Robotic-assisted unicompartmental knee arthroplasty in a patient with combined medial compartment arthritis and subchondral defect of the medial femoral condyle

Subchondral defects, or severe osteoarthritic changes, of the medial compartment may complicate component positioning and require proper planning and exact placement to ensure adequate and stable fixation and proper postoperative kinematics. This is a case report on our experience with a CT-based robotic tactile guidance system for unicompartmental knee replacement in a patient with combined medial compartment degenerative joint disease and subchondral defect of the medial femoral condyle. Using the TGS in this case, an exact burring process of the femoral cavity adjacent to the subchondral defect resulted in accurate burring of the cavity depth and width, while preservation of the surrounding supporting bony boundary was possible.