The current approaches to treating articular cartilage defects in the knee comprise a spectrum from pharmacologic therapies to total knee arthroplasty. Nonsurgical treatment can include anti-inflammatory medications, bracing, and physical therapy. Surgical treatments include reconstructive repair of a small or large defect using microfracture, osteochondral autograft transplantation, autologous chrondrocyte transplantation, or osteochondral allograft transplantation; realignment procedures including osteotomies; and unicompartmental arthroplasty. A comprehensive algorithm can be used to determine the appropriate treatment for knee defects.