Patella Instability

Patellar instability is a condition in which the kneecap moves out of its normal position. This can happen partially, known as subluxation, or completely, known as dislocation. The patella is designed to glide smoothly within a groove at the end of the thigh bone (femur) when bending or straightening the knee. When it moves out of this groove, the knee can become unstable, painful, and prone to further injuries. Dr. Stephanie Boden, a fellowship-trained sports medicine expert at the University of Louisville, specializes in diagnosing and treating patellar instability to help patients regain stability and function in their knee.

Several factors can contribute to patellar instability, including anatomical differences, traumatic injury, and muscle imbalances. The most common causes include:

1. Anatomical differences – In the case of patellar instability, anatomic differences can include a shallow groove, a high-riding patella (patella alta), or misaligned leg bones, which make it easier for the kneecap to shift out of place. These structural variations may be inherited or develop over time, increasing the risk of knee instability.
2. Ligamentous laxity – Loose ligaments can make the knee joint more flexible than normal, increasing the risk of instability. This condition may be inherited or related to connective tissue disorders.
3. Traumatic injury – Direct blows to the knee or sudden twisting movements can cause the patella to dislocate. These injuries frequently occur during sports or accidents.
4. Muscle weakness or imbalance – Weakness in the muscles around the hip and thigh can lead to improper patellar tracking, making the kneecap more likely to shift out of place.
5. Repetitive stress – Activities that involve repeated kneeling, jumping, or pivoting can place excessive stress on the patella, increasing the risk of instability over time.

Dr. Stephanie Boden at the University of Louisville frequently treats athletes and active individuals who experience patellar instability due to high-impact movements and sports injuries.

The most noticeable symptom of patellar instability is the feeling that the kneecap is slipping, shifting, or moving out of place. Some individuals experience only occasional discomfort, while others suffer repeated episodes of dislocation or subluxation. Symptoms include:

• Pain, especially when bending the knee, walking up or down stairs, or engaging in physical activities
• Swelling, which may occur after a dislocation or repeated episodes of instability
• A popping or cracking sound when the patella moves out of place
• Weakness in the knee, making it feel as though it might give out
• Difficulty bearing weight on the affected leg, leading to instability during walking or sports activities

Dr. Stephanie Boden at the University of Louisville emphasizes the importance of recognizing these symptoms early. Delayed diagnosis and treatment can increase the risk of long-term damage and may require more invasive interventions.

Accurate diagnosis is essential for effective treatment. Dr. Stephanie Boden at the University of Louisville conducts a thorough evaluation that includes a detailed medical history, physical examination, and imaging tests. The diagnostic process includes:

• Medical history: Dr. Boden will inquire about previous knee injuries, episodes of dislocation or subluxation, and the specific activities that cause symptoms. She also assesses family history, as some anatomical factors contributing to patellar instability can be inherited.
• Physical examination: She will carefully examine how the kneecap moves within the knee joint, check for any abnormalities in muscle strength and alignment, and evaluate swelling, tenderness, and ligament stability. Specific tests may be performed to assess patellar mobility.
• X-rays: These images help detect bone abnormalities, signs of previous dislocations, or alignment issues that contribute to instability.
• MRI: This test provides a detailed view of soft tissues, including cartilage and ligaments, which may be damaged from repeated instability.
• CT scan: In some cases, a CT scan may be used to get a more detailed assessment of the knee’s anatomy, particularly the shape of the femoral groove and the position of the patella.

These diagnostic steps allow Dr. Stephanie Boden at the University of Louisville to determine the severity of patellar instability and develop a treatment plan tailored to each patient’s needs.