Evaluation of patients presenting with knee pain: Part I. History, physical examination, radiographs, and laboratory tests.

Family physicians frequently encounter patients with knee pain. Accurate diagnosis requires a knowledge of knee anatomy, common pain patterns in knee injuries, and features of frequently encountered causes of knee pain, as well as specific physical examination skills. The history should include characteristics of the patient's pain, mechanical symptoms (locking, popping, giving way), joint effusion (timing, amount, recurrence), and mechanism of injury. The physical examination should include careful inspection of the knee, palpation for point tenderness, assessment of joint effusion, range-of-motion testing, evaluation of ligaments for injury or laxity, and assessment of the menisci. Radiographs should be obtained in patients with isolated patellar tenderness or tenderness at the head of the fibula, inability to bear weight or flex the knee to 90 degrees, or age greater than 55 years.