One of the most common causes of knee pain and musculoskeletal conditions presenting to our clinic is patellofemoral pain syndrome. Patellofemoral pain syndrome typically develops over time and is a general condition describing pain in front of the knee that surrounds the patella (knee cap) and worsens with squatting, sitting, running, and going up and down stairs. Although it is most prevalent in athletes and young adults, it is also common in nonathletes and older adults. Patellofemoral pain not only impacts individuals in the short-term, but as many as 90% of patients report that they have had pain for at least five years since the initial onset of symptoms and 25% report pain lasting up to 20 years.
As one of the largest joints in the body, the knee is composed of three bones, the femur (thighbone), tibia (shinbone), and patella (kneecap). Although there are multiple ligaments that hold the tibia and femur together as well as other tendons and structures within the joint, the structures involved in local patellofemoral mechanics are primarily composed of the quadriceps muscle group (located on the front of the thigh), the quadriceps tendon, the patella, and the patellar tendon. When the knee is bent and straightened, the patella glides up and down the trochlear grove of the femur. When these joint mechanics are altered, the patella isn't able to glide up and down as smoothly as it was designed to. This can lead to my least favorite word – pain.
Although the causes are not completely understood, research shows that there are generally multiple contributors to patellofemoral pain syndrome. Causes can be local to the knee but altered mechanics of the hip are often the culprit. These altered mechanics are commonly caused by muscle weakness in specific muscle groups of the hip including the abductors, external rotators, and extensors. These weaknesses lead to stress on the patellofemoral joint because the altered hip mechanics can cause the patella to glide incorrectly. Moreover, during the stance phase of walking or running, when only one foot is contacting the ground, the muscles on the outside of your hip activate to enable your body to avoid tipping over towards your unsupported side. When those hip muscles are weak however, this causes your knee to go into "genu valgum" or a knock knee position (as shown in the diagram below), altering the mechanics of your entire leg and you guessed it – the patellofemoral joint.
Often symptoms from patellofemoral pain syndrome can be treated with a lower quarter strengthening program. A recent systematic review composed of 673 participants published in the Journal of Orthopedic and Sports Physical Therapy (JOSPT) found that hip and knee strengthening is more effective than knee strengthening alone in decreasing pain while increasing overall function for people with patellofemoral pain syndrome. The same journal has provided a list of the best evidence-based hip exercises for strengthening your hip extensors and abductors. The link to these exercises can be found here:
If knee pain is interfering with your activities and stopping you from the things that you enjoy, a physical therapist can perform an objective evaluation on the causes of your knee pain as well as generate a customized treatment plan to help you reach your goals in restoring your health.
Come see us today so we can help you feel better, move better, and decrease pain.
Ryan Tollis, PT, DPT
Orthopedic Rehabilitation Associates