When the removal depth in micro milling is downsized, the effect of the crystal grain in material becomes relatively large. The crystal grain in materials, therefore, should be downsized to achieve ...high qualities and high reliabilities of the micro devices. The study discusses the effect of the crystal grain size on the surface finish, burr formation and the affected layer in micro milling of stainless steel. The crystal grains are reduced to an average size of 1.5μm by repetition of material forming and phase transformation. The milling tests were performed to measure the cutting forces, the surface finishes, the burr shapes and the thicknesses of the affected layers. The force component ratio of the fine grained steel is higher than that of the standard steel. The shearing force decreases in cutting of the fine grained steel; meanwhile, the friction and/or the indentation forces increase. Burr formation is reduced when the crystal grain size is small. In cutting of the standard steel, X component in the cutting force suddenly drops near the end of the groove and a large burr is formed on the edge of the groove. The affected layer largely depends on the crystal grain size. The thickness of the affected layer remarkable decreases in milling of the fine grained steel.
The connection of "Classification in Automobile Styling" and "Design Cognition" was discussed. The sample of various automobile temporarily was classified into "Universal Category", "Category by ...model representative of the Universal", "Category by similarity of styles", and "Category by subjective judgment". We generated exaggerated images of samples from various "Average" images of groups in categories, asked people to select the most realistic image from each groups and got the exaggerated degree of the most realistic images. And then we asked people to select the most realistic image from each images. As a result, it was found that the category that people identify a characteristic were "2BOX Style" and "3BOX Style", in case of a total of distance from "Average" model to the sample, people chose the image which matched "Average" images of these categories, or matched "Original" images of the sample.
Today, people utilizing a department store desire quickly understandable layout for merchandise. We look the connection of knowledge among merchandises of utilize as similarity of the knowledge, and ...plot it on three dimensions by using MDA. Therefore, we got 5 groups and the part of the merchandise category. According to these classification, we created four zoning plans (A-1, A-2, B, C). We judged this by AHP from the point of understandable layout for merchandise, select the most proper zoning plan. As a result, in where department store being composed of plural floors, by the vertical zoning based on the category which is gotten from similarity of the knowledge and the floor zoning based on positional relations between merchandises, merchandise and axis, we found it is able to contribute to the improvement in understanding of the position of merchandise and the layout of floor.
Introduction
The purpose of this study was to perform medial meniscus (MM) centralization for medial meniscus extrusion (MME) associated with medial meniscus posterior root tear (MMPRT) and to ...examine the short-term results. The hypothesis is that arthroscopic centralization as an augmentation of MMPRT repair improves clinical outcomes and the extrusion distance of MM in short-term results.
Materials and methods
Twenty-six patients (mean age 62.1 ± 6.0 years) who underwent arthroscopic centralization as an augmentation of MMPRT repair were included. Clinical evaluation was performed before and 2 years after surgery using Lysholm score and knee injury and osteoarthritis outcome score (KOOS). Image evaluation used MRI and plain X-ray images. The extrusion distance and MME ratio were compared on MRI images before and 2 years after surgery. The degree of osteoarthritis (OA) was evaluated using Kellgren–Lawrence classification. The degree of OA and hip–knee–ankle (HKA) angle were compared by plane X-ray images before and 2 years after surgery.
Results
In clinical results, both Lysholm score and KOOS improved significantly after surgery. In image evaluation, the extrusion distance decreased significantly from 4.8 ± 0.7 mm before surgery to 2.7 ± 0.3 mm 2 years after surgery (
p
< 0.05). The MME ratio was significantly improved from 40.2 ± 7.0% before surgery to 22.6 ± 3.6% after surgery (
p
< 0.05). There was no significant difference in HKA angle at 2 years after surgery (
p
= 0.13).
Conclusions
The arthroscopic centralization for medial meniscal extrusion associated with MMPRT significantly improved clinical outcomes and the extrusion distance of MM. It is also one of the surgical techniques that can suppress medial meniscus extrusion.
Level of evidence
IV, therapeutic case series.
Purpose
This study aimed to compare the clinical outcomes and postoperative activities of arthroscopic ankle lateral ligament (ALL) repair alone with arthroscopic ALL repair and reinforcement by the ...inferior extensor retinaculum (IER) for chronic ankle instability (CAI).
Materials and methods
All patients who underwent arthroscopic repair for CAI between 2017 and 2019 were evaluated. The Japanese Society for Surgery of the Foot (JSSF) scale and self-administered foot evaluation questionnaire (SAFE-Q), and duration between the surgery and walking without any support, jogging, and complete return to sports were evaluated and compared. The exclusion criteria were (1) follow-up period of < 1 year after surgery, (2) the presence of associated ankle lesions requiring treatment during the same operative procedure, including patients with subfibular ossicle bigger than 5 mm on radiographs, chondral or osteochondral defect, bony impingement, deltoid ligament tear, fibular tendon pathology, or posterior ankle impingement, and (3) patients who underwent revision surgery.
Results
We identified 126 patients who underwent surgery for CAI and subsequently excluded 36 patients on account of a short follow-up period (< 1 year), additional surgery, and previous surgery. The remaining 90 eligible patients included arthroscopic ALL repair alone (group A,
n
= 44) and arthroscopic ALL repair with reinforcement by the inferior extensor retinaculum (group G,
n
= 46) groups. There was no significant difference in the postoperative activities nor in the preoperative or postoperative JSSF scale and SAFE-Q between the two groups. However, significant differences were seen in the mean surgical time (15.5 ± 8.1 vs 20.1 ± 7.6,
P
= 0.013).
Conclusion
This study showed no difference in clinical outcomes between the two groups. However, arthroscopic ALL repair with reinforcement by IER resulted in a longer surgical time than arthroscopic ALL repair alone.
Level of evidence
Retrospective comparative study, level III.
