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Principles of Health: Occupational Therapy & Physical Therapy

Patellofemoral Pain Syndrome (PPS)

by William E. Burns

Specialties and related fields: Orthopedics; Sports medicine; Primary care; Physical therapy

Definition: pain in the front of the knee, worsened with sitting, squatting, or running for an extended time

KEY TERMS

patella: kneecap

femur: thigh bone

quadriceps: four muscles located in the front of the thigh, responsible for knee extension

Patellofemoral pain syndrome (PPS) is pain occurring in the front of the human knee, often due to wear and stress. The term patella is the kneecap, the bone cap of the knee joint, and femoral refers to the femur or thigh bone. The patellofemoral joint is one of the two joints of the human knee, the other being the tibiofemoral. The syndrome can appear in one knee or both knees. It is one of the most common injuries caused by running. PPS is also known as “runner’s knee” or “jumper’s knee,” although it can occur in non-runners as well, and “anterior knee pain syndrome.” A specific disease or condition does not cause it. In addition to pain, another occasional symptom of PPS is popping or cracking sounds from the knee. In extreme cases, the knee may give way.

PPS is a clinical diagnosis, made usually by history and physical examination. An X-ray or magnetic resonance imaging (MRI) scan are generally not considered necessary for diagnosing PPS. In some cases, they may be used to rule out other explanations for the pain, such as arthritis in patients over fifty years old or a dislocated patella or other injury. PPS is also distinguished from bursitis of the knee, which causes pain in the patella area but has a completely different physical cause. Chondromalacia patellae are sometimes treated as a synonym for PPS, but it can be distinguished as a syndrome specifically caused by the degeneration of the cartilage of the knee joint. PPS must also be distinguished from patellofemoral osteoarthritis (PF OA), which generally occurs in older patients and has characteristic radiographic findings, including narrowed joint space and osteophytes or bone spurs.

CAUSES AND SYMPTOMS

PPS is a multifactorial condition, but certain elements can increase the risk of development of PPS. Repetitive exercise straining the knee can cause PPS, in addition to running and jumping, cycling, climbing stairs, and squatting. The onset of PPS is often associated with a change in exercise routine, such as adding a new exercise that puts pressure on the knee joint. However, exercise or other physical activity is unnecessary for PPS since it can also appear in sedentary people. Weakness or inflexibility of the quadriceps muscles in the thigh can cause PPS. Core strength deficiencies, which cause weakened pelvic stability, are also implicated in developing PPS. Women are particularly vulnerable to PPS, as well as to other injuries of the knee, due to the slight inward curve of a woman’s hip bone, which increases the stress on the knee joint. Patellofemoral pain is often intermittent. It can appear during exercise or exertion, making exercise impossible. Still, it can also appear when going up or down stairs or after sitting for a long time in one position with the knee bent, as at a desk or a movie or theater (known as the “theater sign”). Specialists in sports medicine frequently encounter patellofemoral pain syndrome. Pain is often difficult for patients to localize.

Information on Patellofemoral Pain Syndrome (PPS)

Causes: repetitive knee strain, quadriceps weakness, diminished core strength, patellar tracking/malalignment

Symptoms: anterior knee pain, “buckling,” “creaking,” or pain with standing after prolonged sitting

Duration: pain may be gradual or acute in onset and can continue unless treatment or preventive measures initiated

Treatments: rest, ice, activity limitation, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, physical therapy, stretches, quadriceps, and core strengthening

One cause of PPS is poor patella tracking along the femur when the knee is bent, which irritates the cartilage where the patella grinds against the femur rather than moving straight up and down. A slight misalignment of the patella aggravated by stress or repeated impact may lead to PPS. Patellar misalignment may be caused by exercise or exertion with flat feet or poorly fitted shoes that increase the pronation or rolling of the foot, which again puts strain on the knee.

TREATMENT

To prevent PPS, some doctors recommend exercises to increase the flexibility and strength of the quadriceps. Runners should avoid hard surfaces and gradually add uphill running to their routines. Properly fitting shoes are also valuable in preventing PPS. Theatergoers can try to get aisle seats, so they have room to straighten their legs occasionally.

Once patellofemoral pain strikes, immediate treatments to reduce it include ice packs and rest. NSAIDs and acetaminophen are also used to soothe the pain, although they have little effect beyond a few hours. Long-term treatments for PPS are based on physical therapy and are successful in over half of all cases. They include strengthening the quadriceps muscles to restore muscle balance and restricting those activities that cause pain. Hip strengthening has also been shown to be of some effectiveness. Knee braces, which restrict the knee’s range of motion, may be helpful, although the clinical evidence for braces is weak. Evidence for the benefits of patellar taping, another commonly used treatment, is also weak. There are very few extreme cases for which surgery is recommended. Exercises and stretches are crucial to reduce the likelihood of developing PPS again. Evidence suggests that foot orthotics combined with physical therapy may be more effective in reducing PPS symptoms than physical therapy alone. Still, it is unclear which patient population benefits the most from this. The use of intra-articular corticosteroid injections for PPS pain relief has limited evidence.

If PPS is caused by exercise, some doctors recommend changing or minimizing exercise routines, particularly switching to activities that have less impact on the knee, such as swimming or cycling, and ensuring that the shoes used for exercise fit properly. Exercises involving squatting, such as burpees, irritate the knees and may need to be suspended. Practitioners of various alternative medicine techniques such as acupuncture, chiropractic, and Pilates claim the ability to treat PPS, but such claims are not backed by scientific evidence.

PERSPECTIVE AND PROSPECTS

PPS is an active area of medical research. Research into PPS and other forms of anterior knee pain is funded by the Patellofemoral Foundation, a nonprofit organization founded in 2002 and headquartered in Farmington, Connecticut. The organization cosponsors an annual award for excellence in patellofemoral research along with the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine. It promotes knowledge of the patellofemoral joint among physicians and surgeons. A biannual series of “Patellofemoral Pain Research Retreats and Clinical Symposia” is held for physicians and other clinicians dealing with the problem.

SIGNIFICANCE

Occupational therapists can play a role in managing PPS by addressing the impact of pain on an individual’s daily activities and functional abilities. Here are some ways occupational therapy can help individuals with PPS:

  • Activity modification: Occupational therapists assess the activities that exacerbate PPS symptoms and work with individuals to modify or adapt those activities. They may suggest alternative techniques, equipment, or environmental modifications that reduce knee joint stress and minimize pain during functional tasks.

  • Joint protection and biomechanical training: Occupational therapists educate individuals about proper body mechanics and knee joint protection techniques. They may show patients how to maintain good posture, distribute weight evenly, and avoid movements that place excessive stress on the patellofemoral joint.

  • Strengthening and flexibility exercises: Occupational therapists can develop individualized exercise programs to improve the strength and flexibility of the muscles around the knee, including the quadriceps, hamstrings, and hip muscles. Strengthening exercises help stabilize the knee joint and reduce pain, while flexibility exercises improve joint mobility and prevent muscle imbalances.

  • Activity-specific training: Occupational therapists focus on enhancing an individual’s ability to engage in meaningful activities affected by PPS. For example, if someone experiences pain while climbing stairs, the therapist may provide strategies and exercises to improve stair negotiation and increase the individual’s confidence and independence.

  • Assistive devices and orthotics: Occupational therapists can evaluate the need for assistive devices or orthotic supports, such as knee braces or patellar taping, to provide stability and pain relief. They can recommend and guide the proper use and fitting of these devices.

  • Pain management techniques: Occupational therapists can teach various pain management techniques to help individuals cope with PPS symptoms. Pain abatement techniques may include relaxation exercises, heat or cold therapy, and positioning techniques to alleviate pain and discomfort.

  • Education and self-management: Occupational therapists provide education about PPS, its causes, and self-management strategies. They educate individuals about the importance of rest, proper nutrition, and weight management to support optimal knee health. Occupational therapists also promote self-advocacy, empowering individuals to communicate their needs and make informed decisions regarding their activities and lifestyle choices.

It is important to note that the specific interventions in occupational therapy for PPS would be tailored to the individual’s unique needs, goals, and the severity of their condition. Collaborating with a healthcare team, including physical therapists and orthopedic specialists, can further enhance the effectiveness of the overall treatment plan for PPS.

Further Reading

1 

Berry, Tiffany, et al. “Effect of Pain On Hip and Knee Kinematics During a Prolonged Run in Female Runners with Patellofemoral Pain Syndrome.” XXXIIth International Symposium on Biomechanics in Sport, 12-16 July 2014, Johnson City, Tennessee.

2 

Mulcahey, Mary K., Carolyn M. Hettrich, and Daniel Liechti. “Patellofemoral Pain Syndrome.” Oct. 2020, orthoinfo.aaos.org/topic.cfm?topic=A00680.

3 

LaBella, Cynthia. “Patellofemoral Pain Syndrome: Evaluation and Treatment.” Primary Care: Clinics in Office Practice, vol. 31, no. 4, 2004, pp. 977-1003.

4 

Papadopoulos, Konstantinos, et al. “A Systematic Review of Reviews in Patellofemoral Pain Syndrome: Exploring the Risk Factors, Diagnostic Tests, Outcome Measurements and Exercise Treatment.” Open Sports Medicine Journal, vol. 9, 2015, pp. 7-17.

5 

Petersen, Wolf, et al. “Patellofemoral Pain Syndrome.” Knee surgery, Sports Traumatology, Arthroscopy, vol. 22, no. 10, 2014, pp. 2264-74.

6 

Rogers, Thomas, et al. “Structured Rehabilitation Model for Patients with Patellofemoral Pain Syndrome.” Sports Injuries, 2015, pp. 1605-16, doi:10.1007/ 978-3-642-36569-0_286.

7 

Thomeé, Roland, Jesper Augustsson, and Jon Karlsson. “Patellofemoral Pain Syndrome.” Sports Medicine, vol. 28, no. 4, 1999, pp. 245-62.

8 

van der Heijden, R. A., et al. “Exercise for Treating Patellofemoral Pain Syndrome: An Abridged Version of Cochrane Systematic Review.” European Journal of Physical and Rehabilitation Medicine, vol. 52, no. 1, 2016, pp. 110-33.

9 

Waryasz, Gregory R., and Ann Y. McDermott. “Patellofemoral Pain Syndrome (PFPS): A Systematic Review of Anatomy and Potential Risk Factors.” Dynamic Medicine: DM, vol. 7, no. 9, 2008, doi:10.1186/1476-5918-7-9.

Citation Types

Type
Format
MLA 9th
Burns, William E. "Patellofemoral Pain Syndrome (PPS)." Principles of Health: Occupational Therapy & Physical Therapy, edited by Michael A. Buratovich, Salem Press, 2023. Salem Online, online.salempress.com/articleDetails.do?articleName=POHTherapy_0068.
APA 7th
Burns, W. E. (2023). Patellofemoral Pain Syndrome (PPS). In M. A. Buratovich (Ed.), Principles of Health: Occupational Therapy & Physical Therapy. Salem Press. online.salempress.com.
CMOS 17th
Burns, William E. "Patellofemoral Pain Syndrome (PPS)." Edited by Michael A. Buratovich. Principles of Health: Occupational Therapy & Physical Therapy. Hackensack: Salem Press, 2023. Accessed December 14, 2025. online.salempress.com.