Surfer's neurapraxia - an uncommon surfing injury of the saphenous nerve.

Surfer's neurapraxia is a rare surfing injury of the saphenous nerve secondary to persistent compression of the saphenous nerve along the medial thigh by the surfboard when paddling prone and while sitting upright on the board waiting for a wave. Symptoms may be nonspecific and consist of pain in the medial thigh with or without radiation along the saphenous nerve distribution (medial leg, medial ankle, medial arch of the foot). The saphenous nerve tension test can be utilized to reproduce the symptoms of surfer's neurapraxia. Treatment consists of conservative management while refractory cases may benefit from injection with local anesthetic. The authors propose the Obana Plan (WATER) for prevention of surfer's neurapraxia, consisting of Wetsuits, Abduction, Timing, Exercise, and Rest. Overall, surfer's neurapraxia is a benign condition that can be prevented and managed conservatively.

Python tooth-inspired fixation device for enhanced rotator cuff repair.

Rotator cuff repair surgeries fail frequently, with 20 to 94% of the 600,000 repairs performed annually in the United States resulting in retearing of the rotator cuff. The most common cause of failure is sutures tearing through tendons at grasping points. To address this issue, we drew inspiration from the specialized teeth of snakes of the Pythonoidea superfamily, which grasp soft tissues without tearing. To apply this nondamaging gripping approach to the surgical repair of tendon, we developed and optimized a python tooth-inspired device as an adjunct to current rotator cuff suture repair and found that it nearly doubled repair strength. Integrated simulations, 3D printing, and ex vivo experiments revealed a relationship between tooth shape and grasping mechanics, enabling optimization of the clinically relevant device that substantially enhances rotator cuff repair by distributing stresses over the attachment footprint. This approach suggests an alternative to traditional suturing paradigms and may reduce the risk of tendon retearing after rotator cuff repair.

2-Octyl-Cyanoacrylate Mesh Dressings for Total Joint Arthroplasty: Dressing Design Influences Risks of Wound Complications.

BACKGROUND: Recent liquid adhesive skin closure systems with a mesh patch and a 2-octyl cyanoacrylate liquid formula have shown promising results in total joint arthroplasty. Chemical accelerators are typically included to promote the rapid polymerization of 2-octyl cyanoacrylate. The goal of the study is to distinguish designs and wound complication differences between 2 similar systems. METHODS: An 18-week retrospective study was conducted from July to December 2023, including 207 total hip arthroplasty and 212 total knee arthroplasty cases from 4 attending surgeons at 1 institution that used 1 of 2 dressing designs. Both dressings had a 2-octyl cyanoacrylate liquid adhesive formula that applied topically to a polyester-based mesh overlaying the wound. Mesh A (used in 274 cases) included an accelerator, a quaternary ammonium salt, on the mesh patch, whereas Mesh B (used in 145 cases) included a similar accelerator within the adhesive applicator. RESULTS: Wound complications (3.2 versus 7.6%; X2 = 3.86; df = 1; P = .049), early periprosthetic joint infections (0 versus 2.8%; X2 = 7.63; df = 1; P = .006), and 90-day reoperations for wound complications (0.4 versus 3.4%; X2 = 6.39; df = 1; P = .011) were significantly lower in patients who received Mesh A versus B, respectively. There was no difference in superficial surgical site infections (0.7 versus 0%; X2 = 1.06; df = 1; P = .302) or allergy rates (3.3 versus 4.1%; X2 = 0.12; df = 1; P = .655) between Mesh A and B. CONCLUSIONS: We observed significantly different performance in wound complications, early postoperative periprosthetic joint infections, and 90-day reoperation between the 2 designs. Having the accelerator in the applicator rather than on the mesh patch may lead to premature polymerization before bonding appropriately with the mesh to create the desired wound closure and seal. LEVEL OF EVIDENCE: Level III.

What are our patients asking Google about acromioclavicular joint injuries?-frequently asked online questions and the quality of online resources.

Background: Management of acromioclavicular (AC) joint injuries has been an ongoing source of debate, with over 150 variations of surgery described in the literature. Without a consensus on surgical technique, patients are seeking answers to common questions through internet resources. This study investigates the most common online patient questions pertaining to AC joint injuries and the quality of the websites providing information. Hypothesis: 1) Question topics will pertain to surgical indications, pain management, and success of surgery and 2) the quality and transparency of online information are largely heterogenous. Methods: Three AC joint search queries were entered into the Google Web Search. Questions under the "People also ask" tab were expanded in order and 100 results for each query were included (300 total). Questions were categorized based on Rothwell's classification. Websites were categorized by source. Website quality was evaluated by the Journal of the American Medical Association (JAMA) Benchmark Criteria. Results: Most questions fell into the Rothwell Fact category (48.0%). The most common question topics were surgical indications (28.0%), timeline of recovery (13.0%), and diagnosis/evaluation (12.0%). The least common question topics were anatomy/function (3.3%), evaluation of surgery (3.3%), injury comparison (1.0%), and cost (1.0%). The most common websites were medical practice (44.0%), academic (22.3%), and single surgeon personal (12.3%). The average JAMA score for all websites was 1.0 ± 1.3. Government websites had the highest JAMA score (4.0 ± 0.0) and constituted 45.8% of all websites with a score of 4/4. PubMed articles constituted 63.6% (7/11) of government website. Comparatively, medical practice websites had the lowest JAMA score (0.3 ± 0.7, range [0-3]). Conclusion: Online patient AC joint injury questions pertain to surgical indications, timeline of recovery, and diagnosis/evaluation. Government websites and PubMed articles provide the highest-quality sources of reliable, up-to-date information but constitute the smallest proportion of resources. In contrast, medical practice represents the most visited websites, however, recorded the lowest quality score. Physicians should utilize this information to answer frequently asked questions, guide patient expectations, and help provide and identify reliable online resources.

The Variability of MCID, SCB, PASS, and MOI Thresholds for PROMs in the Reverse Total Shoulder Arthroplasty Literature: A Systematic Review.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) is a common procedure utilized to address degenerative pathologies of the glenohumeral joint and rotator cuff. Increased reliance on patient-reported outcome measures (PROMs) has placed emphasis on the utilization of the minimum clinically important difference (MCID), substantial clinical benefit (SCB), patient acceptable symptom state (PASS), and maximal outcome improvement (MOI) thresholds to assess the clinical efficacy of RTSA. In this study, we systematically reviewed the MCID, SCB, PASS, and MOI thresholds reported for PROMs following RTSA. METHODS: PubMed, Embase, MEDLINE, Cochrane Library, and Google Scholar were queried for articles from Jan. 1, 2000-Aug. 31, 2023 reporting MCID, SCB, PASS, or MOI values for PROMs following RTSA. Patient demographic data, study characteristics, MCID/SCB/PASS/MOI thresholds, and threshold calculation methods were extracted. RESULTS: 141 articles were screened with 39 ultimately included, comprising 11,984 total patients that underwent RTSA. 34 (87%) studies reported MCID thresholds, 20 (51%) reported SCB, 5 (13%) reported PASS, and 2 (5%) reported MOI. 25/39 (64%) studies referenced a previous study when reporting MCID, SCB, PASS, or MOI values, 11 (28%) used an anchor-based method to calculate threshold values, 1 (3%) used a distribution-based method, and 2 (5%) used both anchor and distribution methods. There were 19 newly calculated MCID (11), SCB (5), PASS (1), and MOI (2) thresholds. For five of the six most utilized PROMs (ASES, SST, Constant, UCLA, SPADI), the range of reported MCID values exceeded 50% of the most common threshold. For three of the six, the range of SCB values exceeded 25% of the most common threshold. CONCLUSION: There is substantial variability in the MCID and SCB threshold values reported in the RTSA literature. Standardizing the methodologic calculation and utilization of MCID, SCB, PASS, and MOI thresholds for RTSA may allow for improved assessment of PROMs.

"Trend" Statement Use in the Orthopaedic Literature.

INTRODUCTION: For research to effectively guide clinical decision making, appropriate interpretation of data is paramount. The P -value is a useful tool for guiding the interpretation of data. However, despite its utility, the P -value is not without limitations. Of particular concern is the use of "trend statements" to describe non-statistically significant findings, a practice which introduces subjectivity and variability into data interpretation and can lead to the drawing of undue conclusions. METHODS: An audit of original research articles published from January 2022 to December 2022 in four high-impact orthopaedic journals was conducted. The selected journals were queried to identify instances in which a non-statistically significant result was labeled as a "trend." The use of trend statements and associated information was recorded and analyzed. RESULTS: One thousand two hundred sixty articles were included in the analysis. 81 articles (6.4%) included a trend statement to describe a non-statistically significant result. Only two articles (2.5%) formally defined what constituted a trend. In 28.8% of cases, the associated P -value was > 0.10. DISCUSSION: Trend statements are used to describe non-statistically significant findings with moderate frequency in the orthopaedic literature. Given the potentially misleading effects of trend statements, efforts should be made to mitigate their use. If trend statements are to be used, attention should be paid to defining what constitutes a "trend", explicitly acknowledging the lack of statistical significance of the finding to which the trend statement refers, and avoiding drawing undue conclusions from non-statistically significant data.

The subacromial bursa modulates tendon healing after rotator cuff injury in rats.

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Preoperative planning with three-dimensional CT vs. three-dimensional magnetic resonance imaging does not change surgical management for shoulder instability.

Background: This study aims to determine the effect of time and imaging modality (three-dimensional (3D) CT vs. 3D magnetic resonance imaging (MRI)) on the surgical procedure indicated for shoulder instability. The hypothesis is there will be no clinical difference in procedure selection between time and imaging modality. Methods: Eleven shoulder surgeons were surveyed with the same ten shoulder instability clinical scenarios at three time points. All time points included history of present illness, musculoskeletal exam, radiographs, and standard two-dimensional MRI. To assess the effect of imaging modality, survey 1 included 3D MRI while survey 2 included a two-dimensional and 3D CT scan. To assess the effect of time, a retest was performed with survey 3 which was identical to survey 2. The outcome measured was whether surgeons made a "major" or "minor" surgical change between surveys. Results: The average major change rate was 14.1% (standard deviation: 7.6%). The average minor change rate was 12.6% (standard deviation: 7.5%). Between survey 1 to the survey 2, the major change rate was 15.2%, compared to 13.1% when going from the second to the third survey (P = .68). The minior change rate between the first and second surveys was 12.1% and between the second to third interview was 13.1% (P = .8). Discussion: The findings suggest that the major factor related to procedural changes was time between reviewing patient information. Furthermore, this study demonstrates that there remains significant intrasurgeon variability in selecting surgical procedures for shoulder instability. Lastly, the findings in this study suggest that 3D MRI is clinically equivalent to 3D CT in guiding shoulder instability surgical management. Conclusion: This study demonstrates that there is significant variability in surgical procedure selection driven by time alone in shoulder instability. Surgical decision making with 3D MRI was similar to 3D CT scans and may be used by surgeons for preoperative planning.

Graft Resorption After Posterior Distal Tibial Allograft Augmentation for Posterior Shoulder Instability: A Case Report.

CASE: A 19-year-old man underwent arthroscopic posterior glenoid reconstruction with a distal tibia allograft (DTA) after failing 2 posterior, soft-tissue instability surgeries. Although he experienced near-complete resolution of symptoms and return to sport, graft resorption was noted 7 months postoperatively. The patient underwent revision surgery for screw removal. CONCLUSION: Graft resorption has not previously been reported in the setting of arthroscopic DTA use for posterior instability. It is believed that stress shielding contributed to resorption. In such situations, screw removal may be warranted. Consideration of alternative fixation techniques and additional investigation into the causes, clinical significance, and optimal management of posterior DTA resorption are warranted.

The Finger, Wrist, and Shoulder are the Most Commonly Injured Areas in Youth Volleyball Players but the Incidence of Injuries Decreased Overall Between 2012 and 2022.

Purpose: To analyze epidemiology, mechanisms, and diagnoses of upper extremity volleyball injuries in youth who present to United States emergency departments. Methods: Data from the National Electronic Injury Surveillance System were analyzed for upper extremity volleyball injuries in patients ≤18 years old from January 1, 2012, to December 31, 2022. Data were collected for body part, diagnosis, mechanism of injury, and disposition. Weighted national estimates were calculated using the hospitals' corresponding statistical sample weights. Linear regressions were used to analyze annual trends. χ2 tests were used to analyze categorical variables. Results: A weighted national estimate of 131,624 upper extremity volleyball-related injuries occurred in the study period. Average age was 13.9 ± 2.3 years. Female patients constituted 77.6% of patients; 99.3% of patients did not require admission. The most common body parts injured were fingers (43.0%), wrists (22.8%), and shoulders (12.2%). The most common identifiable mechanisms of injury were impacts with the floor (19.4%), impacts with the ball (14.7%), and spikes/serves (5.7%). Most common diagnoses were strains/sprains (42.6%) and fractures (19.5%). Most common locations of fracture were fingers (57.4% of all fractures), wrists (16.6%), and lower arms (12.4%). There was a decrease of 544 overall injuries per year (P = .03, 95% confidence interval [CI] -1031 to -58). Female players experienced more contusions/abrasions (16.0% vs 9.9%, P < .001) and strains/sprains (46.1% vs 30.4%, P < .001) compared with male players. Female patients had decreases of 513 overall injuries (P = .01, 95% CI -881 to -144), 349 strains/sprains (P = .002, 95% CI -530 to -168), 102 contusions/abrasions (P = .008, 95% CI 170 to -34), and 92 fractures per year (P = .03, 95% CI -175 to -10). Conclusions: Youth volleyball players are at risk of upper extremity injury, particularly involving the fingers, wrist, and shoulder. Despite increasing national participation in youth volleyball, there is a decreasing incidence of upper extremity injuries. Level of Evidence: Level IV, prognostic case series.

The impact of implicit narrator reliability on production of information.

Previous research established that readers acquire accurate and inaccurate information from fiction. The current study explored factors that might moderate these effects. Participants read fictional stories that each contained three assertions. The first two assertions in each story were either correct information or implausible misinformation, allowing a manipulation of the (implicit) credibility of the narrator. The last assertion in each story was the critical one, and was correct information, implausible misinformation, or plausible misinformation. After reading, participants answered general knowledge questions that were related to the critical assertions they encountered during reading. Encountering misinformation led to lower accuracy than being presented with correct information, and being presented with plausible misinformation led to higher production of that misinformation. The narrator credibility manipulation interacted with the type of critical assertion: When the critical assertion was presented accurately in a story, credible narrators presenting true critical assertions led to greater accuracy on the general knowledge test than when noncredible narrators presented this same information. These findings are discussed with respect to theories of validation during language comprehension.

Job satisfaction and practice characteristics of shoulder and elbow surgeons: a survey of American Shoulder and Elbow Surgeons society members.

BACKGROUND: The purpose of this study is to assess the current trends in fellowship training, career satisfaction, practice characteristics, and surgical case volume among shoulder and elbow surgeons. METHODS: A web-based, anonymous 25-item survey was sent to the membership of the American Shoulder and Elbow Surgeons (ASES) in October of 2022. Questions posed included respondent demographics, fellowship training, career satisfaction, practice characteristics, and surgical case characteristics. Descriptive statistics were performed to report demographic information, assess job and training satisfaction rates, and evaluate practice characteristics. Chi-squared and independent samples t-tests were performed to analyze satisfaction rates, job applications, and surgical case volume with regard to years in practice and practice setting. RESULTS: Twenty percent (243/1248) of ASES members satisfactorily completed the survey. Of the 243 ASES member respondents, 97% (236/243) stated that they would pursue their fellowship training again. Ninety-eight percent (239/243) of respondents were satisfied with their specialty choice. One-hundred percent (242/243) were satisfied with their training in shoulder. Seventy-two percent (176/243) were satisfied with their training in elbow. Seventy-four percent (179/243) were satisfied with their job availability and 85% (207/243) were satisfied with their job location. The mean total number of orthopedic surgical cases per year was 393 ± 171. The mean total number of shoulder cases per year was 253 ± 149. The mean total number of elbow cases per year was 41 ± 41. Physicians who have been in practice for 11 years or more were comparatively more satisfied (90% vs. 80%) with their job location (P value = .008) and job availability (81% vs. 64%, P value < .001). Additionally, senior surgeons completed more orthopedic (431 vs. 347, P value < .001) and shoulder (279 vs. 220, P value = .002) cases annually than surgeons earlier in their careers. Satisfaction rates, job applications, and surgical case volume did not associate with practice setting. CONCLUSIONS: The majority of ASES member shoulder and elbow surgeons are satisfied with their training, their case volume and complexity, and their specialty choice. Fewer surgeons are satisfied with their elbow training and overall elbow case volume remains low among shoulder and elbow surgeons. Shoulder and elbow surgeons earlier in their careers perform fewer surgical cases, are less satisfied with their job availability and location, and completed more job applications for their first job after fellowship when compared to more senior surgeons.

Post-operative Baseplate Radiographic Evaluation Using Routine pre-Operative CT.

Background: There is limited data evaluating post-operative component position and fixation in reverse shoulder arthroplasty (RSA). Therefore, the purpose of this study was to evaluate baseplate position and fixation using routine pre-operative CT and post-operative radiographs. Methods: A retrospective analysis of a series consecutive patient who underwent primary RSA was performed. Pre-operative and post-operative glenoid retroversion and inclination were measured using radiographs aligned with projection silhouettes of 3D scapula models in Mimics software. Baseplate retroversion and inclination were measured followed by evaluating for the presence of radiolucent lines (RLLs). Results: Twenty-four patients met inclusion criteria. The average age was 73.4 ± 10.7 years (range, 45-89 years). Radiographic follow-up was 3.4 ± 1.3 years. Post-operative glenoid baseplate retroversion was 2 ± 10 degrees (range, 30 to -9). Post-operative glenoid baseplate inclination was 3.8 ± 9.1 (range, -13 to 19). Five (21%) RSAs had baseplate retroversion >10 degrees. Follow-up radiographs revealed no RLLs around the baseplate, central post, or peripheral screws in any patient. Conclusions: Pre-operative CT imaging enabled evaluation of baseplate component placement and fixation on post-operative radiographs. Baseplate version was within 10 degrees of neutral in 79% (19/24) of patients. No RLLs or loss of fixation were found in any cases. Level of Evidence: Level IV: Diagnostic Study.

Determining the True Incidence of Glenohumeral Instability Among Players in the National Football League: An Epidemiological Study of Non-Missed Time Shoulder Instability Injuries.

Background: Shoulder instability encompasses a spectrum of glenohumeral pathology ranging from subluxation to dislocation. While dislocation frequently leads to removal from play, athletes are often able to play through subluxation. Previous research on glenohumeral instability among athletes has largely focused on missed-time injuries, which has likely disproportionately excluded subluxation injuries and underestimated the overall incidence of shoulder instability. Purpose: To describe the epidemiology of shoulder instability injuries resulting in no missed time beyond the date of injury (non-missed time injuries) among athletes in the National Football League (NFL). Study Design: Descriptive epidemiology study. Methods: The NFL's electronic medical record was retrospectively reviewed to identify non-missed time shoulder instability injuries during the 2015 through 2019 seasons. For each injury, player age, player position, shoulder laterality, instability type, instability direction, injury timing, injury setting, and injury mechanism were recorded. For injuries that occurred during games, incidence rates were calculated based on time during the season as well as player position. The influence of player position on instability direction was also investigated. Results: Of the 546 shoulder instability injuries documented during the study period, 162 were non-missed time injuries. The majority of non-missed time injuries were subluxations (97.4%), occurred during games (70.7%), and resulted from a contact mechanism (91.2%). The overall incidence rate of game-related instability was 1.6 injuries per 100,000 player-plays and was highest during the postseason (3.5 per 100,000 player-plays). The greatest proportion of non-missed time injuries occurred in defensive secondary players (28.4%) and offensive linemen (19.8%), while kickers/punters and defensive secondary players had the highest game incidence rates (5.5 and 2.1 per 100,000 player-plays, respectively). In terms of direction, 54.3% of instability events were posterior, 31.9% anterior, 8.5% multidirectional, and 5.3% inferior. Instability events were most often anterior among linebackers and wide receivers (50% and 100%, respectively), while posterior instability was most common in defensive linemen (66.7%), defensive secondary players (58.6%), quarterbacks (100.0%), running backs (55.6%), and tight ends (75.0%). Conclusion: The majority of non-missed time shoulder instability injuries (97.4%) were subluxations, which were likely excluded from or underreported in previous shoulder instability studies due to the inherent difficulty of detecting and diagnosing shoulder subluxation.

The Fragility of Statistical Significance in Sham Orthopaedic Surgery: A Systematic Review of Randomized Controlled Trials.

OBJECTIVES: The purpose of this study was to determine the stability of statistical findings among sham surgery randomized controlled trials (RCTs) in orthopaedic surgery using fragility analysis. METHODS: PubMed systematic review was conducted to include studies reporting dichotomous outcomes pertaining to sham surgery. The final review included eight RCTs involving only partial meniscectomies and vertebroplasties from 2009 to 2020. With a fixed sample size with dichotomous outcome measures (events versus non-events), the Total Fragility Index (TFI), which is composed of the fragility index (FI) and reverse fragility index (RFI), was calculated by altering the ratio of events to non-events in an iterative fashion until results were reversed from significant to nonsignificant findings (FI) or vice versa (RFI). The TFI, FI, and RFI were divided by their sample sizes to obtain the respective total fragility quotient, fragility quotient (FQ), and reverse fragility quotient. Median fragility indices and quotients were reported for all studies. RESULTS: The eight RCTs included 50 dichotomous outcomes involving either partial meniscectomies or vertebroplasties, with a median TFI and total fragility quotient of 5 [interquartile range (IQR) 4 to 6] and 0.035 (IQR 0.028 to 0.048), respectively, indicating that a median of five total patients or 3.5 per 100 patients would need to experience a different outcome to reverse significant or insignificant findings for each of the eight trials. Among the 8 statistically significant ( P < 0.05) outcome events (16%), the respective FI and FQ were 2 (IQR 1 to 5) and 0.018 (IQR 0.010 to 0.044). Among the 42 statistically insignificant outcome events (84%), the respective RFI and reverse fragility quotient were 5 (IQR 4 to 6) and 0.04 (IQR 0.034 to 0.048). The median number of patients lost to follow-up was 1.5 (IQR 0.5 to 2). CONCLUSION: The unstable findings in partial meniscectomy and vertebroplasty sham surgical RCTs undermine their study conclusions and recommendations. We recommend using fragility analysis in future sham surgical RCTs to contextualize statistical findings. LEVEL OF EVIDENCE: Level IV; Systematic Review.

Clavicle Nonunion and Malunion: Surgical Interventions for Functional Improvement.

Clavicle nonunion and malunion are relatively uncommon but, when symptomatic, can result in pain and dysfunction that requires surgical intervention. Various reconstructive and grafting techniques are available to achieve stable fixation and union. In the setting of persistent nonunion, vascularized bone grafting may be necessary. A thorough understanding of the patient's type of nonunion and potential for healing is crucial for achieving satisfactory results because is thoughtful preoperative planning and surgical fixation.

Artificial intelligence-based applications in shoulder surgery leaves much to be desired: a systematic review.

Background: Artificial intelligence (AI) aims to simulate human intelligence using automated computer algorithms. There has been a rapid increase in research applying AI to various subspecialties of orthopedic surgery, including shoulder surgery. The purpose of this review is to assess the scope and validity of current clinical AI applications in shoulder surgery literature. Methods: A systematic literature review was conducted using PubMed for all articles published between January 1, 2010 and June 10, 2022. The search query used the terms as follows: (artificial intelligence OR machine learning OR deep learning) AND (shoulder OR shoulder surgery OR rotator cuff). All studies that examined AI application models in shoulder surgery were included and evaluated for model performance and validation (internal, external, or both). Results: A total of 45 studies were included in the final analysis. Eighteen studies involved shoulder arthroplasty, 13 rotator cuff, and 14 other areas. Studies applying AI to shoulder surgery primarily involved (1) automated imaging analysis including identifying rotator cuff tears and shoulder implants (2) risk prediction analyses including perioperative complications, functional outcomes, and patient satisfaction. Highest model performance area under the curve ranged from 0.681 (poor) to 1.00 (perfect). Only 2 studies reported external validation. Conclusion: Applications of AI in the field of shoulder surgery are expanding rapidly and offer patient-specific risk stratification for shared decision-making and process automation for resource preservation. However, model performance is modest and external validation remains to be demonstrated, suggesting increased scientific rigor is warranted prior to deploying AI-based clinical applications.

The subacromial bursa is a key regulator of the rotator cuff and a new therapeutic target for improving repair.

Rotator cuff injuries result in over 500,000 surgeries performed annually, an alarmingly high number of which fail. These procedures typically involve repair of the injured tendon and removal of the subacromial bursa. However, recent identification of a resident population of mesenchymal stem cells and inflammatory responsiveness of the bursa to tendinopathy indicate an unexplored biological role of the bursa in the context of rotator cuff disease. Therefore, we aimed to understand the clinical relevance of bursa-tendon crosstalk, characterize the biologic role of the bursa within the shoulder, and test the therapeutic potential for targeting the bursa. Proteomic profiling of patient bursa and tendon samples demonstrated that the bursa is activated by tendon injury. Using a rat to model rotator cuff injury and repair, tenotomy-activated bursa protected the intact tendon adjacent to the injured tendon and maintained the morphology of the underlying bone. The bursa also promoted an early inflammatory response in the injured tendon, initiating key players in wound healing. In vivo results were supported by targeted organ culture studies of the bursa. To examine the potential to therapeutically target the bursa, dexamethasone was delivered to the bursa, prompting a shift in cellular signaling towards resolution of inflammation in the healing tendon. In conclusion, contrary to current clinical practice, the bursa should be retained to the greatest extent possible and provides a new therapeutically target for improving tendon healing outcomes. One Sentence Summary: The subacromial bursa is activated by rotator cuff injury and regulates the paracrine environment of the shoulder to maintain the properties of the underlying tendon and bone.

Comparing Skill Acquisition and Validity of Immersive Virtual Reality with Cadaver Laboratory Sessions in Training for Reverse Total Shoulder Arthroplasty.

Immersive virtual reality (iVR) allows surgical trainees to practice skills without risking harm to patients or the need for cadaveric training resources. However, iVR has never been directly compared with cadaver training, the longtime gold standard for surgical skill training. We aimed to compare skill acquisition using cadaver laboratory and iVR training methods for augmented baseplate implantation during reverse total shoulder arthroplasty (rTSA). Methods: In a randomized controlled trial, junior orthopaedic surgery residents were assigned to a 1-hour training with either iVR or a cadaveric laboratory session with shoulder specimens. Before training, all participants viewed an overview lecture and technique video demonstrating key steps of augmented baseplate implantation for rTSA. Participants were assessed by a blinded evaluator using validated competency checklists during cadaveric glenoid baseplate implantation. Continuous and categorial variables were analyzed using the 2-sample t test and Fisher exact test. Results: Fourteen junior residents (3 incoming matched postgraduate year [PGY1], 6 PGY1s, 1 PGY2, and 4 PGY3s) were randomized to training with either iVR (n = 6) or cadaver laboratory (n = 8). There were no significant differences in demographic data, previous experience with rTSA, or previous use of iVR (p > 0.05). There were no significant difference in total Objective Structured Assessment of Technical Skill score (91.2% [15.2] vs. 93.25% [6.32], -0.1406 to 0.1823, p = 0.763), Global Rating Scale score (4.708 [0.459] vs. 4.609 [0.465], -0.647 to 0.450, p = 0.699), or time to completion (546 seconds [158] vs. 591 seconds [192], -176.3 to 266.8, p = 0.655) in cadaveric glenoid baseplate implantation. Average cost of iVR hardware and a 1-year software license was $4,900, and average cost of a single cadaver laboratory was $1,268.20 per resident. Conclusions: Among junior orthopaedic residents, there is similar skill acquisition when training with either cadaver laboratory or iVR. Although additional research into this field is needed, iVR may provide an important and cost-effective tool in surgical education. Clinical Relevance: Emerging simulation and iVR technology simulation in surgical training programs can increase access to effective and high-level surgical training across the globe and improve quality of care.