What is Patellofemoral Pain Syndrome?
Patellar tendon pain, commonly also referred to a patellar tendinopathy, patellar tendonosis or patellar tendonitis occurs because your patellar tendon becomes overstressed. The different suffixes actually describe different states of the tendon. The suffix “osis” refers to long-term degeneration of the tendon usually without inflammation, ‘itis’ refers to a more acute inflammation stage and ‘opothy’ refers to general degeneration of a tendon.
Patellofemoral pain (PFP) accounts for up to 17% of knee pain seen generally, and up to 40% of knee problems seen in the sporting population (1), with up to 7% of adolescents between the ages of 15 and 19 years suffering with the condition (2). The condition is more common in young adolescents, especially those active in sport, and is also seen in military recruits. In addition to active individuals, inactive adolescents who are subjected to a sudden increase in walking and/or stair climbing may also suffer.
In both groups the condition represents an inability of tissue to adapt to increased loading. PFP is variously described as anterior knee pain, chondromalacia patellae, patella malalignment syndrome and patellofemoral pain syndrome. The condition typically presents as a dull ache over the anterior aspect of the knee, worse following prolonged sitting and when descending stairs. Although more common in youth, the condition can occur at any age and is typically associated with patellofemoral osteoarthritis (OA) in seniors.
Structure And Function Of The Patellofemoral Joint
The patella is the largest sesamoid bone (bone lying within a tendon) in the body, attached above to the quadriceps tendon and below to the patellar tendon. Medially and laterally the patellar retinacula (fibrous tissue to the side of the patella) offer support. The breadth of the pelvis and close proximity of the knee creates an outward (valgus) angle of the tibia compared to the femur. Coupled with this, the direction of pull of the quadriceps is along the shaft of the femur and that of the patellar tendon is almost vertical. The difference between the two lines of pull is known as the Q angle and is often considered an important determinant of knee health. Normal values for the Q angle are in the region of 15–20°.
In full extension, the patella does not contact the femur, but lies in a slightly outward (lateral) position. As knee flexion progresses, the patella should move inwards (medially). If it moves laterally it will butt against the prominent lateral femoral condyle and the lateral edge of the patellar groove of the femur.
Throughout flexion, different areas of the patellar undersurface are compressed onto the femur below. At 20° flexion, the inferior pole of the patella is compressed, and by 45° the middle section is affected. At 90° flexion, compression has moved to the superior aspect of the knee. In a full squatting position, with the knee reaching 135° flexion, only the medial and lateral areas of the patella are compressed.
How Does Patellar Tendonitis Happen?
The patellar tendon runs from the bottom border of the kneecap (patella bone) and attaches to the shin bone (tibia). It acts as an extension of the thigh muscles and works to straighten the knee by transferring forces from the thigh muscles (quadriceps).
The tendon works hard during activities like jumping, landing, and squatting and is therefore common in athletes who sports like basketball, volleyball, netball, or participate in ballet or running. But you don’t have to be an athlete to have patellar tendon pain, simple daily chores of climbing stairs, repetitive kneeling down at home or at work could also cause patellar tendinopathy.
Do You Suffer With This?
Do you suffer from sharp pain on, or just below, the knee cap during physical activity, occasionally followed by a dull ache for some time after the activity? Do you feel stiffness in the knee, like a tight band is restricting movement, especially when bending the knee? And you can’t really remember a specific incident that trigged the pain, but instead the pain has been developing slowly over the past few weeks?
If so, the chances are you probably have patellar tendon pain, commonly also called patellar tendinopathy, patellar tendonosis or patellar tendonitis.It occurs because your patellar tendon becomes over-stressed. This occurs frequently in athletes involved in ‘jumping’ sports (hence why it is often nicknamed Jumper’s Knee).
What Can Be Done About My Knee Pain?
Patellar tendon pain can be very restricting and frustrating as the pain can linger for weeks. It’s possible that you won’t need complete rest and may not have to stop exercise all together. With a little self-discipline and help from a physical therapist your patellar tendon pain could be resolved in a matter of weeks. Initial treatments may focus on pain relief.
Massage therapy to the tendon and surrounding thigh muscles can promote the repair process and decrease pain. Manual therapy can be performed to stretch tight TIME-SAVING RESOURCES FOR PHYSICAL AND MANUAL THERAPISTS muscles surrounding the knee and relieve stiffness in the joint. Taping or strapping can relieve pain in the short term, your therapist can apply this or teach you how to do it. Knee braces can also be helpful in pain relief.
Treatments will then focus on rehabilitation. This is the important part where you can take control of your recovery. The entire lower limb, from your pelvis to your foot needs to work together with the knee to withstand the forces of daily activities and exercise.
So, strengthening weak calf, thigh and/or buttock muscles will help reduce the burden on the patellar tendon. Your therapist will give you daily exercises to do that will progress in difficulty as your symptoms improve.
Making sure your leg is well aligned will also ensure each muscle and joint is working together harmoniously. This may require stretching exercises to lengthen tight muscles. Your physical therapist may refer you to a podiatrist for foot orthotics which will give your leg better support and alignment.