By Lori A Bolgla, PT, PhD, MAcc, ATC, and Michelle C Boling, PhD, LAT, ATC
Patellofemoral pain (PFP), also known as anterior knee pain, is one of the most common but complex knee problems to manage. PFP affects approximately 23% of the general population and 29% of adolescents. Moreover, females are twice as likely to develop PFP as males. Long considered a “self-limiting” problem, recent evidence has suggested that PFP is an ongoing disease process that can progress to patellofemoral joint osteoarthritis in later years. This trend highlights the importance of the development and implementation of evidence-based interventions.
PFP is characterized by pain and tenderness around and behind the patella. Individuals primarily complain of symptoms during weight-bearing activities that require repetitive knee flexion. Common complaints of pain occur during walking, running, stair ambulation, squatting, and kneeling. Many people also report pain resulting from excessive compression after sitting for a long time with the knee flexed. Other impairments associated with PFP include 1) quadriceps and gluteal muscle weakness; 2) decreased quadriceps, hamstring, and calf flexibility; and 3) faulty hip and knee movement during dynamic activities.
Fortunately, non-surgical intervention is the preferred treatment approach. The most supported treatment includes exercises to strengthen the quadriceps and gluteal muscles. The important point is that all exercises, especially the quadriceps, be performed in a pain-free manner. Popular quadriceps strengthening exercises include non–weight-bearing (eg, flexing and extending the knee while sitting on the edge of a table) and weight-bearing (eg, squats and leg press) knee extension exercises. A key element for performing these exercises correctly is the range (arc) of knee motion. Non–weight-bearing knee extension exercises should be performed from 90 degrees to 45 degrees of knee flexion. Weight-bearing knee extension exercises should be performed from 0 degrees (the knee extended) to 45 degrees of knee flexion. Exercising in these ranges of motion has been shown to reduce stress to the patellofemoral joint.
Many individuals, especially females, with PFP exhibit gluteal muscle weakness. The most recent scientific evidence suggests that gluteal weakness results from inactivity following PFP onset (ie, hip weakness does not cause PFP). Exercises that target the hip extensors, external rotators, and abductors should be part of a comprehensive treatment plan. While the mechanism of pain relief from gluteal exercises is not readily evident, outcome-based research supports their inclusion. Another consideration is an initial focus on gluteal exercises for those with PFP who initially cannot perform pain-free quadriceps exercise. The reason for this approach is to enable exercise that does not cause increased patellofemoral joint stress and pain. However, quadriceps-specific exercises should be introduced as patellofemoral joint tissues becomes less irritated and can be performed in a pain-free manner.
About the National Athletic Trainers’ Association
The National Athletic Trainers’ Association (NATA) recently published their position statement “Management of Individuals With Patellofemoral Pain,” to provide recommendations to healthcare professionals to help identify risk factors and manage PFP.
While quadriceps and gluteal exercise are an important treatment strategy, other factors deserve attention. An individual with PFP should stretch the quadriceps, hamstring, and calf muscles as tightness can lead to patellofemoral joint compression. Another source of compression may result from faulty hip and knee movement during dynamic activities such as walking, running, stair ambulation, and squatting. Examples of faulty hip and knee movements include not keeping the pelvis level and/or having the patella point inward during these activities. Movement re-training strategies that focus on keeping the pelvis level and patella facing forward during such activities can be beneficial. [figure]
Other popular treatment strategies include patella taping and foot inserts (orthoses). Patella taping, with the goal of improving patella position, has not necessarily been shown to be more effective in reducing pain than quadriceps exercise alone. However, patella taping should be considered if it facilitates pain-free quadriceps exercise. Foot inserts are another popular treatment strategy. Like patella taping, foot inserts may not necessarily benefit all individuals with PFP. The most current evidence suggests that a certain group of those with PFP who exhibit a low foot arch during weight-bearing activities may benefit from inserts.
Finally, the most important treatment strategy is patient education. Patients should be educated on the importance of treatment compliance and activity modification. Individuals with PFP should avoid pain-provoking activities such as stair ambulation, kneeling, and prolonged sitting with the knee bent. Runners with PFP should consider cross-training activities like swimming. Training regimens also deserve review to determine possible contributing factors, such as an increase in mileage, change in terrain, and/or focus on up- and down-hill running. If identified, modifications should be made to minimize PFP symptoms.
In summary, PFP is one of the most common but complex knee problems to manage. Unlike many problems that have a single contributing factor, PFP is multifaceted and does not respond favorably to a “one-size-fits-all” treatment strategy. For those experiencing PFP, consultation with a rehabilitation professional is recommended for an individually tailored intervention.
Full text from the National Athletic Trainers’ Association position statement, “Management of Individuals With Patellofemoral Pain,” is available in the September issue of the Journal Athletic Training.
Lori A Bolgla, PT, PhD, MAcc, ATC, lead author of the NATA position statement, is a professor of physical therapy and Kellett chair in the College of Allied Health Sciences at Augusta University in Augusta, Georgia. Her research interests include patellofemoral pain syndrome, lower extremity overuse syndromes, and the female athlete.
Michelle C. Boling, PhD, LAT, ATC, co-author of the NATA position statement, is associate professor of clinical and applied movement sciences in the Brooks College of Health at the University of North Florida in Jacksonville, Florida. Her research focuses on injury prevention, biomechanics, and sports related knee injuries.