The effect of defect localization on spontaneous repair of osteochondral defects in a Göttingen minipig model: a retrospective analysis of the medial patellar groove versus the medial femoral condyle

Abstract

Various animal models for experimental osteochondral defect healing have been used in orthopaedic research. Two main defect locations were chosen: the patellar groove or the central part of the medial femoral condyles (MFC). To date, it is not clear whether both locations display similar patterns in critical size osteochondral defect healing. We retrospectively analysed both locations in our minipig model hypothesizing that they show similar healing pattern. Thirty-five defects were analysed after three or 12 months. Osteochondral defects were 10 mm deep and 6.3 mm (MFC, n ¼ 19) in diameter or 8 mm and 5.4 mm, respectively (trochlear groove [TG], n ¼ 16). Semi-quantitative histological scoring and histomorphological evaluation were carried out. Both defect locations showed fillings of fibrous and fibrocartilage-like repair tissue. The osseous defect was closed by endochondral bone formation in the MFC. Semi-quantitative scoring did not show differences, whereas qualitative histomorphological analysis more frequently showed cartilaginous repair tissue in MFC defects. There was more frequent subchondral bone cyst formation in MFC location (P ¼ 0.05), TG defects resulted in lower postoperative pain. Both defect localizations are suitable for studies on osteochondral healing. Since regenerating with less hyaline-like repair tissue and less subchondral cyst formation, TG is more favourable for experimental osteochondral defect healing in this model.

Quantitative ultrasound biomicroscopy for the analysis of healthy and repair cartilage tissue

“…In this study a significant correlation between IRC and indentation stiffness was apparent for the stiffness values measured with low preload. Similarly, correlations between IRC and the compressive modulus could be also detected for healthy and osteoarthritic cartilage in other studies Kiviranta et al, 2007). However, those associations have to be interpreted with care for two reasons:…”

“…UBM proved to be a valuable non-destructive methodology that allows both morphological and functional characterization of cartilage and other biological tissues (Toyras et al, 1999;Cherin et al, 2001;Nieminen et al, 2002;Pellaumail et al, 2002;Hattori et al, 2004;Saarakkala et al, 2006;Kiviranta et al, 2007;Leicht et al, 2008). This study focused on quantitative ultrasound biomicroscopy for the evaluation of cartilage repair tissue.…”

“…To date, valid parameters for the determination of the proteoglycan content by ultrasound analysis have still to be established. For this purpose, the role of sound velocity or frequency dependent attenuation measurements have been discussed in recent studies, however with inconsistent results so far (Pellaumail et al, 2002;Toyras et al, 2003;Kiviranta et al, 2007;Wang et al, 2008).…”

“…Recent studies have shown that the IRC and AIB are sensitive parameters to detect changes of articular cartilage that occur in ageing, osteoarthritis or following collagenase treatment (Cherin et al, 1998;Foster et al, 2000;Cherin et al, 2001;Spriet et al, 2005; Kiviranta et al, 2007). However, the validity of these quantitative ultrasound parameters has not been shown for the evaluation and characterization of cartilage repair tissues.…”

“…However, the validity of these quantitative ultrasound parameters has not been shown for the evaluation and characterization of cartilage repair tissues. This pilot study investigated the applicability of UBM in the knee joint of miniature pigs, which is an established animal model for cartilage repair studies Blanke et al, 2009;Jung et al, 2009). The aim was to capture various structural and functional parameters associated to surface morphology, cell morphology and distribution, extracellular matrix composition, and subchondral bone integrity.…”