Fig. 2. 3D printing meniscal scaffold combining autologous synovium transplant facilitates meniscal regeneration and protects cartilage from macroscopic view in porcine subtotal meniscectomy model.

(A) 3D printing meniscal scaffold combining autologous synovium transplantation after preparation of subtotal meniscectomy in porcine medial meniscus [(A1) the preparation of subtotal meniscectomy in medial meniscus, black arrow represents medial meniscus; (A2) meniscal scaffold is transplanted anatomically and fixed with peripheral residual meniscal tissue using sutures; (A3) autologous synovium is harvested from suprapatellar bursa and covered on the surface of scaffold; (A4) the bone block of medial collateral ligament upper attachment site is fixed anatomically using nail, black arrow represents medial collateral ligament]. (B) Arthroscopic examination of knee joint of PCL scaffold + synovium transplant group at 2 months postoperatively [(B1) the performance of arthroscopic examination; (B2) joint conditions under arthroscope, red arrow represents PCL scaffold, MFC, medial femoral condyle]. (C) The macroscopic appearance of regenerated tissue and cartilage status of PCL scaffold + synovium transplant group at 2 months postoperatively (1, the regenerated tissue located in the tibia, black dotted lines represent anterior and posterior attachment ligament, yellow dotted line represents contour of regenerated tissue; 2, the regenerated tissue; 3, native meniscus; 4, the tibial plateau cartilage; 5, the femoral condyle cartilage, blue arrow represents cartilage wear; 6, cartilage in the trochlea; 7, cartilage in the patella; 8, good bone healing of medial collateral ligament upper attachment site as indicated by green arrow). (D) Macroscopic appearance of regenerated tissue and cartilage status of PCL scaffold + synovium transplant group at 4 months postoperatively. (E) Macroscopic appearance of knee joint of sham group at 4 months postoperatively.