This Article Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lietman, S. A. Articles by Reddi, A. H. Search for Related Content PubMed PubMed Citation Articles by Lietman, S. A. Articles by Reddi, A. H.

The temporal sequence of spontaneous repair of osteochondral defects in the knees of rabbits is dependent on the geometry of the defect

¹ Department of Orthopaedic Surgery
² Department of Comparative Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
³ Centre for Tissue Regeneration and Repair, Department of Orthopaedic Surgery, University of California, Davis, School of Medicine Sacramento, Sacramento, California 95817, USA.

Correspondence should be sent to Dr S. A. Lietman at the Department of Orthopaedic Surgery, Johns Hopkins Outpatient Centre, Room 5251, 601 North Caroline Street, Baltimore, Maryland 21205, USA.

Damage to articular cartilage is a common injury, for which there is no effective treatment. Our aims were to investigate the temporal sequence of the repair of articular cartilage and to define a critical-size defect.

Full-thickness defects were made in adult male New Zealand white rabbits. The diameter (1 to 4 mm) of the defects was varied in order to determine the effect that the size and depth of the defect had on its healing. The defects were made in the femoral groove of the knee with one defect per knee and eight knees per group. The tissues were fixed in formalin at days 3, 7, 14, 21, 28, 42, 84 and 126 after operation and the sections stained with Toluidine Blue. These were then examined and evaluated for several parameters including the degree of metachromasia and the amount of subchondral bone which had reformed in the defect.

The defects had a characteristic pattern of healing which differed at different days and for different sizes of defect. Specifically, the defects of 1 mm first peaked in terms of metachromasia at day 21, those of 2 mm at day 28, followed by defects of 3 mm and 4 mm. The healing of the subchondral bone was slowest in defects of 1 mm.