title: Neoligamentization process of BTPB used for ACL graft: histological evaluation from 6 months to 10 years.
abstract: Following anterior cruciate ligament (ACL) reconstruction with the middle third part patellar tendon, the graft undergoes histological rearrangement due to biomechanical action, which transforms it into a structure similar to the normal ACL. The purpose of our study was to make a qualitative and quantitative histological evaluation, by transmission electron microscopy (TEM), of the neoligamentization process of a bone-patellar tendon-bone (BTPB) graft used as pro-ACL at different follow-up times. We analysed the ultrastructure of collagen fibrils by focusing on their size and distribution with respect to a normal patellar tendon and a normal ACL used as controls. Our results showed that up to 24 months follow-up, progressive ultrastructural changes towards the normal ACL were observed. At longer times after surgery (48 and 120 months) no further changes were evident and the ultrastructure showed a marked reduction in large fibrils, which was typical of the control patellar tendon, and a significant increase in small fibrils. The ultrastructure seemed to combine fibrils from two different morphological units. The BPTB graft used as ACL underwent a transformation process for up to two years. After that period the transformation ceased and for ten years failed to reach the ultrastructural aspect of a normal ACL. However, from an architectural point of view the graft was slowly transformed into a structure similar to ACL with respect to the different mechanical stresses the ligament has to sustain.
authors.affiliation: Istituti Ortopedici Rizzoli, Bologna, Italy. S.Zaffagnini@biomec.ior.it <S.Zaffagnini@biomec.ior.it>
authors.forename: S
authors.initials: S
authors.lastname: Zaffagnini
authors.forename: V
authors.initials: V
authors.lastname: De Pasquale
authors.forename: L
authors.initials: L
authors.lastname: Marchesini Reggiani
authors.forename: A
authors.initials: A
authors.lastname: Russo
authors.forename: P
authors.initials: P
authors.lastname: Agati
authors.forename: B
authors.initials: B
authors.lastname: Bacchelli
authors.forename: M
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D050376:Bone-Patellar Tendon-Bone Grafting / Q000473:pathology*; D016022:Case-Control Studies; D003094:Collagen / Q000648:ultrastructure; D004547:Elastic Tissue / Q000648:ultrastructure; D004549:Elastin / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000648:ultrastructure; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D017847:Patellar Ligament / Q000648:ultrastructure*
chemical_list: D016326:Extracellular Matrix Proteins; C437744:oxytalan; D003094:Collagen; D004549:Elastin