Patellar Maltracking: Causes, Risk Factors, and Prevention

How do you get patellar Maltracking?

Patellar maltracking occurs when the kneecap (patella) moves abnormally within the thigh bone's (femur) groove during knee movement, often shifting laterally. This condition typically arises from a complex interplay of anatomical predispositions, muscular imbalances, biomechanical dysfunctions, and repetitive stress.

Understanding Patellar Maltracking

Patellar maltracking, often a primary contributor to Patellofemoral Pain Syndrome (PFPS), describes the abnormal motion of the patella as the knee flexes and extends. Ideally, the patella glides smoothly within the trochlear groove of the femur. When maltracking occurs, the patella deviates from this optimal path, frequently shifting too far to the outside (lateral side), causing increased friction and stress on the articular cartilage and surrounding soft tissues. This can lead to pain, grinding sensations (crepitus), and a feeling of instability.

The Biomechanics of Normal Patellar Tracking

The patella acts as a fulcrum for the quadriceps muscle group, increasing its mechanical advantage during knee extension. Its movement is dictated by a delicate balance of forces:

• Quadriceps Pull: The quadriceps tendon pulls the patella superiorly. The four heads of the quadriceps (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) exert distinct pulling forces.
• Vastus Medialis Obliquus (VMO): A crucial part of the vastus medialis, the VMO has fibers that insert medially into the patella, providing a critical medial stabilizing pull that counteracts the larger, more laterally pulling vastus lateralis.
• Lateral Retinaculum: This fibrous band on the outer side of the patella helps stabilize it laterally.
• Trochlear Groove: The V-shaped groove in the femur acts as a physical guide for the patella.
• Patellar Ligament: Connects the patella to the tibia, pulling it inferiorly.

Normal tracking depends on the harmonious interplay of these structures, ensuring the patella stays centered within the trochlear groove throughout the knee's range of motion.

Primary Causes and Contributing Factors

Patellar maltracking is rarely due to a single cause but rather a combination of factors that disrupt the delicate balance of forces acting on the kneecap.

Anatomical Factors

Certain inherent structural characteristics can predispose individuals to patellar maltracking:

• Shallow Trochlear Groove (Trochlear Dysplasia): If the groove in the femur is too flat or shallow, it provides less bony constraint, allowing the patella to slide out of place more easily.
• Patella Alta (High-Riding Patella): When the patella sits higher than normal on the femur, it engages the trochlear groove later in knee flexion, making it less stable in the initial degrees of movement.
• Increased Q-Angle: The Q-angle (quadriceps angle) is the angle formed by a line from the anterior superior iliac spine (ASIS) to the center of the patella and a line from the center of the patella to the tibial tuberosity. A larger Q-angle (more common in females due to wider pelvis) increases the lateral pull on the patella.
• Tibial Torsion: Excessive external rotation of the tibia relative to the femur can also increase the effective Q-angle.
• Genu Valgum (Knock-Knees): This alignment abnormality places increased valgus stress on the knee, which can contribute to lateral patellar tracking.

Muscular Imbalances and Weakness

Discrepancies in muscle strength and flexibility are significant contributors to maltracking:

• Vastus Medialis Obliquus (VMO) Weakness/Inhibition: The VMO is critical for medially stabilizing the patella. If it is weak or inhibited relative to the vastus lateralis, the patella will be pulled excessively laterally.
• Tightness of Lateral Structures: A tight vastus lateralis, iliotibial band (ITB), or lateral retinaculum can exert an abnormal lateral pull on the patella.
• Hip Muscle Weakness: Weakness in the hip abductors (e.g., gluteus medius) and external rotators (e.g., gluteus maximus, piriformis) can lead to dynamic valgus of the knee during activities like squatting, running, or jumping. This "knee caving in" motion effectively increases the Q-angle dynamically, promoting lateral patellar shift.
• Core Weakness: A weak core can compromise pelvic stability, indirectly affecting hip and knee biomechanics.

Biomechanical Factors

How the body moves and interacts with the ground can significantly influence patellar tracking:

• Foot Pronation: Excessive or prolonged pronation (flattening) of the foot can cause internal rotation of the tibia, which in turn increases the Q-angle and lateral forces on the patella.
• Poor Movement Patterns: Incorrect form during exercises (e.g., squats with knees caving in) or sports-specific movements can repeatedly stress the patellofemoral joint and contribute to maltracking.

Trauma and Injury

Direct or indirect trauma to the knee can also lead to maltracking:

• Patellar Dislocation or Subluxation: A prior dislocation or partial dislocation (subluxation) can stretch or tear the medial patellofemoral ligament (MPFL), a primary medial stabilizer, making recurrent maltracking or instability more likely.
• Direct Blow: A direct impact to the kneecap can disrupt its alignment or damage surrounding structures.

Activity Levels and Training Errors

Overuse and improper training methods can exacerbate or initiate patellar maltracking:

• Sudden Increase in Activity: Rapidly increasing the volume, intensity, or frequency of activities that load the knee (e.g., running, jumping, cycling) without adequate conditioning.
• Repetitive Stress: Activities involving repetitive knee flexion and extension, especially with poor biomechanics, can lead to cumulative microtrauma.
• Inappropriate Footwear: Worn-out or unsupportive shoes can alter foot mechanics and impact knee alignment.

Risk Factors for Patellar Maltracking

While overlapping with causes, specific risk factors heighten the likelihood of developing patellar maltracking:

• Female Gender: Due to a generally wider pelvis leading to a larger Q-angle, and often greater ligamentous laxity.
• Adolescence/Growth Spurts: Rapid growth can sometimes lead to temporary muscle imbalances or changes in bone alignment.
• Participation in Certain Sports: Activities involving repetitive jumping, deep squats, cutting, or sudden changes in direction (e.g., basketball, volleyball, soccer, running).
• Previous Knee Injury: Especially prior patellar dislocations.
• Sedentary Lifestyle: Can lead to muscle weakness and imbalances.
• Obesity: Increased load on the knee joint.

Recognizing the Symptoms

While this article focuses on how maltracking occurs, it's important to recognize its common symptoms:

• Anterior Knee Pain: Pain around or behind the kneecap, especially with activities like climbing stairs, squatting, running, or prolonged sitting with bent knees.
• Grinding or Popping Sensations (Crepitus): Felt during knee movement.
• Feeling of Instability: A sensation that the kneecap might "give way" or slide out of place.
• Swelling: May occur after activity.

Prevention and Management Strategies

Understanding the causes of patellar maltracking is key to its prevention and management. Strategies typically involve:

• Targeted Strengthening: Focusing on the VMO, hip abductors, hip external rotators, and core muscles.
• Flexibility Training: Stretching tight structures like the IT band, hamstrings, quadriceps, and lateral retinaculum.
• Biomechanical Correction: Addressing foot mechanics (e.g., orthotics for overpronation) and improving movement patterns during exercise and daily activities.
• Progressive Training: Gradually increasing activity levels to allow the body to adapt.
• Proper Footwear: Wearing supportive shoes appropriate for the activity.

When to Seek Professional Help

If you experience persistent knee pain, instability, or suspect patellar maltracking, it is crucial to consult a healthcare professional. A physician, physical therapist, or sports medicine specialist can accurately diagnose the underlying causes through a thorough examination and, if necessary, imaging studies, and develop a personalized treatment plan. Early intervention can prevent further damage and improve long-term outcomes.