Patellofemoral Pain Syndrome

PFPS is primarily caused by abnormal tracking of the patella within the trochlear groove. Research published in the Journal of Orthopaedic & Sports Physical Therapy (JOSPT, 2019) suggests that this maltracking is rarely due to one factor. Instead, it is a 'perfect storm' of biomechanical issues. When the patella does not track centrally, the pressure is distributed over a smaller surface area of cartilage, leading to high localized stress and pain.

Non-Modifiable Risk Factors

• Sex: Females are at a higher risk due to a wider 'Q-angle' (the angle between the hip and the knee), which increases lateral pull on the kneecap.
• Anatomy: Some individuals are born with a shallow trochlear groove (trochlear dysplasia), making the patella naturally less stable.

Modifiable Risk Factors

• Overuse: Sudden increases in training volume, intensity, or frequency (the 'too much, too soon' phenomenon).
• Muscle Imbalance: Weakness in the hip abductors (gluteus medius) and the quadriceps (specifically the VMO or vastus medialis obliquus).
• Foot Mechanics: Excessive foot pronation (flat feet) can cause the tibia to rotate internally, forcing the knee into a position that stresses the patellofemoral joint.
• Footwear: Wearing worn-out shoes or shoes without adequate arch support during high-impact activities.

According to data from the American Academy of Family Physicians (AAFP), 'Runner's Knee' is most common in active individuals under age 40. High-risk groups include long-distance runners, cyclists, and military recruits. A 2021 study found that specialized athletes who focus on a single sport are at a higher risk than those who participate in multi-sport training.

Prevention is possible through evidence-based strategies:

• Gradual Progression: Follow the '10% rule,' increasing weekly mileage or intensity by no more than 10%.
• Strength Training: Regularly performing exercises for the hips and quads to ensure the patella is supported.
• Proper Footwear: Replacing running shoes every 300–500 miles to maintain proper cushioning and alignment.

Diagnosis is primarily clinical, meaning it is based on a thorough history and physical examination. There is no single 'gold standard' test; instead, a healthcare provider looks for a cluster of findings.

Your provider will likely perform several provocative tests:

• Patellar Compression Test: Applying pressure to the kneecap while you contract your quadriceps.
• Patellar Tilt Test: Checking the mobility of the kneecap to see if it is too tight on the lateral (outer) side.
• Functional Assessment: Observing your form during a single-leg squat or step-down to look for 'valgus' (knee caving).
• Palpation: Checking for tenderness along the edges of the patella.

• X-rays: Usually performed to rule out other issues like fractures or advanced osteoarthritis. Specialized 'sunrise views' can show how the patella sits in the groove.
• MRI: Not typically required for a standard PFPS diagnosis but may be used if the doctor suspects a meniscus tear, ligament injury, or significant cartilage damage (chondromalacia patella).
• Blood Tests: Generally not used unless the provider needs to rule out inflammatory arthritis (like Rheumatoid Arthritis) or infection.

Clinicians often use the 2018 International Consensus criteria, which require: 1) Pain around or behind the patella, 2) Pain aggravated by at least one activity that loads the joint in flexion (squatting, stairs, running), and 3) Exclusion of other causes of anterior knee pain.

Conditions that mimic PFPS include:

• Patellar Tendonitis (Jumper's Knee): Pain is specifically at the bottom tip of the kneecap.
• IT Band Syndrome: Pain is on the outside of the knee.
• Hoffa’s Fat Pad Impingement: Pain is below the kneecap, deep in the joint.
• Knee Osteoarthritis: Typically seen in older adults with morning stiffness.

The primary goals of treatment are to reduce pain, improve the tracking of the kneecap, and return the patient to their desired level of activity. Success is measured by the ability to perform daily tasks and sports without pain and by improved scores on functional scales like the Kujala Anterior Knee Pain Scale.

According to the 2018 Patellofemoral Pain Consensus Statement, exercise therapy is the gold standard of treatment. This includes a combination of hip and knee strengthening. Passive treatments like ultrasound or laser therapy are generally not recommended as standalone treatments.

While medication does not fix the underlying biomechanical cause, it is used to manage symptoms during the acute phase.

• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): These work by inhibiting COX enzymes to reduce prostaglandins that cause pain and inflammation. They are preferred when there is noticeable swelling or acute irritation. Side effects include gastrointestinal upset or, with long-term use, kidney strain.
• Oral Analgesics: These work on the central nervous system to alter the perception of pain. They are used for patients who cannot tolerate NSAIDs. They do not reduce inflammation but can help with the 'dull ache' of PFPS.
• Topical Analgesics: Creams or gels containing NSAIDs or cooling agents can provide localized relief with fewer systemic side effects.

If exercise alone is insufficient, healthcare providers may recommend:

• Patellar Taping (McConnell Taping): Using specialized tape to manually shift the patella into a better position, which can provide immediate, short-term pain relief during exercise.
• Foot Orthotics: For patients with excessive foot pronation, custom or over-the-counter inserts can help align the kinetic chain.

• Physical Therapy: Focuses on strengthening the gluteus medius and the quadriceps, as well as stretching tight structures like the hamstrings and calves.
• Blood Flow Restriction (BFR) Training: Allows patients to gain muscle strength using very light weights, which is helpful if heavy lifting is too painful.
• Surgery: Rarely indicated for PFPS. It is only considered if there is a clear structural abnormality (like a lateral release for a tilted patella) that has failed 6–12 months of intensive physical therapy.

Most patients see significant improvement within 6 to 12 weeks of a consistent exercise program. Monitoring involves tracking the 'pain-free' duration of activities like running or walking.

> Important: Talk to your healthcare provider about which approach is right for you.

While PFPS is biomechanical, nutrition supports tissue repair. Research in the Journal of Athletic Training suggests that adequate protein intake is essential for muscle hypertrophy (growth) during physical therapy. Some evidence suggests that collagen supplementation, when taken 30-60 minutes before exercise, may support tendon and cartilage health, though more large-scale human trials are needed.

• Low-Impact Options: During the flare-up phase, switch from running to swimming, elliptical training, or rowing to maintain cardiovascular fitness without overloading the joint.
• Specific Exercises: Focus on 'clamshells,' 'side-lying leg raises,' and 'quad sets.' Avoid deep squats (past 90 degrees) initially, as this maximizes joint pressure.

Rest does not mean total inactivity. 'Relative rest' involves staying active while avoiding the specific activities that cause pain. Sleep is when the body repairs micro-damage to the tissues; aim for 7–9 hours of quality sleep.

Chronic pain can lead to central sensitization, where the nervous system becomes hyper-reactive. Techniques like Mindfulness-Based Stress Reduction (MBSR) have been shown to help patients manage chronic musculoskeletal pain by lowering cortisol and improving pain tolerance.

• Acupuncture: Some studies suggest acupuncture may provide short-term pain relief for PFPS, though it does not address the underlying muscle weakness.
• Yoga: Can be beneficial for flexibility, but certain poses (like 'Hero Pose') can put excessive stress on the kneecap and should be modified.

Encourage the patient to stick to their physical therapy routine, as consistency is the most difficult part of PFPS recovery. Help them track their progress to stay motivated during the 2-3 month recovery window.

The prognosis for PFPS is generally good, but it requires active participation. According to a study in the British Journal of Sports Medicine, approximately 70-80% of patients report significant improvement with a structured exercise program. However, if left untreated, PFPS can become a chronic condition that persists for years.

• Patellofemoral Osteoarthritis: Long-term maltracking can lead to the premature breakdown of cartilage, eventually resulting in arthritis.
• Quadriceps Atrophy: Chronic pain leads to 'arthrogenic muscle inhibition,' where the brain stops fully activating the quad muscles to protect the joint, leading to weakness.

Management is often about 'load management.' This means understanding your body's limits and not increasing exercise volume too quickly. Many athletes continue their hip and core strengthening exercises 1-2 times a week indefinitely to prevent recurrence.

Most people with PFPS can return to full activity, including marathons and high-impact sports. The key is maintaining a 'strong foundation' (hips and quads) and being mindful of biomechanics.

Contact your healthcare provider if:

• Pain does not improve after 6 weeks of rest and gentle exercise.
• Pain begins to occur during rest or wakes you up at night.
• You experience a 'locking' sensation where the knee gets stuck in one position.