A new analytical cut-off point for determining 18 years of age using MRI on medial clavicular epiphysis

Evaluation of the ossification of the medial clavicular epiphysis plays a key role in forensic age estimation. The purpose of the present study was to assess a new numerical cut-off at the age of 18 years, taking into consideration Magnetic Resonance (MR) images of the medial clavicular epiphysis. We analyzed 163 MR scans of Italian subjects aged between 14 and 25 years. Using the data obtained we calculated two ratios: REM-1 (ratio between the length of the whole epiphysis and the length of the metaphysis) and REM-2 (ratio between the length of epiphyseal-metaphyseal fusion and the length of the metaphysis). In 68 out of 163 cases it was not possible to measure REM-2. The reproducibility was demonstrated using the Intraclass Correlation Coefficient (ICC) (Cronbach’s alpha > 0.80). REM-1 and REM-2 were compared in each category of age (adult and minor) by the Wilcoxon signed-rank test. The cut-off points for measurements of REM-1 and REM-2 were determined by logistic regression. For REM-1, the cut-off scores were 0.83 for all individuals (accuracy = 94.77%) and males (accuracy = 96.05%), and 0.86 for females (accuracy = 92.30%). For REM-2, the cut-off values were 0.40 for all individuals and males (accuracy = 100.00%), and 0.41 for females (accuracy = 100.00%). Finally, receiver operating characteristic (ROC) curves for age classification based on REM-1 and REM-2 were constructed, showing that REM-2 had the highest discriminative power. Thus, a new cut-off model for predicting the age of majority has been introduced, conducting a quantitative analysis thanks to the use of a high-resolution imaging tool.     

Polarity-specific high-definition transcranial direct current stimulation of the anterior and posterior default mode network improves remote memory retrieval

BackgroundPrevious studies show that activity in the posterior default mode network (pDMN), including the posterior cingulate cortex and the precuneus, is correlated with the success of long-term episodic memory retrieval. However, the role of the anterior DMN (aDMN) including the medial prefrontal cortex is still unclear. Some studies show that activating the medial prefrontal cortex improves memory retrieval while other studies show deactivation of the medial prefrontal cortex in successful retrieval of episodic memories, suggesting a possible functional dissociation between the aDMN and pDMN.ObjectiveIn the current study, we aim to causally explore this probable dissociation using high-definition transcranial direct current stimulation (HD-tDCS).MethodsWe perform a randomised double-blinded two-visit placebo-controlled study with 84 healthy young adults. During Visit 1 they learn 75 Swahili-English word-associations. Seven days later, they randomly receive either anodal, cathodal or sham HD-tDCS targeting the pDMN or aDMN while they recall what they have previously learned.ResultsWe demonstrate that anodal stimulation of the pDMN and cathodal stimulation of the aDMN, equally improve the percentage of Swahili-English word-associations recalled 7 days after learning.ConclusionsModulating the activity in the aDMN and pDMN causally affect memory retrieval performance. HD-tDCS of the aDMN and pDMN shows that anodal stimulation of the pDMN and cathodal stimulation of the aDMN increases memory retrieval performance one week after the learning phase. Given consistent evidence, it is highly likely that we are increasing the activity in the pDMN with anodal pDMN stimulation. However, it is not clear if cathodal HD-tDCS targetting aDMN works via decoupling from the pDMN or via indirectly disinhibit pDMN.     

Preferential responses to faces in superior temporal and medial prefrontal cortex in three-year-old children

Perceiving faces and understanding emotions are key components of human social cognition. Prior research with adults and infants suggests that these social cognitive functions are supported by superior temporal cortex (STC) and medial prefrontal cortex (MPFC). We used functional near-infrared spectroscopy (fNIRS) to characterize functional responses in these cortical regions to faces in early childhood. Three-year-old children (n = 88, M(SD) = 3.15(.16) years) passively viewed faces that varied in emotional content and valence (happy, angry, fearful, neutral) and, for fearful and angry faces, intensity (100%, 40%), while undergoing fNIRS. Bilateral STC and MPFC showed greater oxygenated hemoglobin concentration values to all faces relative to objects. MPFC additionally responded preferentially to happy faces relative to neutral faces. We did not detect preferential responses to angry or fearful faces, or overall differences in response magnitude by emotional valence (100% happy vs. fearful and angry) or intensity (100% vs. 40% fearful and angry). In exploratory analyses, preferential responses to faces in MPFC were not robustly correlated with performance on tasks of early social cognition. These results link and extend adult and infant research on functional responses to faces in STC and MPFC and contribute to the characterization of the neural correlates of early social cognition.     

Selective fixation of the medial malleolus in unstable ankle fractures

BackgroundWhilst the lateral malleolus appears to be crucial in controlling anatomical reduction of the talus, the role of the medial malleolus is less clear. Medial sided complications including infection, damage to local structures and symptomatic hardware are not without morbidity. This study compares the outcomes of patients with bimalleolar or trimalleolar ankle fractures who underwent fibular nail stabilisation with or without medial malleolar fixation.MethodsFrom a prospective single-centre trauma database, we identified 342 patients over a nine-year period who underwent fibular nail insertion to stabilise a bimalleolar or trimalleolar ankle fracture. Isolated lateral malleolar fractures were excluded. Demographic data, clinical outcomes, radiographic evaluation, return to work and sport, and patient reported outcomes, including Olerud-Molander Ankle Score (OMAS), EuroQol-5D (EQ-5D) and Manchester-Oxford Foot Questionnaire (MOXFQ) were collected.ResultsThis study included 247 patients with a mean age of 66.7 years (range, 25–96 years), of whom 200 were female (81%). Medial malleolar fixation was not performed in 54 cases (22%). There was no significant difference between groups with respect to failure of fixation (p = 0.634) or loss of talar reduction (p = 0.157). No patient required surgery for a symptomatic medial malleolar non-union. Medial sided complications occurred in 32 (16%) of the fixation group, of whom 20 (10%) required further surgery. At a mean mid-term follow-up of 4.8 years (range, 8 months – 9 years) there was no significant difference between the non-fixation and fixation groups with respect to the median OMAS (85 vs 80; p = 0.885) or median EQ-5D (0.80 vs 0.81; p = 0.846). Patient satisfaction was not significantly different between the two groups (85/100 vs 87/100; p = 0.410).ConclusionNon-operative management of the medial malleolar component of an unstable ankle fracture treated with a fibular nail may reduce the rate of post-operative complications without compromising the patient reported outcome.     

双侧锁定接骨板固定干骺端粉碎性股骨远端骨折的生物力学研究

目的 通过生物力学测试明确双侧锁定接骨板治疗干骺端粉碎性股骨远端骨折的各项力学特性。方法 采用16根力学测试专用股骨建立干骺端粉碎性股骨远端骨折（AO分型为C2.3型）模型，分为2组，对照组为单纯外侧解剖锁定接骨板固定，观察组为外侧解剖锁定接骨板和内侧锁定加压接骨板联合固定，每组8根人工骨，其中5根依次进行扭转负荷测试、轴向负荷测试和循环轴向负荷测试，检测扭转刚度、轴向刚度、股骨远端内侧压缩位移和内侧骨折端的微动；剩余3根进行极限负荷测试，记录内固定失败时的最大载荷。结果 ①扭转及垂直负荷测试中，观察组的扭转及轴向刚度分别为（4.28±0.43） Nm/deg、（1 850.14±99.88） N/mm，明显高于对照组的（2.26±0.09） Nm/deg、（884.02±68.15） N/mm；②轴向循环负荷测试中，两组模型均未出现螺钉松动或钢板断裂等内固定失败的情况，但对照组骨折端内侧间隙缩小（1.54±0.24） mm，明显大于观察组的（0.15±0.08） mm；③对照组内侧骨折块的微动位移为（3.25±0.21） mm，也明显高于观察组的（0.17±0.05） mm；④轴向极限负荷测试中，观察组发生骨折间隙明显缩窄或内固定失败时的极限载荷为（18 118.33±133.33） N，明显高于对照组的（6 334.33±34.39） N。上述数据组间比较，差异均有统计学意义（P均＜0.05）。结论 双侧锁定接骨板固定干骺端粉碎性股骨远端骨折可明显增加固定强度，从而为骨折愈合提供更稳定的生物力学环境。     

Changes in knee extensor strengths before and after medial patellofemoral ligament reconstruction

Objective: Quadriceps dysfunction has been suggested as a complication after medial patellofemoral ligament (MPFL) reconstruction. The purpose of this study was to investigate changes in knee extensor strength before and after MPFL reconstruction.

Methods: Twenty patients who underwent MPFL reconstruction for unilateral recurrent patellar dislocation (18 females and 2 males; mean age 20.8 ± 7.6 years) were examined. The peak isometric torque at 60° and 90° of knee flexion and isokinetic knee extensor strength at speeds of 60°/s and 90°/s in operated and non-operated legs were measured using a dynamometer preoperatively and 6 months, 1 year, and 2 years postoperatively. The following parameters were evaluated: (1) body weight-adjusted muscle strength, (2) improvement index (post-/preoperative value × 100) (%), and (3) extensor strength ratio (operated/non-operated value × 100) (%).

Results: The mean knee extensor strength in both operated and non-operated legs significantly increased 2 years after surgery compared with that before surgery. At 2 years postoperatively, the improvement indexes of the isometric knee extensor strength at 60° and 90° and of the isokinetic knee extensor strength at 60°/s and 90°/s were 237%, 192%, 318%, and 186%, respectively, in the operated legs and 144%, 124%, 140%, and 140%, respectively, in the non-operated legs. At 2 years postoperatively, the mean isometric knee extensor strength ratios at 60° and 90° and the isokinetic knee extensor strength ratios at 60°/s and 180°/s were 81%, 84%, 81%, and 82%, respectively.

Conclusions: Knee extensor strength was improved in most patients after MPFL reconstruction, at least compared with that before surgery, although an approximately 20% deficit against the non-operated legs remained even 2 years after surgery.