Osteoarthritis is a chronic, progressive and degenerative disease of old age, with constantly increasing number of patients. It is initially characterized by the loss and deterioration of cartilage tissue, followed by degenerative changes that affect all of the joint bodies. Clinically, patients report pain, stiffness that disappears with exercise or movement, crepitations during movement, painful palpation of the joint, decreased range of motion, joint deformations, muscle atrophy and contractures. X-ray imaging can reveal narrowing of the joint space, osteophytes, subchondral bone sclerosis, cystic changes and bone and joint deformities. Clinical presentation of the disease does not have to match radiologic findings, but radiologic findings are used as criteria for diagnosis and to determine and plan surgical intervention. As a treatment of osteoarthritis, education, physical therapy, medications and surgery are available. Pharmacological treatments involve use of analgesics drugs, non-steroid anti-inflammatory drugs, intra-articular injections of glucocorticoids, with or without anesthetics and hyaluronate injections. Surgical treatment options can be palliative, causal, arthroplasty and arthrodesis. Palliative procedures are used to relive symptoms, while causal procedures remove deformities that can lead to osteoarthritis. Arthroplasty is the best method of choice in older patients and arthrodesis is used as a last resort, when arthroplasty fails. Arthroplasty is a surgical procedure that forms an artificial joint and resembles the biological joint both, anatomically and functionally. With this procedure, hip and knee replacement are usually performed and those are two extremely successful operations. Materials used to make endoprostheses are polyethylene plastic, medical ceramics and certain metals. Endoprostheses can be fixated in the bone using special medical cement, or without it. Endoprosthesis that doesn’t require cement has a rugged surface and bone tissue grows into it, holding it securely in place. Hybrid forms use cement on some parts, while other parts do not require it. There are also partial and total forms of endoprostheses. Partial endoprostheses replace only one joint body and total endoprostheses replace all joint bodies with artificial joint. After arthroplasty, rehabilitation is needed in order to return the patient to his or hers daily routine. Rehabilitation begins in hospital, by educating the patient about limitations and possibilities of endoprosthesis and learning how to perform basic actions, such as going to the toilet with crutches, or walking with two and later with one crutch. Alongside physiotherapist, a workout plan is made and a patient has to stick with it. The point of the workout is to increase muscle strength, proprioception and coordination and by doing this, ensuring the stability of endoprosthesis. Workout routine should be preserved even a few years after the procedure, in order to prevent deterioration of the endoprosthesis.