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Journal of Bone and Joint Surgery - British Volume, Vol 91-B, Issue 8,
1110-1119.
doi: 10.1302/0301-620X.91B8.22057 Copyright © 2009 by British Editorial Society of Bone and Joint Surgery Perilesional changes of focal osteochondral defects in an ovine model and their relevance to human osteochondral injuriesP. Hepp, MD, Assistant Professor, Orthopaedic Surgeon1; G. Osterhoff, MD, Research Fellow1; M. Niederhagen, MD, Pathologist2; B. Marquass, MD, Orthopaedic Surgeon1; T. Aigner, MD, MSc, Professor of Histopathology3; A. Bader, MD, Professor and Chairman4; C. Josten, MD, Professor and Chairman1; and R. Schulz, PhD, Head of Cartilage Research Group4
1 Department of Trauma and Reconstructive Surgery University of Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany. Correspondence should be sent to Dr P. Heppe; e-mail: pierre.hepp{at}medizin.uni-leipzig.de
Perilesional changes of chronic focal osteochondral defects were assessed in the knees of 23 sheep. An osteochondral defect was created in the main load-bearing region of the medial condyle of the knees in a controlled, standardised manner. The perilesional cartilage was evaluated macroscopically and biopsies were taken at the time of production of the defect (T0), during a second operation one month later (T1), and after killing animals at three (T3; n = 8), four (T4; n = 8), and seven (T7; n = 8) months. All the samples were histologically assessed by the International Cartilage Repair Society grading system and Mankin histological scores. Biopsies were taken from human patients (n = 10) with chronic articular cartilage lesions and compared with the ovine specimens. The ovine perilesional cartilage presented with macroscopic and histological signs of degeneration. At T1 the International Cartilage Repair Society Subchondral Bone score decreased from a mean of 3.0 (SD 0) to a mean of 1.9 (SD 0.3) and the Matrix score from a mean of 3.0 (SD 0) to a mean of 2.5 (SD 0.5). This progressed further at T3, with the International Cartilage Repair Society Surface grading, the Matrix grading, Cell Distribution and Cell Viability grading further decreasing and the Mankin score rising from a mean of 1.3 (SD 1.4) to a mean of 5.1 (SD 1.6). Human biopsies achieved Mankin grading of a mean of 4.2 (SD 1.6) and were comparable with the ovine histology at T1 and T3. The perilesional cartilage in the animal model became chronic at one month and its histological appearance may be considered comparable with that seen in human osteochondral defects after trauma.
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