Patellofemoral Pain: Current evidence and ideas for the future
The Effect of Foot Manipulations on Patellofemoral Pain Syndrome
The knee is one of the most commonly injured sites of the lower extremities with Patellofemoral Pain Syndrome (PFPS) being one of the most common problems. The incidence rate has been reported to be 22/1000 per year (1). The incidence in the female population was 33/1000 per year and 15/1000 per year for the male population. Females are reported to have 2.23 times more chance of developing PFPS than their male counter parts (1). The incidence risk was reported to be 9.66/100 in female athletes (2).
Gender was not a significant predictor of prevalence of PFPS, but females were 25% more likely to have a history of PFPS compared to males (1). The prevalence reported in the cohort was 13.5%, with prevalence numbers in the female and male population was 15.3% and 12.3% respectively (1). Myer (2) reported a point prevalence of 16.3/100 female athletes and 1.09 per 1000 athletic exposures.
The following criteria was put forward to diagnose PFPS: Retropatellar pain during at least two of the following activities, ascending/descending stairs, hopping/jogging, prolonged sitting, kneeling, and squatting, negative findings on examination of knee ligaments, menisci, bursa, plica, and pain on palpation of the patellar facets or femoral condyles (1). A systematic review by Cook (3) concludes that the research done until now is of such poor quality that no conclusion can be drawn to the best test for PFPS.
Various risk factors have been proposed for the development of PFPS: Onset timing of Vastus Medialis, flexibility of the Quadriceps muscle, a reduction in jump height, increase in medial patellar mobility (4). Individuals with PFPS have showed decreased soft tissue mobility of the gastrocnemius and soleus (4,5). A meta analysis of pooled results from several studies found weak knee extension measured by peak torque to be a risk factor for PFPS (6). Overuse and an increase in physical activity have commonly been reported as risk factors, as well as anthropometric variables, Q-angle, and kinematic variables, but the evidence is not conclusive (6). Boling (7) reported decreased knee flexion during landing and increased hip internal rotation to be risk factors. Myer (2) reported increased valgus knee position during a landing task in patients with PFPS.
The etiology of the condition has been proposed to be a loss of tissue homeostasis due to increased load on the joint (8), and small alterations in the functioning of the lower extremity can lead to increased stress on the patellofemoral joint (9).
Historically traditional therapeutic interventions have focused on either local treatments to the knee like patellar mobilizations, taping, soft tissue mobilization of the structures surrounding the knee or strengthening the hip muscles to avoid internal rotation of the hip, manipulation of the SI joint and/or lumbar spine (10–12). Even though there is fair evidence for the use of manual therapy on the knee and/or full kinetic chain for patients with PFPS (12), until now no one has investigated the effect of foot manipulations on PFPS.
What is the difference between manipulations of the foot (I) and exercise therapy (C) in reducing pain (O) in young adults with Patellofemoral Pain Syndrome (PFPS) (P).
Individuals with a limited ankle dorsiflexion range of motion (ROM) often display less sagittal plane motion at the knee and trunk (13–15), and show a greater medial knee displacement, and increased knee valgus (16–18). Patients who showed medial knee displacement during an overhead squat had a 20% decrease in passive ankle dorsiflexion (19). There is also a link between sagittal plane ankle motion and frontal plane knee motion (16). Individuals with a limited ankle dorsiflexion also showed decreased activity of the Vastus group (16).
It has been hypothesized that an increased frontal plane motion at the knee may play a role in the development of PFPS due to increased loading of the patellofemoral joint (20). Patients with PFPS show altered patellofemoral joint kinematics as a result of excessive internal rotation of the femur (21,22). Cronström (23) identified decreased ankle range of motion as a modifiable factor for knee abduction.
Individuals with increased ankle dorsiflexion in a weight-bearing lunge showed increased knee flexion and ankle dorsiflexion displacement and peak knee flexion during single leg and overhead squats, but not during a drop landing task (24). Increased sagittal plane motion in all lower extremity joints is believed to absorb and dissipate landing forces (13).
Limited ankle dorsiflexion has been hypothesized to encourage subtalar joint eversion and thus tibial internal rotation, which again will encourage femoral internal rotation and knee valgus (25). Barton (26) showed the link between greater rearfoot eversion, tibial internal rotation, and hip adduction in patients with PFPS and the control group. On the other hand, Burns (27) showed that individuals with pes cavus have a decreased weight bearing ankle dorsiflexion range of motion compared to individuals with a pes planus or normal foot type.
Dill (24) argues that most research done on ankle dorsiflexion ROM and PFPS has been performed with a non-weight bearing measurement while functional movements are mostly performed in weight bearing. To achieve a full ROM in a functional task such as a lunge or squat in a weight bearing position individuals should have a full range of motion in the foot as well as the ankle joint. In accordance with the findings of Devita (13), this would further absorb and dissipate landing forces and would decrease the frontal plane motion seen in patients with PFPS (16–18).
It could be hypothesized that increasing foot mobility, and thus improving total range of motion of the ankle foot complex could lead to greater activation of the Vastus group and possibly the gluteus group by allowing the tibia to go into medial rotation together with the femur, putting the gluteus in a position of pre-stretch, and by increasing dorsal flexion of the ankle, one could increase the activity of the quadriceps.
By allowing the tibia to move freely into internal rotation, by allowing controlled pronation, one could possibly decrease the share forces at the patellofemoral joint. The relative motions of the tibia and femur would decrease, as well as the Q-angle of the hip. The lateral forces acting on the patella would decrease due to the improved line of pull from the quadriceps as the tibial tuberosity moves in line with the femur. This is in line with the biomechanical model proposed by Powers (10).
1. Boling M, Padua D, Marshall S, Guskiewicz K, Pyne S, Beutler A. Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scand J Med Sci Sport. 2010;20(5):725–30.
2. Myer GD, Ford KR, Barber Foss KD, Goodman A, Ceasar A, Rauh MJ, et al. The incidence and potential pathomechanics of patellofemoral pain in female athletes. Clin Biomech. 2010;
3. Cook C, Mabry L, Reiman MP, Hegedus EJ. Best tests/clinical findings for screening and diagnosis of patellofemoral pain syndrome: A systematic review. Physiotherapy. 2012;98:93–100.
4. Witvrouw, Erik, Lysens, Roeland, Bellemans, Johan, Cambier, Dirk, Vanderstraeten G. Intrinsic Risk Factors For the Development of Anterior Knee Pain in an Athletic Population. Am J Sports Med. 2000;28(4):480–9.
5. Piva SR, Goodnite EA, Childs JD. Strength Around the Hip and Flexibility of Soft Tissues in Individuals With and Without Patellofemoral Pain Syndrome. J Orthop Sports Phys Ther. 2005;35(12):793–801.
6. Lankhorst, Nienke, E., Bierma-Zeinstra, Sita M.A., Middelkoop van M. Risk Factors for Patellofemoral Pain Syndrome: A systematic Review. J Orthop Sports Phys Ther. 2012;42(2):81–94.
7. Boling MC, Padua DA, Marshall SW, Guskiewicz K, Pyne S, Beutler A. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome. The joint undertakeing to monitor and prevent ACL injury cohort. Am J Sports Med. 2009;37(11):2108–16.
8. Dye SF. The Pathophysiology of Patellofemoral Arthritis. Clin Orthop Rehabil Res. 2005;436:100–10.
9. Feller JA, Amis AA, Andrish JT, Arendt EA, Erasmus PJ, Powers CM. Surgical Biomechanics of the Patellofemoral Joint. Arthrosc - J Arthrosc Relat Surg. 2007;
10. Powers CM. The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther. 2003;33(11):639–46.
11. Powers CM. The Influence of Abnormal Hip Mechanics on Knee Injury: A Biomechanical Perspective. J Orthop Sports Phys Ther. 2010;40(2):42–51.
12. Brantingham JW, Bonnefin D, Perle SM, Cassa TK, Globe G, Pribicevic M, et al. Manipulative therapy for lower extremity conditions: Update of a literature review. Journal of Manipulative and Physiological Therapeutics. 2012.
13. Devita, Paul, Skelly WA. Effect of Landing Stiffness on Joint Kinetics and Energy in the Lower Extremity. Med Sci Sports Exerc. 1992;24(1):108–15.
14. Blackburn JT, Padua DA. Influence of trunk flexion on hip and knee joint kinematics during a controlled drop landing. Clin Biomech. 2008;23(3):313–9.
15. Fong CM, Blackburn JT, Norcross MF, McGrath M, Padua DA. Ankle-dorsiflexion range of motion and landing biomechanics. J Athl Train. 2011;
16. Macrum E, Bell DR, Boling M, Lewek M, Padua D. Effect of limiting ankle-dorsiflexion range of motion on lower extremity kinematics and muscle-activation patterns during a squat. J Sport Rehabil [Internet]. 2012;21(2):144–50. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22100617
17. Sigward, Susan, M., Ota, Susuma, Powers CM. Predictors of Frontal Plain Knee Excursion During a Drop Land in Young Female Soccer Players. J Orthop Sports Phys Ther. 2008;38(11):661–7.
18. Pollard, CD, Sigward SM PC. Limited Hip and Knee Flexion During Landing Is. Clin Biomech. 2011;25(2):1–12.
19. Bell DR, Padua DA, Clark MA. Muscle Strength and Flexibility Characteristics of People Displaying Excessive Medial Knee Displacement. Arch Phys Med Rehabil. 2008;
20. Green ST. Patellofemoral syndrome. In: Journal of Bodywork and Movement Therapies. 2005.
21. Powers CM, Ward SR, Fredericson M, Guillet M, Shellock FG. Patellofemoral Kinematics During Weight-Bearing and Non–Weight-Bearing Knee Extension in Persons With Lateral Subluxation of the Patella: A Preliminary Study. J Orthop Sport Phys Ther. 2003;33:677–85.
22. Souza RB, Draper CE, Fredericson M, Powers CM. Femur rotation and patellofemoral joint kinematics: a weight-bearing magnetic resonance imaging analysis. J Orthop Sport Phys Ther [Internet]. 2010;40(5):277–85. Available from: http://ezproxy.gvsu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=rzh&AN=2010655480&site=ehost-live&scope=site
23. Cronström A, Mark Creaby BW, Jenny Nae B, Eva Ageberg B. Modifiable Factors Associated with Knee Abduction During Weight-Bearing Activities: A Systematic Review and Meta- Analysis. Sport Med. 2016;
24. Dill KE, Begalle RL, Frank BS, Zinder SM, Padua DA. Altered knee and ankle kinematics during squatting in those with limited weight-bearing-lunge ankle-dorsiflexion range of motion. J Athl Train. 2014;49(6):723–32.
25. Tiberio D. The effect of excessive subtalar joint pronation on patellofemoral mechanics: a theoretical model. J Orthop Sports Phys Ther. 1987;9(4):160–5.
26. Barton CJ, Levinger P, Crossley KM, Webster KE, Menz HB. The relationship between rearfoot, tibial and hip kinematics in individuals with patellofemoral pain syndrome. Clin Biomech. 2012;27:702–5.
27. Burns J, Crosbie J. Weight bearing ankle dorsiflexion range of motion in idiopathic pes cavus compared to normal and pes planus feet. Foot. 2005;15(2):91–4.