Fig. 1

a–g Human cadaveric knees (a) and synovial joint capsule tissue (b) were obtained from 16 donors. Osteochondral plugs were harvested from the femoropatellar and condylar regions of human cadaveric distal femur using Mosaicplasty tool set (c). Synovial explants were cut from the synovial joint capsule obtained from the same donor. Cartilage-bone plugs (3.5 mm in diameter and up to 5 mm deep) were harvested (d, e) to set up cartilage-bone cocultures (f) and cartilage-bone-synovium cocultures (g). i, j Cartilage bone plug was held using rubber and foam rings (h) inside polysulfone injury chamber (i) to apply a single injurious unconfined compressive impact stress (15 MPa/s to peak stress of 5 MPa, held at 5MPa for 0.4 s, then unloaded at 15 MPa/s) on the cartilage surface in the incubator-housed loading apparatus (j) to simulate PTOA-like injury