Figure 1: Surgical procedure. Columnar construct (6.3 mm in diameter and 6 mm in height) for the implantation (a). A cylindrical osteochondral defect in each medial condyle before implantation (b). The construct composed of approximately 1,920 spheroids of AT-MSCs was autografted into the osteochondral defect in the right hind limb (c). Nothing was implanted into the left limbs (control defects; B). The white portions under the construct are a construct sill (asterisk) and a mold (double asterisks).