RESUMEN
The evaluation of a patient with knee osteoarthritis (OA) has 3 main components: clinical history, physical examination, and radiographic imaging. The clinician should assess for inciting and aggravating factors for the knee pain as well as for the presence of any mechanical symptoms. A history of prior knee injury or surgery can suggest the development of early osteoarthritis. A thorough physical examination of the knee should be performed. Some features of OA include limited range of motion, crepitus in the patellofemoral compartment, and joint line tenderness. Depending on the severity of OA varus or valgus alignment can develop. Special tests such as the McMurray for meniscal tears may cause increased pain as patients with OA will often have degenerative meniscal tears. Weight bearing radiographs can confirm the diagnosis of OA. Several scales exist to grade the severity of OA with the Kellgren-Lawrence being one that is often used. Radiographic features of OA include joint space narrowing, osteophytes, sclerosis of bone and bone end deformities. If after the above evaluation the diagnosis is still unclear, advanced imaging or laboratory testing can be performed to evaluate for alternative diagnoses.