Slowly digestible property of highly branched α-limit dextrins produced by 4,6-α-glucanotransferase from Streptococcus thermophilus evaluated in vitro and in vivo.

Starch molecules are first degraded to slowly digestible α-limit dextrins (α-LDx) and rapidly hydrolyzable linear malto-oligosaccharides (LMOs) by salivary and pancreatic α-amylases. In this study, we designed a slowly digestible highly branched α-LDx with maximized α-1,6 linkages using 4,6-α-glucanotransferase (4,6-αGT), which creates a short length of α-1,4 side chains with increasing branching points. The results showed that a short length of external chains mainly composed of 1-8 glucosyl units was newly synthesized in different amylose contents of corn starches, and the α-1,6 linkage ratio of branched α-LDx after the chromatographical purification was significantly increased from 4.6% to 22.1%. Both in vitro and in vivo studies confirmed that enzymatically modified α-LDx had improved slowly digestible properties and extended glycemic responses. Therefore, 4,6-αGT treatment enhanced the slowly digestible properties of highly branched α-LDx and promises usefulness as a functional ingredient to attenuate postprandial glucose homeostasis.

Cost savings of outpatient versus standard inpatient total knee arthroplasty.

BACKGROUND: With diminishing reimbursement rates and strained public payer budgets, a high-volume inpatient procedure, such as total knee arthroplasty (TKA), is a common target for improving cost efficiencies. METHODS: This prospective case-control study compared the cost-minimization of same day discharge (SDD) versus inpatient TKA. We examined if and where cost savings can be realized and the magnitude of savings that can be achieved without compromising quality of care. Outcome variables, including detailed case costs, return to hospital rates and complications, were documented and compared between the first 20 SDD cases and 20 matched inpatient controls. RESULTS: In every case-control match, the SDD TKA was less costly than the inpatient procedure and yielded a median cost savings of approximately 30%. The savings came primarily from costs associated with the inpatient encounter, such as surgical ward, pharmacy and patient meal costs. At 1 year, there were no major complications and no return to hospital or readmission encounters for either group. CONCLUSION: Our results are consistent with previously published data on the cost savings associated with short stay or outpatient TKA. We have gone further by documenting where those savings were in a matched cohort design. Furthermore, we determined where cost savings could be realized during the patient encounter and to what degree. In carefully selected patients, outpatient TKA is a feasible alternative to traditional inpatient TKA and is significantly less costly. Furthermore, it was deemed to be safe in the perioperative period.

CONTEXTE: Dans le contexte de budgets publics serrés et de taux de remboursement à la baisse, une intervention chirurgicale en service interne à volume élevé, comme l'arthroplastie totale du genou, est souvent ciblée pour améliorer le rapport coût­efficacité. MÉTHODES: Cette étude cas­témoins prospective a fait une analyse de minimisation des coûts de l'arthroplastie totale du genou en chirurgie d'un jour et en service interne. Nous avons examiné si et où des économies peuvent être réalisées et l'ampleur des économies pouvant être obtenues sans compromettre la qualité des soins. Les variables dépendantes, notamment les coûts détaillés des cas, le taux de retour à l'hôpital et les complications, ont été documentées, puis comparées entre les 20 premiers cas de chirurgie d'un jour et 20 cas­témoins appariés de chirurgie en service interne. RÉSULTATS: Pour chaque appariement cas­témoins, l'arthroplastie totale du genou en chirurgie d'un jour était moins coûteuse que la chirurgie en service interne et a généré des économies médianes d'environ 30 %. Les économies découlaient principalement des coûts associés à l'hospitalisation du patient tels que les coûts de l'unité de soins chirurgicaux, de la pharmacie et des repas du patient. Après 1 an, ni l'un ni l'autre des 2 groupes ne présentait de complications majeures, de retours à l'hôpital ou de réadmissions. CONCLUSION: Nos résultats concordent avec les données antérieures publiées sur les économies associées à l'arthroplastie totale du genou pratiquée en chirurgie d'un jour ou en service interne de courte durée. Nous sommes allés plus loin en documentant également où les économies se situaient dans un modèle cas­témoins. De plus, nous avons déterminé les aspects de la rencontre avec le patient où des économies pourraient être réalisées et l'ampleur de ces économies. Chez des patients soigneusement choisis, l'arthroplastie totale du genou en chirurgie d'un jour est une solution de rechange envisageable à l'arthroplastie totale du genou traditionnelle en service interne et est beaucoup moins coûteuse. De plus, elle a été jugée sécuritaire en période périopératoire.

Migration pattern of a cobalt-chrome monoblock acetabular component after metal-on-metal hip resurfacing.

OBJECTIVES: The purpose of this study was to study the initial fixation and migration pattern of a monoblock acetabular component used for a metal on metal hip resurfacing using Einzel Bild Roentgen Analyse (EBRA). METHODS: 99 patients with a mean age of 49.6 years (range 28.5-66.3 years) of whom 14 were bilateral underwent a hip resurfacing (Conserve Plus®, MicroPort, Memphis, TN) for a total of 113 resurfacings. Acetabular component orientation was noted with 35 of the 113 components (31.0%) having a lucency >2 mm on the immediate postoperative radiograph. RESULTS: The mean follow-up for our cohort of 113 hips is 50 months (2-79 months). When examining the 2-year migration mark, 37 of the 113 hips exceeded the threshold of 0.5 mm/year with a median total migration of 1.40 mm (range 1.02-4.24). 6 resurfacings underwent revision surgery for aseptic loosening of the acetabular component at a mean time of 43.6 months. Presence of initial lucency (OR 2.29, p = 0.05) was the only significant predictor of migration over threshold at 2-years. Those that had migrated over the threshold (1.0 mm) at 2 years were at significantly greater risk of continued migration at 4 years. CONCLUSIONS: The migration pattern of this component raises concerns about long term performance, with postoperative lucencies representing a significant factor for future migration.

Outcomes of joint preservation surgery: comparison of patients with developmental dysplasia of the hip and femoroacetabular impingement.

Femoroacetabular impingement (FAI) and developmental dysplasia of the hip (DDH) are fundamentally and structurally different hip abnormalities yet their clinical presentation can often be very similar. We asked whether adult patients surgically treated for DDH when compared with FAI patients achieve (i) better outcome as reflected by the WOMAC Osteoarthritis Index, (ii) higher physical activity as reflected by the UCLA physical activity scale. Five hundred fifty-six patients treated by periacetabular osteotomy for DDH and 540 patients treated for FAI (cam, pincer, or combined) in nine high-volume centers, between 2008 and 2011 were matched using propensity analysis, based on age and BMI. After exclusions, 144 pairs were evaluated on WOMAC, SF-12 Health Survey, modified Harris Hip Score (mHHS) and UCLA scale at pre and post-operations. At pre-operative evaluation, FAI patients showed lower scores on WOMAC (total, stiffness, function) and SF-12 physical. Statistically significant improvements in the outcome scores were observed from pre to post-operative time points in both treatment groups. Once FAI and DDH patients were compared, FAI patients showed lower scores on most of the outcome measures. However, these differences diminished in time, with only SF-12 mental and mHHS scores remaining significantly lower at 2-year follow-up. Because of more advanced disease at presentation, patients with FAI had an inferior clinical outcome compared with patients with DDH after surgical correction. Further prospective studies are required to better describe the long-term clinical benefits of hip joint preservation surgery.

Working toward benchmarks in orthopedic OR efficiency for joint replacement surgery in an academic centre.

BACKGROUND: The introduction of 4-joint operating rooms (ORs) to meet provincial wait time targets represented a major change in practice, providing an opportunity to optimize patient care within an OR time allotment of 8 hours. We reviewed our success rate completing 4 joint replacements within 8 hours and defined benchmarks for successful completion. METHODS: We reviewed the surgeries performed in the 4-joint ORs between May and October 2012. Using prospectively collected data from the Surgical Information Management System, each surgery time was divided into the following components: anesthesia preparation time (APT), surgical preparation time (SPT), procedure duration, anesthesia finishing time (AFT) and turnover time. We defined success as 4 joint replacements being completed within the allotted time. RESULTS: We reviewed 49 4-joint OR days for a total of 196 joint surgeries. Of the 49 days, 24 (49%) were successful. Only 2 surgeons had a success rate greater than 50%. Significant predictors of success were APT (odds ratio 1.09, 95% confidence interval [CI] 1.02-1.16), procedure duration (odds ratio 1.02, 95% CI 1.00-1.05) and AFT (odds ratio 1.19, 95% CI 1.06-1.34). We calculated probabilities for each component and derived benchmark times corresponding to the probability of 0.60. These benchmarks were APT of 9 min, SPT of 14 min, procedure duration of 68 min, AFT of 4 min and turnover of 15 min. CONCLUSION: We established benchmark times for the successful completion of 4 primary joint replacements within an 8-hour shift. Targeted interventions could maximize OR efficiency and enhance multidisciplinary care delivery.

CONTEXTE: Afin d'atteindre les cibles provinciales en matière de temps d'attente, on a mis en service des blocs opératoires (BO) dédiés à la réalisation de 4 arthroplasties consécutives. Cette mesure a représenté un changement de pratique majeur et a offert une occasion d'optimiser les soins aux patients à l'intérieur du temps opératoire alloué, soit 8 heures. Nous avons examiné notre taux de succès à effectuer 4 arthroplasties en 8 heures et défini les critères de réussite. MÉTHODES: Nous avons passé en revue les chirurgies effectuées dans les BO dédiés entre mai et octobre 2012. À l'aide des données prospectives fournies par le système de gestion des données chirurgicales, la durée de chaque intervention a été divisée en 5 temps : temps de préparation de l'anesthésie (TPA), temps de préparation chirurgicale (TPC), durée de l'intervention, temps de finalisation de l'anesthésie (TFA) et temps de roulement. La réussite était définie comme la réalisation complète de 4 arthroplasties à l'intérieur des temps alloués. RÉSULTATS: Nous avons analysé 49 jours de BO dédiés, totalisant 196 chirurgies articulaires. Sur les 49 jours, 24 (49 %) ont été couronnés de succès. Seulement 2 chirurgiens ont obtenu un taux de réussite supérieur à 50 %. Les principaux prédicteurs de succès étaient le TPA (rapport des cotes 1,09, intervalle de confiance [IC] de 95 % 1,02­1,16), la durée de l'intervention (rapport des cotes 1,02, IC de 95 % 1,00­1,05) et le TFA (rapport des cotes 1,19, IC de 95 % 1,06­1,34). Nous avons calculé les probabilités pour chaque composante et inféré les critères de durée correspondant à la probabilité de 0,60. Les critères ont été définis comme suit : TPA 9 minutes, TPC 14 minutes, durée de l'intervention 68 minutes, TFA 4 minutes et roulement 15 minutes. CONCLUSION: Nous avons établi des durées cibles pour chacune des étapes menant à la réalisation complète de 4 arthroplasties primaires à l'intérieur d'un quart de travail de 8 heures. L'application des cibles aux interventions pourraient maximiser l'efficience des BO et améliorer la prestation des soins multidisciplinaires.

What factors predict improvements in outcomes scores and reoperations after the Bernese periacetabular osteotomy?

BACKGROUND: The Bernese periacetabular osteotomy (PAO) has entered its fourth decade and is frequently used for corrective osteotomy in patients with acetabular dysplasia. Although our capacity to preserve the joint after corrective osteotomy is excellent, gaining a better understanding on how well patients function after this surgery is important as well. QUESTIONS/PURPOSES: (1) What changes in patient-reported outcomes scores occur in patients treated with PAO for hip dysplasia in the setting of a single-surgeon practice? (2) What are the predictors of clinical function and survivorship? METHODS: All 67 patients presenting to a single surgeon's clinic with hip dysplasia treated with PAO between October 2005 and January 2013 were prospectively followed. Baseline demographic data as well as pre- and postoperative radiographic and functional measurements were obtained with a minimum of 1-year followup. Radiographic criteria included Tönnis grade, Tönnis angle, minimum joint space width, center-edge angle, presence of crossover sign, medial translation of the hip center, and alpha angle. We also used validated outcome measures including the WOMAC, the UCLA Activity Scale, and the SF-12. Multiple regression analysis was used to determine predictors of functional outcome scores. RESULTS: There were increases in WOMAC, UCLA, and SF-12 Physical scores. Higher preoperative alpha angle was associated with a lower postoperative WOMAC score (ß=-0.47; 95% confidence interval [CI], -0.92 to -0.02; R2=0.08; p=0.04). The 5-year Kaplan-Meier survivorship was 94.1% (95% CI, 90.7-97.5) with reoperation (ie, hip arthroscopy and/or total hip arthroplasty) used as the endpoint for failure. With the limited numbers available, we could not identify any demographic or radiographic factors associated with reoperation. CONCLUSIONS: Overall survivorship for the PAO at our center at 5 years is comparable to other clinical series with overall functional scores improving. A greater alpha angle preoperatively was associated with poorer patient-reported outcome scores. Further research is needed to determine how and when intraarticular cartilage damage associated with dysplasia needs to be addressed. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Imagine Jane and identify John: face identity aftereffects induced by imagined faces.

It is not known whether prolonged exposure to perceived and imagined complex visual images produces similar shifts in subsequent perception through selective adaptation. This question is important because a positive finding would suggest that perception and imagery of visual stimuli are mediated by shared neural networks. In this study, we used a selective adaptation procedure designed to induce high-level face-identity aftereffects--a phenomenon in which extended exposure to a particular face facilitates recognition of subsequent faces with opposite features while impairing recognition of all other faces. We report here that adaptation to either real or imagined faces produces a similar shift in perception and that identity boundaries represented in real and imagined faces are equivalent. Together, our results show that identity information contained in imagined and real faces produce similar behavioral outcomes. Our findings of high-level visual aftereffects induced by imagined stimuli can be taken as evidence for the involvement of shared neural networks that mediate perception and imagery of complex visual stimuli.

Differences in attentional involvement underlying the perception of distinctive and typical faces.

Differences in human faces can be evaluated along a continuum that ranges from 'distinctive' to 'typical.' We examined processing differences between distinctive and typical faces by two attentional tasks that induce attentional blink (AB). Given that AB is believed to reflect temporal or capacity limits of attention, stimuli that survive AB are believed to be associated with greater processing efficiency. In a change-detection task, participants were required to detect changes in the two pairs of faces that were presented in rapid succession. Changes involving the distinctive face of a pair were more likely to be detected than those involving a typical face. In a face-identification task, distinctive faces embedded in a rapid serial visual presentation (RSVP) stream were identified with a greater accuracy than typical faces. Together, our results suggest that distinctive faces are associated with greater processing efficiency and may be explained in terms of perceptual salience, a stimulus dimension known to attract attention.

Representations of familiar and unfamiliar faces as revealed by viewpoint-aftereffects.

A viewpoint-dependent aftereffect occurs after prolonged viewing of a stimulus of a particular orientation, with the result that the test image is perceived to be facing away from the adapting orientation. Prior psychophysical work has led to the suggestion that the visual brain encodes a limited range of viewpoint information with regard to complex images. In this study, we investigated whether familiar faces were susceptible to a viewpoint aftereffect. Familiar faces are believed to be represented in a view-invariant manner, whereas unfamiliar faces are represented in a viewpoint-dependent manner. Adaptation to both familiar and unfamiliar faces influenced the perception of viewpoint of subsequent face images. However, category-specific transfer of a repulsive viewpoint-dependent aftereffect was observed with unfamiliar faces. Our results suggest that neural networks that mediate viewpoint information are also involved in view-invariant representation of familiar faces.