Microstructural remodeling of articular cartilage following defect repair by osteochondral autograft transfer.

ABSTRACT: To assess collagen network alterations occurring with flow and other abnormalities of articular cartilage at medial femoral condyle (MFC) sites repaired with osteochondral autograft (OATS) after 6 and 12 months, using quantitative polarized light microscopy (qPLM) and other histopathological methods.The collagen network structure of articular cartilage of OATS-repaired defects and non-operated contralateral control sites were compared by qPLM analysis of parallelism index (PI), orientation angle (?) relative to the local tissue axes, and retardance (?) as a function of depth. qPLM parameter maps were also compared to ICRS and Modified O'Driscoll grades, and cell and matrix sub-scores, for sections stained with H&E and Safranin-O, and for Collagen-I and II.Relative to non-operated normal cartilage, OATS-repaired regions exhibited structural deterioration, with low PI and more horizontal ?, and unique structural alteration in adjacent host cartilage: more aligned superficial zone, and reoriented deep zone lateral to the graft, and matrix disorganization in cartilage overhanging the graft. Shifts in ? and PI from normal site-specific values were correlated with histochemical abnormalities and co-localized with changes in cell organization/orientation, cloning, or loss, indicative of cartilage flow, remodeling, and deterioration, respectively.qPLM reveals a number of unique localized alterations of the collagen network in both adjacent host and implanted cartilage in OATS-repaired defects, associated with abnormal chondrocyte organization. These alterations are consistent with mechanobiological processes and the direction and magnitude of cartilage strain.

SUBMITTER: Raub CB 

PROVIDER: S-EPMC3684698 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature