Patellar Maltracking: Understanding Kneecap Misalignment, Causes, Symptoms, and Treatment

What is it called when your kneecap is out of alignment?

When your kneecap, or patella, is out of alignment, it's broadly referred to as patellar maltracking or patellar tracking disorder. More severe forms include patellar subluxation (partial dislocation) and patellar dislocation (complete displacement).

Introduction to Patellar Misalignment

The kneecap (patella) is a small, triangular bone that sits within the quadriceps tendon at the front of the knee. Its primary role is to protect the knee joint and act as a fulcrum, increasing the mechanical advantage of the quadriceps muscles during knee extension. For optimal function, the patella needs to glide smoothly within a groove at the end of the thigh bone (femur), known as the trochlear groove. When this smooth tracking is disrupted, leading to the patella moving abnormally or "out of alignment," it can cause pain, instability, and functional limitations. This condition is a common source of anterior knee pain, particularly among athletes and active individuals.

Common Terminology for Kneecap Misalignment

Several terms are used to describe instances where the kneecap is out of alignment, each varying slightly in its specific meaning and severity:

• Patellar Tracking Disorder (PTD): This is a general term describing any condition where the patella does not move smoothly within the trochlear groove. It often involves the patella shifting too far to one side, typically the lateral (outer) side, during knee flexion and extension.
• Patellofemoral Pain Syndrome (PFPS): While not exclusively a misalignment term, PFPS is often caused or exacerbated by patellar maltracking. It refers to pain around or behind the kneecap, often worsened by activities that load the patellofemoral joint like squatting, stair climbing, or prolonged sitting.
• Patellar Maltracking: This term is synonymous with patellar tracking disorder, indicating that the patella is not following its normal, optimal path.
• Patellar Instability: This describes a feeling or actual occurrence of the kneecap "giving way" or feeling loose. It can range from a subtle sensation to a complete dislocation.
• Patellar Subluxation: This is a partial or incomplete dislocation of the patella. The kneecap moves out of the trochlear groove but then spontaneously returns to its normal position. This can cause acute pain and a feeling of the knee "giving out."
• Patellar Dislocation: This is a complete displacement of the patella from the trochlear groove. The kneecap typically shifts to the outside of the knee and does not return to its position without manual manipulation or medical intervention. This is a significant injury requiring immediate medical attention.

Anatomy and Biomechanics of the Patellofemoral Joint

Understanding the structures involved is crucial to grasping patellar misalignment:

• Bones: The patella (kneecap), femur (thigh bone), and tibia (shin bone) form the knee joint. The patella articulates with the trochlear groove on the distal end of the femur.
• Tendons: The quadriceps tendon connects the quadriceps muscles to the top of the patella. The patellar tendon connects the bottom of the patella to the tibial tuberosity on the shin bone. These tendons form the "extensor mechanism" of the knee.
• Ligaments: The medial patellofemoral ligament (MPFL) is a crucial stabilizer on the inner side of the kneecap, preventing it from dislocating laterally.
• Muscles: The quadriceps femoris group (vastus medialis, vastus lateralis, vastus intermedius, rectus femoris) are paramount. Imbalances, particularly weakness in the vastus medialis obliquus (VMO) – the innermost part of the quadriceps – relative to the stronger vastus lateralis (outer quadriceps), can pull the patella laterally. Other muscles, like the gluteal muscles (gluteus medius, gluteus maximus) and hip rotators, also influence knee alignment indirectly.
• Trochlear Groove: This is the shallow, V-shaped groove on the femur where the patella sits and glides. Its depth and shape are critical for stable patellar tracking.

Causes of Patellar Misalignment

Patellar misalignment can arise from a combination of factors:

• Structural/Anatomical Factors:
  • Shallow Trochlear Groove: A naturally shallow or flat trochlear groove (trochlear dysplasia) provides less bony restraint, making the patella more prone to slipping out.
  • Patella Alta: A high-riding patella, meaning it sits higher than normal in the trochlear groove, reducing its engagement in the groove, especially in early knee flexion.
  • Increased Q-Angle: The Q-angle is the angle formed by the quadriceps muscle pulling on the patella relative to the patellar tendon. A larger Q-angle (common in individuals with wider hips, valgus knees, or pronated feet) increases the lateral pull on the patella.
  • Foot Mechanics: Excessive pronation (flat feet) can internally rotate the tibia and femur, altering the alignment of the knee and increasing stress on the patellofemoral joint.
• Muscular Imbalances:
  • Weak VMO: As mentioned, a weak vastus medialis obliquus compared to the vastus lateralis allows the stronger outer muscle to pull the patella laterally.
  • Tight Lateral Structures: A tight iliotibial (IT) band, vastus lateralis, or lateral retinaculum (connective tissue on the outer side of the patella) can pull the patella outwards.
  • Weak Hip Abductors and External Rotators: Weakness in the gluteus medius and other hip muscles can lead to excessive hip adduction and internal rotation during movement, placing increased stress on the knee and contributing to maltracking.
  • Tight Hamstrings or Quadriceps: Imbalances in flexibility can alter the overall mechanics of the kinetic chain.
• Trauma/Injury:
  • A direct blow to the kneecap or a sudden twisting motion of the knee can cause subluxation or dislocation.
  • Damage to the MPFL during an initial dislocation significantly increases the risk of recurrent instability.
• Overuse/Repetitive Stress:
  • Activities involving repetitive knee bending (running, cycling, jumping, squatting) can exacerbate maltracking, leading to irritation and inflammation of the joint surfaces.

Signs and Symptoms

The symptoms of patellar misalignment can vary in intensity and presentation:

• Anterior Knee Pain: This is the most common symptom, typically felt around or behind the kneecap. It often worsens with activities like climbing stairs, squatting, kneeling, running, or prolonged sitting with bent knees ("theater sign").
• Clicking, Popping, or Grinding (Crepitus): Sensations or sounds felt during knee movement, indicating friction or abnormal contact between the patella and femur.
• Catching or Giving Way: A sensation that the knee is momentarily locking or buckling, often due to the patella momentarily getting caught or slipping.
• Instability: A feeling that the kneecap is loose or might slip out of place.
• Swelling: May occur, especially after acute subluxation or dislocation, due to irritation or inflammation within the joint.
• Visible Displacement: In cases of dislocation, the kneecap will be visibly out of place, usually shifted to the outside of the knee.

Diagnosis

Diagnosing patellar misalignment typically involves a thorough assessment by a healthcare professional:

• Physical Examination: The clinician will assess gait, posture, range of motion, muscle strength and flexibility, and perform specific tests to evaluate patellar tracking, stability, and tenderness. They will look for signs of Q-angle abnormalities, VMO atrophy, or lateral retinacular tightness.
• Imaging Studies:
  • X-rays: Can reveal patella alta (high-riding patella), trochlear dysplasia, and general bony alignment. Specific views, like a merchant view, are used to assess patellar tracking.
  • MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues (ligaments, tendons, cartilage) and can identify damage to the MPFL, cartilage defects, or bone bruises associated with dislocation.
  • CT Scan (Computed Tomography): May be used to assess bone morphology, trochlear depth, and rotational alignment of the femur and tibia, which can contribute to maltracking.

Management and Treatment Strategies

Treatment for patellar misalignment typically begins with conservative approaches, with surgery reserved for severe or recurrent cases.

• Conservative Management:
  • Rest and Activity Modification: Reducing activities that aggravate symptoms.
  • RICE Protocol: Rest, Ice, Compression, Elevation for acute pain and swelling.
  • Physical Therapy: The cornerstone of conservative treatment. A tailored program focuses on:
    • Strengthening: Targeting the VMO, gluteal muscles (abductors, external rotators), and core muscles to improve hip and knee stability.
    • Stretching: Addressing tightness in the IT band, hamstrings, quadriceps, and gastrocnemius.
    • Proprioception and Neuromuscular Control: Exercises to improve balance and coordination, re-educating the knee to move correctly.
    • Gait and Movement Pattern Retraining: Correcting faulty movement mechanics during functional activities.
  • Orthotics: Custom or over-the-counter shoe inserts can correct excessive foot pronation, which may improve knee alignment.
  • Bracing/Taping: Patellar stabilizing braces or specific taping techniques (e.g., McConnell taping) can help guide the patella into a more centralized position, reducing pain and improving tracking.
  • Pharmacological Interventions: Over-the-counter pain relievers (NSAIDs) can help manage pain and inflammation.
• Surgical Interventions: Considered when conservative methods fail or for recurrent dislocations, especially with significant anatomical abnormalities.
  • Lateral Release: Cutting the tight lateral retinaculum to reduce outward pull on the patella (less common as a standalone procedure now).
  • Medial Patellofemoral Ligament (MPFL) Reconstruction: Reconstructing the torn MPFL using a tendon graft to stabilize the patella medially, preventing lateral dislocation.
  • Tibial Tubercle Osteotomy (TTO): Involves cutting and repositioning the bony attachment of the patellar tendon on the shin bone to improve patellar tracking and reduce pressure on the joint.
  • Trochleoplasty: Reshaping a shallow trochlear groove to provide a deeper, more stable path for the patella.

Prevention

While not all cases of patellar misalignment are preventable, particularly those with significant anatomical predispositions, several strategies can help reduce the risk or manage symptoms:

• Balanced Strength Training: Emphasize strengthening the vastus medialis obliquus, gluteal muscles (especially gluteus medius and maximus), and core musculature. Avoid over-reliance on exercises that disproportionately strengthen the vastus lateralis.
• Flexibility and Mobility: Regularly stretch the quadriceps, hamstrings, hip flexors, and especially the iliotibial band to prevent tightness that can pull the patella out of alignment.
• Proper Footwear and Orthotics: Wear supportive shoes appropriate for your activity. Consider custom or over-the-counter orthotics if you have excessive foot pronation.
• Gradual Progression in Training: Avoid sudden increases in training volume or intensity, especially in activities involving repetitive knee bending. Allow your body to adapt.
• Listen to Your Body: Pay attention to early signs of knee pain or discomfort. Addressing issues promptly can prevent them from escalating into more significant problems.
• Maintain a Healthy Weight: Excess body weight increases the load on the knee joints, exacerbating pain and potentially contributing to tracking issues.

Conclusion

When your kneecap is out of alignment, it falls under the umbrella of patellar tracking disorder or patellar maltracking, with more severe forms being subluxation or complete dislocation. This condition arises from a complex interplay of anatomical factors, muscular imbalances, and biomechanical stressors. Understanding these underlying causes is crucial for effective management. While the symptoms can be debilitating, a comprehensive approach involving targeted physical therapy, activity modification, and, in some cases, surgical intervention, can significantly improve outcomes. For anyone experiencing persistent knee pain or instability, consulting with a healthcare professional, such as a sports medicine physician, orthopedist, or physical therapist, is the first step towards an accurate diagnosis and a personalized treatment plan.