A knee joint is repaired by implanting a trochlear implant component, a patellar implant component and an anti-abrasion stud. The stud has a bearing surface, a bone-facing surface and a fixation post. The fixation post is implanted in the distal femur so that the bearing surface of the stud stands above the patient's native articular cartilage. The stud and trochlear component are implanted in close enough proximity to limit contact between the patellar component and the native articular cartilage around the trochlear component during flexion and extension of the knee joint.