title: Osteochondral regeneration with a novel aragonite-hyaluronate biphasic scaffold: up to 12-month follow-up study in a goat model.
abstract: BACKGROUND
  The regeneration of articular hyaline cartilage remains an elusive goal despite years of research. Recently, an aragonite-hyaluronate (Ar-HA) biphasic scaffold has been described capable of cartilage regeneration over a 6-month follow-up period. This study was conducted in order to assess the fate of the regenerated osteochondral tissue in a 12-month-long validated caprine model.
  
  
  OBJECTIVE
  The hypothesis was that the implantation of the Ar-HA implant leads to tissue regeneration and maturation.
  
  
  METHODS
  A two-arm caprine model of a critical osteochondral defect compares the fate of acute osteochondral defects (group A) to Ar-HA implanted defects (group B).
  
  
  METHODS
  Critical 6 mm in diameter and 10-mm in depth osteochondral defects were created in the load-bearing medial femoral condyle of 20 mature goats and randomized into two groups. In group A (n = 6), a blood clot spontaneously filled the defect; in group B (n = 14), a single Ar-HA implant reconstructed the defect. The animals were sacrificed after either 6 or 12 months. Parameters assessed included clinical evaluation, x-rays, micro-CT, ultrasound and histology at both time points, and specimen high-field magnetic resonance imaging with T2 mapping at the 12-month time point.
  
  
  RESULTS
  In most group A animals, the defects were not reconstructed (1/3 at 6 months, and 0/3 at 12 months). Defects in group B were mostly reconstructed (5/7 at 6 months and 6/7 at 12 months). Group A defects were either empty or contained fibrous repair tissue; while group B filling was compatible with hyaline cartilage and normal bone.
  
  
  CONCLUSIONS
  Ar-HA scaffolds implanted in critical osteochondral defects result in hyaline cartilage formation and subchondral bone regeneration. The results improved at the 12-month time point compared to the 6-month time point, indicating a continuous maturation process without deterioration of the repair tissue.
  
  
  CONCLUSIONS
  Osteochondral defects are common in humans; the results of the current study suggest that an acellular Ar-HA scaffold might induce cartilage and subchondral bone regeneration.
authors.affiliation: II Orthopedic division and NanoBiotechnology Lab, Rizzoli Orthopedic Institute, Bologna, Italy. e.kon@biomec.ior.it.
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Kon
authors.affiliation: II Orthopedic division and NanoBiotechnology Lab, Rizzoli Orthopedic Institute, Bologna, Italy. g.filardo@biomec.ior.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Filardo
authors.affiliation: Havat Daat Co., Beit Berl, Kfar Saba, Israel. jonshani4@gmail.com.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Shani
authors.affiliation: Cartiheal Ltd., Atir Yeda 17, Kfar Saba, Israel. nir@cartiheal.com.
authors.forename: Nir
authors.initials: N
authors.lastname: Altschuler
authors.affiliation: Center for Advanced Sports Medicine, Knee and Shoulder, Millburn, NJ, USA. levyas1979@gmail.com.
authors.forename: Andrew
authors.initials: A
authors.lastname: Levy
authors.affiliation: Cartilage Restoration Center: Advanced Orthopedic Centers and Clinical Prof. Orthopedic Surgery V.C.U. Med. Ctr., Richmond, VA, USA. kzaslav@advancedortho.me.
authors.forename: Ken
authors.initials: K
authors.lastname: Zaslav
authors.affiliation: Osteoporosis and Translational Research, UNSW University, Sydney, NSW, Australia. j.eisman@garvan.org.au.
authors.forename: John E
authors.initials: JE
authors.lastname: Eisman
authors.affiliation: Department of Orthopedics, Rabin Medical Center, Petah Tikwa, Israel. dror61@gmail.com.
authors.forename: Dror
authors.initials: D
authors.lastname: Robinson
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000008:administration & dosage*; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005269:Femur / Q000502:physiology*; D005500:Follow-Up Studies; D006041:Goats; D006820:Hyaluronic Acid / Q000008:administration & dosage*; D023421:Models, Animal; D013997:Time Factors; D054457:Tissue Scaffolds / Q000639:trends*; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D006820:Hyaluronic Acid; D002119:Calcium Carbonate