Early Radiographic and Clinical Outcomes of an Additive-Manufactured Acetabular Component.

Background: Additive manufacturing has recently gained popularity and is widely adopted in the orthopaedic industry. However, there is a paucity of literature on the radiographic and clinical outcomes of these relatively novel components. The aim of this study was to assess the 2-year clinical and radiographic outcomes of a specific additive-manufactured acetabular component in primary total hip arthroplasty. Methods: We performed a retrospective review of 60 patients who underwent primary total hip arthroplasty with the use of the Stryker's TRIDENT II acetabular component. Evaluation of radiographs was performed at 6 weeks, 1 year, and 2 years postoperatively. Radiographs were evaluated for radiolucencies in Charnley and DeLee zones, signs of biologic fixation, and acetabular inclination and anteversion measurements. Patient-reported outcomes and complications were also obtained. Results: There were no cases of component loosening or changes in component position during follow-up, with an average follow-up time of 1.7 years. A radiolucent line was identified in one patient in zone 1 at 6 weeks; this was absent at 1 year. Radiographic signs of cup biologic fixation were present in 85% of cases by final follow-up. The average inclination was 45.1 (SD = 4.0), and the average anteversion was 26.9 (SD = 5.2). Patient-Reported Outcomes Measurement Information System scores significantly increased at the final follow-up, and there were no complications in this cohort. Conclusions: This study demonstrated excellent radiographic and clinical outcomes with this novel additive-manufactured acetabular component at early follow-up. Although longer-term follow-up is warranted, this additively manufactured highly porous titanium acetabular component demonstrated excellent biologic fixation and reliable fixation at mid-term follow-up.

Accelerometer-Based Navigation in Primary Total Knee Arthroplasty Leads to Improved Alignment but No Change in Patient-Reported Outcomes.

BACKGROUND: Computer and accelerometer-based navigation (ABN) tools have demonstrated improved mechanical alignment in primary total knee arthroplasty (TKA). ABN, in particular, is attractive due to avoidance of pins and trackers. Prior literature has yet to demonstrate an associated improvement in functional outcomes using ABN compared to conventional instrumentation (CONV). The purpose of this study was to compare alignment and functional outcomes between CONV and ABN in primary TKA in a large patient series. METHODS: A retrospective study of 1,925 TKAs performed by a single surgeon sequentially was performed. There were 1,223 TKAs performed with CONV and measured resection technique. There were 702 TKAs performed with distal femoral ABN and restricted kinematic alignment goals. We compared radiographic alignment, Patient-Reported Outcomes Measurement Information System scores, rates of manipulation under anesthesia, and needs for aseptic revisions between cohorts. Chi-squared, Fisher's exact, and t-tests were used to compare demographics and outcomes. RESULTS: The ABN cohort had higher rates of neutral alignment postoperatively than the CONV cohort (ABN 74% versus CONV 56%, P < .001). Rates of manipulation under anesthesia (ABN 2.8% versus CONV 3.4%, P = .382) and aseptic revision (ABN 0.9% versus CONV 1.6%, P = .189) were similar. The Patient-Reported Outcomes Measurement Information System physical function (ABN 42.6 versus CONV 42.9, P = .4554), physical health (ABN 63.4 versus CONV 63.3, P = .944), mental health (ABN 51.4 versus CONV 52.7, P = .4349), and pain (ABN 32.7 versus CONV 30.9, P = .256) scores were similar. CONCLUSION: ABN is valuable in its ability to improve postoperative alignment but does not improve complication rates or patient-reported functional outcomes.

Gaining access to the unknown: Preschoolers privilege unknown information as the target of their questions about verbs.

Children are opportunistic word learners, making passive use of nearly any available cue to link labels and referents. However, children may also actively drive their word learning by inquiring about unknown labels. Until recently, research has largely overlooked active word learning mechanisms. In the current study, two experiments investigated the emergence of preschoolers' ability to tailor their questions about words and definitions to maximize information gains. Experiment 1 tested whether 3- and 5-year-olds' frequency of questionasking differed for known and unknown verbs in a referential communication task. Results revealed that 3- and 5-year-olds (N = 36) asked more questions about unknown verbs (M = 3.86) than about known verbs (M = 0.22, p < .001), but this tendency was greater for 5-year-olds (M = 6.11) than for 3-year-olds (M = 1.35, p < .001), suggesting a developmental difference in information-seeking proficiency. Experiment 2 tested whether 3- and 5-year-olds' frequency of question asking about unknown verbs differed when words were embedded in definitions of high- and low-informative quality. Results demonstrated that 3- and 5-year-olds (N = 42) asked questions about unknown verbs more when provided with uninformative definitions (M = 0.86) compared with informative definitions (M = 0.05, p = .028), suggesting a sensitivity to definition quality that drives preschoolers' information search for word meanings. These findings offer insight into children's information seeking during exposure to new words. Results advance the characterization of children's active verbal information seeking in shaping their word learning.