What is Patellofemoral Pain Syndrome?
Patellofemoral Pain Syndrome (PFPS) is one of the most common knee complaints of both the young active sportsperson and the elderly. It is the medical term for pain felt underneath your kneecap, where your patella (kneecap) articulates with your femur, known as your patellofemoral joint. It occurs primarily due to excessive patellofemoral joint pressure. This increase in pressure is most likely caused by a maltracking kneecap, which in time, affects the joint surface behind the kneecap (retropatellar joint).
PFPS affect 25% of the population at some time in their lives, but it is more common in athletes. The sports where patellofemoral pain syndrome typically presents are those when running, jumping and landing or the squatting position is required. Sports include running, tennis, netball, football, volleyball, basketball, skiing and other jumping sports.
What are the symptoms of PFPS?
The onset of your kneecap pain is most often gradual rather than traumatic.
PFPS symptoms typically present during weight-bearing or activities that involve compressive loads such as squatting, kneeling, hopping, running or using stairs are commonly painful. As your PFPS progresses, your knee may become painful while walking and then ultimately even at rest. You can also experience kneecap pain when you are in sustained knee bend, e.g. sitting in a chair.
Why is my knee sore?
Your patella glides typically up and down through the femoral groove. As your knee bends there is an increase in pressure behind the kneecap. This retropatella pressure further increases if the patella does not move smoothly through the groove, but rather maltracks, meaning it travels more to one side, making it rub against the femur.
Repeated trauma causes an increase in your retro patellar joint forces, which can lead to kneecap pain, joint irritation and eventually degeneration of your patella joint surface. The most common causes of patellar misalignment are muscle imbalances and reduced biomechanical control.
As mentioned, PFPS can be caused by muscle imbalances and biomechanical abnormalities. Firstly, we will discuss muscle imbalances and how they effect your patellofemoral joint. Your quadriceps attach to the patella and the patella tendon, which connects to the top of your shin. If there is a muscle imbalance between the medial (inner) and lateral (outer) quadriceps muscles, your patella will track laterally in the groove. Vastus lateralis (VL), which pulls your patella up and outwards, and the vastus medialis oblique (VMO), which is the only quadriceps muscle that pulls your kneecap up and slightly in, are the muscles that are often ‘out of balance’ or have a reduced capacity for load. Common reasons for reduced strength or your VMO include knee injury, post-surgery, swelling or inactivity. The longstanding tightness of your lateral knee structures (lateral retinaculum, VL, and ITB) will encourage your kneecap to drift laterally over time, especially if your VMO is not performing optimally.
There are a number of biomechanical factors that can increase the pressure on your patellofemoral joint, potentially leading to the development of PFPS. Your hip muscles have been shown in the research to be very important in the control of your thigh. Reduced gluteal muscle strength and control allows your knee to rotate medially (inward) and apply a relative lateral displacement of the patella. Most successful rehabilitation programs require assessment and correction of your hip and buttock muscle control.
Foot posture (eg. flat feet) can allow your knee to rotate medially (inwards) and result in a lateral deviation of your patella. When imperfect biomechanics repeat, with walking or running, that unfortunate habit repeatedly places load on your patellofemoral joint in a unhelpful manner.
PFPS treatment
PHASE I – Symptom Reduction
Your physiotherapist will likely implement a range of treatments in order to reduce your symptoms. This can include:
- Manual therapy techniques such as massage trigger point therapy and dry needling of the hip and thigh musculature. Gentle exercises such as stretching, heat packs, de-loading taping techniques.
- Activity modification and advice specific to PFPS which may include minimising stair climbing, running and jumping activities and a temporary reduction in exercise.
- A home exercise program will be implemented by your physio most likely focussing on reducing muscular tightness and improving quadriceps muscle strength.
PHASE II – Restoring Normal Movement and Strength
- You will gradually begin a supervised exercise program focussing on dynamic motor control and strength of the muscles supporting your knee and hip – increasing the capacity or your knee to tolerate load. This can be in the form of clinical pilates and/or a gym based program.
- As the capacity of your musculature improves, your physio will progress your home exercise and supervised exercise programs into more functional positions/postures.
- Depending on your chosen work, sport or activities of daily living, your physio will aim to restore your function to safely allow you to return to your desired activities in line with your specific treatment goals.
PHASE III – Restoring Full Function & Preventing a Recurrence
- The last stage of your rehabilitation aims at returning you to your desired activities. Everyone has different demands for their hips that will determine what specific treatment goals you need to achieve. For some people, it only is to walk around the block. Others, for example, may wish to return to basketball or soccer. Your physiotherapist will tailor your rehabilitation to help you achieve these goals.
- PFPS has a tendency to return if participation to the treatment plan and rehabilitation is not sufficient.
- This fine-tuning of your knee and hip biomechanics by addressing any deficits in core strength and balance is important in the prevention of a recurrence. Your physio will guide you through self-management techniques to reduce and manage any future symptom increases.
If you are experiencing knee pain and would like to have a FREE assessment by a Physiotherapist or Exercise Physiologist, book in to Back in Motion Aspendale Gardens here.