Biomechanics and Pathoanatomy of Posterior Shoulder Instability.

Posterior glenohumeral instability represents a wide spectrum of pathoanatomic processes. A key consideration is the interplay between the posterior capsulolabral complex and the osseous anatomy of the glenoid and humeral head. Stability is dependent upon both the presence of soft tissue pathology (eg, tears to the posteroinferior labrum or posterior band of the inferior glenohumeral ligament, glenoid bone loss, reverse Hill Sachs lesions, and pathologic glenoid retroversion or dysplasia) and dynamic stabilizing forces. This review highlights unique pathoanatomic features of posterior shoulder instability and associated biomechanics that may exist in patients with posterior glenohumeral instability.

Social and Demographic Health Disparities in Shoulder and Elbow Surgery.

BACKGROUND: Racial and ethnic health disparities are important factors that contribute to outcomes in orthopedic surgery. With the increasing rates of common shoulder surgeries being performed, understanding all factors that contribute to patient outcomes is essential. There are several key socioeconomic and demographic factors, including insurance status, ethnicity, and Race, which have been implicated to impact both access to high-quality shoulder and elbow care and outcomes following shoulder and elbow surgery. In this review article, we seek to highlight the literature pertaining to social and demographic disparities in shoulder and elbow surgery for the purpose of providing policy makers and clinicians key information to optimize the equitable delivery of high-quality medical care to patients of all socioeconomic backgrounds. METHODS: A literature review of PubMed was conducted using several keywords with defined inclusion and exclusion criteria. RESULTS: A total of 22 articles were included across shoulder arthroplasty, rotator cuff repair, shoulder instability, and elbow arthroplasty. Multiple disparities were identified in the literature across Race, ethnicity, insurance status, and social determinants of health. CONCLUSIONS: Our search of the literature demonstrated significant disparities in shoulder and elbow surgeries, showing that racial, ethnic, and socioeconomic factors adversely affect patient outcomes due to decreased access quality care. To improve equity, recommendations include shifting care to high-volume and outpatient centers and increasing geographical diversity and access to surgical and rehabilitative care.

Artificial Intelligence Large Language Models Address Anterior Cruciate Ligament Reconstruction: Superior Clarity and Completeness by Gemini Compared to ChatGPT-4 in Response to American Academy of Orthopedic Surgeons Clinical Practice Guidelines.

PURPOSE: To assess the ability of ChatGPT-4 and Gemini to generate accurate and relevant responses to the 2022 American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines for ACLR. METHODS: Responses from ChatGPT-4 and Gemini to prompts derived from all 15 AAOS guidelines were evaluated by seven fellowship trained orthopedic sports medicine surgeons using a structured questionnaire assessing five key characteristics on a scale from 1-5. The prompts were categorized into three areas: Diagnosis and Preoperative Management, Surgical Timing and Technique, and Rehabilitation and Prevention. Statistical analysis included mean scoring, standard deviation, and two-sided t-tests to compare the performance between the two LLMs. Scores were then evaluated for inter-rater reliability (IRR). RESULTS: Overall, both LLMs performed well with means scores > 4 for the five key characteristics. Gemini demonstrated superior performance in overall clarity (4.848 ± 0.36 vs 4.743 ± 0.481, p = 0.034), but all other characteristics demonstrated non-significant differences (p = >0.05). Gemini also demonstrated superior clarity in the surgical timing and technique (p= 0.038) as well as the prevention and rehabilitation (p= 0.044) sub-categories. Additionally, Gemini had superior performance completeness scores in the rehabilitation and prevention sub-category (p= 0.044), but no statistically significant differences were found amongst the other sub-categories. The overall IRR was found to be 0.71 (moderate). CONCLUSION: Both Gemini and ChatGPT-4 demonstrate an overall good ability to generate accurate and relevant responses to question prompts based on the 2022 AAOS clinical practice guidelines for ACLR. However, Gemini demonstrated superior clarity in multiple domains in addition to superior completeness for questions pertaining to rehabilitation and prevention. CLINICAL RELEVANCE: The current study addresses a current gap in the LLM and ACLR literature by comparing the performance of ChatGPT-4 to Gemini, which is growing in popularity with more than 300 million individual uses in May 2024 alone. Moreover, the results demonstrated superior performance of Gemini in both clarity and completeness, which are critical elements of a tool being used by patients for educational purposes. Additionally, the current study uses question prompts based on the AAOS CPG which may be used as a method of standardization for future investigations on performance of LLM platforms. For these reasons, the authors believe that the results of the current study would be of interest to both the readership of Arthroscopy and patients, alike.

Association of Vitamin D Deficiency With Distal Biceps Injury: A Retrospective Analysis of 336,320 Patients.

BACKGROUND: This study explores the association between vitamin D deficiency and distal biceps tendon injuries, illustrating that, although vitamin D deficiency is associated with prolonged hospital stays and various musculoskeletal problems, its connection to distal biceps tendon injuries is unknown. HYPOTHESIS: Vitamin D deficiency is associated with an elevated risk of distal biceps injury but not with increased rates of subsequent surgery or revision surgery. STUDY DESIGN: Case-control study. LEVEL OF EVIDENCE: Level 3. METHODS: A 1:1 matched retrospective comparative study of 336,320 vitamin-D-deficient patients was performed using PearlDiver data (between January 1, 2011 and October 31, 2018). Cohorts, with a mean age of 55.7 ± 13.2 years, underwent multivariate logistic regression to calculate distal biceps tendon injury and surgical repair incidence according to age and sex, while controlling for demographics and comorbidities. RESULTS: The 1-year incidence of distal biceps tendinopathy in vitamin-D-deficient patients was 118 per 100,000 person-years (95% CI) compared with 44.3 per 100,000 person-years in matched controls. Male patients with vitamin D deficiency were at a greater risk for distal biceps tendinopathy after 1 and 2 years (adjusted odds ratio [aOR] = 2.81, 2.08-3.83; aOR = 2.80, 2.21-3.56). Female patients were also at a greater risk after both years (aOR = 1.69, 1.27-2.27; aOR = 1.57, 1.26-1.96). Vitamin D deficiency was not associated with an elevated risk of surgical repair or revision surgery. CONCLUSION: In a nationwide cohort, a diagnosis of vitamin D deficiency elevated the risk of distal biceps tendinopathy but did not raise the rate of surgical repair or revision. As a result, prevention strategies in the form of vitamin supplementation should be increased for athletes.Clinical Relevance: These findings emphasize the clinical relevance of monitoring vitamin D levels in patients at risk for musculoskeletal injuries, and providing adequate care to those involved in high-demand physical activities.Strength of Recommendation: B.

Alpha-2-Macroglobulin Attenuates Posttraumatic Osteoarthritis Cartilage Damage by Inhibiting Inflammatory Pathways With Modified Intra-articular Drilling in a Yucatan Minipig Model.

BACKGROUND: Posttraumatic osteoarthritis (PTOA) arises secondarily to joint trauma and is driven by catabolic inflammatory pathways. Alpha-2-macroglobulin (α2M) is a naturally occurring proteinase inhibitor found in human serum and synovial fluid that binds proteases as well as proinflammatory cytokines involved in the pathogenesis of PTOA. PURPOSE: (1) To investigate the therapeutic potential of intra-articular α2M injections during the acute stages of PTOA by inhibiting inflammatory pathways driven by the cytokines expressed by the synovium in a large preclinical Yucatan minipig model and (2) to determine if 3 intra-articular α2M injections have greater chondroprotective effects compared with 1 intra-articular injection. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 48 Yucatan minipigs were randomized into 4 groups (n = 12 each): (1) modified intra-articular drilling (mIAD) and saline (mIAD + saline), (2) mIAD and 1 intra-articular α2M injection (mIAD +α2M-1), (3) mIAD and 3 α2M injections (mIAD +α2M-3), and (4) sham control. Surgical hindlimbs were harvested at 15 weeks after surgery. Cartilage degeneration, synovial changes, inflammatory gene expression, and matrix metalloproteinase levels were evaluated. Gait asymmetry was measured before and after surgery using a pressure-sensing walkway system. RESULTS: Macroscopic lesion areas and microscopic cartilage degeneration scores were lower in the mIAD +α2M-1 and mIAD +α2M-3 groups compared with the mIAD + saline group (P < .05) and similar to those in the sham group (P > .05). Synovial membrane scores of the mIAD +α2M-1 and mIAD +α2M-3 groups were lower than that of the mIAD + saline group (P < .05) and higher than that of the sham group (P < .05). Interleukin-1 beta, nuclear factor kappa B, and tumor necrosis factor alpha mRNA expression in the synovium and matrix metalloproteinase-1 levels in synovial fluid were significantly lower in the mIAD +α2M-1 and mIAD +α2M-3 groups compared with the mIAD + saline group (P < .05). No significant differences were observed between the mIAD +α2M-1 and mIAD +α2M-3 groups for all measured outcomes. There were early changes in gait (P < .05) between preoperative and postoperative time points for the mIAD + saline, mIAD +α2M-1, and mIAD +α2M-3 groups that normalized by 15 weeks. CONCLUSION: Animals receiving early α2M treatment exhibited less cartilage damage, milder synovitis, and lower inflammation compared with animals with no α2M treatment. These results exemplify the early anti-inflammatory effects of α2M and provide evidence that intra-articular α2M injections may slow the progression of PTOA. CLINICAL RELEVANCE: In patients presenting with an acute joint injury, an early intervention with α2M may have the potential to reduce cartilage degeneration from catabolic pathways and delay the development of PTOA.

An Update on Emerging Techniques and Considerations in Revision Anterior Cruciate Ligament Reconstruction.

¼ The rate of primary anterior cruciate ligament reconstruction (ACLR) failure in at-risk populations remains unacceptably high and necessitates thorough evaluation of native alignment and concomitant injuries.¼ Posterior tibial slope of >12° is a substantial risk factor of ACLR failure and should be corrected through anterior closing wedge osteotomy.¼ Varus malalignment of >5° exacerbates stress on the ACL graft, increases ACLR failure risks, and should be considered for correction through high tibial osteotomy at the time of revision ACLR.¼ Injuries to the anterolateral ligamentous complex are prevalent in ACL ruptures, and high-risk patients have shown benefit from anterolateral ligament reconstruction or lateral extra-articular tenodesis in the revision setting.¼ Addressing posterolateral corner, collateral ligament, and meniscal injuries, during revision ACLR, is vital to mitigate increased graft forces and optimize knee stability and functional outcomes.

Structure and Function Are Not the Same: The Case for Restoring Mechanoreceptor Continuity Following Anterior Cruciate Ligament Injury.

Anterior cruciate ligament (ACL) injury, particularly in increasingly young and active adolescents, continues to pose a clinical challenge with re-injury rates reported as high as 30%. Evidence also suggests that current standard-of-care ACL reconstruction (ACLR) does not mitigate post-traumatic osteoarthritis (PTOA) risk. Bridge- enhanced ACL restoration (BEAR) is a recently developed and tested ACL surgery that promotes primary healing of the native ACL with excellent early results. BEAR has shown to reduce signs of early PTOA compared to ACLR in an animal model. Here, we describe a theoretical framework related to re-innervation that can clarify why the outcomes of ACLR and BEAR surgeries differ. We also discuss how ongoing and new challenges in determining return-to-sport readiness following the competing surgeries may differ, and how emerging imaging tools and measures of neuromuscular function may aid in clinical decision-making to decrease the likelihood of re-injury and PTOA risk.

Arm Injuries and Prevention Proficiency in High School Fastpitch Softball Players: A Survey of Players, Parents, and Coaches.

Arm injuries are common in youth fastpitch softball players. To characterize arm injuries and assess injury prevention knowledge, we administered a cross-sectional online survey and injury prevention quiz to high school fastpitch softball players, parents, and coaches. Associations between throwing habits and adverse arm outcomes were computed. Surveys were collected from 123 high school players, 59 parents, and 28 coaches, totaling 210 responses. Nearly half (48.8%) of players saw a doctor for arm pain. Riseball pitchers were less likely to undergo surgery than non-riseball pitchers (P = .008). Outfield/utility players trended toward more frequent arm pain compared to alternative position groups (P = .086). On injury prevention quizzes, players, parents, and coaches averaged scores of 56-65% correct, with players scoring below parents (P = .011) and coaches (P = .006). In conclusion, high school softball players frequently seek medical attention for arm pain, and injury prevention knowledge is consistently lacking.

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 the American Shoulder and Elbow Surgeons 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.

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.

Diversity, Equity, and Inclusion in Orthopaedic Surgery: Local and National Efforts.

Orthopaedic surgery has not experienced the same increase in diversity as other surgical subspecialties over time. Professional orthopaedic societies across the nation, including the American Academy of Orthopaedic Surgeons, are now making sincere efforts to improve diversity, equity, and inclusion (DEI) within the field. Several national groups provide funding to support DEI -related research as well as scholarships to national meetings. Others are more focused on mentorship and mitigation of residency attrition amongst underrepresented minorities (URMs). Individual residency programs, including the Department of Orthopaedics at Brown University, are engaging in community outreach to attract more diverse candidates to orthopaedics and providing away rotation scholarship support for medical students that identify as female or URMs. These local and national efforts will hopefully lead to a more inclusive environment for all trainees and practitioners within orthopaedics and ultimately improved orthopaedic care for all patients.

A Posterior Acromial Bone Block Augmentation Is Biomechanically Effective at Restoring the Force Required To Translate the Humeral Head Posteriorly in a Cadaveric, Posterior Glenohumeral Instability Model.

PURPOSE: To assess the biomechanical utility of a posterior acromial bone block (PABB) for the treatment of posterior glenohumeral instability. METHODS: Ten fresh-frozen cadaveric specimens were obtained based upon an a priori power analysis. A 2.5-cm scapular spine autograft was harvested from all shoulders. A custom robot device was used to apply a 50-N compressive force to the glenohumeral joint. The humeral head was translated 10 mm posteroinferiorly at 30 degrees from the center of the glenoid at a rate of 1.0 mm/s in 6 consecutive conditions: (1) intact specimen, (2) intact with PABB, (3) posterior capsulolabral tear, (4) addition of the PABB, (5) removal of the PABB and repair of the capsulolabral tear (LR), and (6) addition of the PABB with LR. The maximum force required to obtain this translation was recorded. Paired t tests were performed to compare relevant testing conditions. RESULTS: Ten cadavers with a mean ± SD age of 54.4 ± 13.1 years and mean ± SD glenoid retroversion of 6.5 ± 1.0 degrees were studied. The PABB provided greater resistance force to humeral head translation compared to the instability state (instability, 29.3 ± 15.3 N vs PABB, 47.6 ± 21.0 N; P = .001; 95% confidence interval [CI], -27.6 to -10.0). When comparing PABB to LR, the PABB produced higher resistance force than LR alone (PABB, 47.6 ± 21.0 N; LR, 34.2 ± 20.5 N; P = .012; 95% CI, -23.4 to -4.1). An instability lesion treated with the PABB, with LR (P = .056; 95% CI, -0.30 to 20.4) or without LR (P = .351; 95% CI, -6.8 to 15.7), produced resistance forces similar to the intact specimen. CONCLUSIONS: A PABB is biomechanically effective at restoring the force required to translate the humeral head posteriorly in a cadaveric, posterior glenohumeral instability model. A posterior acromial bone block is a biomechanically feasible option to consider in patients with recurrent posterior instability. CLINICAL RELEVANCE: Augmentation of the posterior acromion may be a biomechanically feasible option to treat posterior shoulder instability.

Significant Association between a Diagnosis of Hypovitaminosis D and Rotator Cuff Tear, Independent of Age and Sex: A Retrospective Database Study.

PURPOSE: As high rates of vitamin D deficiency have been demonstrated in orthopedic patient cohorts, this study aimed to characterize the association between a diagnosis of hypovitaminosis D and primary rotator cuff tear (RCT), primary rotator cuff repair (RCR), and postoperative complications in different sex and age cohorts. METHODS: In this retrospective cohort study using PearlDiver, a nationwide administrative claims database, records for all patients aged 30 to 89 yr who received a diagnosis of hypovitaminosis D between January 1, 2011, and October 31, 2018, were queried. Rates of primary RCT, primary RCR, and postoperative complications including subsequent surgery were calculated within sex- and age-specific cohorts and compared with matched control cohorts using multivariable logistic regression. RESULTS: Among the 336,320 patients included in the hypovitaminosis D cohort, these patients were significantly more likely to experience an RCT (odds ratio (OR), 2.70; 95% confidence interval (CI), 2.55-2.85) as well as a full-thickness RCT (OR, 2.36; 95% CI, 2.17-2.56) specifically within 2 yr of their diagnosis. Women with hypovitaminosis D were more likely to undergo surgery to address their full-thickness tears (OR, 1.37; 95% CI, 1.09-1.74). There was no difference in the rates of revision RCR or irrigation and debridement. However, women with hypovitaminosis D were significantly more likely to undergo manipulation under anesthesia (OR, 1.16; 95% CI, 1.03-1.31). CONCLUSIONS: Patients diagnosed with hypovitaminosis D were significantly more likely to suffer from a primary RCT and to undergo manipulation under anesthesia within a year of their RCR. Although many risk factors for RCT are unmodifiable, vitamin D deficiency is a readily modifiable risk factor with several treatment regimens demonstrating positive effects on musculoskeletal health.

Peroneus Longus Tendon Autograft May Present a Viable Alternative for Anterior Cruciate Ligament Reconstruction: A Systematic Review.

PURPOSE: To examine the available literature to better understand the objective and patient-reported outcomes using peroneus longus tendon (PLT) autograft compared with more commonly used autografts, such as the quadrupled hamstring tendons (HT), in patients undergoing primary for anterior cruciate ligament reconstruction (ACLR). METHODS: A comprehensive search of published literature in PubMed, Web of Science, Cochrane Library, Ovid, and EMBASE databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria included patients undergoing ACLR with PLT autograft, inclusion of patient-recorded outcome measures, and availability in English language. Publications that included only biomechanical analysis or ACLR with use of allograft or combination grafts were excluded. RESULTS: A total of 16 studies (Level of Evidence range: I-IV) met inclusion criteria, with follow-up ranging from 3 months to 5 years. In the available case series, patient-reported outcomes ranged from Lysholm = 80.7 to 95.1, International Knee Documentation Committee 78.1 to 95.7. In prospective cohorts and randomized controlled trials, PLT performance was comparable with HT autografts (PLT/HT: Lysholm = 88.3-95.1/86.5-94.9, International Knee Documentation Committee = 78.2-92.5/87.4-93.4). The majority of PLT grafts diameters were equal or greater than HT counterparts with a mean of >8 mm (PLT/HT: 7.0-9.0 mm/7.65-8.5 mm). There was minimal donor-site morbidity associated with PLT harvest. CONCLUSIONS: Although limitations exist within the available literature, existing evidence suggests that PLT autograft routinely produces adequately sized grafts with comparable early outcomes to HT autograft and low risk of donor-site morbidity. However, the PLT autograft is yet to demonstrate superiority to any of the more-traditional autograft selections. LEVEL OF EVIDENCE: Level IV, systematic review of Level I-IV studies.

Association of Emergency Department Evaluation With Public Insurance Use and Treatment Delays for ACL Injury.

Background: Utilization of an emergency department (ED) visit for anterior cruciate ligament (ACL) injury is associated with high cost and diagnostic unreliability. Hypothesis: Patients initially evaluated at an ED for an ACL injury would be more likely to be from a lower income quartile, use public insurance, and experience a delay in treatment. Study Design: Cohort study; Level of evidence, 3. Methods: Patients in the Rhode Island All Payers Claims Database who underwent ACL reconstruction (ACLR) between 2012 and 2021 were identified using the Current Procedure Terminology (CPT) code 29888. Patients were stratified into 2 cohorts based on CPT codes for ED or in-office services within 1 year of ACLR. A chi-square analysis was used to test for differences between cohorts in patient and surgical characteristics. Multivariable linear and logistic regression were used to determine how ED evaluation affected timing and outcome variables. Results: While adjusting for patient and operative characteristics, patients in the ED cohort were more likely to have Medicaid (29% vs 12.5%; P < .001) and be in the lowest income quartile (44.6% vs 32.1%; P < .001). ED visit and Medicaid status were associated with increased time to (1) diagnostic magnetic resonance imaging, adding 7.97 days on average (95% CI, 4.14-11.79 days; P < .001) and 8.40 days (95% CI, 3.44-13.37 days; P = .001), respectively; and (2) surgery, adding 20.30 days (95% CI, 14.10-26.49 days; P < .001) and 12.88 days (95% CI, 5.15-20.60 days; P = .001), respectively. Patients >40 years who were evaluated in the ED were 2.5 times more likely to require subsequent ACLR (odds ratio, 2.50 [95% CI, 1.01-6.21]; P = .049). Conclusion: In this study, patients who visited the ED within 1 year before ACLR were more likely to have a lower income, public insurance, increased time to diagnostic imaging, and increased time to surgery, as well as decreased postoperative physical therapy use and increased subsequent ACLR rates in the 40-49 years age-group.

Beach-Chair Versus Lateral Decubitus Positioning for Primary Arthroscopic Anterior Shoulder Stabilization: A Consecutive Series of 641 Shoulders.

BACKGROUND: There are limited data comparing the beach-chair (BC) versus lateral decubitus (LD) position for arthroscopic anterior shoulder stabilization. PURPOSE: To identify predictors of instability recurrence and revision after anterior shoulder stabilization and evaluate surgical position and glenoid bone loss as independent predictors of recurrence and revision at short- and midterm follow-ups. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A consecutive series of 641 arthroscopic anterior stabilization procedures were performed from 2005 to 2019. All shoulders were evaluated for glenohumeral bone loss on magnetic resonance imaging. The primary outcomes of interest were recurrence and revision. Multivariable logistic regression models were used to assess the relationships of outcomes with age, position, glenoid bone loss group, and track. RESULTS: A total of 641 shoulders with a mean age of 22.3 years (SD, 4.45 years) underwent stabilization and were followed for a mean of 6 years. The overall 1-year recurrent instability rate was 3.3% (21/641) and the revision rate was 2.8% (18/641). At 1 year, recurrence was observed in 2.3% (11/487) and 6.5% (10/154) of BC and LD shoulders, respectively. The 5-year recurrence and revision rates were 15.7% (60/383) and 12.8% (49/383), respectively. At 5 years, recurrence was observed in 16.4% (48/293) and 13.3% (12/90) of BC and LD shoulders, respectively. Multivariable modeling demonstrated that surgical position was not associated with a risk of recurrence after 1 year (odds ratio [OR] for LD vs BC, 1.39; P = .56) and 5 years (OR for LD vs BC, 1.32; P = .43), although younger age at index surgery was associated with a higher risk of instability recurrence (OR, 1.73 per SD [4.1 years] decrease in age; P < .03). After 1 and 5 years, surgical position results were similar in a separate multivariable logistic regression model of revision surgery as the dependent variable, when adjusted for age, surgical position, bone loss group, and track. At 5 years, younger age was an independent risk factor for revision: OR 1.68 per SD (4.1 years) decrease in age (P < .05). CONCLUSION: Among fellowship-trained orthopaedic surgeons, there was no difference in rates of recurrence and revision surgery after performing arthroscopic anterior stabilization in either the BC or the LD position at 1- and 5-year follow-ups. In multivariable analysis, younger age, but not surgical position, was an independent risk factor for recurrence.

Arthroscopic Simulation in Orthopaedic Surgery Training.

Surgical simulation has become a commonly utilized and well-researched training adjunct in nearly all surgical specialties. Balancing high-quality orthopaedic surgical training in the face of work hour restrictions and efficiency pressures has become a challenge to educators and trainees alike. Surgical simulation is an opportunity to enhance such training and potentially permit trainees to be better equipped for the operating room. In orthopaedics, various low-fidelity, high-fidelity, and virtual reality simulation platforms are readily available to almost all trainees and permit simulation of a wide array of arthroscopic surgeries. In this review, we seek to highlight the potential utility of simulation-based training in orthopaedic surgery, the various types of available simulators, and review the evidence for simulator use.

The effect of pre-operative shoulder injections on post-operative opioid use, infection and revision following shoulder arthroplasty.

Background: Treatment of glenohumeral osteoarthritis (GHOA) may include conservative management with use of intraarticular injections, prior to considering total shoulder arthroplasty (TSA). The purpose of this study was to assess trends in the use of preoperative cortisone (CO) and hyaluronic acid (HA) injections, as well as investigate the relationship between injection use and infection or revision arthroplasty following TSA. Methods: Pearl Driver was used to identify all patients undergoing TSA for GHOA between 2010 and 2018. Patients were categorized based on the type and number of injections they received. Outcomes of interest included post-operative opioid use, post-operative infection, and risk of revision surgery within 1 year of the index procedure. Results: The incidence of patients receiving a CO or HA injections within 1 year of their TSA decreased by 83% and 54%, respectively. Patients who had received 1 or more steroid injections had higher odds of prolonged opiate use following surgery. Patients that received 1 or 2 CO injection prior to TSA had an increased risk of needing revision surgery. Discussion: Use of intraarticular injections for the management of GHOA has declined. Patients receiving preoperative injections had increased odds of prolonged opiate use and the need for revision surgery.

The Effects of an Osteoarthritic Joint Environment on ACL Damage and Degeneration: A Yucatan Miniature Pig Model.

Posttraumatic osteoarthritis (PTOA) arises secondary to joint injuries and is characteristically driven by inflammatory mediators. PTOA is often studied in the setting of ACL tears. However, a wide range of other injuries also lead to PTOA pathogenesis. The purpose of this study was to characterize the morphological changes in the uninjured ACL in a PTOA inflammatory environment. We retrospectively reviewed 14 ACLs from 13 Yucatan minipigs, 7 of which had undergone our modified intra-articular drilling (mIAD) procedure, which induced PTOA through inflammatory mediators. Seven ACLs were harvested from mIAD minipigs (PTOA) and seven ACLs from control minipigs with no cartilage degeneration (non-PTOA). ACL degeneration was evaluated using histological scoring systems. IL-1ß, NF-κB, and TNF-α mRNA expression in the synovium was measured using qRT-PCR. PTOA minipigs demonstrated significant ACL degeneration, marked by a disorganized extracellular matrix, increased vascularity, and changes in cellular shape, density, and alignment. Furthermore, IL-1ß, NF-κB, and TNF-α expression was elevated in the synovium of PTOA minipigs. These findings demonstrate the potential for ACL degeneration in a PTOA environment and emphasize the need for anti-inflammatory disease-modifying therapies following joint injury.

A novel large animal model of posttraumatic osteoarthritis induced by inflammation with mechanical stability.

OBJECTIVES: Animal models are needed to reliably separate the effects of mechanical joint instability and inflammation on posttraumatic osteoarthritis (PTOA) pathogenesis. We hypothesized that our modified intra-articular drilling (mIAD) procedure induces cartilage damage and synovial changes through increased inflammation without causing changes in gait. METHODS: Twenty-four Yucatan minipigs were randomized into the mIAD (n=12) or sham control group (n=12). mIAD animals had two osseous tunnels drilled into each of the tibia and femur adjacent to the anterior cruciate ligament (ACL) attachment sites on the left hind knee. Surgical and contralateral limbs were harvested 15 weeks post-surgery. Cartilage degeneration was evaluated macroscopically and histologically. Synovial changes were evaluated histologically. Interleukin-1 beta (IL-1ß), nuclear factor kappa B (NF-κB), and tumor necrosis factor alpha (TNF-α) mRNA expression levels in the synovial membrane were measured using quantitative real-time polymerase chain reaction. IL-1ß and NF-κB levels in chondrocytes were assessed using immunohistochemistry. Load asymmetry during gait was recorded by a pressure-sensing walkway system before and after surgery. RESULTS: The mIAD surgical knees demonstrated greater gross and histological cartilage damage than contralateral (P<.01) and sham knees (P<.05). Synovitis was present only in the mIAD surgical knee. Synovial inflammatory marker (IL-1ß, NF-κB, and TNF-α) expression was three times higher in the mIAD surgical knee than the contralateral (P<.05). Chondrocyte IL-1ß and NF-κB levels were highest in the mIAD surgical knee. In general, there were no significant changes in gait. CONCLUSIONS: The mIAD model induced PTOA through inflammation without affecting gait mechanics. This large animal model has significant applications for evaluating the role of inflammation in PTOA and for developing therapies aimed at reducing inflammation following joint injury.