Updated: Sep 22
PATELLOFEMORAL PAIN SYNDROME
What does it mean by Patellofemoral pain syndrome or runner’s knee?
Let’s understand it better!
Patellofemoral pain syndrome (PFPS) which is more commonly known as runner’s knee is a painful condition attributed to the patella and how it behaves in the front of the knee.
PFPS has a high prevalence within the sporting population with one study of 2159 presentations to sports medicine clinics reporting 5.4% PFPS among 25% of the population presenting the case of knee pain. Older patients or runners at a higher age level usually present with signs of patellofemoral osteoarthritis (PFOA).
A key factor in PFPS development is the dynamic valgus of the lower extremity, which leads to lateral patellar mal-tracking. Causes of dynamic valgus include weak hip muscles and rearfoot eversion with pes pronates valgus. These factors can also be observed in patients with PFOA.
1. Morphological anomalies (weak hip muscles and rearfoot eversion with pes pronates valgus.)
2. Femorotibial malrotation.
3. Ligamentous insufficiencies with poor proprioception.
Identifying the root cause amongst multiple causes:-
· Runner’s knee can be caused by overtraining or increasing in distance, speed or intensity of training too sudden or too soon or too rapid. Descending hills have a high patellofemoral load. The solution is a graded return to running, avoiding downhill action.
· The glutes and the quadriceps muscle play a pivotal role in causing PFPS. An important consideration is how to strengthen them without an increase in PF load loading them in a pain-free zone.
· Poor single-leg balance and control of single-knee buckling are common in PFPS. Working on control of movement could improve this. Taping has been suggested it improves the timing of VMO contraction as well as reduce pain.
· Tightness in the ITB is one of the very common conditions arising leading to knee pain by pulling the patella slightly laterally (towards the outside of the knee) leading to an increase in the load on the joint. The quadriceps attach to the patella directly and so any tightness in this muscle will affect the way the patella moves and potentially increase the load upon it. Hamstring and calf tightness can increase patella load indirectly by the way they affect knee movement. Gradually work into this stretch and make sure your knee is on a pillow or something soft as the stretch itself can increase the load on the patella.
· Another cause could be faulty running form. Foot strike, stride length, overpronation, supination and hip adduction of it can indirectly affect the loading on the PF joint. Variables in these are all also totally normal. It can be hard to determine, what if anything to change and how to do it.
Excellent work from @runblogger has looked into foot strike and running form in more detail, one conclusion he made is that increasing step rate and reducing stride length may reduce the load on the knee. Reducing stride length can be a relatively easy way to reduce the load on the knee during running. Further assessment of a correct form via new assessment tools such as running gait analysis can prove useful.
Sites:-unspecific anterior pain & Lateral knee pain. Pain is typically felt under the patella, not down the outside of the knee.
Aggravating factors:- heavy loading – squatting, lunging, kneeling, going down stairs, running downhill This is sometimes called moviegoers knee Usually, there is no true locking or giving way of the knee and minimal swelling. The knee may feel stiff but usually has a full range of movement. There may also be clicking or grinding also clinically known as crepitus.
1. Medial and lateral patellar passive mobility, (not more than 1-2 quarters of patellar diameter .)
2. Patellar tilt test
3. Patellar apprehension test
4. Sign for detecting patellofemoral tracking(full extension open kinetic chain position.)
5. Assessment of rotation axes of lower extremity
6. Muscular hypertrophy
The position of the patella concerning the femur and tibia will have a direct effect on the loading of the joint. Sometimes this is referred to as the Q angle “.
1. One of the causes can be Overpronation of the foot especially if associated with hip adduction.
2. Patella position can be altered by taping (McConnell taping) but this works only as a temporary relief.
3. Assessment from a physiotherapist will help you identify and treat the cause accordingly.
RETURN TO RUNNING:-
1. Settle symptoms and inflammation by reducing the load on the patella and surrounding tissues
2. Identify the cause of the problem
3. Rehab to deal with the cause
4. Gradually “reload” the area and return to normal running
5. Better outcomes have been reported if the proximal strengthening programme is started before functional strength compared with the initial knee strengthening programme approach.
6. Taping and bracing have also been proved useful in the acute phase of recovery.
OFFLOAD, REHAB, RELOAD!
CLOSED CHAIN EXERCISES
A closed Kinetic Chain means an exercise where the foot is fixed and the body moves e.g. Squats, lunges, and step-ups.
· Exercises can be better tolerated in the knee flexion range of 0-45*
· Mini squats, step-ups, wall sits, and leg presses can be started.
OPEN CHAIN EXERCISES
Open Kinetic Chain means an exercise where the foot is not fixed and is free to move e.g. Kicking a ball, leg curl, or hamstring curl.
· Exercises can be better tolerated in the knee flexion range of 90-50 degrees and 20-0 degrees.
· Short arc exercises to strengthen the quadriceps muscles can be included in the programme.
Running is composed of both open-chain movements as the leg swings through the air and a closed chain, as the foot strikes the ground.
Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007 Jan 15;75(2):194-202. PMID: 17263214.
Petersen W, Rembitzki I, Liebau C. Patellofemoral pain in athletes. Open Access J Sports Med. 2017 Jun 12;8:143-154. doi: 10.2147/OAJSM.S133406. PMID: 28652829; PMCID: PMC5476763.