Kneecap / Patellar Instability

The symptoms of patellar instability can vary depending on the severity and frequency of the dislocation or subluxation (partial dislocation). Common symptoms include:

• Knee pain often felt in the front of the knee, particularly during activities that involve bending the knee, such as climbing stairs, running, or squatting.
• The knee may become swollen, particularly after an episode of dislocation or subluxation.
• A sensation that the knee might buckle or give out, particularly during weight-bearing activities.
• In more severe cases, the patella may completely dislocate and visibly shift to the side of the knee.
• Difficulty fully bending or straightening the knee.
• A general sense of the knee being unstable or wobbly, especially during movement.

Patellar instability can be caused by several factors, including:

• Bone Structure: Some people naturally have a shallower or differently shaped groove in their thigh bone, which can make it easier for the kneecap to slip out of place.
• Loose Ligaments: Individuals with looser ligaments (often due to genetic conditions like Ehlers-Danlos syndrome) may experience greater knee instability.
• Trauma: A direct blow to the knee or a sudden twist can force the patella out of its groove.
• Muscle Imbalance: Weakness or imbalance in the muscles around the knee, particularly the quadriceps, can contribute to instability.
• Previous Injury: A history of patellar dislocation or subluxation can increase the likelihood of future episodes.

Dr. Ahsan will review your medical history and inquire about your symptoms, previous injuries and what may have caused them. He will perform a physical examination to assess knee stability, alignment, and muscle strength. Dr. Ahsan will order X-rays to evaluate the alignment of the patella and rule out fractures or other bone abnormalities. An MRI will provide detailed images of the soft tissues, including ligaments, tendons, and cartilage, to assess any damage or structural abnormalities. Sometimes he may also order a CT scan to get a more detailed view of the bone structure and alignment.

1. Patellar dislocation: Patellar dislocation occurs when the kneecap (patella) slips out of its normal position in the groove at the end of the thigh bone (femur). Once the patella has dislocated, there is an increased risk of it happening again, particularly if the underlying cause of instability is not addressed.
2. Chronic Pain: Repeated dislocations or subluxations (partial dislocations) can lead to ongoing pain in the knee, particularly during activities that involve bending or putting weight on the knee.
3. Damage to Cartilage: Each dislocation can damage the cartilage on the underside of the patella or within the trochlear groove of the femur, potentially leading to long-term issues like patellofemoral arthritis.
4. Knee Instability: Over time, repeated episodes of instability can weaken the ligaments and muscles around the knee, making the joint feel less stable and more prone to injury.
5. Reduced Mobility: Chronic instability can limit a person’s ability to engage in physical activities, leading to a decreased range of motion and overall reduced knee function.
6. Development of Arthritis: The repeated trauma to the knee joint from dislocations can increase the risk of developing osteoarthritis in the knee at a younger age than typically expected.
7. Weakness and Muscle Atrophy: Ongoing instability may cause some muscles around the knee to weaken or atrophy (shrink), which can further exacerbate instability and reduce the knee’s overall strength.

Managing patellar instability effectively is crucial to minimizing these risks and preserving knee function over time.

Treatment for patellar instability depends on the severity of the condition and the specific needs of the patient. Options include:

1. Conservative Management:

• Physical Therapy: Strengthening the muscles around the knee, particularly the quadriceps, to improve stability and support for the patella.
• Bracing: Knee braces can help keep the patella in place during activity and prevent further dislocations.
• Activity Modification: Avoiding activities that exacerbate symptoms, such as high-impact sports or exercises that put excessive strain on the knee.
• Medications: Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): These can help reduce pain and inflammation associated with patellar instability.

Most patients are treated conservatively with nonsurgical treatment after the initial patellar instability episode. If recurrent patellar instability persists, surgery is often recommended.

2. Surgery:

• Medial Patellofemoral Ligament (MPFL) Reconstruction: In cases where the ligament on the inside of the knee is damaged, reconstructive surgery can be performed to stabilize the patella. This is typically performed with a Semitendinosis tendon allograft (cadaveric tissue).
• Trochleoplasty: In patients with a shallow trochlear groove, this surgery deepens the groove to better accommodate the patella.
• Realignment Procedures: For patients with significant anatomical misalignment, realignment surgery can correct the tracking of the patella. This included tibial tubercle osteotomy, distal femoral osteotomy, and proximal tibial osteotomy.

Patellar instability is a condition that can significantly impact mobility and quality of life, but with appropriate diagnosis and treatment, many patients can achieve relief from symptoms and prevent further episodes.