title: Influence of gradual elongation to the patella tendon insertion in rabbits.
abstract: The purpose of this study was to examine the histological changes at the patella tendon (PT) insertion site under gradual elongation in rabbits. Gradual elongation of the PT was performed using external fixation for 4 weeks, with a lengthening speed of 0.5 mm/day (elongation group; n = 24). Rabbits in the sham group underwent the same surgical procedure without gradual elongation (sham group; n = 24). Eight animals were sacrificed 1, 2 and 4 weeks after surgery in each group, respectively. Average thicknesses of stained glycosaminoglycan (GAGs) areas by Safranin-O staining in the total cartilage layer and the uncalcified fibrocartilage layer in the elongation group were significantly higher than that in the sham group at 4 weeks (p < 0.05) and that in the intact PT group (n = 6, p < 0.05). In the elongation group, the peak in the average thicknesses of the stained GAGs areas in the total cartilage layer and the uncalcified fibrocartilage layer were observed at 4 weeks. Gradual elongation of PT insertion significantly affected the increase in the average thicknesses of the stained GAGs areas in the cartilage layer especially in the uncalcified fibrocartilage layer at 4 weeks in rabbits. Clinically, insertions of tendon and ligament can extend during gradual elongation using external fixation more than 4 weeks after the operation.
authors.affiliation: Department of Orthopaedic Surgery, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami Ami-machi, Inashiki-gun, Ibaraki 300-0394, Japan. mutsuzaki@ipu.ac.jp.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Mutsuzaki
authors.affiliation: Department of Agriculture, Ibaraki University, 3-21-1 Chuuou, Ami-machi, Inashiki-gun, Ibaraki 300-0393, Japan. hiromi@mx.ibaraki.ac.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakajima
authors.affiliation: Department of Rehabilitation Medicine, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami Ami-machi, Inashiki-gun, Ibaraki 300-0394, Japan. wadano@ipu.ac.jp.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Wadano
authors.affiliation: Department of Agriculture, Ibaraki University, 3-21-1 Chuuou, Ami-machi, Inashiki-gun, Ibaraki 300-0393, Japan. hiromi@mx.ibaraki.ac.jp.
authors.forename: Shintarou
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Orthopaedic Surgery, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan. sakane-m@md.tsukuba.ac.jp.
authors.forename: Masataka
authors.initials: M
authors.lastname: Sakane
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology; D006025:Glycosaminoglycans / Q000378:metabolism; D008297:Male; D017847:Patellar Ligament / Q000378:metabolism / Q000601:surgery*; D011817:Rabbits
chemical_list: D006025:Glycosaminoglycans