Fig. 5

Harvesting of osteochondral plugs. a The punch (arrow # 1) is adjusted to take an osteochondral plug from the trochlea of a right knee of a Göttingen Minipig (GM). Four defects on the facets of the trochlea were created previously by the instruments described in Figs. 1 and 8b. The isolated trochlea is fixated between the jaws of a bench vise, and the punch is adjusted over the defect area which is located at the medial facet before punching. The circle indicates the defect area located at the lateral facet after a healing period (regenerated tissue) of 48 weeksFootnote

Collagen I scaffold without cells, provided by Amedrix, Esslingen, Germany.

. The two distally located defects are not visible. In the proximal parts of the trochlea (arrows # 2), untreated cartilage can serve as control tissue. b If the plug stays fixed at the bony bottom, it can be broken out with a hand-held tool, which can be disassembled afterwards to extract the sample (the arrow indicates the bony end of the plug with 5 mm in diameter). c Osteochondral cylindrical plug from an untreated knee joint (GM) after harvesting with a 5-mm diameter punch serving as control specimen. Guidelines (red lines) are drawn in for the analysis of the parallelism of the sides and the perpendicularity of the cartilage surface (top) to the perpendicular bisectors of the sides.