Patella alta

Patella alta is a condition characterized by an abnormally high riding patella (kneecap) in relation to the femur. It is often diagnosed through imaging techniques such as X-ray or MRI, with the Caton-Deschamps index being one of the most commonly used methods for measurement. This condition can be congenital or acquired, and it is associated with an increased risk of patellar dislocation, chondromalacia patellae, and anterior knee pain.

Causes

Patella alta can arise from several causes, including congenital abnormalities, where the individual is born with a high-riding patella, or through acquired conditions such as patellar tendon elongation after injury or surgery. It is also seen in individuals with certain conditions like Marfan syndrome or Ehlers-Danlos syndrome, which affect the connective tissues in the body.

Symptoms

Common symptoms of patella alta include instability of the knee, frequent patellar dislocation, difficulty in straightening the knee, and anterior knee pain. The condition may also lead to a noticeable gap or high appearance of the kneecap.

Diagnosis

Diagnosis of patella alta primarily involves imaging studies. The Caton-Deschamps index, which compares the distance from the bottom of the patellar articular surface to the anterior tibial plateau with the length of the patellar articular surface itself, is a widely used method. An index greater than 1.2 is typically indicative of patella alta. Other methods include the Insall-Salvati ratio, Blackburne-Peel ratio, and the modified Insall-Salvati ratio.

Treatment

Treatment for patella alta varies depending on the severity of the condition and the symptoms presented. Non-surgical options include physical therapy to strengthen the muscles around the knee and improve its stability. Bracing or taping may also be used to help position the patella correctly. Surgical options are considered when conservative treatments fail, and may include procedures to shorten the patellar tendon or realign the patella to improve its tracking.

Complications

If left untreated, patella alta can lead to complications such as recurrent patellar dislocation, increased wear and tear on the cartilage of the patella (leading to chondromalacia patellae), and chronic knee pain. These complications can significantly impact an individual's quality of life by limiting physical activity and causing persistent discomfort.

Prevention

Preventive measures for patella alta are limited, especially in cases where the condition is congenital. For individuals at risk of acquiring patella alta due to injury or surgery, preventive measures may include targeted physical therapy to maintain the strength and flexibility of the knee joint and proper post-surgical care to ensure appropriate healing of the patellar tendon.