During diagnosis of runner's knee, the physician must rule out other conditions, such as patellar tendinitis (jumper’s knee), meniscus tear, and iliotibial band friction syndrome. If symptoms appear consistent with runner’s knee, the physician must determine the root cause. While important, determining the precise cause of patellofemoral pain can be challenging, and include a full review of the patient’s medical and sports history, physical examination, imaging (usually x-rays are sufficient), and biomechanical evaluation (strength, flexibility, running technique).
In order to determine the specific nature and severity of the injury, a physician will ask questions such as the following:
- When did the pain begin?
- How did it begin?
- How specifically does the pain feel? (Sharp, aching, throbbing, etc.)
- What types of movement make it worse?
- Whether or not the injury is related to a patient’s prior medical history.
- If there has been a previous knee injury of record.
Tracking symptoms prior to an appointment can help a patient accurately report symptoms. For example, the patient may keep a diary of symptoms or use a phone app to record symptoms.
A physical exam tests the stability, motion, and function of the knee. The physician will evaluate the knee for symptoms such as swelling and stiffness, observe tracking of the patella, and palpitate the knee, using his or her hands to feel for any abnormalities. Strength, flexibility, and movement patterns of the hip, foot, and ankle are also examined, as they affect the motion of the knee.
If the physician has not been able to determine a specific cause of runner’s knee pain through a physical examination, then more comprehensive imaging tests may be necessary. In order to identify the cause of the problem, doctors will typically use one of the two methods:
- X-ray: If the physician suspects that the problem causing runner’s knee pain is improper movement of the patella over the femur, X-ray will be the initial method of imaging. This image will allow the physician to visualize the location of the patella on the femur, identify potential bone spurs, or detect arthritis.
- Magnetic resonance imaging (MRI): Unlike X-rays, MRIs provide an image of the knee’s soft tissues. Doctors will be more likely to use this noninvasive imaging method if they suspect a problem with the meniscus, tendons, or ligaments of the knee.
Once a physician has arrived at a diagnosis, a patient will be recommended a course of treatment.