By Jessica Heath and Neal Goulet, Drayer Physical Therapy Institute
You might have “runner’s knee,” but you don’t have to be a runner to get it. Your pain may have been dubbed “moviegoer’s knee” even if you prefer other forms of entertainment.
Each description is among the multiple terms used to describe patellofemoral pain syndrome, or PFPS. It refers to pain at the front of the knee and in and around the patella, or the kneecap.
The pain is common among athletes, active teenagers, older adults and laborers and comprises approximately one-fourth of all reported knee pain, according to the American Physical Therapy Association.
Pain typically occurs with activity, but it also can result from prolonged sitting (watching a movie, riding on an airplane). It affects more women than men. Most often, patients can avoid surgery.
Causes of PFPS are many, including overuse, excessive weight, patellar tracking disorder, wear and tear under the kneecap. However, new research is challenging the way we think about the mechanical roots of patellofemoral pain. The new focus: the femur, or thigh bone, the longest and strongest bone in the body.
Among people who have PFPS, it is common that the femur rotates under the patella. Think of this as a corkscrew motion, or what we commonly refer to as being knock-kneed (genu valgum).
But what causes this?
When we bend and extend our legs, the patella glides through a groove in the femur. But if the bones don’t line up properly, the result is a “malalignment” that can accelerate wear between the bones and even damage protective cartilage.
To compensate for this, treatment often has focused on improving the strength of the quadriceps muscles with an eye toward improving the patella’s tracking in the femoral groove.
Other remedies included taping or bracing the knee and even surgeries. They all focused on the patella – and yet in many cases the pain persisted.
Dynamic MRIs challenged the notion that the patella was the issue. The images revealed that the patella stays still; rather, it’s the femur that rotates. This has led to a change in focus, to hip strengthening and retraining of the mechanics of the lower extremity.
Improving strength in the lateral hip, the theory goes, can help to reduce how much the femur rotates.
Surgery is considered a last resort in the treatment of PFPS. Most patellofemoral pain responds to physical therapy with an exercise and stretching program, according to the International Cartilage Repair Society.
Non-operative treatment most often fails when the most current therapy is not used. Prior to the focus on improving hip strength, patients with continuing pain ultimately opted for surgery.
Several surgeries were developed in an attempt to reduce pain; however, the success rate is quite low. Among the most popular surgeries:
• Lateral release: The intent of this procedure is to assist with patella positioning. The procedure was designed to decrease the amount of pull from the structures on the lateral (outside) knee.
• Quadriceps tendon transfer: Most often used with recurrent patella dislocations, this procedure is intended to relocate the attachment of the tendon to provide more stability to the joint and prevent further dislocation.
• Arthroscopic surgery: Also known as chondromalacia, this may be recommended if the cartilage on the back of the knee becomes soft and frayed.
Often, even with surgical procedures completed, the underlying lower extremity mechanics continue to persist.
Physical therapy can play an important role in correcting the mechanical problem that underlies patellofemoral pain. When PFPS is the result of a change in activity level or worsened by a specific activity, treatment typically focuses on activity modification. For example, patellofemoral pain brought on by running in a marathon will be treated with rest, ice, over-the- counter anti-inflammatories, and a slow return to activities.
For chronic pain, treatment historically involved strengthening the quadriceps and stretching the hamstring and iliotibial band; the latter is fibrous tissue that runs down the outside of the thigh from the hip to the shin.
Now, the primary focus is on improving hip strength. The hip extensors contribute 25 percent of energy absorption during landing. If the hip muscles are not strong enough, that load is transmitted to other lower-extremity joints, the knee in particular.
Physical therapy focuses on these areas:
1. Gluteus medius strengthening: Weakness in this broad, thick muscle, which sits on the outside of the pelvis, may cause the femur to angle inward and rotate abnormally with obvious implications for PFPS.
2. Trunk stabilization: Exercises to strengthen the core muscles.
3. Proprioception/balance: Research has shown that patients with PFPS have impaired proprioception, which is our ability to control our limbs without looking directly at them.
4. Femoral mechanics: This involves training the proper alignment of the femur.
Cues often are needed to prevent femoral internal rotation and adduction in order to maintain correct alignment.
In most cases, exercises learned in physical therapy must be continued for the rest of the patient’s life to maintain proper alignment between the femur and patella.
The best news is that 80 to 90 percent of PFPS patients recover fully without surgery and are able to resume their previous activities.
Article originally published here.
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