Diagnosis

Your doctor will want to know exactly how you hurt your knee. He or she will ask about:

• The type of movement that caused the injury (knee twist, sudden stop, pivot, direct contact, hyperextension)

• Whether you felt a pop inside your knee when the injury happened

• How long it took for swelling to appear

• Whether severe knee pain sidelined you immediately after the injury

• Whether your knee immediately felt unsteady and could not bear weight

The doctor will examine both your knees, comparing your injured knee with your uninjured one. During this exam, the doctor will check your injured knee for signs of swelling, deformity, tenderness, fluid inside the knee joint, and discoloration. If you don't have too much pain and swelling, the doctor will evaluate your knee's range of motion, and will pull against the ligaments to check their strength. During the exam, you will bend your knee and the doctor will gently pull forward or push backward on your lower leg where it meets the knee.

If the results of your physical exam suggest you have a significant knee injury, you will need diagnostic tests to further evaluate your knee. These may include standard X-rays to check for ligament separation from bone or fracture. Tests may also include a magnetic resonance imaging (MRI) scan or camera-guided knee surgery (arthroscopy).

Expected Duration

How long a knee sprain lasts depends on the specific type of knee sprain, the severity of your injury, your rehabilitation program and the types of sports you play. In general, milder Grade I and Grade II MCL or LCL sprains can heal within 2 to 4 weeks, but other types of knee sprains may take 4 to 12 months.