Ever had pain around the front or side of the knee that just suddenly started? It might feel vague and hard to describe and can occur in different places around the front of the knee. Sometimes it can come on very suddenly and other times it can slowly be getting worse. Maybe you have noticed your knee hurts when watching a movie, AKA the “moviegoer” sign, or when going up/down stairs, running, squatting, or even jumping. Anterior knee pain that is either behind the knee cap (retropatellar) and/or around the kneecap (peripatellar) is commonly referred to as PatelloFemoral Pain (PFP). There is no imaging or specific testing that can diagnose you for PFP and therefore after ruling out other knee pain causes it is ruled in as a diagnosis based on a cluster of signs and symptoms. Onset is often delayed and is typically progressive.
PFP is one of the more common diagnoses for knee pain and has been cited with up to a prevalence of 85%, but most commonly being cited at 25%1. PFP occurs in a wide variety of ages with most references citing females greater than males and typically occurs more in the active population2, 3.
Previously patellofemoral pain was considered a condition that was common in adolescents and would eventually resolve on its own overtime however it has been reported that 50%-56% of adolescents report persistent knee pain 2 years after their initial diagnosis4, 5 and therefore can have a substantial impact on quality of life while living, such as loss of physical function, loss of self-identity, pain-related confusion and fear, and concern for the future.6
When developing patellofemoral pain research has shown that people demonstrate decreased quadriceps force production and decreased hip strength which often contribute to altered biomechanics (altered form) during dynamic movements; this means that when the knee goes though a bending motion, whether it is running, jumping, squatting, pivoting, it tends to move excessively in frontal plane movement ( knee collapsing inwards or outwards ).7 It has also been reported that people who are experiencing PFP have a lower pain threshold, meaning things that usually wouldn’t cause pain might now be leading to more pain. The bad news is that the longer duration of symptoms prior to intervention the overall poorer function and worse pain; however with appropriate treatment it has been reported a resolution in symptoms in over 73% of cases.8
Recent guidelines have placed people with PFP into 4 categories in order to identify appropriate treatment.
- Overuse/overload: When there is an increase in magnitude and/or frequency of patellofemoral joint loading at a rate that surpasses the ability of the patellofemoral joint tissues to recover1.
We usually see this in someone who might have started training for an event too quickly or at the start of sport conditioning after an offseason.
- Hip Strength deficits: When identifying patient’s with PFP a lack of hip strength was a correlating finding.
This subgroup of people is often seen in females more than males however the reason in the resulting hip weakness remains unclear. Recent literature has shown after beginning a hip and knee strengthening program that this subgroup did respond favorably.
- Movement Coordination Deficits: For those who demonstrate an increase in knee valgus movement ( or knee collapsing inward compared to the toes) during dynamic activities such as running and jumping, the altered mechanics can impart increased stress to the patellofemoral joint leading to PFP. This subcategory of people may respond favorably to gait retraining and movement re-education interventions.
- Mobility impairments: Here there can be instances of hypermoblity (too much movement) or hypomobility (not enough flexibility) that can lead to PFP.
Hypermobility: Though too much movement at the patella itself can cause knee pain another correlated finding with PFP was increased foot pronation (flat feet or foot collapsing inwards when standing). For this group of people a foot orthosis is recommended as an adjunctive treatment.
Hypomobility: More often seen in PFP is a lack of flexibility of structures around the knee causing increased compressive forces at the PFJ. Commonly seen are tightness in the hamstrings, quadriceps, gastrocnemius, soleus, lateral retinaculum and iliotibial band. There also has been some evidence linking a lack of hip external and internal rotation leading to an increase in stress at the patellofemoral joint. This subcategory of people may benefit from a stretching and ROM program.
In summary the literature suggests nonsurgical interventions for individuals with PFP that includes the goal of trunk, hip, thigh and LE strengthening and stretching exercises to address muscle performance deficits, movement coordination deficits, and mobility impairments as well as adjunct treatments such as patellar taping or foot orthosis.1 Patellofemoral pain does not go away insidiously and the sooner interventions are applied the better the outcomes.
If you have anterior knee pain, do not wait! Seek out your Physical Therapist and let them guide you back to your normal activities and more!
- Steven Jelmini, PT, DPT, OCS
Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a proper health care professional.
- Willy W.R, Hoglund T.L, Barton J.C, et al. Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability and Health From the Academy of Orthopaedic Physical Therapy Association. JOSPT. 2019;49(9.): CPG1-CPG95. https://www.jospt.org/doi/10.2519/jospt.2019.0302
- Boling M, , Padua D, , Marshall S, , Guskiewicz K, , Pyne S, , Beutler A. and Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scand J Med Sci Sports. 2010; 20: 725– 730.
- Tenforde AS, , Sayres LC, , McCurdy ML, , Collado H, , Sainani KL, , Fredericson M. and Overuse injuries in high school runners: lifetime prevalence and prevention strategies.
- Rathleff CR, , Olesen JL, , Roos EM, , Rasmussen S, , Rathleff MS. and Half of 12–15-year-olds with knee pain still have pain after one year. Dan Med J. 2013; 60: A4725
- Rathleff MS, , Rathleff CR, , Olesen JL, , Rasmussen S, , Roos EM. and Is knee pain during adolescence a self-limiting condition? Prognosis of patellofemoral pain and other types of knee pain. Am J Sports Med. 2016; 44: 1165– 1171
- Smith BE, , Moffatt F, , Hendrick P, , et al.. The experience of living with patellofemoral pain—loss, confusion and fear-avoidance: a UK qualitative study. BMJ Open. 2018; 8: e018624.
- Hespanhol LC, Jr., , van Mechelen W, , Verhagen E. and Effectiveness of online tailored advice to prevent running-related injuries and promote preventive behaviour in Dutch trail runners: a pragmatic randomised controlled trial. Br J Sports Med.2018; 52: 851– 858. https://doi.org/10.1136/bjsports-2016-097025
- Kannus P, , Natri A, , Paakkala T, , Järvinen M. and An outcome study of chronic patellofemoral pain syndrome. Seven-year follow-up of patients in a randomized, controlled trial. J Bone Joint Surg Am. 1999; 81: 355– 363.