Unicompartmental knee arthroplasty (UKA) is the treatment of isolated compartment osteoarthritis. The principal purpose of UKA is to substitute the broken cartilage of the knee.UKA has had mixed reported results and still remains a controversial procedure.Recently,adherence to more stringent patient selection criteria and refined surgical technique has resulted in improved clinical outcomes and survivorship. The popularization of UKA as a more tissue-sparing procedure and minimally invasive alternative to total knee arthroplasty and high tibial osteotomy has also played an integral role in its recent resurgence. Many different prostheses have emerged, some with exceptional long-term results.Long-term prospective analyses will be critical in determining the role of UKA as a mainstay in the treatment of single compartment knee degenerative joint disease. This review details the history, evolution,indication and contraindication,surgical technique and clinical therapeutic effect of UKA.