Patellofemoral Syndrome: Signs, Symptoms, and When to Seek Help

What are the signs that a person has patellofemoral syndrome?

Patellofemoral Syndrome (PFS), often referred to as "runner's knee," primarily manifests as anterior knee pain, typically felt around or behind the kneecap, especially exacerbated by activities involving knee bending under load, such as squatting, stair climbing, or prolonged sitting.

Understanding Patellofemoral Syndrome (PFS)

Patellofemoral Syndrome (PFS) is a common musculoskeletal condition characterized by pain originating from the patellofemoral joint – the articulation between the patella (kneecap) and the femur (thigh bone). The pain arises from irritation or degeneration of the cartilage on the underside of the patella, or from soft tissue irritation surrounding the joint, often due to abnormal tracking of the patella within the trochlear groove of the femur. This misalignment can lead to increased stress and friction, particularly during dynamic movements.

Key Signs and Symptoms of Patellofemoral Syndrome

Identifying PFS relies on a constellation of symptoms, though the hallmark is anterior knee pain. Understanding these signs is crucial for early recognition and intervention.

• Anterior Knee Pain: This is the most consistent and defining symptom of PFS.

  • Location: The pain is typically felt around or behind the kneecap. It can be diffuse and difficult for individuals to pinpoint precisely.
  • Quality: Often described as a dull ache, but can become sharp with certain movements.
  • Aggravating Factors: The pain characteristically worsens with activities that increase stress on the patellofemoral joint. These include:
    • Stairs: Especially descending stairs, which puts significant eccentric load on the quadriceps.
    • Squatting, Lunging, or Kneeling: Any deep knee bending activity.
    • Prolonged Sitting with Knees Bent ("Theater Sign"): After sitting with flexed knees for an extended period (e.g., in a car, at a desk, or in a movie theater), the pain may be noticeable upon attempting to straighten the leg.
    • Running: Particularly downhill running or running on uneven terrain.
    • Jumping: Activities involving impact.

• Crepitus: This refers to a grinding, popping, clicking, or cracking sensation or sound in the knee, particularly when bending or straightening the joint.

  • Explanation: It results from friction between the patella and the femoral trochlea. While crepitus can be a normal, asymptomatic finding in many individuals, when accompanied by pain, it is a significant indicator of patellofemoral dysfunction.

• Mild Swelling: While not always present, some individuals with PFS may experience subtle, diffuse swelling around the kneecap. This indicates a greater degree of irritation or inflammation within the joint. Significant, sudden swelling is less typical of PFS and might suggest other knee injuries.

• Tenderness to Touch: Palpation around the borders of the patella, particularly along its facets (the undersurface that articulates with the femur), may elicit pain. Tenderness can also be present along the quadriceps or patellar tendons if secondary inflammation is present.

• Feeling of Instability or "Giving Way": Less common than pain and crepitus, some individuals may report a sensation that their knee is going to buckle or "give way." This is often due to pain inhibition of the quadriceps muscles rather than true mechanical instability of the joint.

Differentiating PFS from Other Knee Conditions

It is important to note that while these signs strongly suggest PFS, they are not exclusive to it. Other conditions, such as patellar tendinopathy ("jumper's knee"), IT band syndrome, or even referred pain from the hip or lower back, can present with similar symptoms. A comprehensive assessment by a healthcare professional is essential for an accurate diagnosis.

When to Seek Professional Assessment

If you experience persistent anterior knee pain that interferes with your daily activities, exercise, or quality of life, it is advisable to consult a healthcare professional, such as a physical therapist, orthopedic doctor, or sports medicine physician. Early diagnosis allows for targeted intervention, which can significantly improve outcomes and prevent the condition from becoming chronic. Seek immediate attention if your pain is accompanied by significant swelling, locking of the knee, or a feeling of true mechanical instability.

Conclusion

Patellofemoral Syndrome is a prevalent source of knee pain, primarily characterized by pain around or behind the kneecap, especially aggravated by activities that load the knee in flexion. Recognizing the key signs—anterior knee pain exacerbated by stairs, squats, and prolonged sitting, often accompanied by crepitus—is the first step toward effective management. Understanding these symptoms empowers individuals to seek timely professional guidance and embark on a tailored rehabilitation program aimed at restoring optimal patellofemoral mechanics and alleviating pain.