title: Calcium-phosphate-hybridized tendon directly promotes regeneration of tendon-bone insertion.
abstract: We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with tendons using an alternate soaking process. We characterized the deposited CaP on or in tendons and determined the healing process of anterior cruciate ligament (ACL) grafts by implanting CaP-hybridized free tendons in bone tunnels intra-articularly. Tendons to be implanted were alternately soaked 10 times in a Ca-containing solution and a PO(4)-containing solution for 30 s each. Treated tendons had ash contents threefold that of untreated tendons. Low-crystallinity apatite was found on or in treated tendons. In animal experiments, the CaP-hybridized tendon exhibited osteoclasts at the tendon-bone interface at 5 days after operation. At 2 weeks after operation, there were more osteoclasts and osteoblasts around the tendon than at 5 days after operation. Directly bonded areas were partially found between the implanted tendon and newly formed bone. The formation of a cartilage layer was partially apparent at 3 weeks after operation. The newly formed bone was observed almost around the tendon. We conclude that CaP-hybridized tendons clearly enhance the healing process of ACL grafts at the tendon-bone interface and regenerate a direct insertion-like formation of tendons similar to a normal healthy ACL insertion within 3 weeks after operation.
authors.affiliation: Department of Orthopaedic Surgery, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi, Ibaraki 305-8575, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Mutsuzaki
authors.forename: Masataka
authors.initials: M
authors.lastname: Sakane
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakajima
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ito
authors.forename: Shinya
authors.initials: S
authors.lastname: Hattori
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Miyanaga
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ochiai
authors.forename: Junzo
authors.initials: J
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000502:physiology / Q000637:transplantation; D001672:Biocompatible Materials; D001861:Bone Regeneration; D002130:Calcium Phosphates; D005269:Femur / Q000601:surgery; D008297:Male; D008422:Materials Testing; D011817:Rabbits; D012038:Regeneration; D013710:Tendons / Q000033:anatomy & histology / Q000502:physiology / Q000637:transplantation*; D013977:Tibia / Q000601:surgery; D013997:Time Factors; D014182:Transplantation, Autologous
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates