Concomitant Posterolateral Corner Injuries in Skeletally Immature Patients With Acute Anterior Cruciate Ligament Injuries.

BACKGROUND: Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients. METHODS: Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist. RESULTS: A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19). CONCLUSIONS: Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients. LEVEL OF EVIDENCE: Level IV-diagnostic study.

Traumatic Shoulder Dislocation Among Adolescents: Hill-Sachs Lesion Volume and Recurrent Instability.

BACKGROUND: Accurate assessment of Hill-Sachs lesions (HSLs) and their relationship to the glenoid track is essential to optimizing management following traumatic shoulder dislocation. The purpose of this study was to measure the size of HSLs by a novel method with magnetic resonance (MR) arthrography and to investigate the relationship between lesion size and instability history in adolescents (below 19 y of age) with a history of traumatic dislocation. METHODS: All shoulder MR arthrograms queried to identify HSLs over a 4-year period were retrospectively reviewed and independently evaluated by 2 blinded musculoskeletal radiologists. HSLs were evaluated on axial T1-weighted fat-saturated images. For each consecutive image slice in which the HSL was identified, a freehand region of interest was constructed along the compression fracture cavity. Region of interest sum was multiplied by image slice thickness (and gap between slices if present) to generate a total HSL volume (mm). Subject chart review was then performed to acquire demographic data, including shoulder dislocation history. RESULTS: A total of 30 patients met inclusion criteria and included 22 boys (mean age, 16.3 y) and 8 girls (mean age, 16.4 y). Four patients had a history of 1 traumatic dislocation, 12 had a history of 2, and 14 had a history of ≥3. The average size of the HSL for all patients was 3.8 mm (range, 0.52 to 11 mm). There was no significant difference in HSL volume between the 21 skeletally immature (3.7 mm) and 9 skeletally mature (4.2 mm) patients (P=0.67). Patients with a history of 1, 2, or 3+ dislocations had an average HSL volume of 1.3, 3.7, and 4.7 mm, respectively. The measurement method revealed excellent interreader reliability (P=0.00). There was a statistically significant difference between dislocation history group mean HSL volumes (P=0.019), as well as a statistically significant difference between the number of dislocations and lesion volume (P=0.011). CONCLUSIONS: HSLs can be effectively measured in adolescent patients using MR arthrography and patients with larger HSLs have more recurrent instability episodes, potentially meriting greater and earlier attention to the defect. LEVEL OF EVIDENCE: Prognostic/diagnostic study level IV.

mTOR attenuates the inflammatory response in cardiomyocytes and prevents cardiac dysfunction in pathological hypertrophy.

Previous studies have suggested that inhibition of the mammalian target of rapamycin (mTOR) by rapamycin suppresses myocardial hypertrophy. However, the role of mTOR in the progression of cardiac dysfunction in pathological hypertrophy has not been fully defined. Interestingly, recent reports indicate that the inflammatory response, which plays an important role in the development of heart failure, is enhanced by rapamycin under certain conditions. Our aim in this study was to determine the influence of mTOR on pathological hypertrophy and to assess whether cardiac mTOR regulates the inflammatory response. We generated transgenic mice with cardiac-specific overexpression of wild-type mTOR (mTOR-Tg). mTOR-Tg mice were protected against cardiac dysfunction following left ventricular pressure overload induced by transverse aortic constriction (TAC) (P < 0.01) and had significantly less interstitial fibrosis compared with littermate controls (WT) at 4 wk post-TAC (P < 0.01). In contrast, TAC caused cardiac dysfunction in WT. At 1 wk post-TAC, the proinflammatory cytokines interleukin (IL)-1ß and IL-6 were significantly increased in WT mice but not in mTOR-Tg mice. To further characterize the effects of mTOR activation, we exposed HL-1 cardiomyocytes transfected with mTOR to lipopolysaccharide (LPS). mTOR overexpression suppressed LPS-induced secretion of IL-6 (P < 0.001), and the mTOR inhibitors rapamycin and PP242 abolished this inhibitory effect of mTOR. In addition, mTOR overexpression reduced NF-κB-regulated transcription in HL-1 cells. These data suggest that mTOR mitigates adverse outcomes of pressure overload and that this cardioprotective effect of mTOR is mediated by regulation of the inflammatory reaction.

Publication rates of podium versus poster presentations at the American Orthopaedic Society for Sports Medicine meetings: 2006-2010.

BACKGROUND: Presentations at scientific meetings are often used to influence clinical practice, yet many presentations are not ultimately published in peer-reviewed journals. Previously reported publication rates for orthopaedic specialties have varied from 34% to 52%. In addition, the publication rate of accepted abstracts is a strong indicator of meeting quality, and it has a potential effect on clinical practice. To date, no studies have investigated publication rates in the field of sports medicine, and specifically for abstracts presented at American Orthopaedic Society for Sports Medicine (AOSSM) meetings. PURPOSE: To determine the overall publication rate of abstracts presented at AOSSM annual meetings and whether there were differences in publication rates between poster and podium presentations. STUDY DESIGN: Descriptive epidemiology study. METHODS: A comprehensive search was performed using PubMed and Google Scholar for all published manuscripts pertaining to abstracts presented at the 2006 to 2010 AOSSM annual meetings. Abstracts were classified according to presentation type (podium, poster) and subsequently were categorized into subspecialty area and study design. For published abstracts, the journal and publication date were recorded. RESULTS: A total of 1665 abstracts were submitted to AOSSM annual meetings from 2006 to 2010, with 444 abstracts accepted (26.7% overall acceptance rate); there were 277 podium presentations and 167 posters. Of these 444 abstracts, 298 (67.1%) were published within 3 years in peer-reviewed journals. The overall publication rates for podium and poster presentations were 73.3% and 56.9%, respectively. For the combined years of 2006 to 2010, podium presentations were 2.08 (95% CI, 1.39-3.11) times more likely to be published compared with poster presentations. CONCLUSION: The overall publication rate of abstracts presented at AOSSM annual meetings (67.1%) was much higher than that reported for other orthopaedic meetings (34%-52%), highlighting the overall educational value and information quality of AOSSM meetings. In addition, there was a significant difference in the overall publication rates for podium and poster presentations. These data suggest that the quality and type of poster and podium presentations may not be equal, and these potential differences should be kept in mind when considering changes in clinical practice according to type of meeting presentation. Furthermore, AOSSM annual meeting program planners should consider these results when investigating ways to further improve the quality of research presented.

Development of a Large Animal Model of Osteochondritis Dissecans of the Knee: A Pilot Study.

BACKGROUND: Treatment of osteochondritis dissecans (OCD) of the knee is challenging, and evidence for stage-dependent treatment options is lacking. Basic science approaches utilizing animal models have provided insight into the etiology of OCD but have yet to produce a reliable and reproducible large animal model of the disease on which to test new surgical strategies. PURPOSE/HYPOTHESES: The purpose of this study was to develop an animal model featuring an OCD-like lesion in terms of size, location, and International Cartilage Repair Society (ICRS) grading. The hypothesis was that surgical creation of an osteochondral defect followed by placement of a barrier between parent bone and progeny fragment would generate a reproducible OCD-like lesion. STUDY DESIGN: Controlled laboratory study. METHODS: Bilateral osteochondral lesions were created in the medial femoral condyles of 9 Yucatan minipigs. After lesion creation, a biodegradable membrane was interposed between the progeny and parent bone. Five different treatment groups were evaluated at 2 weeks: a control with no membrane (ctrl group; n = 4), a slowly degrading nanofibrous poly(∊-caprolactone) membrane (PCL group; n = 4), a fenestrated PCL membrane with 1.5-mm holes covering 25% of surface area (fenPCL group; n = 4), a collagen membrane (Bio-Gide) (CM group; n = 3), and a fenestrated CM (fenCM group; n = 3). Five unperturbed lateral condyles (1 from each treatment group) served as sham controls. After euthanasia on day 14, the lesion was evaluated by gross inspection, fluoroscopy, micro-computed tomography (micro-CT), and histology. To quantify changes between groups, a scoring system based on gross appearance (0-2), fluoroscopy (0-2), and micro-CT (0-6) was established. Micro-CT was used to quantify bone volume per total volume (BV/TV) in a defined region surrounding and inclusive of the defect. RESULTS: The no scaffold group showed healing of the subchondral bone at 2 weeks, with continuity of subchondral bone elements. Conversely, condyles treated with PCL or CM showed substantial remodeling, with loss of bone in both the progeny fragment and surrounding parent bone. When these membranes were fenestrated (fenPCL and fenCM groups), bone loss was less severe. Histological analysis showed no integration in the cartilage layer in any treatment group, while fibrous tissue formed between the parent and progeny fragments. Micro-CT showed significant differences in mean BV/TV between the PCL (27.4% ± 2.3%) and the sham (47.7% ± 1.4%) or no scaffold (54.9% ± 15.1%) groups (P < .01 and P < .05, respectively). In addition, a significant difference in bone loss was evident between the PCL and fenPCL groups (mean BV/TV, 46.6% ± 15.2%; P < .05), as well as between the PCL and fenCM (mean BV/TV, 50.9% ± 3.5%) and fenPCL groups (P < .01). Grading by 6 blinded reviewers using an OCD scoring system with 3 subcategories showed a significant difference between control and PCL groups. CONCLUSION: This study successfully developed a large animal model of OCD-like lesions in the knee joint of Yucatan minipigs. The lesions generated matched characteristics of an ICRS grade 3 OCD lesion in humans. These findings set the stage for ongoing model refinement as well as exploration of novel interventional therapies to restore function and bone and cartilage patency in individuals affected by this rare but significant disease. CLINICAL RELEVANCE: This developed model will serve as a platform on which to further investigate the natural course as well as emerging treatment options for OCD.

United States medical school graduate interest in radiology residency programs as depicted by online search tools.

Recent media publications have indicated a tough job market in medical specialty positions for medical school graduates, specifically in the field of radiology. Internet search tools, such as Google Trends, have proved useful in the prediction of certain diseases on the basis of the search volume index for a specific term. The authors hypothesized that online search tools might be useful in the prediction of US medical school graduates' interest in residency positions in radiology. Google Trends indicated an increase over time in searches for "radiology salary" and a decrease over time in searches for "radiology residency." National Resident Matching Program results for diagnostic radiology showed an increase from 2004 to 2009 in the percentage of US graduates entering radiology but a dramatic drop from 2010 to 2013. This occurred even while the total number of US graduates active in the National Resident Matching Program increased. This finding might have been foretold on the basis of online query result trends. Online search data may be a useful insight into the interests of US medical school graduates and may be predictive of unfilled radiology residency positions and eventual increased shortages of community radiologists coming from US medical schools.

The thrower's shoulder.

Throwers, or athletes who engage in repetitive overhead motions, are a unique subset of athletes that experience distinct shoulder injuries. Athletes engaged in baseball comprise the majority of patients seeking orthopedic care for throwing related injuries. Injuries specific to throwers most commonly involve the labrum and the undersurface of the rotator cuff. In addition, tissue changes in both the anterior and posterior glenohumeral capsule are common with repetitive overhead motions. These capsular changes alter. This article will examine the pathomechanics of injuries to throwers, elaborate means of diagnoses of cuff and labral injury and discuss recent advances in both non-operative and operative interventions, including preventative principles.

Myocyte injury along myofibers in left ventricular remodeling after myocardial infarction.

Left ventricular (LV) remodeling following myocardial infarction (MI) is considered to contribute to cardiac dysfunction. Though myofiber organization is a key component of cardiac structure, functional and anatomical features of injured myofiber during LV remodeling have not been fully defined. We investigated myocyte injury after acute MI in a mouse model. Mice were subjected to surgical coronary occlusion/reperfusion by left anterior descending coronary artery (LAD) ligation and examined at 1 week and 4 weeks post-MI. Magnetic resonance imaging (MRI) analysis demonstrated a significant decrease in systolic regional wall thickening (WT) in the border and remote zones at 4 weeks post-MI compared to that at 1 week post-MI (-86% in border zone, P<0.05, and -77% in remote zone, P<0.05). Histological assays demonstrated that a broad fibrotic scar extended from the initial infarct zone to the remote zone along mid-circumferential myofibers. Of particular note was the fact that no fibrosis was found in longitudinal myofibers in the epi- and endo-myocardium. This pattern of the scar formation coincided with the helical ventricular myocardial band (HVMB) model, introduced by Torrent-Guasp. MRI analysis demonstrated that the extension of the fibrotic scar along the band might account for the progression in cardiac dysfunction during LV remodeling.