Osteochondral regeneration with a novel aragonite-hyaluronate biphasic scaffold: up to 12-month follow-up study in a goat model.

Elizaveta Kon,Andrew Levy,John E Eisman,Giuseppe Filardo,Jonathan Shani,Dror Robinson,Nir Altschuler,Ken Zaslav

doi:10.1186/s13018-015-0211-y

Abstract

BackgroundThe 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.Hypothesis/purposeThe hypothesis was that the implantation of the Ar-HA implant leads to tissue regeneration and maturation.Study designA 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).MethodsCritical 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.ResultsIn 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.ConclusionAr-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.Clinical relevanceOsteochondral 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.

Highlights

Group A defects were either empty or contained fibrous repair tissue; while group B filling was compatible with hyaline cartilage and normal bone
Clinical relevance: Osteochondral defects are common in humans; the results of the current study suggest that an acellular Ar-hyaluronic acid (HA) scaffold might induce cartilage and subchondral bone regeneration
Numerous surgical approaches have been proposed over the years to treat chondral or osteochondral lesions [1, 2], but native hyaline cartilage regeneration has not been achieved by any available treatment

Summary

Introduction

Numerous surgical approaches have been proposed over the years to treat chondral or osteochondral lesions [1, 2], but native hyaline cartilage regeneration has not been achieved by any available treatment. Two approaches to treat articular cartilage are feasible: exogenous-cell-based techniques or locally recruited stem-cell-based techniques. The optimal scaffold should allow bone repair in the subchondral area (a goal quite difficult to achieve as the bone tends to be a mixture of compact and woven bone [6]) and migration of mesenchymal stem cells and chondrocytes into the superficial cartilaginous layers, with new cartilage formation at the articular surface [6]. This study was conducted in order to assess the fate of the regenerated osteochondral tissue in a 12-month-long validated caprine model.

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