Research Spotlight

Marquez-Arabia, W. H., J. Gomez-Hoyos, M. Gomez, I. Florez, J. A. Gallo, F. Monsalve, L. F. Arias and H. D. Martin (2017). “Influence of aging on microvascular supply of the gluteus medius tendon: A cadaveric and histologic study.” Arthroscopy 33(7): 1354-1360.

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PURPOSE: The purpose of this cadaveric study was to assess the relation between age and microvascular supply of 3 areas of the gluteus medius tendon using a previously validated CD31 immunohistochemistry staining technique. METHODS: Twenty-four fresh-frozen gluteus medius specimens were obtained through a posterolateral approach to the hip. Specimens aged 18 years or older, of either sex, and of any race were considered for this study. The average age of donors was 47.3 years (range, 18-68 years). Each sample was divided into 3 portions: musculotendinous, tendinous, and tendon-bone junction. H&E staining was used for qualitative structural analysis, and then all samples underwent staining with CD31 immunohistochemistry for quantitative assessment of vessels per square millimeter. A comparison of the microvessel density between zones according to age was performed by an analysis of variance. To evaluate the relation between microvessel supply and age, a regression model with curvilinear estimation was used. The data were fitted to a quadratic model. RESULTS: Vascular supply in transversal and longitudinal cuts regardless of the zone was, on average, 53.9 +/- 32.1 vessels/mm2 and 51.1 +/- 19.3 vessels/mm2, respectively. All the areas of the tendon showed a strength of relation (R) ranging from 0.41 to 0.76 between age and vascular supply. In addition, the proportion of vascular supply change explained by age (R2) was significant in most cases (ranging from 0.17 to 0.56, with P < .05). CONCLUSIONS: There is a chronological relation between aging and microvascular supply of the gluteus medius tendon, in which an initial increase occurs from 18 years of age to 30 to 40 years of age, with a progressive decrease after 50 years of age. CLINICAL RELEVANCE: The findings of our study may have implications for increased vulnerability of the gluteus medius tendon and decreased healing potential.

Nguyen, A. D., S. J. Spechler, M. N. Shuler, R. F. Souza and K. B. Dunbar (2017). “Unique clinical features of los angeles grade d esophagitis suggest that factors other than gastroesophageal reflux contribute to its pathogenesis.” J Clin Gastroenterol: 2017 Jun [Epub ahead of print].

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BACKGROUND: The Los Angeles (LA) grade of reflux esophagitis (A to D) is assumed to reflect severity of the underlying gastroesophageal reflux disease (GERD). Thus, LA-D esophagitis patients might be expected to have the most conditions predisposing to GERD (eg, obesity, hiatal hernia), and the highest frequency of GERD symptoms. GOALS: The main goal of this study is to compare clinical features of patients with the most severe (LA-D) and mildest (LA-A) grades of esophagitis. STUDY: For this comparative study, we searched our endoscopy database for patients diagnosed with LA-D or LA-A esophagitis, reviewed their endoscopic images, and reviewed medical records of the first 100 we confirmed to have LA-D or LA-A esophagitis. RESULTS: Compared with LA-A patients, LA-D patients were older (mean age, 65+/-13.4 vs. 56+/-13.4 y; P<0.001), had lower body mass index (25.9+/-5.6 vs. 29.4+/-5.3; P<0.001), were more frequently hospitalized (70% vs. 3%; P<0.001), and in the intensive care unit (15% vs. 0%; P<0.001), and had significantly more serious cardiopulmonary disorders and gastrointestinal bleeding. Conversely, a GERD history was more common in LA-A than LA-D patients (67% vs. 45%; P=0.002). Hiatal hernia was more frequent in LA-A patients than LA-D patients, but not significantly (48% vs. 36%; P=0.09). CONCLUSIONS: LA-D esophagitis primarily affects hospitalized, older, nonobese patients who often have serious comorbidities, and no history of GERD or hiatal hernia. In contrast, LA-A patients are generally younger, obese outpatients who often have a history of GERD and hiatal hernia without serious comorbidities. These profound differences between LA-A and LA-D patients suggest that factors other than typical GERD contribute to LA-D esophagitis pathogenesis.

Nasir, J. M., W. Pomeroy, A. Marler, M. Hann, T. Baykaner, R. Jones, R. Stoll, K. Hursey, A. Meadows, J. Walker and S. Kindsvater (2017). “Predicting determinants of atrial fibrillation or flutter for therapy elucidation in patients at risk for thromboembolic events (predate af) study.” Heart Rhythm 14(7): 955-961.

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BACKGROUND: Atrial fibrillation (AF) is the most common clinically significant cardiac rhythm disorder. There is considerable interest in screening for AF, as it is a leading cause of stroke, and oral anticoagulants (OACs) have been shown to significantly reduce the risk of stroke in patients with AF. Improved screening for AF with subsequent treatment may help improve long-term outcomes, but the optimal patient population and screening intensity are unknown. OBJECTIVES: In this study, we prospectively evaluated the use of the CHA2DS2-VASc score for the prediction of new-onset AF using insertable cardiac monitors (ICMs) and examined whether this screening led to the initiation of OAC therapy. METHODS: We enrolled 245 subjects with no history of AF and CHA2DS2-VASc score >/=2 to be screened for AF with an ICM. The ICMs were programmed to record AF episodes >/=6 minutes in duration. Subjects were followed for 18 months with monthly remote interrogations and all events adjudicated by cardiologists. In subjects diagnosed with AF, medical records were reviewed to determine subsequent care. RESULTS: During a mean follow-up of 451 +/- 185 days, the incidence of AF was 22.4% (95% confidence interval 17.2%-27.7%) with a mean time to detection of 141.3 +/- 139.5 days. Among subjects newly diagnosed with AF, 76.4% were prescribed anticoagulation with either a novel OAC (n = 38) or warfarin (n = 4). CONCLUSION: In this large prospective cohort of subjects with CHA2DS2-VASc scores >/=2, 22.4% were newly diagnosed with AF and the majority of these subjects were given OACs, suggesting a potential role of ICMs in AF screening.

Naessens, J. M., M. B. Van Such, R. E. Nesse, J. A. Dilling, S. J. Swensen, K. M. Thompson, J. M. Orlowski and P. J. Santrach (2017). “Looking under the streetlight? A framework for differentiating performance measures by level of care in a value-based payment environment.” Acad Med 92(7): 943-950.

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The majority of quality measures used to assess providers and hospitals are based on easily obtained data, focused on a few dimensions of quality, and developed mainly for primary/community care and population health. While this approach supports efforts focused on addressing the triple aim of health care, many current quality report cards and assessments do not reflect the breadth or complexity of many referral center practices.In this article, the authors highlight the differences between population health efforts and referral care and address issues related to value measurement and performance assessment. They discuss why measures may need to differ across the three levels of care (primary/community care, secondary care, complex care) and illustrate the need for further risk adjustment to eliminate referral bias.With continued movement toward value-based purchasing, performance measures and reimbursement schemes need to reflect the increased level of intensity required to provide complex care. The authors propose a framework to operationalize value measurement and payment for specialty care, and they make specific recommendations to improve performance measurement for complex patients. Implementing such a framework to differentiate performance measures by level of care involves coordinated efforts to change both policy and operational platforms. An essential component of this framework is a new model that defines the characteristics of patients who require complex care and standardizes metrics that incorporate those definitions.

Liu, G. T., B. C. Balldin, J. R. Zide and C. T. Chen (2017). “A biomechanical analysis of interference screw versus bone tunnel fixation of flexor hallucis longus tendon transfers to the calcaneus.” J Foot Ankle Surg 56(4): 813-816.

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The flexor hallucis longus tendon transfer is commonly used to restore function in chronic Achilles tendon ruptures and chronic Achilles tendinopathy. The tendon is often secured to the calcaneus either through a bone tunnel or by an interference screw. We hypothesized that tenodesis using the bone tunnel method would be mechanically superior to interference screw fixation for flexor hallucis longus transfers. Eight matched pairs of cadaveric specimens were assigned randomly to the bone tunnel or interference screw technique and were loaded to failure. Biomechanical analysis was performed to evaluate the ultimate strength, peak stress, Young’s modulus, failure strain, and strain energy. Unpaired comparison, paired comparison, and linear regression analyses were used to determine statistical significance. A slight 22% +/- 9% decrease in Young’s modulus and a 52% +/- 18% increase of strain energy were found in the interference screw group. However, no differences in ultimate strength, peak stress, or failure strain were seen between the 2 groups on paired comparison. Our findings suggest that interference screw fixation provides similar spontaneous biomechanical properties to the use of a bone tunnel for flexor hallucis longus transfer to the calcaneus. The interference screw is a practical option for fixation of the flexor hallucis longus tendon to the calcaneus and can be performed through a single incision approach.