Loose Body Versus Trochlear Biopsy Matrix-Induced Autologous Chondrocyte Implantation (MACI) MOCART Scores and IKDC Reported Outcomes in Pediatric Patients.

BACKGROUND: Matrix-induced autologous chondrocyte implantation (MACI) has shown promising results in the treatment of osteochondral lesions of the knee. A recent study showed similar viability comparing chondrocytes harvested from the intercondylar notch compared to those harvested from osteochondral loose bodies. However, there is limited evidence assessing how these different biopsies perform clinically. The goal of this study was to compare both radiographic and patient-reported outcomes in patients with patellar and femoral osteochondral lesions treated with MACI using either a standard intercondylar notch biopsy or an osteochondral loose body biopsy. METHODS: A retrospective study was performed on all pediatric autologous chondrocyte implantation procedures performed from 2014 to 2017 at a single institution. Patients were divided into 2 groups: one group had cartilage derived from a standard intercondylar notch biopsy (n=9) and the other group had cartilage derived from an osteochondral loose body found within the ipsilateral knee (n=10). At a minimum of 1-year postimplantation, magnetic resonance imagings of the operative knee were performed and the Magnetic Resonance Observation of Cartilage Repair Tissue Knee Score (MOCART 2.0) knee score was used to assess the integrity and quality of the cartilage repair tissue. Interclass correlation coefficients were calculated between the 2 groups. International Knee Documentation Committee (IKDC) outcome scores were determined at a minimum 2 years post-implantation. RESULTS: The interclass correlation coefficient between three independent examiners for the MOCART scoring was excellent at 0.94. With regards to the MOCART score, the loose body group had an insignificant 17-point lower median score at 63 [interquartile range (IQR): 58 to 89] compared to the intercondylar group at 80 (IQR: 65 to 90) ( P =0.15). There was no difference in IKDC scores with the loose body group having a median score of 82 (IQR: 65 to 95) and the intercondylar group having a median score of 84 (IQR: 53 to 99) ( P =0.90). CONCLUSION: These results demonstrate that osteochondral loose bodies can be used as viable harvest site in MACI procedures with no difference in functional and radiographic outcomes at 2 years postimplantation. This may limit both short and long-term donor site morbidity. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Ocean convergence and the dispersion of flotsam.

Floating oil, plastics, and marine organisms are continually redistributed by ocean surface currents. Prediction of their resulting distribution on the surface is a fundamental, long-standing, and practically important problem. The dominant paradigm is dispersion within the dynamical context of a nondivergent flow: objects initially close together will on average spread apart but the area of surface patches of material does not change. Although this paradigm is likely valid at mesoscales, larger than 100 km in horizontal scale, recent theoretical studies of submesoscales (less than ∼10 km) predict strong surface convergences and downwelling associated with horizontal density fronts and cyclonic vortices. Here we show that such structures can dramatically concentrate floating material. More than half of an array of ∼200 surface drifters covering ∼20 × 20 km2 converged into a 60 × 60 m region within a week, a factor of more than 105 decrease in area, before slowly dispersing. As predicted, the convergence occurred at density fronts and with cyclonic vorticity. A zipperlike structure may play an important role. Cyclonic vorticity and vertical velocity reached 0.001 s-1 and 0.01 ms-1, respectively, which is much larger than usually inferred. This suggests a paradigm in which nearby objects form submesoscale clusters, and these clusters then spread apart. Together, these effects set both the overall extent and the finescale texture of a patch of floating material. Material concentrated at submesoscale convergences can create unique communities of organisms, amplify impacts of toxic material, and create opportunities to more efficiently recover such material.

Preoperative 3D Modeling and Printing for Guiding Periacetabular Osteotomy.

INTRODUCTION: Achieving adequate acetabular correction in multiple planes is essential to the success of periacetabular osteotomy (PAO). Three-dimensional (3D) modeling and printing has the potential to improve preoperative planning by accurately guiding intraoperative correction. The authors therefore asked the following questions: (1) For a patient undergoing a PAO, does use of 3D modeling with intraoperative 3D-printed models create a reproducible surgical plan to obtain predetermined parameters of correction including lateral center edge angle (LCEA), anterior center edge angle (ACEA), Tonnis angle, and femoral head extrusion index (FHEI)? and (2) Can 3D computer modeling accurately predict when a normalized FHEI can be achieved without the need for a concomitant femoral-sided osteotomy? METHODS: A retrospective review was conducted on 42 consecutive patients that underwent a PAO. 3D modeling software was utilized to simulate a PAO in order to achieve normal LCEA, ACEA, Tonnis angle, and FHEI. If adequate FHEI was not achieved, a femoral osteotomy was simulated. 3D models were printed as intraoperative guides. Preoperative, simulated and postoperative radiographic ACEA, LCEA, Tonnis angle, and FHEI were measured and compared statistically. RESULTS: A total of 40 patients had a traditional PAO, and 2 had an anteverting-PAO. The simulated LCEA, ACEA, Tonnis angle, and FHEI were within a median difference of 3 degrees, 1 degrees, 1 degrees, and 0% of postoperative values, respectively, and showed no statistical difference. Of those that had a traditional PAO, all 34 patients were correctly predicted to need a traditional acetabular-sided correction alone and the other 6 were correctly predicted to need a concomitant femoral osteotomy for a correct prediction in 100% of patients. CONCLUSION: This study demonstrates that for PAO surgery, 3D modeling and printing allow the surgeon to accurately create a reproducible surgical plan to obtain predetermined postoperative hip coverage parameters. This new technology has the potential to improve preoperative/intraoperative decision making for hip dysplasia and other complex disorders of the hip.

Assessment of Cartilage Growth After Biopsy of Osteochondral Loose Bodies in Adolescent Knees for Use in Autologous Chondrocyte Implantation.

BACKGROUND: The goal of this study is to determine whether harvested cartilage from an osteochondral loose body maintains the same viability for implantation as cartilage harvested from the traditional locations within the adolescent knee for autologous chondrocyte implantation (ACI). METHODS: A retrospective study was performed on all ACI procedures performed from 2014 to 2017 at a single institution. Biopsies were derived from 2 groups: osteochondral loose body verses the intercondylar notch. The viability, yield, identity, potency, and density were obtained from each sample in addition to basic demographics and concomitant injuries. A total of 12 patients with osteochondral loose bodies 14.6 (SD=2.9) and 20 patients 13.6 (SD=3.3) with intercondylar notch biopsies were evaluated for the study. RESULTS: In the microscopic and histologic comparison, there was no significant difference in viability: 94% in the loose bodies and 93% in the intercondylar notch groups, identity: 7.4 d5L versus 6.3 d5L, or yield. Minimum yield is presented as different units in Carticel (1.2×10 cells/vial) and matrix-induced ACI (>8500 relative fluorescent units) products; however, there was no difference between groups and all samples were above the acceptable limit. Minimum identity value is recorded as d5L> -2.00 and all samples were above this limit. In addition, no sample had signs of contamination or endotoxin in either group. CONCLUSION: These results demonstrate an alternative method for obtaining cartilage biopsies in ACI procedures that may limit short-term and long-term donor site morbidity. LEVEL OF EVIDENCE: Level III.

The medial epicondyle of the distal femur is the optimal location for MRI measurement of semitendinosus and gracilis tendon cross-sectional area.

PURPOSE: Graft diameter ≥ 8 mm reduces the risk of failure after anterior cruciate ligament reconstruction (ALCR) with hamstring tendon autograft. Pre-operative measurement of gracilis (GT) and semitendinosus (ST) cross-sectional area using MRI has been utilized but the optimal location for measurement is unknown. The main purpose of this study was to examine the cross-sectional areas of GT + ST at different locations and develop a model to predict whether a doubled hamstring graft of GT + ST will be of sufficient cross-sectional area for ACLR. METHODS: A retrospective review was performed of 154 patients who underwent primary ACLR using doubled hamstring autograft. Cross-sectional area measurements of GT + ST on pre-operative MRI axial images were made at three locations: medial epicondyle (ME), tibiofemoral joint line (TJL), and tibial physeal scar (TPS) and calculated the correlation of intra-operative graft size for each location using the Pearson's correlation coefficient. A receiver operating characteristic (ROC) established a threshold that would predict graft diameter ≥ 8 mm. RESULTS: Measurement of GT + ST at the ME had a stronger correlation (r = 0.389) to intra-operative graft diameter than measurements at the TJL (r = 0.256) or TPS (r = 0.240). The ROC indicated good predictive value for hamstring graft diameter ≥ 8 mm based on MRI measurement at the ME with the optimal threshold with the highest sensitivity and specificity as 18 mm2. CONCLUSION: Cross-sectional area measurement of GT + ST at the ME correlated most closely to intra-operative diameter of a doubled hamstring autograft compared to measurements at the TJL or the TPS. As graft diameter < 8 mm is correlated with higher failure rates of ACL surgery, the ability to pre-operatively predict graft diameter is clinically useful. LEVEL OF EVIDENCE: Level III, prognostic study.

Submesoscale dispersion in the vicinity of the Deepwater Horizon spill.

Reliable forecasts for the dispersion of oceanic contamination are important for coastal ecosystems, society, and the economy as evidenced by the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 and the Fukushima nuclear plant incident in the Pacific Ocean in 2011. Accurate prediction of pollutant pathways and concentrations at the ocean surface requires understanding ocean dynamics over a broad range of spatial scales. Fundamental questions concerning the structure of the velocity field at the submesoscales (100 m to tens of kilometers, hours to days) remain unresolved due to a lack of synoptic measurements at these scales. Using high-frequency position data provided by the near-simultaneous release of hundreds of accurately tracked surface drifters, we study the structure of submesoscale surface velocity fluctuations in the Northern Gulf of Mexico. Observed two-point statistics confirm the accuracy of classic turbulence scaling laws at 200-m to 50-km scales and clearly indicate that dispersion at the submesoscales is local, driven predominantly by energetic submesoscale fluctuations. The results demonstrate the feasibility and utility of deploying large clusters of drifting instruments to provide synoptic observations of spatial variability of the ocean surface velocity field. Our findings allow quantification of the submesoscale-driven dispersion missing in current operational circulation models and satellite altimeter-derived velocity fields.

Treatment of Snapping Scapula Syndrome in Children and Adolescents.

PURPOSE: The purpose of this study was to review 2 separate cohorts of young patients treated for snapping scapula: those treated surgically and those managed nonoperatively. METHODS: A retrospective IRB-approved review was conducted on 18 pediatric aged patients (19 shoulders): 12 patients (average age 13.3) were treated nonoperatively, 6 patients (average age 15.4) (7 shoulders) were treated operatively. Demographic and clinical data were collected from medical records and 2 questionnaires for level of activity, return to sport, subjective satisfaction from treatment, and preoperative/postoperative levels of pain. The American Shoulder and Elbow Society (ASES) score was measured for both groups. RESULTS: Mean follow-up for nonoperative patients was 43.7 months (range, 20 to 116 mo). Pretreatment subjective pain levels were 5.2 (scale 1 to 10), posttreatment were 1.5. There was a 75% return to play rate, and an overall 75% satisfaction rate. Posttreatment ASES scores were 90.0. Mean follow-up for surgical patients was 129.5 months (range, 68 to 177 mo). Pretreatment subjective pain level was 8.6, posttreatment was 0.75. There was an 83% return to play rate, and an overall 100% satisfaction rate. There were no complications. Posttreatment ASES scores were 92.6. CONCLUSIONS: Outcomes for nonoperative treatment of snapping scapula are good for young patients. Surgical management of snapping scapula is a safe and viable treatment option for patients who fail nonoperative treatment. LEVEL OF EVIDENCE: Level IV.

Medial Discoid Meniscus in Children: A Multicenter Case Series of Clinical Features and Operative Results.

BACKGROUND: The discoid medial meniscus is a rare congenital anomaly of the knee. The literature is limited to small case series. PURPOSE/HYPOTHESIS: Our purpose is to report the clinical manifestations and operative treatments of discoid medial menisci in children from multiple centers in North America. We hypothesized that symptoms and signs, arthroscopic findings, surgical treatments, and outcomes are similar to those for symptomatic discoid lateral menisci. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review identified patients with a diagnosed discoid medial meniscus confirmed at surgery across 8 children's hospitals between January 2000 and June 2021. The literature on discoid lateral menisci was reviewed and summarized for comparison. RESULTS: A total of 21 patients (9 female, 12 male) with 22 discoid medial menisci were identified. The mean ± SD age at the time of diagnosis was 12.8 ± 3.8 years. The most common symptoms and signs were locking and/or clunking, present in 12 of 22 knees (55%), similar to that reported in patients with discoid lateral menisci. Twelve discoid medial menisci were complete (55%); 8, incomplete (36%); and 2, indeterminate (9%). Tears were present in 13 knees, most commonly horizontal cleavage (54%). Five discoid medial menisci were unstable (23%): 3 for posterior tears and 2 for rim insufficiency. All 22 knees underwent arthroscopic saucerization, and of the 13 torn menisci, 7 (54%) were repaired. The median follow-up was 24 months (range, 2-82 months). Four knees underwent reoperation. All knees that required reoperation had undergone repair for a posteriorly located tear. There was a significant association between operative repair and need for reoperation (P = .0048). High rates of peripheral instability were also noted in case series of patients with discoid lateral menisci. CONCLUSION: Patient presentations and treatments for those with discoid medial menisci were similar to those reported for patients with discoid lateral menisci. Knees with discoid medial menisci also demonstrated instability attributed to peripheral insufficiency and posterior tears. Tears were present in over half of knees with discoid medial menisci, and reoperation was more common in knees that underwent repair of tears than those without repair.

Does the American College of Surgeons New Level I Children's Surgery Center Verification Affect Treatment Efficiency and Narcotic Administration in Treating Pediatric Trauma Patients with Femur Fracture?

BACKGROUND: In 2015, the American College of Surgeons (ACS) created a new hospital improvement program to enhance the performance of pediatric care in US hospitals. The Children's Surgery Verification (CSV) Quality Improvement Program is predicated on the idea that pediatric surgical patients have improved outcomes when treated at children's hospitals with optimal resources. Achieving ACS level I CSV designation at pediatric trauma centers may lead to greater benefits for pediatric trauma patients; however, the specific benefits have yet to be identified. We hypothesize that achieving the additional designation of ACS level I CSV is associated with decreased narcotic use perioperatively and improved efficiency when managing pediatric patients with femur fractures. STUDY DESIGN: This study is a retrospective analysis of traumatic pediatric orthopaedic femur fractures treated at a verified level I pediatric trauma center before and after CSV designation (2010 to 2014 vs 2015 to 2019). Efficiency parameters, defined as time from admission to surgery, duration of surgery, and duration of hospital stay, and narcotic administration in oral morphine equivalents (OMEs) were compared. RESULTS: Of 185 traumatic femur fractures analyzed, 80 occurred before meeting ACS level I CSV criteria, and 105 occurred after. Post-CSV, there was a significant decrease in mean wait time from admission to surgery (16.64 hours pre-CSV, 12.52 hours post-CSV [p < 0.01]) and duration of hospital stay (103.49 hours pre-CSV, 71.61 hours post-CSV [p < 0.01]). Narcotic usage was significantly decreased in both the preoperative period (40.61 OMEs pre-CSV, 23.77 OMEs post-CSV [p < 0.01]) and postoperative period (126.67 OMEs pre-CSV, 45.72 OMEs post-CSV [p < 0.01]). CONCLUSIONS: Achieving ACS level I CSV designation is associated with increased efficiency and decreased preoperative and postoperative narcotic use when treating pediatric trauma patients.

A Fresh Glimpse into Cartilage Immune Privilege.

The increasing prevalence of degenerative cartilage disorders in young patients is a growing public concern worldwide. Cartilage's poor innate regenerative capacity has inspired the exploration and development of cartilage replacement treatments such as tissue-engineered cartilages and osteochondral implants as potential solutions to cartilage loss. The clinical application of tissue-engineered implants is hindered by the lack of long-term follow-up demonstrating efficacy, biocompatibility, and bio-integration. The historically reported immunological privilege of cartilage tissue was based on histomorphological observations pointing out the lack of vascularity and the presence of a tight extracellular matrix. However, clinical studies in humans and animals do not unequivocally support the immune-privilege theory. More in-depth studies on cartilage immunology are needed to make clinical advances such as tissue engineering more applicable. This review analyzes the literature that supports and opposes the concept that cartilage is an immune-privileged tissue and provides insight into mechanisms conferring various degrees of immune privilege to other, more in-depth studied tissues such as testis, eyes, brain, and cancer.

Treatment of Dysplasia Epiphysealis Hemimelica with Autologous Chondrocyte Implantation: A Case Report.

Case: We present a case of dysplasia epiphysealis hemimelica (DEH) involving the posteromedial distal femur in a 4-year-old girl. The patient underwent lesion resection with internal fixation of the articular cartilage followed by autologous chondrocyte implantation (ACI) to restore the articular surface and epiphysis. At the 7-year follow-up, the patient had no pain or difficulty with participation in sports. Advanced imaging showed a stable articular surface with evidence of durable cartilage integration. Conclusion: DEH is a rare disease often treated by resection. In cases where the articular surface of the knee is involved, we have demonstrated that augmentation with ACI can be an effective treatment option.

Comprehensive Arthroscopic Characterization of Discoid Meniscus Tears and Instability Using the PRiSM Discoid Meniscus Classification.

The discoid meniscus is a congenital abnormality, with the vast majority occurring in the lateral meniscus. More commonly seen in pediatric populations, patients present with acute or chronic knee symptoms such as joint line pain, audible or palpable mechanical symptoms, and the inability to achieve terminal extension. The classic discoid classification system by Watanabe excludes anterior and horizontal instability and tearing that commonly occur with this pathology. A comprehensive classification, the Pediatric Research in Sports Medicine (PRiSM) Discoid Meniscus Classification, was developed to include these characteristics. To complement this classification system, we describe a complete arthroscopic examination of the discoid meniscus, assessing meniscal width, height, instability, and tearing. For thorough anterior assessment, the importance of medial portal viewing with lateral portal probing is highlighted. Assessment of the meniscus for tearing and instability should be performed before and after saucerization. Consistent use of a comprehensive classification system and a diagnostic arthroscopic exam will improve the understanding, treatment, and quality of research in the discoid meniscus.

Measuring the impact of a "Virtual Pediatric Trauma Center" (VPTC) model of care using telemedicine for acutely injured children versus the standard of care: study protocol for a prospective stepped-wedge trial.

BACKGROUND: The current standard of care in the treatment of children with physical trauma presenting to non-designated pediatric trauma centers is consultation with a pediatric trauma center by telephone. This includes contacting a pediatric trauma specialist and transferring any child with a potentially serious injury to a regionalized level I pediatric trauma center. This approach to care frequently results in medically unnecessary transfers and may place undue burdens on families. A newer model of care, the "Virtual Pediatric Trauma Center" (VPTC), uses telemedicine to make the expertise of a level I pediatric trauma center virtually available to any hospital. While the use of the VPTC model of care is increasing, there have been no studies comparing the VPTC to standard care of injured children at non-designated trauma centers with respect to patient- and family-centered outcomes. The goal of this study is to compare the current standard of care to the VPTC with respect to family-centered outcomes developed by parents and community advisory boards. METHODS: We will use a stepped-wedge trial design to enroll children with physical trauma presenting to ten hospitals, including level II, level III, and non-designated trauma centers. The primary outcome measures are parent/family experience of care and distress 3 days following injury. Secondary aims include 30-day healthcare utilization, parent/family out-of-pocket costs at 3 days and 30 days after injury, transfer rates, and parent/family distress 30 days following injury. We expect at least 380 parents/families of children will be eligible for the study following an emergency department physician's request for a level I pediatric trauma center consultation. We will evaluate parent/family experience of care and distress using previously validated instruments, healthcare utilization by family recollection and medical record abstraction, and out-of-pocket costs using standard economic analyses. DISCUSSION: We expect that the findings from this study will inform other level I pediatric trauma centers and non-pediatric trauma centers on how to improve their systems of care for injured children. The results will help to optimize communication, confidence, and shared decision-making between parents/families and clinical staff from both the transferring and receiving hospitals. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04469036. Registered July 13, 2020 before start of inclusion.

COVID-19 and Youth Sports: What Are the Risks of Getting Back on the Field Too Quickly?

The widespread shutdown in response to the coronavirus disease 2019 (COVID-19) pandemic, although varied across state and county levels, has undoubtedly impacted everyone to some degree. Within the pediatric population, the closure of schools and organized youth athletic programs has resulted in a unique situation that has made athletes physically deconditioned and at risk for injury. As sports and competition gradually restart, there are considerable risks to the skeletally immature athlete. The anatomic and physiologic changes that occur to bone and cartilage during growth make the young athlete particularly susceptible to both acute and overuse injuries. In the context of the pandemic, deconditioning, obesity, lack of variety, and the resultant mental health burden pose unique challenges in ensuring that young athletes safely return to the field. This review aims to identify risk factors for sport-related injuries and to outline strategies for minimizing these injuries as pediatric patients return-to-play after COVID-19. [Pediatr Ann. 2021;50(11):e465-e469.].

Three-Year Outcomes After MACI for Glenoid Cartilage Loss in an Adolescent Athlete: A Case Report.

CASE: We report the 3-year outcomes of a 14-year-old boy who anteriorly dislocated his shoulder playing football and suffered a 9-cm2 chondral defect of the anterior glenoid and subsequently treated with matrix-applied characterized autologous chondrocytes (MACI) of the defect with open labral repair. CONCLUSION: The management of glenohumeral chondral lesions in adolescent patients remains a challenge. Our case of the successful treatment of a glenoid chondral defect with MACI offers hope as a potential treatment option for adolescent patients with this challenging problem.

Orthopaedic In-Training Examination: History, Perspective, and Tips for Residents.

Introduced in 1963, the orthopaedic in-training examination (OITE) is a standardized, national test administered annually to orthopaedic residents by the American Academy of Orthopaedic Surgeons. The examination consists of 275 multiple-choice questions that cover 11 domains of orthopaedic knowledge, including basic science, foot and ankle, hand, hip and knee, oncology, pediatrics, shoulder and elbow, spine, sports medicine, trauma, and practice management. The OITE has been validated and is considered predictive of success in both orthopaedic surgery residency and on the American Board of Orthopaedic Surgery part I examination. This article provides a historical overview of the OITE, details its current structure and scoring system, and reviews currently available study materials. For examination preparation, the residents are encouraged to (1) start the examination preparation early, (2) practice on old OITE or self-assessment examination questions, (3) focus on the questions answered incorrectly, (4) focus on comprehension over memorization, and (5) recognize and avoid burnout. Finally, the residents should have a systemic way of approaching each multiple-choice question, both during practice and on the actual examination.

Defining length stability in paediatric femoral shaft fractures treated with titanium elastic nails.

INTRODUCTION: Optimal paediatric femoral shaft fracture patterns or lengths amenable to titanium elastic nail stabilization have not been well defined. The purpose of this study is to identify radiographic parameters predictive of treatment failure with flexible intramedullary nails based upon fracture morphology. METHODS: A retrospective review was performed of all femoral shaft fractures treated with flexible intramedullary nails over a five-year period. All patients with at least six weeks of postoperative radiographic imaging were included. Fracture characteristics included location, pattern, length, obliquity, angulation, translation and shortening. Postoperative radiographs were reviewed to determine shortening and angulation. RESULTS: There were 58 patients with 60 femoral shaft fractures stabilized with titanium nails, with 46 healing within acceptable parameters and 14 considered malunions. Six of the 14 malunions developed complications requiring early unplanned intervention. No patients in the treatment success group had a complication. Between the treatment success and failure groups, fracture pattern, location, length, obliquity, angulation, translation or shortening were not statistically different. Mean nail canal fill was significantly lower in the failure group (0.72 versus 0.81; p = 0.0146), with a receiver operating characteristic curve identifying canal fill 76% as the optimal threshold. CONCLUSION: This is the first study to measure the length and obliquity of paediatric femoral shaft fractures and to determine their relationship to radiographic alignment after healing. None of the preoperative fracture characteristics were predictive of malalignment or shortening. We recommend the use of larger nail sizes in the treatment of paediatric femoral shaft fractures, especially if there is concern for residual instability. LEVEL OF EVIDENCE: IV.

What Neuromonitoring Changes Can Be Expected During Hip Arthroscopy in the Pediatric Population?

BACKGROUND: As its indications have evolved, hip arthroscopy is now performed more frequently in pediatric patients. However, despite this increase, there is a lack of evidence in the literature about its safety in this population in regard to traction injury of the nerves of the lower extremity. PURPOSE: To determine neuromonitoring changes of the sciatic, femoral, and obturator nerves during hip arthroscopy in the pediatric population and determine the rate of and risk factors for clinical neurapraxia. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review was performed of all pediatric patients who underwent hip arthroscopy with neuromonitoring from December 2013 to October 2018. Neuromonitoring included somatosensory evoked potentials (SSEPs) in the peroneal and posterior tibial nerves and electromyography (EMG) signal for the obturator, femoral, and peroneal and posterior tibial nerves. Traction was applied using a radiolucent traction table. We recorded total traction time, surgery time, SSEP changes >50% after traction application, and EMG activity. We also recorded whether there was a clinical neurapraxia and when nerve function returned, and analyzed surgical and patient characteristic data for risk factors for neurapraxia. RESULTS: A total of 89 patients had hip arthroscopy (median traction time, 69 minutes). SSEP changes >50% occurred in 78% of patients in the peroneal nerve and 73% in the posterior tibial nerve. EMG activity was observed in 9% of patients in the obturator nerve, 8% in the femoral nerve, 12% in the peroneal nerve, and 8% in the posterior tibial nerve. Clinical neurapraxia was seen in 19% of patients in either the peroneal nerve or posterior tibial nerve but resolved by 2 days postoperatively. Those who sustained a neurapraxia had a 32-minute longer surgery and 6-minute longer traction time. The clinical rate of neurapraxia of the pudendal nerve was 0%. CONCLUSION: Neuromonitoring changes are common during hip arthroscopy and nearly 1 in 5 pediatric patients will have some decreased sensation in either the peroneal or the posterior tibial nerve that resolves within 1 to 2 days after surgery. In pediatric patients, longer surgery and traction times during hip arthroscopy are associated with a higher rate of neurapraxia than that reported for adults.

Potential effect of bio-surfactants on sea spray generation in tropical cyclone conditions.

Despite significant improvement in computational and observational capabilities, predicting intensity and intensification of major tropical cyclones remains a challenge. In 2017 Hurricane Maria intensified to a Category 5 storm within 24 h, devastating Puerto Rico. In 2019 Hurricane Dorian, predicted to remain tropical storm, unexpectedly intensified into a Category 5 storm and destroyed the Bahamas. The official forecast and computer models were unable to predict rapid intensification of these storms. One possible reason for this is that key physics, including microscale processes at the air-sea interface, are poorly understood and parameterized in existing forecast models. Here we show that surfactants significantly affect the generation of sea spray, which provides some of the fuel for tropical cyclones and their intensification, but also provides some of the drag that limits intensity and intensification. Using a numerical model verified with a laboratory experiment, which predicts spray radii distribution starting from a 100 µm radius, we show that surfactants increase spray generation by 20-34%. We anticipate that bio-surfactants affect heat, energy, and momentum exchange through altered size distribution and concentration of sea spray, with consequences for tropical cyclone intensification or decline, particularly in areas of algal blooms and near coral reefs, as well as in areas affected by oil spills and dispersants.

Bilateral Destructive Hip Disease from Untreated Juvenile Idiopathic Arthritis.

We report a novel case of a pediatric patient with bilateral hip destruction from untreated Juvenile idiopathic arthritis (JIA). She was presented at the age of 9 with hip pain associated with bilateral acetabular dysplasia and a dislocated left femoral head. Only 1.5 years later, the patient developed complete destruction of the left femoral head and dislocated right femoral head. The authors have not identified literature describing a similar case report of bilateral femoral head destruction resulting from Persistent Oligoarticular JIA. Pediatric patients presenting with rapidly evolving destructive process should be evaluated for rheumatologic, infectious, and spinal etiologies.