A surgical implant for replacing hyaline cartilage in a knee or other articulating synovial joint has an anchoring side on one side of the implant adapted for fixing the implant to one of the bones in the joint, and a bearing surface on the opposite side of the implant for lubricious rubbing and sliding contact with another bone in the joint. The anchoring side can be configured with an irregular surface for tissue ingrowth. The bearing side can include hydrogel. The implant can be rolled up from an original shape and surgically inserted by arthroscopic means, and opens into its original shape when released inside the joint.