A three-dimensional printed porous implant combined with bone grafting following curettage of a subchondral giant cell tumour of the proximal tibia: a case report

Background: Subchondral bone is commonly affected in cases of giant cell tumour (GCT) of the proximal tibia. Numerous studies have stated that retaining a sufficient subchondral bone layer could decrease the possibilities of postoperative degenerative changes and mechanical failure of the knee joint. However, the most commonly used methods of cement packing only or cement packing combined bone grafting have some limitations regarding the protection of subchondral bone after surgery. Our paper describes our attempt to reconstruct a tumorous defect associated with the subchondral area in the proximal tibia with a three-dimensional (3D)-printed porous implant combined with bone grafting and our evaluation of the short-term outcomes. Case presentation: A 42-year-old man with a Campanacci grade II GCT visited our institution for initial assessment. Radiographs showed a tumour located at the epiphyseal part of the proximal tibia, and had invaded the subchondral area. Considering that the residual subchondral bone had to be protected, we used an autograft to ensure a high integration rate between the graft and host subchondral bone. We also used three-dimensional (3D) printing technology to design and fabricate a personalized porous implant to mechanically support the graft and subchondral area and help avoid degenerative changes and mechanical failure. At the last follow-up at 29 months postoperatively, the patient had satisfactory limb function and no further damage was seen to the subchondral area and articular surface. Conclusions: The 3D-printed porous implant combined bone grafting may be a feasible option in the reconstruction of defects that are close to the subchondral area following extensive intracurettage of GCTs. Moreover, it can result in good postoperative function and low complication rates. However, consistent follow-up is required to clarify its long-term outcomes.