The patellofemoral pain syndrome is a general term used to describe the pain present on the anterior surface of the knee. It is often referred to as the “runner’s or jumper’s knee” because it is often observed in athletes, especially women and young people, although it is also observed in non-athletic patients. The pain and stiffness it causes makes it very difficult to climb stairs or bend a knee or even to perform many daily activities. The causes that can contribute to the appearance of this syndrome are many. Problems with the alignment of the patella or even the excessive use of the joint in high energy sports contribute to the development of this syndrome.
Symptoms are often alleviated with the help of a special physiotherapy program with specific exercises.
The knee is the largest joint in the body and one of the most vulnerable to injuries. It consists of 4 basic structures: Bones, cartilage, ligaments and tendons.
Bones: Three bones are involved to create the knee joint; the femur, the tibia and the patella.
Articular cartilage: The ends of the femur and tibia, as well as the interior surface of the patella are covered by articular cartilage. This soft structure helps the bones to slide smoothly in both flexion and extension.
Meniscus: Two crescent-shaped structures act as shock absorbers between the femur and the tibia. They differ from the articular cartilage in that the meniscus is hard and elastic to help support and stabilize the knee. When one usually talks about cartilage injury to the knee, it usually refers to meniscus rupture.
Ligaments: The bones are joined together by means of ligaments. The 4 main knee ligaments act as strong ropes (straps) that hold the bones together and offer stability to the knee.
Collateral ligaments: These are located on both sides of the knee. The lateral collateral ligament is located on the inner side the knee and the medial collateral ligament on the outer side. The collateral ligaments control the movement of the bones on the lateral axis and protect the knee against abnormal movements.
The quadriceps femoris is located on the anterior surface of the knee. Tendons of the quadriceps muscle attach to the tibia and help stabilize the patella. Some knee structures make sliding and moving easier. For example, the patella slides into a groove in the lower end of the femur called the femoral groove. During extension-flexion of the knee, the patella slides into this groove. The articular cartilage, which has a slippery-sliding texture, contributes to the smooth sliding of bones. Another factor contributing to smooth slipping is the synovial membrane, which also produces a small amount of fluid that lubricates the joint.
In addition, just below the rim of the patella there is a piece of fat, called the fat pad of the patella, which reduces vibration in the joint.
The patellofemoral pain syndrome is caused by irritation of aesthetic nerve endings in soft tissues around the bones of the knee or the patella. These soft tissues relate to the tendons, ligaments, the fat pad beneath the patella and the synovial membrane that compose the knee joint. In some cases of patellar pain, a pathological condition called patellar chondromalacia occurs. This condition causes thinning, degeneration and breakage of the articular cartilage located on the inner surface of the patella. Since the articular cartilage lacks aesthetic nerves, its wear is not accompanied by pain. It can, however, lead to pain caused by synovial irritation and be manifested as pain in the underlying bone.
OVERUSE – STRAIN
In many cases, the patellofemoral pain syndrome is caused by vigorous activities that subject the knee to repetitive loads, such as jogging, squatting and stair climbing. It can also be caused by changes in exercise patterns, which may be related to the frequency of exercise (such as increased workouts per week or even training intensity), such as running longer distances.
Other factors that may contribute to the syndrome are:
- The use of inappropriate sports shoes during exercise.
- Changes in the terrain and the environment in which the games are played
POOR (PATHOLOGICAL) PATELLAR BALANCE
The aforementioned syndrome can also be caused by the abnormal sliding of the patella on the femoral groove. In this way the knee tilts in one direction or the other when bending or flexing. Finally, an important cause may be the soft tissue irritation caused by the increased contact force between the posterior surface of the patella and the femoral groove.
Factors that contribute to abnormal sliding of the patella include:
- Problems with the alignment of the lower extremities from the thighs to the ankles. These problems can lead to a condition in which the patella is very high relative to the femur, a condition called “patella alta” or it may even be lower (patella baja).
- Muscle imbalance or weakness, especially in the quadriceps on the anterior surface of the thigh. When the knee is bent or fully extended, the muscle and tendon of the quadriceps help to maintain the patella within the femoral groove. A weak quadriceps muscle or when the latter has no muscular balance and symmetry can cause abnormal sliding of the patella within the femoral groove.
The most common symptom of the patellofemoral pain syndrome is a diffuse indefinite feeling of pain on the anterior surface of the knee. This pain, which is progressively increasing and activity-dependent, may be present on one of the two knees or even bilaterally. Other common symptoms are:
- Pain during activity (mainly knee bending activity), such as climbing, running, jumping or squatting.
- Pain after prolonged sitting posture with knees bent, such as when watching a movie.
- Pain related to changing activity or even changing sports equipment or finally changing the surface where the sporting activity is performed.
- Pain accompanied by “clicking or cracking” sounds in the knee joint and especially after an attempt to get up after a prolonged sitting posture.
In many cases the patellofemoral pain syndrome will improve after a home exercise program.
CHANGE OF ACTIVITIES
It is good to stop the activities that cause the problem until the pain subsides. This may entail the replacement of these activities by other lower-intensity ones that charge less the knee joint. Bicycle and swimming are excellent low-intensity activities. Finally, weight loss for overweight patients is very useful because it reduces load charging.
The RICE method:
This method involves rest, ice therapy, leg lifting and bandaging.
Rest: Avoid charging the affected leg
Ice therapy: Apply ice pads for 20 minutes, several times a day. Direct contact of the ice with the skin is prohibited.
Bandaging: To avoid further edema, it is advisable to lightly tie the knee with an elastic bandage, leaving a hole in the patella area
Lifting: As often as possible, the affected leg should be raised in an upright position, at the height of the heart.
Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen can help reduce edema and relieve pain. If this does not happen, contact your treating physician for further evaluation.
During clinical examination, the doctor receives a detailed medical history by asking questions about the intensity and nature of pain. In addition, he will ask when the symptoms first appeared and during which activities they got worse. During palpation, the physician gently moves, puts pressure on the patella and asks the patient to perform squats and jumps. Finally, the physician will examine the patellar slide within the femoral groove, while excluding some other pathological conditions by examining:
- The normal shafts of the lower extremities
- Knee stability and range of motion of all lower extremity joints
- Painful points in the patella
- Muscle tone and strength of the femoral muscles
The diagnosis is usually clinical and no further imaging tests are needed. However, radiological examination of the knee can rule out any concomitant problems.
The purpose of treatment is to relieve pain and restore the range of motion and strength of the knee. In most cases, the patellofemoral pain syndrome is treated conservatively (non-surgically).
Along with changing activities and receiving NSAIDs, the Orthopedist may recommend:
PHYSIOTHERAPY: Specific exercises under guiding help to regain range of motion and strength. In particular, strengthening the quadriceps muscle helps to stabilize the patella.
FOOTWEAR INSERTS: Special footwear inserts that help align and stabilize the lower leg, reduce knee loads.
Surgical treatment is very rarely employed to treat the patellofemoral pain syndrome. It can be used in cases that did not respond to conservative treatment.
ARTHROSCOPY: The surgeon inserts a small camera into the knee through small incisions. With the help of special tools he can interfere with various structures in the joint.
- Surgical Washout: In some cases, removing the damaged articular cartilage from the surface of the patella can provide pain relief.
- Lateral Release: The release of the collateral ligaments loosens the tissues and allows the patella to slide properly and unhindered.
TRANSLOCATION OF THE TIBIAL TUBEROSITY: In some cases the alignment of the patella is achieved by translocating the tibial tuberosity (osteotomy) and fixing it inwards with screws on the knee. In this way the patella slides smoothly and with less friction on the femoral groove.
The patellofemoral pain syndrome is usually treated by simple means. It can relapse if the patient does not modify their daily activities or their training method. It is important to maintain the strength of the muscles that surround and move the knee (quadriceps, biceps) and the range of motion of the joint.
The additional measures a patient can take are:
- Use appropriate footwear for daily activities
- Stretch and warm-up before exercising
- Limit knee-straining exercises
- Maintain a healthy body weight