An arthroplasty system may include a first prosthesis to be fixed to a first bone of a joint, a second prosthesis to be fixed to a second bone of the joint for articulation with the first prosthesis, and one or more adapters to be fixed to the first prosthesis for articulation with the second prosthesis to modify the stability of the second prosthesis relative to the first prosthesis. The system may include one or more articular inserts to be coupled to the second prosthesis for articulation with the first prosthesis and/or the adapter(s). The articular inserts may be fixed or mobile bearing relative to the second prosthesis. Each adapter and corresponding articular insert may modify stability differently.