Early Outcomes of a Universal Femoral Component with an Ultracongruent Insert.

INTRODUCTION: A primary total knee arthroplasty (TKA) system was introduced with a modern universal femoral design with a wide range of size and constraint options to accommodate a variety of patient anatomy, while incorporating streamlined instrumentation for maximum operating room efficiency and economy. The purpose of this study is to review the early clinical outcomes and survivorship at minimum two-year follow up with this knee system. MATERIALS AND METHODS: From September 2015 to December 2019, 797 patients (1004 knees) underwent primary total knee arthroplasty (TKA) at our center with the TJO Klassic® Complete Primary Knee System (Total Joint Orthopedics Inc., Salt Lake City, Utah) with ultracongruent bearings and were available for study with minimum two-year follow up. All office and hospital records were reviewed for patient demographics, preoperative and postoperative clinical assessments, including range of motion, Knee Society Scores (KSS), University of California at Los Angeles (UCLA) activity scales, complications, and reoperations. RESULTS: Mean follow up was 3.1 years (range, 2-6; standard deviation [SD] ±1.0). There were 471 female patients (59%) and 326 male patients (41%). Mean age at surgery was 69.3 years and mean body mass index was 32.9kg/m2. An all-polyethylene tibial component was used in 305 knees (30.4%) while a modular titanium tibial baseplate with polyethylene insert was used in 699 (69.6%). The patella was left unresurfaced in 381 knees (37.9%). KS scores, including pain component, clinical, and functional, as well as UCLA scores, all improved significantly (p<0.001). Two patients (3 knees) underwent revision. One patient required two-staged revision for treatment of infection in both knees, and one patient required patellar revision for aseptic loosening. Kaplan-Meier survival at 6.2 years was 98.4% (95% CI: ±0.97%) to endpoint of revision of any part for any cause and 99.6% (95% CI: ±0.36%) to endpoint of aseptic revision. CONCLUSIONS: At early minimum two-year follow up, this modern universal complete knee system used with ultracongruent bearings demonstrates excellent clinical outcomes and survival.

Age of Acquisition Modulates Alpha Power During Bilingual Speech Comprehension in Noise.

Research on bilingualism has grown exponentially in recent years. However, the comprehension of speech in noise, given the ubiquity of both bilingualism and noisy environments, has seen only limited focus. Electroencephalogram (EEG) studies in monolinguals show an increase in alpha power when listening to speech in noise, which, in the theoretical context where alpha power indexes attentional control, is thought to reflect an increase in attentional demands. In the current study, English/French bilinguals with similar second language (L2) proficiency and who varied in terms of age of L2 acquisition (AoA) from 0 (simultaneous bilinguals) to 15 years completed a speech perception in noise task. Participants were required to identify the final word of high and low semantically constrained auditory sentences such as "Stir your coffee with a spoon" vs. "Bob could have known about the spoon" in both of their languages and in both noise (multi-talker babble) and quiet during electrophysiological recording. We examined the effects of language, AoA, semantic constraint, and listening condition on participants' induced alpha power during speech comprehension. Our results show an increase in alpha power when participants were listening in their L2, suggesting that listening in an L2 requires additional attentional control compared to the first language, particularly early in processing during word identification. Additionally, despite similar proficiency across participants, our results suggest that under difficult processing demands, AoA modulates the amount of attention required to process the second language.

Electrophysiology reflects the influence of discourse context on auditory semantic processing in bilinguals.

Most language experiences take place at the level of multiple sentences. However, previous studies of second language (L2) comprehension have typically focused on lexical- and sentence-level processing. Our study addresses this gap by examining auditory discourse comprehension in 32 English/French bilinguals. We tested the prediction of the noisy channel model (Futrell & Gibson, 2017) that bilinguals will rely more on top-down, discourse-level cues in L2 because these are common across languages, as opposed to the language-specific associations of an often weaker L2. We further hypothesized that these effects could be influenced by individual differences, such that participants with lower L2 proficiency or working memory would have more difficulty building and maintaining discourse context. Specifically, we measured the N400 response, an index of automatic semantic processing. Participants heard three-sentence stories with prime and target words in the final sentence whose lexical association was manipulated, as was the congruence of the target with the preceding discourse. Overall, our results support the noisy channel model of language comprehension in a sample of highly proficient bilinguals. We observed larger N400 effects of discourse congruence than lexical association, and the difference between these 2 conditions was greater in the L2 than in the L1. Additionally, the effects of lexical association were limited to the L1 and predicted by individual differences in language dominance but not working memory. These findings suggest that bilinguals do indeed make greater use of top-down, supralinguistic information in their L2 compared with their L1. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Second language lexical development and cognitive control: A longitudinal fMRI study.

In this paper we report a longitudinal functional magnetic resonance imaging (fMRI) study that tested contrasting predictions about the time course of cognitive control in second language (L2) acquisition. We examined the neural correlates of lexical processing in L2 learners twice over the course of one academic year. Specifically, while in the scanner, participants were asked to judge the language membership of unambiguous first and second language words, as well as interlingual homographs. Our ROI and connectivity analyses reveal that with increased exposure to the L2, overall activation in control areas such as the anterior cingulate cortex decrease while connectivity with semantic processing regions such as the middle temporal gyrus increase. These results suggest that cognitive control is more important initially in L2 acquisition, and have significant implications for understanding developmental and neurocognitive models of second language lexical processing.