Anatomy
There are 4 bones associated with the knee (femur, tibia and patella, fibula). There are many muscles, ligaments and other structures in or around the knee joint.
Knee joint:
A. Patella (Kneecap)
B. Tibiae (Shinbone)
C. Meniscus lateralis (Outer meniscus)
D. Femur (Femur)
Cause of the problem
Patellofemoral pain syndrome (PFPS) is a very common and often long-lasting condition in young people under the age of 25 and covers a typical clinical symptom complex without a definite cause. There are many theoretical considerations about the triggering cause of PFPS (malalignment, instability with poor knee control, Hoffa’s fat body at the front of the knee, flatfoot, etc.
Symptoms
The condition usually develops gradually and is characterised by pain at the front of the joint (behind and around the kneecap), related to physical activity including weight bearing, squatting, driving and stair climbing. Locking-like cases (pseudo-locking) and a feeling of knee failure are described. The pain is often bilateral. The discomfort disappears slowly, but even with appropriate rehabilitation, more than half of patients still have pain and reduced physical function 5-8 years after the onset of pain.
Examination
Anterior knee pain (PFPS) is primarily a clinical diagnosis. It is important to rule out specific causes of the pain that require specific treatment (plica, osteoarthritis, jumper’s knee, runner’s knee, ACL injury etc). Usually, general clinical examination by a professional is sufficient, but imaging (X-ray, ultrasound and MRI scans) may be indicated in cases of fluid in the knee, trauma or lack of progress (Pacini P, et al. 2023).
Treatment
Treatment includes relief from the pain-inducing activities until the discomfort subsides. Then, a slowly increasing rehabilitation programme within the pain threshold can be started, with the primary goal being to strengthen the muscles around the knee. Lighter painkillers can be tried. There is no evidence that the knee is damaged by strain, although the pain is temporarily aggravated. Thus, there is no link between PFPS and osteoarthritis. There is no surgical option.
The effect of training is relatively modest, but a risk in anterior knee pain (PFPS) is psychological factors with fear avoidance (Glaviano NR. et al., 2022 ), where patients limit their physical activity to reduce their symptoms, which can result in social isolation, anxiety and inactivity with weight gain (increased BMI). It is therefore important to continue to engage in some form of physical activity in a controlled and safe manner, which can help prevent chronic pain, reduced physical function and maintain the social environment (Selhorst M. et al., 2023).
Bandage and inserts
Kneecap stabilising tape, see tape, and insoles can be tried (Chen Z, et al. 2022), but the evidence for efficacy is limited.
Complications
If no progress is made, you need to consider whether the diagnosis is correct. This will often require additional examinations (X-ray, ultrasound, MRI scan or possibly arthroscopy).
In particular, the following should be considered:
