lower rates of infectious complications when compared to IV vancomycin. However, previous analyses included SA cohorts with both complete and incomplete vancomycin administration. Therefore, it is currently unclear whether cefazolin still maintains a prophylactic advantage to vancomycin when it is appropriately indicated and sufficiently administered at the time of surgical incision. This study evaluated the comparative efficacy of cefazolin and complete vancomycin administration for surgical prophylaxis in primary shoulder arthroplasty with respect to infectious complications. METHODS: A retrospective cohort study was conducted utilizing a single institution total joint registry database, where all primary SA types (hemiarthroplasty, anatomic total shoulder arthroplasty, reverse shoulder arthroplasty) performed between 2000 to 2019 for elective and trauma indications using IV cefazolin or complete vancomycin administration as the primary antibiotic prophylaxis were identified. Vancomycin was primarily indicated for patients with a severe self-reported penicillin or cephalosporin allergy and/or MRSA colonization. Complete administration was defined as at least 30 minutes of antibiotic infusion prior to incision. All included SA had at least 2 years of clinical follow-up. Multivariable Cox proportional hazard regression was used to evaluate all-cause infectious complications including survival free of prosthetic joint infection (PJI). RESULTS: The final cohort included 7,177 primary SA, 6,879 (95.8%) received IV cefazolin and 298 (4.2%) received complete vancomycin administration. Infectious complications occurred in 120 (1.7%) SA leading to 81 (1.1%) infectious reoperations. Of the infectious complications 41 (0.6%) were superficial infections and 79 were (1.1%) PJIs. When categorized by administered antibiotics, there were no differences in rates of all infectious complications (1.6% vs. 2.3%; P = .352), superficial complications (0.5% vs. 1.3%; P = .071), PJI (1.1% vs. 1.0%; P = .874), or infectious reoperations (1.1% vs. 1.0%; P = .839). On multivariable analyses, complete vancomycin infusion demonstrated no difference in rates of infectious complications compared to cefazolin administration (hazard ratio [HR], 1.50 [95% confidence interval (CI), 0.70 to 3.25]; P = .297), even when other independent predictors of PJI (male sex, prior surgery, and Methicillin-resistant Staphylococcus aureus colonization) were considered. CONCLUSIONS: In comparison to cefazolin, complete administration of vancomycin (infusion to incision time greater than 30 minutes) as the primary prophylactic agent does not adversely increase the rates of infectious complications and PJI. Prophylaxis protocols should promote appropriate indications for the use of cefazolin or vancomycin, and when necessary, ensure complete administration of vancomycin to mitigate additional infectious risks after primary SA.

Efficacy of ADIPOR1 and ADIPOR2 peptide-agonist AdipoRon in preventing contracture in a rabbit model of arthrofibrosis.

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty-six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K-wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16-week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10-week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose-dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals.

Complications of antibiotic cement spacers used for elbow infections.

BACKGROUND: Antibiotic cement spacers have been widely used in the treatment of joint infections. There are no commercially available antibiotic spacers for the elbow. Instead, they are typically fashioned by the surgeon at the time of surgery using cement alone or a combination of cement with sutures, Steinmann pins, external fixator components, or elbow arthroplasty components. There is no consensus regarding the ideal elbow antibiotic spacer and no previous studies have examined the complications associated with these handmade implants in relation to their unique structural design. METHODS: We retrospectively reviewed 55 patients who had 78 static antibiotic cement spacers implanted between January 1998 and February 2021 as part of a 2-stage treatment plan for infection of an elbow arthroplasty, other elbow surgery, or primary elbow infection. Several antibiotic spacer structures were used during the study period. For analysis purposes, the spacers were classified into linked and unlinked spacers based on whether there was a linking mechanism between the humerus and the ulna. Complications related to these spacers that occurred either during the implantation, between implantation and removal, or during removal were recorded and analyzed from chart review and follow-up x rays. Reoperations due to spacer-related complications were also recorded. RESULTS: Among the 55 patients (78 spacers), there were 23 complications, including 17 minor and 6 major complications. The most common complication of unlinked spacers (intramedullary [IM] dowels, beads and cap spacer) was spacer displacement. Other complications included IM dowel fracture and difficulty locating beads during spacer removal. The major complications of linked cement spacers included two periprosthetic humerus fractures after internal external fixator cement spacers and re-operation due to breakage and displacement of one bushing cement spacer. The major complications of unlinked cement spacers included two reoperations due to IM dowel displacement and one reoperation due to displacement of beads. Among patients who had removal of all components and those with native joints, there was no statistically significant difference between internal external fixator cement spacers and unlinked cement spacers in minor complication rates (30% vs. 16%, P = .16), major complication rates (7% vs. 8%, P = .85) and reoperation rates (0% vs. 8%, P = .12). CONCLUSIONS: Static handmade antibiotic elbow spacers have unique complications related to their structural designs. The most common complication of linked and nonlinked cement spacers were failure of the linking mechanism and displacement, respectively. Surgeons should keep in mind the possible complications of different structures of cement spacers when choosing 1 antibiotic spacer structure over another.

Proximal Humerus Reconstruction for Bone Sarcomas: A Critical Analysis.

¼ The proximal humerus is a common location for primary bone tumors, and the goal of surgical care is to obtain a negative margin resection and subsequent reconstruction of the proximal humerus to allow for shoulder function.¼ The current evidence supports the use of reverse total shoulder arthroplasty over hemiarthroplasty when reconstructing the proximal humerus after resection of a bone sarcoma if the axillary nerve can be preserved.¼ There is a lack of high-quality data comparing allograft prosthetic composite (APC) with endoprosthetic reconstruction of the proximal humerus.¼ Reverse APC should be performed using an allograft with donor rotator cuff to allow for soft-tissue repair of the donor and host rotator cuff, leading to improvements in shoulder motion compared with an endoprosthesis.

A practical guide to the development and deployment of deep learning models for the orthopaedic surgeon: Part III, focus on registry creation, diagnosis, and data privacy.

Deep learning is a subset of artificial intelligence (AI) with enormous potential to transform orthopaedic surgery. As has already become evident with the deployment of Large Language Models (LLMs) like ChatGPT (OpenAI Inc.), deep learning can rapidly enter clinical and surgical practices. As such, it is imperative that orthopaedic surgeons acquire a deeper understanding of the technical terminology, capabilities and limitations associated with deep learning models. The focus of this series thus far has been providing surgeons with an overview of the steps needed to implement a deep learning-based pipeline, emphasizing some of the important technical details for surgeons to understand as they encounter, evaluate or lead deep learning projects. However, this series would be remiss without providing practical examples of how deep learning models have begun to be deployed and highlighting the areas where the authors feel deep learning may have the most profound potential. While computer vision applications of deep learning were the focus of Parts I and II, due to the enormous impact that natural language processing (NLP) has had in recent months, NLP-based deep learning models are also discussed in this final part of the series. In this review, three applications that the authors believe can be impacted the most by deep learning but with which many surgeons may not be familiar are discussed: (1) registry construction, (2) diagnostic AI and (3) data privacy. Deep learning-based registry construction will be essential for the development of more impactful clinical applications, with diagnostic AI being one of those applications likely to augment clinical decision-making in the near future. As the applications of deep learning continue to grow, the protection of patient information will become increasingly essential; as such, applications of deep learning to enhance data privacy are likely to become more important than ever before. Level of Evidence: Level IV.

Rotator cuff tears.

Rotator cuff tears are the most common upper extremity condition seen by primary care and orthopaedic surgeons, with a spectrum ranging from tendinopathy to full-thickness tears with arthritic change. Some tears are traumatic, but most rotator cuff problems are degenerative. Not all tears are symptomatic and not all progress, and many patients in whom tears become more extensive do not experience symptom worsening. Hence, a standard algorithm for managing patients is challenging. The pathophysiology of rotator cuff tears is complex and encompasses an interplay between the tendon, bone and muscle. Rotator cuff tears begin as degenerative changes within the tendon, with matrix disorganization and inflammatory changes. Subsequently, tears progress to partial-thickness and then full-thickness tears. Muscle quality, as evidenced by the overall size of the muscle and intramuscular fatty infiltration, also influences symptoms, tear progression and the outcomes of surgery. Treatment depends primarily on symptoms, with non-operative management sufficient for most patients with rotator cuff problems. Modern arthroscopic repair techniques have improved recovery, but outcomes are still limited by a lack of understanding of how to improve tendon to bone healing in many patients.

Reverse shoulder arthroplasty megaprosthesis for surgical management of severe proximal humeral bone loss.

BACKGROUND: Shoulder arthroplasty in the setting of severe proximal humerus bone loss can be challenging. The purpose of this study was to evaluate the outcomes of a modular segmental megaprosthesis when implanted in a reverse configuration for complex primary arthroplasty, reconstruction at the time of oncologic resection, and revision shoulder arthroplasty. MATERIALS AND METHODS: A Joint Registry Database was queried to identify all shoulder arthroplasties performed at a single institution using the Comprehensive Segmental Revision System reverse shoulder arthroplasty (SRS-RSA; Zimmer Biomet). A retrospective review of electronic medical records and radiographs was performed to record demographic data, indication, outcomes, complications, and revision surgery. RESULTS: Between February 2012 and October 2022, a total of 76 consecutive SRS-RSAs were implanted. An analysis of patients with minimum 12-month follow-up yielded 53 patients with a mean follow-up of 4.1 ± 2.43 years. Surgical complication rate in this cohort was observed in 41.5% (22 of 53) of cases. Overall, the revision rate at final follow-up was 26.4% (14 of 53), with a significant difference between the primary and revision cohorts. The number of prior surgeries was a significant risk factor for revision surgery, with a hazard ratio of 1.789 (95% confidence interval 1.314-2.436, P < .001). When analyzing aseptic humeral loosening rates across study cohorts, a significant difference was found between the primary arthroplasty (0%, n = 0) and the revision arthroplasty cohorts (22.2%, n = 6) (P = .04). DISCUSSION: Reverse shoulder arthroplasty using a modular segmental megaprosthesis remains a reasonable salvage option for shoulder reconstruction in the setting of proximal humeral bone loss. Because of the substantial bone loss and soft tissue deficiencies typically present in these cases, surgeons should educate patients on the relatively high complication rate, particularly when used in the setting of a previous failed arthroplasty.

Artificial intelligence-based three-dimensional templating for total joint arthroplasty planning: a scoping review.

PURPOSE: The purpose of this review is to evaluate the current status of research on the application of artificial intelligence (AI)-based three-dimensional (3D) templating in preoperative planning of total joint arthroplasty. METHODS: This scoping review followed the PRISMA, PRISMA-ScR guidelines, and five stage methodological framework for scoping reviews. Studies of patients undergoing primary or revision joint arthroplasty surgery that utilised AI-based 3D templating for surgical planning were included. Outcome measures included dataset and model development characteristics, AI performance metrics, and time performance. After AI-based 3D planning, the accuracy of component size and placement estimation and postoperative outcome data were collected. RESULTS: Nine studies satisfied inclusion criteria including a focus on computed tomography (CT) or magnetic resonance imaging (MRI)-based AI templating for use in hip or knee arthroplasty. AI-based 3D templating systems reduced surgical planning time and improved implant size/position and imaging feature estimation compared to conventional radiographic templating. Several components of data processing and model development and testing were insufficiently covered in the studies included in this scoping review. CONCLUSIONS: AI-based 3D templating systems have the potential to improve preoperative planning for joint arthroplasty surgery. This technology offers more accurate and personalized preoperative planning, which has potential to improve functional outcomes for patients. However, deficiencies in several key areas, including data handling, model development, and testing, can potentially hinder the reproducibility and reliability of the methods proposed. As such, further research is needed to definitively evaluate the efficacy and feasibility of these systems.

Editorial Commentary: Subtle Degenerative Tears That So Commonly Involve the Upper Third of the Subscapularis Are Oftentimes Missed.

Subtle degenerative tears that so commonly involve the upper third of the subscapularis are oftentimes missed. However, there are physical examination, imaging, and arthroscopic findings that are highly suggestive of subscapularis tearing. Positive belly-press and bear hug tests, a thinner and longer subscapularis tendon, subscapularis muscle, belly loss of bulk or fatty infiltration, narrow coracohumeral distance, and biceps pathology are indicative. Artificial intelligence-based predictive algorithms can estimate the likelihood of subscapularis tearing based on a combined analysis of these and other features. Improved outcomes should logically be expected for those shoulders with subscapularis tears that are identified and repaired. Finally, some research suggests that debridement remains an alternative to repair; however, pending future research, debridement is not the author's preferred treatment.

Early Arthroscopic Debridement May Be More Cost-Effective Than Nonoperative Management for Symptomatic Osteochondritis Dissecans Lesions of the Capitellum.

Purpose: To compare the cost-effectiveness of an initial trial of nonoperative treatment to that of early arthroscopic debridement for stable osteochondritis dissecans (OCD) lesions of the capitellum. Methods: A Markov Chain Monte Carlo probabilistic model was developed to evaluate the outcomes and costs of 1,000 simulated patients undergoing nonoperative management versus early arthroscopic debridement for stable OCD lesions of the capitellum. Health utility values, treatment success rates, and transition probabilities were derived from the published literature. Costs were determined on the basis of the typical patient undergoing each treatment strategy at our institution. Outcome measures included costs, quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER). Results: Mean total costs resulting from nonoperative management and early arthroscopic debridement were $5,330 and $21,672, respectively. On average, early arthroscopic debridement produced an additional 0.64 QALYS, resulting in an ICER of $25,245/QALY, which falls well below the widely accepted $50,000 willingness-to-pay (WTP) threshold. Overall, early arthroscopic debridement was determined to be the preferred cost-effective strategy in 69% of patients included in the microsimulation model. Conclusion: Results of the Monte Carlo microsimulation and probabilistic sensitivity analysis demonstrated early arthroscopic debridement to be a cost-effective treatment strategy for the majority of stable OCD lesions of the capitellum. Although early arthroscopic debridement was associated with higher total costs, the increase in QALYS that resulted from early surgery was enough to justify the cost difference based on an ICER substantially below the $50,000 WTP threshold. Level of Evidence: Level III, economic computer simulation model.

Lower Trapezius Transfer for Irreparable Posterosuperior Rotator Cuff Tears.

PURPOSE OF REVIEW: Functionally irreparable posterosuperior rotator cuff tears (FIRCT) represent a substantial source of morbidity for many patients. Several surgical options can be considered for the salvage of FICRTs. Transfer of the tendon of the lower trapezius to the greater tuberosity, originally described for surgical management of the paralytic shoulder, has emerged as an attractive option, particularly for patients with external rotation lag and those looking for strength restoration. The purpose of this publication is to review the indications, surgical technique, and reported outcomes of this procedure. RECENT FINDINGS: Lower trapezius transfer (LTT) to the greater tuberosity in patients with irreparable posterosuperior rotator cuff tears has been reported to be associated with satisfactory outcomes and low reoperation rates. It seems to be particularly effective in improving external rotation motion and strength, even when the teres minor is involved. In patients with a reparable infraspinatus, minimal fatty infiltration, and an intact teres minor, the outcome of LTT may be similar to that of superior capsule reconstruction (SCR), but LTT is more beneficial otherwise. The hospital cost of LTT has been reported to be less than the cost of SCR and equivalent to the cost of reverse arthroplasty. When reverse arthroplasty has been performed after a failed LTT, the outcome and complication rates do not seem to increase. LTT provides satisfactory outcomes for many patients with a posterosuperior FIRCT, particularly when they present preoperatively with an external rotation lag sign, involvement of the teres minor, or a desire to improve strength.

Lower Trapezius Transfer Improves Clinical Outcomes With a Rate of Complications and Reoperations Comparable to Other Surgical Alternatives in Patients with Functionally Irreparable Rotator Cuff Tears: A Systematic Review.

PURPOSE: To analyze the clinical outcomes of lower trapezius transfer (LTT) for patients with functionally irreparable rotator cuff tears (FIRCT) and summarize the available literature regarding complications and reoperations. METHODS: After registration in the International prospective register of systematic reviews (PROSPERO [CRD42022359277]), a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Inclusion criteria were English, full-length, peer-reviewed publications with a level of evidence IV or higher reporting on clinical outcomes of LTT for FIRCT. Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus via Elsevier databases were searched. Clinical data, complications and revisions were systematically recorded. RESULTS: Seven studies with 159 patients were identified. The mean age range was 52 to 63 years, 70.4% of the patients included were male, and the mean follow-up time ranged between 14 and 47 months. At final follow-up, LTT lead to improvements in range of motion, with reported forward elevation (FE) and external rotation (ER) mean gains of 10° to 66° and 11° to 63°, respectively. ER lag was present before surgery in 78 patients and was reversed after LTT in all shoulders. Patient-reported outcomes were improved at final follow-up, including the American Shoulder and Elbow Society score, Shoulder Subjective Value and Visual Analogue Scale. The overall complication rate was 17.6%, and the most reported complication was posterior harvest site seroma/hematoma (6.3%). The most common reoperation was conversion to reverse shoulder arthroplasty (5%) with an overall reoperation rate of 7.5%. CONCLUSIONS: Lower trapezius transfer improves clinical outcomes in patients with irreparable rotator cuff tears with a rate of complications and reoperations comparable to other surgical alternatives in this group of patients. Increases in forward flexion and ER are to be expected, as well as a reversal of ER lag sign when present before surgery. LEVEL OF EVIDENCE: Level IV, systematic review of Level III-IV studies.

A Machine Learning Model Demonstrates Excellent Performance in Predicting Subscapularis Tears Based on Pre-Operative Imaging Parameters Alone.

PURPOSE: To develop a machine learning model capable of identifying subscapularis tears before surgery based on imaging and physical examination findings. METHODS: Between 2010 and 2020, 202 consecutive shoulders underwent arthroscopic rotator cuff repair by a single surgeon. Patient demographics, physical examination findings (including range of motion, weakness with internal rotation, lift/push-off test, belly press test, and bear hug test), and imaging (including direct and indirect signs of tearing, biceps status, fatty atrophy, cystic changes, and other similar findings) were included for model creation. RESULTS: Sixty percent of the shoulders had partial or full thickness tears of the subscapularis verified during surgery (83% of these were upper third). Using only preoperative imaging-related parameters, the XGBoost model demonstrated excellent performance at predicting subscapularis tears (c-statistic, 0.84; accuracy, 0.85; F1 score, 0.87). The top 5 features included direct signs related to the presence of tearing as evidenced on magnetic resonance imaging (MRI) (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology. CONCLUSIONS: In this study, machine learning was successful in predicting subscapularis tears by MRI alone in 85% of patients, and this accuracy did not decrease by isolating the model to the top features. The top five features included direct signs related to the presence of tearing as evidenced on MRI (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology. Last, in advanced modeling, the addition of physical examination or patient characteristics did not make a significant difference in the predictive ability of this model. LEVEL OF EVIDENCE: Level III, diagnostic case-control study.

Deep learning to automatically classify very large sets of preoperative and postoperative shoulder arthroplasty radiographs.

BACKGROUND: Joint arthroplasty registries usually lack information on medical imaging owing to the laborious process of observing and recording, as well as the lack of standard methods to transfer the imaging information to the registries, which can limit the investigation of various research questions. Artificial intelligence (AI) algorithms can automate imaging-feature identification with high accuracy and efficiency. With the purpose of enriching shoulder arthroplasty registries with organized imaging information, it was hypothesized that an automated AI algorithm could be developed to classify and organize preoperative and postoperative radiographs from shoulder arthroplasty patients according to laterality, radiographic projection, and implant type. METHODS: This study used a cohort of 2303 shoulder radiographs from 1724 shoulder arthroplasty patients. Two observers manually labeled all radiographs according to (1) laterality (left or right), (2) projection (anteroposterior, axillary, or lateral), and (3) whether the radiograph was a preoperative radiograph or showed an anatomic total shoulder arthroplasty or a reverse shoulder arthroplasty. All these labeled radiographs were randomly split into developmental and testing sets at the patient level and based on stratification. By use of 10-fold cross-validation, a 3-task deep-learning algorithm was trained on the developmental set to classify the 3 aforementioned characteristics. The trained algorithm was then evaluated on the testing set using quantitative metrics and visual evaluation techniques. RESULTS: The trained algorithm perfectly classified laterality (F1 scores [harmonic mean values of precision and sensitivity] of 100% on the testing set). When classifying the imaging projection, the algorithm achieved F1 scores of 99.2%, 100%, and 100% on anteroposterior, axillary, and lateral views, respectively. When classifying the implant type, the model achieved F1 scores of 100%, 95.2%, and 100% on preoperative radiographs, anatomic total shoulder arthroplasty radiographs, and reverse shoulder arthroplasty radiographs, respectively. Visual evaluation using integrated maps showed that the algorithm focused on the relevant patient body and prosthesis parts for classification. It took the algorithm 20.3 seconds to analyze 502 images. CONCLUSIONS: We developed an efficient, accurate, and reliable AI algorithm to automatically identify key imaging features of laterality, imaging view, and implant type in shoulder radiographs. This algorithm represents the first step to automatically classify and organize shoulder radiographs on a large scale in very little time, which will profoundly enrich shoulder arthroplasty registries.