Patellofemoral Pain Syndrome
Background and Etiology
The knee is the largest joint in the body. It is built for weight bearing, stability and mobility. The knee complex is composed of four bones: the femur, tibia, fibula and the patellar (kneecap). There are also three osseous bone-to-bone joints: the patellofemoral joint, tibiofemoral joint and the tibiofibular joint. The patellar (kneecap) is a sesamoid bone, which means it is a bone that is imbedded or located inside a tendon. In the case of the patellar it is imbedded in the quadriceps tendon. The two most common conditions that affect the patellar are patellofemoral pain syndrome and chondromalacia pain syndrome.
Function of the Patellar
- Protects the front of the knee joint.
- Acts as a fulcrum to provide leverage, thus allowing the quadriceps tendon to function more efficiently and produce greater force when straightening the knee.
- The patellar glides up and down in a groove formed between the two condyles of the femur (leg) bone.
Patellofemoral Pain Syndrome is pain that occurs beneath or around the patellar. Common causes include:
- Malalignment or poor tracking of the patellar as it glides up and down the femur or leg bone.
- Malalignment or poor tracking may be caused by quadriceps weakness or muscular tightness (the iliotibial band, lateral retinaculum, hamstrings or quadriceps muscle).
- Poor tracking may cause uneven wear on the undersurface of the patellar as it glides in the femoral groove, producing pain.
- Overloading or over use of the patellofemoral joint due to repetitive squatting, kneeling and impact sports like running
- Obesity places added stress on the patellofemoral joint causing pain.
- Improper foot wear with poor arch support can create imbalances in the patellofemoral joint.
Causes of Chondromalacia
Chondromalacia is the softening or breakdown of cartilage on the undersurface of the patellar. Cartilage is a smooth shiny surface on the patellar that allows it to slide freely over the femur. Common causes include:
- Softening or breakdown of the cartilage can be due to joint degeneration, wear and tear or arthritis.
- Poor tracking of the patellar on the femur can result in wearing on the undersurface of the patellar that causes chondromalacia.
- A sharp blow to the patellar can result in damage to the undersurface of the patellar.
- Knee pain at the patellar especially when squatting, kneeling, running and when taking stairs (especially going down.)
- A sudden feeling of the knee giving way or buckling.
- A feeling of catching, crackling, grinding or sandpaper underneath the knee cap.
- Swelling of the knee joint.
- Pain with sitting for extended periods of time or when getting up from a sitting position.
- Swelling may be present at or along the patellar
- Restriction or limitation in patellar movement.
- A medical evaluation that includes a good medical history and a clinical exam that uses several special tests can often be used to diagnose patellofemoral pain syndrome or chondromalacia.
- X-rays can be used visualize the position of the patellar in the femoral groove.
- Initial treatment of chondromalacia or patellofemoral pain syndrome would include avoidance of the activities that produce pain or stress the patellar (jumping, running, kneeling, stairs and squatting).
- The use of ice to reduce inflammation and pain.
- NSAIDS (nonsteroidal anti-inflammatory drugs)
- Physical Therapy
- The use of a knee brace to stabilize the patellar.
- The use of patellar taping to improve the tracking and alignment of the knee cap during activity and exercise.
- Surgery may be indicated in extreme cases to release the tight structures of the outside of the knee (lateral retinaculum). This procedure is called a lateral release.
Physical Therapy Interventions
Physical Therapists are professionals, educated and trained to administer interventions. As defined by The Guide to Physical Therapist Practice, interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis and the patient or client’s goals.
Physical therapy for a knee chondromalacia and patellofemoral pain syndrome must remain conservative at the onset to avoid aggravating the condition. Emphasis will be on rest, reducing the inflammation and avoiding activities that aggravate the condition. Once the initial inflammation has been reduced, an aggressive program of site specific stretching and strengthening will be initiated to restore normal patellar tracking and stabilize the patellar as it glides over the femur.
Physical Therapy Interventions
Common physical therapy interventions for this condition include:
- Manual Therapeutic Technique (MTT): hands on care including soft tissue massage, stretching and joint mobilization by a physical therapist to improve patellar movement, and reduce tightness of the lateral knee tissues to improve patellar tracking. Use of mobilization techniques can also help to modulate pain.
- Therapeutic Exercises (TE): including stretching and strengthening exercises to regain range of motion and strengthen muscles of the knee to support, stabilize the patellar. The exercise program is designed to improve tracking of the patellar in the femoral groove. In most cases the emphasis is on the medial quadriceps muscles and hip musculature.
- Neuromuscular Reeducation (NMR) to restore stability, retrain the lower extremity and improve movement techniques and mechanics (for example, running, kneeling, squatting and jumping) of the involved lower extremity to reduce stress on the patellofemoral joint in daily activities. Patellar taping can be used to improve the alignment and tracking of the knee cap during activity and exercise.
- Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved knee.
- Home programs: including strengthening, stretching and stabilization exercises and instructions to help the person perform daily tasks and advance to the next functional level.
Avoiding the activities that produce the pain or stress the involved burse is the first line of treatment.
- RICE: Rest, Ice, Compression Elevation should be used to reduce the stress on the burse.
- NSAIDS (non steroidal anti-inflammatory drugs) to reduce pain and inflammation.
- Use of a knee support to stabilize and improve tracking of the patellar
- In cases that are not responsive to conservative measures surgery may be indicated to release the lateral structures of the patellar. This will help realign the patellar in the femoral groove.
In general, patients respond well to conservative treatment of chondromalacia and patellofemoral pain syndrome. It is important that once the pain and inflammation is reduced and patellar tracking and strength are restored that the patient gradually returns back to full activities. Instruction in daily activities or sport performance is helpful to reduce the chance of a reoccurrence of this condition. In most cases full return to activity will take from 4-6 weeks depending on the severity of the condition. Following surgical intervention like a lateral release it may take 6-8 weeks to return to full function. As a preventive measure individuals should:
Make modifications in work or daily activities like avoiding kneeling and squatting, or wearing protective equipment to avoid prolonged pressure or unexpected blows on the patellar.
- Maintain strength and flexibility to reduce stress on the patellar or create imbalances in patellar tracking.
- Avoid highly repetitive activities whenever possible.
- Reduce body weight when indicated.