Patellofemoral pain syndrome (PFPS) is a common condition that causes pain around the knee cap (patella). It affects up to 25% of active people, and is especially common in women.
What are the symptoms?
A dull ache is experienced at the front of the knee or behind the kneecap during activities such as running, jumping, squatting or using stairs. Prolonged sitting in cramped conditions (i.e. in lecture theatres and aircraft) may also be painful. There may be a ‘catching’ sensation, accompanied by sharp pain and momentary weakness.
What causes PFPS?
During activities that involves knee bending (eg. climbing stairs, running, squatting), the patella glides in a groove at the lower end of the thigh bone (femur). The pressure on these structures can reach 2-8 times your body weight during these activities. In patients with PFPS, the patella does not run in the middle of this groove and usually tracks laterally, resulting in increased pressure and irritation. Factors that may contribute to PFPS include:
Muscle weakness and/or fatigue
Muscle and soft tissue tightness
Lower limb bone malalignment
Overuse (eg. excessive training)
Foot biomechanical abnormalities
Can PFPS be prevented? Excessive training and lack of proper conditioning of the muscles are often implicated in PFPS. Hence, if you are at risk, you should adopt the following:
Strength & conditioning Muscles that are involved in running and other lower limb sports should be adequately strengthened, so that they can meet the demands of your sporting and daily activities.
Flexibility This keeps the muscles and soft tissues elastic.
Progressive training Plan your training programme. Give yourself ample time to reach your target mileage or pace. Avoid rapid increases in volume or speed.
Equipment Check that your shoes are not worn-out, as such shoes will not provide adequate support or shock absorption. Choose a shoe with correct fit that is suitable for your particular foot type.
What will my doctor do?
Your doctor will take a medical history, including your daily and physical activities, and perform a physical examination. This will help to exclude other possible causes of knee pain, such as meniscus tears, ligament or tendon injuries. Medical imaging (i.e. ultrasound, magnetic resonance imaging scans or X-rays) may be necessary. These can help the doctor assess the alignment of your kneecap and cartilage thickness. You may also be asked to run on a treadmill so that your gait can be assessed.
How is PFPS Prevented?
Strength, flexibility and conditioning exercises Physiotherapy exercises can help regain the range of motion in your knee and correct the muscle imbalances that affect patella movement. You will be taught exercises to strengthen the core, hip and muscles around the knee. Stretches (please see illustrations provided) to improve flexibility will also be taught. Correct technique is essential, and you should consult your physiotherapist if unsure, or if there is pain during the exercise.
Taping Sports tape may, occasionally, be used to enable you to exercise without pain.
Activity modification Treatment may require 3-6 months. During this period, you should minimise activities that may worsen the condition. These include repetitive, high impact activities that involve knee bending, such as running, stairs, hill-training, step aerobics, roller blading and spinning. Adjust activities to a level that you can comfortably tolerate. You can also replace high-impact activities with exercises such as seated cycling, front crawl swimming, deep water running, rowing and the elliptical trainer.
Footwear modification Your doctor may examine your running shoes and provide advice on suitable shoe types. If necessary, a podiatric consult for further assessment and orthotic (insoles) fitting may be scheduled.
Strengthening exercises The following exercises can be used to condition your body. Please warm-up before each exercise. For all the exercises, perform 15-20 repetitions for each side. Then repeat 2-3 times. Perform these exercises at least 2-3 days every week but your exercise days should not be consecutive.
Tighten your VMO before the rest of the quadriceps. Use your hand to help isolate the muscle.
Hold 30 sec.
Increase the duration of the squat until it reaches 3-5 mins.
Stretches The following exercises can be used to condition your body. Please warm-up before each exercise. For all the exercises, perform 15-20 repetitions for each side. Then repeat 2-3 times. Perform these exercises at least 2-3 days every week but your exercise days should not be consecutive.