Anterior knee pain refers to discomfort felt at the front of the knee, localized around or behind the kneecap. This type of pain is a common complaint, affecting a portion of the population. Anterior knee pain is a symptom, not a diagnosis, indicating an underlying issue.
Common Conditions Leading to Anterior Knee Pain
Patellofemoral Pain Syndrome (PFPS) is a frequent cause of anterior knee pain, often recognized as “runner’s knee.” This condition presents as a dull, aching pain that intensifies with activities like climbing stairs, squatting, or prolonged sitting with bent knees. Overuse, muscle imbalances, or improper movement patterns of the kneecap contribute to its development.
Patellar tendinopathy, also known as “jumper’s knee,” involves irritation or degeneration of the patellar tendon, which connects the kneecap to the shinbone. This condition causes pain localized just below the kneecap, worsening with activity, particularly repetitive jumping and landing. Quadriceps tendinopathy affects the quadriceps tendon located just above the kneecap. Overuse of the quadriceps muscles lead to microscopic tears and inflammation in this tendon.
Bursitis, an inflammation of fluid-filled sacs called bursae, can also cause anterior knee pain. The prepatellar bursa, located in front of the kneecap, can become inflamed from direct impact or prolonged kneeling, leading to pain and swelling. This condition is sometimes called “housemaid’s knee” due to its association with occupations requiring frequent kneeling.
Osgood-Schlatter disease is a common cause of anterior knee pain in adolescents, particularly during growth spurts. It involves inflammation where the patellar tendon attaches to the shinbone (tibial tuberosity), resulting in a painful bump below the kneecap. This condition is seen in active children who engage in sports involving running and jumping.
Chondromalacia patellae refers to the softening and breakdown of cartilage on the underside of the kneecap. While associated with PFPS, it represents a specific finding of cartilage damage rather than being a standalone diagnosis for all anterior knee pain. This condition can lead to grinding sensations or pain that worsens with activities that load the patellofemoral joint.
Other Potential Contributors to Anterior Knee Pain
Biomechanical issues and alignment problems, such as excessive foot pronation (flat feet) or a wide Q-angle (the angle between the hip and the kneecap), alter knee mechanics. These misalignments increase stress on the kneecap, leading to discomfort.
Muscle imbalances and weakness also play a role. Weakness in the quadriceps muscles, particularly the vastus medialis obliquus (VMO), or tightness in the hamstrings and iliotibial (IT) band disrupt the proper tracking of the kneecap. Weak gluteal muscles further contribute to poor knee alignment and increased strain during movement.
Overuse and training errors are common triggers for anterior knee pain. Sudden increases in activity intensity or duration, insufficient rest, or improper technique during exercise overload the knee structures. Training on hard or uneven surfaces also contributes to repetitive stress injuries.
Inappropriate footwear, such as worn-out or ill-fitting shoes, alter gait patterns and place undue stress on the knee joint. Footwear choices affect how forces are distributed through the lower limbs, impacting knee health.
Direct trauma or repetitive microtrauma to the knee lead to chronic anterior knee pain over time. Even minor, repeated impacts accumulate and cause persistent discomfort.
Identifying the Cause of Anterior Knee Pain
A healthcare professional begins the diagnostic process by taking a comprehensive medical history. This involves asking about the onset of pain, its duration, specific activities that worsen or alleviate it, and any prior injuries to the knee. Understanding the patient’s activity level and symptoms helps narrow down potential causes.
A physical examination follows, where the healthcare provider assesses the knee. This includes palpation to identify areas of tenderness, checking the range of motion of the knee joint, and evaluating muscle strength around the hip and knee. Observing gait and assessing knee alignment are important components of the examination.
Imaging studies may be utilized, though not necessary, especially for common conditions like PFPS where X-rays appear normal. X-rays can help rule out bone abnormalities, while magnetic resonance imaging (MRI) provides detailed views of soft tissues and cartilage.
When to Consult a Healthcare Professional
It is advisable to consult a healthcare professional if anterior knee pain persists despite rest, ice, and over-the-counter pain relievers for several days or weeks. If the pain intensifies or becomes more frequent, seeking medical advice is recommended.
Certain accompanying symptoms warrant prompt medical attention. These include swelling, redness, or warmth around the knee, or if a fever develops. An inability to bear weight on the affected leg, audible clicking, popping, or grinding sounds, or a sensation of the knee giving way are concerning signs. If the pain began immediately after a specific injury or trauma, or if it interferes with daily activities, work, or exercise, professional evaluation.