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Kenichiro Murata,1 Tsukasa Kumai,2 Norikazu Hirose2 1Graduate School of Sport Sciences, Waseda University, Nishi-tokyo, Japan; 2Faculty of Sport Sciences, Waseda University, Saitama, JapanCorrespondence: Norikazu HiroseFaculty of Sport Sciences, Waseda University, 2-579-15, Mikajima, Tokorozawa, Saitama 359-1192, JapanTel/Fax +81 42-451-1022Email toitsu_hirose@waseda.jpPurpose: Lateral ankle sprain (LAS) in childhood can result in lateral malleolus avulsion fractures; additionally, bone nonunion may occur. Physical maturity relates to the development of bone morphology and physical functionality. It is unknown how changes in physical functionality attributable to physical maturity affect young soccer players with abnormal lateral malleolus (ALM) morphology. Hence, the present study aimed to investigate the bone morphology of the lateral malleolus in young soccer players and to examine its relationship with physical functionality at different maturity levels.Subjects and Methods: Two hundred and ninety young soccer players aged 6– 15 years were included. The presence of ALM was assessed using ultrasonography. The subjects were allocated to three groups based on physical maturity (Pre-, Mid-, and Post-peak height velocity age [PHVA]). The prevalence of ALM and the relationship between ALM and physical maturity were examined for body composition, foot pressure distribution, foot alignment, ankle mobility, and single-leg balance.Results: The prevalence of ALM was 17.6%. For physical maturity, the post-PHVA group showed a decrease in ankle dorsiflexion and eversion and an increase in one-leg hop distance compared to the Pre-PHVA group (P < 0.05). In the ALM group, the center of pressure during heel raising was distributed laterally in the Post-PHVA (P < 0.01), and the weight-bearing dorsiflexion angle was decreased in the Mid- and Post-PHVA (P < 0.05).Conclusion: In the Post-PHVA young soccer players, decreased ankle dorsiflexion and eversion and increased one-leg hop distance were observed. The ALM group exhibited lateral loading during heel raising in the Post-PHVA group and decreased weight-bearing ankle dorsiflexion angle in the Mid- and Post-PHVA groups. The findings indicate the importance of secondary prevention of LAS and ultrasonography. Prospective studies of LAS in young athletes are required in the future.Keywords: lateral ankle sprain, ultrasonography, physical maturity, physical function, soccer

Takanori Kumai,1 Naoko Yui,1 Kanaka Yatabe,1 Chizuko Sasaki,2 Ryoji Fujii,3 Mitsuko Takenaga,3 Hiroto Fujiya,1 Hisateru Niki,4 Kazuo Yudoh3 1Department of Sports Medicine, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8511, Japan; 2Institute for Ultrastructural Morphology, St Marianna University Graduate School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan; 3Department of Frontier Medicine, Institute of Medical Science, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan; 4Department of Orthopaedic Surgery, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan Purpose: We previously created a self-assembled cartilage-like complex in vitro from only three cartilage components, hyaluronic acid (HA), aggrecan (AG) and type II collagen, without other materials such as cross-linking agents. Based on this self-organized AG/HA/collagen complex, we have created three novel types of biphasic cartilage and bone-like scaffolds combined with hydroxyapatite (HAP) for osteochondral tissue engineering. These scaffolds have been developed from self-assembled cartilage component molecules and HAP at the nanometer scale by manipulating the intermolecular relations. Patients and methods: The surface structure of each self-organized biphasic cartilage and bone-like scaffold was evaluated by scanning electron microscopy, whereas the viscoelasticity was also analyzed in vitro. Three types of artificial cartilage–HAP conjugates were implanted into an osteochondral defect in rat knee joints, and bone and cartilage tissues of the implanted site were examined 4 and 8 weeks after implantation. The tissues were examined histopathologically to evaluate the effects of the implantation on the articular cartilage and subchondral bone tissues. Results: Our in vitro and in vivo data reveal that the self-organized biphasic cartilage and bone-like scaffold conjugated with HAP are superior to the scaffold with no HAP in both cartilage regeneration and subchondral bone regeneration. Conclusion: Our present study indicates that the self-organized biphasic cartilage and bone-like scaffold, which is conjugated with an HAP layer, may have potential not only to repair articular cartilage defects but also to ameliorate the degeneration of subchondral bone in the diseases with osteochondral defect. Keywords: cartilage tissue engineering, subchondral bone, articular cartilage, osteoarthritis, self assembly, hydroxyapatite

Chronic ankle instability (CAI) causes impairment in proprioception, such as ankle joint position sense and plantar cutaneous sensation. Although plantar vibration stimulation may be effective as a means of enhancing proprioception, its efficacy remains ambiguous. This study aimed to clarify the immediate effects of plantar vibration stimulation on healthy athletes and athletes with CAI. Eight healthy and eight CAI athletes participated in this study, and their joint position sense and cutaneous sensation were evaluated before and after the intervention of plantar vibration stimulation or non-intervention, designed as a cross-over study. There were no significant differences between the healthy group and the CAI group in both joint position and plantar cutaneous sensation. Also, there were no statistically significant changes in either group before or after the intervention. One possible explanation for the absence of differences between the healthy and CAI groups could be attributed to a high Foot and Ankle Ability Measure score. Neither group exhibited any changes in joint position or plantar cutaneous sensation following the vibration intervention. The frequency and amplitude of the vibration stimulation affecting proprioceptors may be different, and the joint position and plantar cutaneous sensation of CAI groups may be comparable with those of healthy participants. [ABSTRACT FROM AUTHOR]

Ankle brace is commonly used to treat and prevent ankle sprain. Its main aim is to restrict supination of the ankle. However, some braces restrict ankle dorsiflexion and plantar flexion. In addition, loosening and loss of restriction after exercise have also been reported. The purpose of this study was to reveal if thin-type ankle brace for ankle sprain restricts ankle dorsiflexion and plantar flexion and its effect of exercise. Five male adults (average age of 30.8 ± 5.2 years) were included in the study. Dorsiflexion and plantar flexion of subjects' right ankle was measured before and after wearing the brace, and before and after exercises. Exercises consisted of performing 20 times of calf raise, full squat, maximum vertical jump, and 5-minute running on a treadmill. Measurement was performed thrice, and their average was statistically analyzed between with and without the brace, and before and after each exercise. The results showed that there was no significant difference between all measured angles of with and without the brace and before and after each exercise. Thin-type ankle brace for ankle sprain have been reported to restrict supination. Considering our results, this brace does not restrict ankle dorsiflexion and plantar flexion. [ABSTRACT FROM AUTHOR]