Pediatric Heterotopic Ossification: A Comprehensive Review.

PURPOSE OF REVIEW: The purpose of this review is to provide a comprehensive analysis of heterotopic ossification (HO) in pediatric patients, including an in-depth examination of the risk factors associated with this condition, current prophylactic measures, and available management strategies. RECENT FINDINGS: HO is a medical disorder in which bone tissue inexplicably develops in soft tissues such as muscles and tendons. It involves the formation of mature, lamellar bone in extra-skeletal soft tissue, and its formation is influenced by oxygen tension, pH, the availability of micronutrients, and mechanical stimulation. HO has many cellular origins, with the most common theory being multipotent cells in local tissue. The diagnosis of HO is typically made based on exam, radiographs, and CT. Management includes both prophylactic nonsurgical options and surgical resection for severe or recalcitrant cases. The review highlights the incidence, risk factors, and management strategies associated with HO in pediatric patients. HO is a rare condition in children, with severe neurologic injury being the most common cause. Pediatric patients most commonly develop HO following severe neurologic injury, followed by trauma and surgery. Current prophylactic measures, include nonsteroidal anti-inflammatory drugs and radiation therapy though limited literature on their use in the pediatric population exists. For recalcitrant symptomatic cases, wide surgical resection can be considered but has a higher risk profile and associated morbidity. This review highlights the need for further pediatric specific research to inform guidelines and management strategies for this debilitating condition.

Preventing and Treating Infection in Reverse Total Shoulder Arthroplasty.

PURPOSE OF REVIEW: Periprosthetic infection after shoulder arthroplasty is relatively uncommon though associated with severe long-term morbidity when encountered. The purpose of the review is to summarize the recent literature regarding the definition, clinical evaluation, prevention, and management of prosthetic joint infection after reverse shoulder arthroplasty. RECENT FINDINGS: The landmark report generated at the 2018 International Consensus Meeting on Musculoskeletal Infection has provided a framework for diagnosis, prevention, and management of periprosthetic infections after shoulder arthroplasty. Shoulder specific literature with validated interventions to reduce prosthetic joint infection is limited; however existing literature from retrospective studies and from total hip and knee arthroplasty allows us to make relative guidelines. One and two-stage revisions seem to demonstrate similar outcomes; however, no controlled comparative studies exist limiting the ability to make definitive recommendations between the two options. We report on recent literature regarding the current diagnostic, preventative, and treatment options for periprosthetic infection after shoulder arthroplasty. Much of the literature does not distinguish between anatomic and reverse shoulder arthroplasty, and further high-level shoulder specific studies are needed to answer questions generated from this review.

Management of Displaced Midshaft Clavicle Fractures in Pediatrics and Adolescents: Operative vs Nonoperative Treatment.

The purpose of the current review is to describe the management of displaced midshaft clavicle fractures in pediatric and adolescent patients. Midshaft clavicle fractures are relatively common in pediatric and adolescent patients. They most commonly occur from direct trauma and are often related to sports participation in adolescents. Recent literature in the management of adult midshaft clavicle fractures has supported operative management due to improved functional outcomes, decreased time to union, leading to early return to activity. A similar trend of increasing frequency in operative management has been seen in pediatric and adolescent patients with no consensus in the literature on optimal management. Nonoperative treatment consists of with a brief period of sling immobilization followed by range of motion. Operative management may be considered for open fractures, fractures with significant neurovascular compromise and soft tissue complications. Studies have shown comparable mid- to long-term functional and patient-reported outcomes after operative and nonoperative management of midshaft clavicle fractures in pediatric patients.

Risk for recurrent instability and reoperation following arthroscopic and open shoulder stabilization in a large cross-sectional population.

Background: Recurrent shoulder instability is an orthopedic problem with potentially long-term functional ramifications. Although arthroscopic stabilization has become increasingly utilized over open stabilization, optimal surgical intervention to minimize recurrent instability remains controversial. Methods: The PearlDiver Mariner database was queried for all cases of open and arthroscopic shoulder stabilization from 2010 to 2019. Utilization trends were aggregated after identifying cohorts of 107,210 and 13,217 patients who respectively underwent arthroscopic or open stabilization using Current Procedural Terminology codes. Subsets from those cohorts with laterality-specific International Classification of Diseases, Tenth Revision codes for shoulder instability were used to evaluate 2-year rates of recurrent instability (presence of shoulder dislocation or revision open or arthroscopic stabilization). Linear regression and chi-squared analysis were used to analyze utilization trends and to compare recurrent instability. Results: Arthroscopic stabilization comprised 90% of all stabilization procedures with annual utilization continuing to increase into 2019. Latarjet utilization increased from 15% to 42% of all open stabilization procedures while open Bankart repair utilization decreased from 56% to 35%. The rate of recurrent instability was 10.2% after arthroscopic stabilization and 12.3% after open stabilization (P = .01). Rates of redislocation (4.0% vs. 2.6%, P < .01), conversion to shoulder arthroplasty (1.2% vs. 0.4%, P < .01), and revision open stabilization (6.8% vs. 2.3%, P < .01) after index open stabilization were significantly higher than after index arthroscopic stabilization. There was no difference in revision stabilization or dislocation rates between open procedures. Conclusion: Despite increasing utilization of coracoid transfer, arthroscopic stabilization is still the dominant modality used for surgical treatment of shoulder instability and in our analysis, showed lower 2-year rates of dislocation, revision open stabilization, and conversion to shoulder arthroplasty.

Infection and Mechanical Complications Are Risk Factors for New Diagnosis of a Mental Health Disorder After Total Joint Arthroplasty.

BACKGROUND: Prior studies have demonstrated that depression is an independent risk factor for developing a prosthetic joint infection (PJI) after total joint arthroplasty (TJA). To our knowledge, there is no literature examining whether PJI or aseptic failure increases the risk of developing a new mental health diagnosis. METHODS: PearlDiver Patient Database (Colorado Springs, CO) was used to identify 80,826 patients who underwent TJA without a pre-existing diagnosis of depression, anxiety, a stress and/or adjustment disorder, and/or current use of a selective serotonin reuptake inhibitor within the year prior to surgery. The odds of developing a new mental health issue or being prescribed a selective serotonin reuptake inhibitor within 1 year of an uncomplicated TJA was compared to those who developed PJI or mechanical failure within 90 days after TJA as well as to those who subsequently underwent revision surgery within 30 days of either complication using Fisher's exact test and Baptista-Pike. RESULTS: A total of 6474 (8%) patients were diagnosed with a new mental health issue after TJA. PJI or mechanical failure led to significantly higher odds of new diagnoses with an odds ratio of 1.67 (95% confidence interval = 1.26, 2.22) and 1.57 (1.24, 2.00), respectively. Undergoing revision surgery for PJI or mechanical failure increased the odds of developing a new mental health diagnosis to 2.10 (1.29, 3.42) and 2.24 (1.36, 3.72), respectively. There was no significant difference comparing those who developed PJI vs those who sustained mechanical complications. CONCLUSION: Patients who sustain complications after TJA are at increased odds of receiving a new mental health diagnosis, an effect further amplified if revision surgery is required.

Racial and Gender Shoulder Arthroplasty Utilization Disparities of High- and Low-Volume Centers in New York State.

INTRODUCTION: The literature has consistently demonstrated utilization disparities in joint replacement procedures, though no studies have evaluated disparities in total shoulder arthroplasty with regard to operative volume. METHODS: We queried the New York (NY) Statewide Planning and Research Cooperative System (SPARCS) database for 32 410 total shoulder arthroplasties performed between 2009 and 2017. Patients were identified using Clinical Classifications Software code 154 for Non-Hip/Knee Arthroplasty and All Patient Refined-Diagnosis Related Group code 322 for Shoulder. Racial groups included Hispanic, non-Hispanic white, non-Hispanic black, and Other. High-volume centers were facilities that performed 2 standard deviations above the mean annual procedures. Utilization rates were calculated by dividing total shoulder arthroplasties per group by the 2010 NY Census population of that group. The Fisher exact test was used to determine significance. RESULTS: Total shoulder arthroplasty utilization increased from 43/100 000 to 73/100 000, two-thirds of which was driven by an increase in white resident utilization. More White residents per 100 000 underwent shoulder arthroplasty than Black, Hispanic, and Other residents per 100 000 residents of their respective race. White residents were 90% more likely than Hispanic residents to undergo total shoulder arthroplasty at high-volume centers (P = .04). There were no differences in utilization rate regarding operative volume comparing Black or Other residents to White residents. More females underwent total shoulder arthroplasty than males, though there was no difference in utilization rate regarding operative volume. CONCLUSION: Though total shoulder arthroplasty utilization nearly doubled, disparities persisted across gender and minority groups particularly in Hispanic utilization as White residents were 90% more likely than Hispanic residents to undergo shoulder arthroplasty at high-volume centers.

Patients With Abnormal Limb Kinetics at 6 Months After Anterior Cruciate Ligament Reconstruction Have an Increased Risk of Persistent Medial Meniscal Abnormality at 3 Years.

BACKGROUND: Several reports have shown that altered biomechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of posttraumatic osteoarthritis. However, it is not fully understood whether altered biomechanics are associated with meniscal changes after ACLR. PURPOSE: To investigate changes in gait and landing biomechanics over a 3-year period and their correlation with meniscal matrix alterations present before and after ACLR through use of magnetic resonance T1ρ/T2 mapping, which can allow detection of early meniscal degeneration. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 36 patients with ACLR and 14 healthy controls were included in this study. All patients underwent magnetic resonance imaging and biomechanical analysis during gait of the injured knee and contralateral knee preoperatively and at 6 months, 1 year, 2 years, and 3 years after ACLR, as well as biomechanical analysis during drop-landing from 6 months to 3 years postoperatively. To evaluate biochemical changes of the mensical matrix, T1ρ/T2 relaxation times of the meniscus were calculated. RESULTS: Mean T1ρ/T2 values of ACLR knees were significantly higher than values in the contralateral and control knees in the posterior lateral and medial horns up to 1 year after surgery; however, the differences were not seen at 3 years after surgery. The ACLR knee exhibited significantly lower peak knee flexion moment and angle during gait at 6 months compared with baseline and continued to decrease until 3 years. The ACLR knee exhibited significantly lower peak vertical ground-reaction force and peak knee flexion moment and angle during landing at 6 months. However, the differences were no longer present at 3 years. Biomechanics at 6 months had significant correlations with changes of mean T1ρ/T2 values in the medial posterior horn from 6 months to 3 years after ACLR. CONCLUSION: Although mean T1ρ/T2 values of meniscus seen before ACLR improved after 3 years, approximately 30% of patients with ACLR did not show decreases from 6 months to 3 years. Patients with abnormal lower limb kinetics of the ACLR knee at 6 months showed less recovery in the medial posterior horn from 6 months to 3 years, suggesting that biomechanical parameters during the early stage of recovery might be potential biomarkers for predicting persistent medial meniscal abnormality after ACLR.

Failed Reverse Shoulder Arthroplasty and Recommendations for Revision.

PURPOSE OF REVIEW: The most common complications warranting revision consideration in reverse shoulder arthroplasty (RSA) include instability and its associated causes: infection, periprosthetic fracture, and glenoid baseplate loosening. Management of complications can be challenging and the nuances of treatment are still being elucidated. The focus of this paper is to review the treatment of the failed RSA and discuss evidence-based recommendations for revision. RECENT FINDINGS: The most common complications requiring revision RSA are instability and infection. The causes for instability can be subdivided into three main subcategories: loss of compression, loss of containment, and impingement. Loss of compression is further broken down into 6 subcategories revolving around abnormal prosthesis positioning, undersized prostheses, or intrinsic soft-tissue tension loss leading to instability. Periprosthetic infection can also lead to instability, yet the most appropriate management for infected RSA remains controversial. Restoring stability by maximizing deltoid and soft tissue tension while avoiding impingement revolves around three basic methods: (1) lateralizing and/or upsizing the glenosphere to an inferior position on the glenoid, (2) use of a more constrained polyethylene insert, and (3) distalizing the humerus by increasing the polyethylene thickness and/or the thickness of the humeral tray. Management of periprosthetic joint infection can be performed in one-stage, two-stage, or "three-stage" procedures all showing good outcomes with two-stage procedures being the most commonly performed. However, persistent positive culture with propriobacterium acnes can occur in up to 25% of cases. In order to limit the associated morbidity from failed revision reverse shoulder arthroplasty, continued research on best management of associated complications is warranted.

Meniscus Form and Function.

The menisci are 2 fibrocartilaginous crescents anchored via bony and ligamentous attachments to surrounding structures. Their biochemical composition and multilayered structure make them ideal for converting compressive forces to tensile forces in addition to improving joint congruity and providing shock absorption to weight bearing. The medial meniscus maintains more attachments at both the horns and the midbody than the lateral meniscus, making it more susceptible to injury. Understanding of the gross anatomy, vascular anatomy, biochemical composition, and microstructure is key to understanding causes of meniscal pathology as well as treatment options for restoring its primary functions.

An Abnormal Tibial Position Is Associated With Alterations in the Meniscal Matrix: A 3-Year Longitudinal Study After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: An altered tibial position is still present despite anterior cruciate ligament (ACL) reconstruction. It has been demonstrated that an abnormal tibial position after an ACL injury may play a role in subsequent injuries to the meniscus, which can lead to early cartilage degeneration. PURPOSE: To determine changes in both the tibial position and the meniscal matrix present before and after ACL reconstruction as well as to evaluate the association between these 2 variables in ACL-injured knees 3 years after reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Bilateral knee magnetic resonance imaging (MRI) of 32 patients with unilateral ACL injuries was performed before reconstruction; 13 control participants also underwent MRI. Follow-up MRI was performed up to 3 years after surgery. Tibial position, internal tibial rotation, and T1ρ and T2 values of the menisci were calculated using an in-house MATLAB program. Student t tests and multiple linear regression were used to compare differences between injured, uninjured, and control knees as well as to assess correlations between the tibial position at 3 years and 3-year changes in quantitative MRI meniscal relaxation values. RESULTS: The tibial position of injured knees was more anterior than that of uninjured knees at baseline, 6 months, and 1, 2, and 3 years (P < .05 for all). The T1ρ and T2 values of the menisci of injured knees were greater than those of uninjured and control knees in the posterior lateral and posterior medial horns up to 1 and 2 years after surgery, respectively (P < .05 for all). The tibial position at 3 years was associated with increased T2 values from baseline to 3 years in the posterior medial horn (ß = 0.397; P = .031) and anterior medial horn (ß = 0.360; P = .040). CONCLUSION: Results of the current study indicate that there is a persistently altered tibial position after ACL reconstruction. Initial preoperative meniscal abnormalities show prolonged but gradual improvement. Additionally, correlations between the tibial position and changes in the medial meniscal matrix suggest that the tibial position may play a role in the increased susceptibility to medial meniscal tears seen after reconstruction. The development of newer surgical techniques must address a persistently altered tibial position. Quantitative MRI is an effective instrument to evaluate meniscal matrix changes and can serve as an early radiological tool for meniscal injuries.

Directed fusion of cardiac spheroids into larger heterocellular microtissues enables investigation of cardiac action potential propagation via cardiac fibroblasts.

Multicellular spheroids generated through cellular self-assembly provide cytoarchitectural complexities of native tissue including three-dimensionality, extensive cell-cell contacts, and appropriate cell-extracellular matrix interactions. They are increasingly suggested as building blocks for larger engineered tissues to achieve shapes, organization, heterogeneity, and other biomimetic complexities. Application of these tissue culture platforms is of particular importance in cardiac research as the myocardium is comprised of distinct but intermingled cell types. Here, we generated scaffold-free 3D cardiac microtissue spheroids comprised of cardiac myocytes (CMs) and/or cardiac fibroblasts (CFs) and used them as building blocks to form larger microtissues with different spatial distributions of CMs and CFs. Characterization of fusing homotypic and heterotypic spheroid pairs revealed an important influence of CFs on fusion kinetics, but most strikingly showed rapid fusion kinetics between heterotypic pairs consisting of one CF and one CM spheroid, indicating that CMs and CFs self-sort in vitro into the intermixed morphology found in the healthy myocardium. We then examined electrophysiological integration of fused homotypic and heterotypic microtissues by mapping action potential propagation. Heterocellular elongated microtissues which recapitulate the disproportionate CF spatial distribution seen in the infarcted myocardium showed that action potentials propagate through CF volumes albeit with significant delay. Complementary computational modeling revealed an important role of CF sodium currents and the spatial distribution of the CM-CF boundary in action potential conduction through CF volumes. Taken together, this study provides useful insights for the development of complex, heterocellular engineered 3D tissue constructs and their engraftment via tissue fusion and has implications for arrhythmogenesis in cardiac disease and repair.