Patients who undergo a replacement of their knees are generally older adults who have dealt with severe knee pain and joint degeneration for a long time. The majority of them are sedentary, and around 1/3 are obese. The knee replacement surgery decreases knee pain and helps patients to live a better life. However, after the surgery, some patients have difficulty performing basic activities such as walking, or going up-down stairs, and the majority remains sedentary and gain weight. These combined problems leave patients at risk of worsening their health. Therefore, a treatment that takes care of all these combined problems is needed. We propose an all-inclusive treatment, called comprehensive behavioral intervention (CBI) that intends to improve the long-term effects of exercise programs. The CBI combines exercise program with promotion of physical activity, orientation on healthy nutrition, and an education approach that promotes self-initiative towards healthy habits. The overall aim of this proposed study is to test how patients post TKA will like the CBI program, how safe the program is, and adapt the program as needed for better acceptability. We believe the CBI will be safe, well tolerated, and will improve the ability of patients to perform physical tasks. We also believe the program will increase the amount of physical activity, will promote maintenance of healthy weight, and will help the patients to obtain and maintain healthy habits. In this study subjects will be selected by a flip of a coin to receive either our CBI program or a more traditional exercise program. Subjects will be tested before and after the treatments. Our measures of main interest are how well subjects move around and how physically active they are. We are also interested on the effect of the interventions on body weight, blood pressure, eating habits, and general health. The team of researchers for this study includes several disciplines. The proposed study will defend the need for a larger study that can have a very important impact on the public health of patients post TKA. The reason for the public health impact is if the physical limitations experiences by patients post TKA are left untreated, they tend to get worse. Furthermore, by increasing physical activity and promoting healthy weight, it may improve general health and prevent chronic diseases. Last, developing educational intervention that promotes self-initiative will result in long-term health benefits post TKA.

Inclusion Criteria:

• Unilateral TKA at least three months prior to, but no longer than six months prior to study participation;
• Surgical technique was a minimally invasive (quadriceps sparing) TKA performed by the same experienced surgeon;
• Provide a written medical clearance to participate in the study;
• Speak fluent English;
• Are older than 50 years.

Exclusion Criteria:

• Have bilateral or TKA revision;
• Have hip or ankle joint replacement;
• Are unable to comfortably bear weight on the surgical knee;
• Had 2 or more falls within past year;
• Have uncontrolled medical condition that would prevent safe participation in the study (uncontrolled blood pressure, dyspnea at rest, cardiovascular disease, absolute contraindications to exercise, and diabetes);
• Participating in regular exercise during prior 6 months;
• Use beta blockers,
• Have a neurological condition that affects locomotion;
• Have had a malignancy, life-threatening illness or surgery in the past six months.