Unicompartmental joint replacement is a good option for some patients. Not too much bone is removed so the patient can have a total joint replacement later if needed. It's often the case that after the first side of the joint becomes arthritic, the other side eventually becomes diseased, too.
As with all operations, problems and complications are possible. In a recent long-term study, researchers noted that younger patients seem to have the best results with the unicompartmental implants. The device lasts longer and needs revision less often than in older patients.
Reasons for revision include disease progression to the other side of the joint or loosening of the implant. There's no way to predict when or to whom this will happen. It's just part of the risk of the procedure.
For the most part, studies show the unicompartmental implants work very well. The patients get pain relief. Motion is restored. They can start to walk again and do more things.