Congenital Patella Dislocation: A Rare Condition Requiring Complex Diagnosis and Multidimensional Treatment

Congenital Patella Dislocation: A Rare Condition Requiring Complex Diagnosis and Multidimensional Treatment

The Cliff News | August 15, 2026. Congenital Patella Dislocation is a rare but serious knee condition where the patella (kneecap) in newborns is dislocated or frequently subluxates from birth. This issue extends beyond simple patellar instability, often involving abnormal development of the knee's extensor mechanism, bone misalignment, and structural deformities like trochlear dysplasia (underdevelopment of the knee joint's groove).

In some instances, it can be part of conditions such as arthrogryposis, Down syndrome, and other skeletal disorders. This condition can affect both knees, significantly impacting a child's physical mobility and quality of life. The primary diagnostic hallmark of this severe condition is the patella's frequent and permanent lateral (outer) positioning within the knee joint.

This can lead to difficulties in bending or fully straightening the knee. This abnormality can result in gait abnormalities and, over time, lead to quadriceps muscle (major front thigh muscle) weakness. Key symptoms include restricted knee movement, pain, a feeling of instability, poor patellar tracking, and, in the long term, early wear-and-tear of the patellofemoral joint (the joint between the patella and femur), leading to osteoarthritis.

In some children, these symptoms are so subtle that diagnosis is significantly delayed, potentially reducing treatment effectiveness. Structural abnormalities and diagnostic complexity are often accompanied by several other associated structural deformities, further complicating diagnosis and treatment. These include genu valgum (knock knees), external tibial torsion (outward twisting of the shin bone), trochlear dysplasia (underdevelopment of the groove in the femur for the patella), increased Q-angle (angle between femur and tibia), lateralized tibial tubercle (outer prominence of the shin bone), tight lateral retinaculum (tissue stabilizing the patella), and a short quadriceps mechanism.

According to clinicians, addressing only the patella's position is insufficient given these complexities. A thorough evaluation of the entire extensor mechanism (group of muscles that straighten the knee) and lower limb alignment is absolutely essential. This ensures that the treatment plan incorporates all associated problems, facilitating a permanent resolution.

Imaging Techniques and Treatment Strategy

Alongside clinical examination, imaging techniques play a crucial role in diagnosing congenital patella dislocation. Typically, initial assessments of patellar position, trochlear shape, and related bony deformities are made using X-rays in anterior-posterior (AP), lateral, and skyline or Merchant views (special knee-flexed X-rays).

For clearer and more detailed information, Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI) are utilized when necessary. CT scans can accurately evaluate the degree of trochlear dysplasia, the Tibial Tubercle-Trochlear Groove (TT-TG) distance (an indicator of patellar tracking), and rotational deformities. MRI can assess patellar alignment along with the condition of joint cartilage, the Medial Patellofemoral Ligament (MPFL), and other soft tissues, identifying potential damage.

Various Treatment Options

The treatment strategy for congenital patella dislocation depends on factors such as the child's age, severity of the deformity, patellar mobility, and overall knee alignment. In younger children, if the dislocation is dynamic and correctable, specific physiotherapy and strengthening exercises for the quadriceps may be beneficial in some cases. However, the role of bracing in this condition is often limited.

If the patella is permanently dislocated from birth, or if pain, instability, and functional problems persist in older children and adolescents, surgery is often required. In cases of permanent structural deformity, surgeries that only stabilize soft tissues may not be sufficient for long-term solutions.

Surgical Interventions and Future Strategy

Various surgical techniques are employed based on the patient's age and type of deformity. These may include lateral retinacular release (loosening the tissue that pulls the patella laterally) or lengthening it, medial soft-tissue reconstruction (reconstruction of the inner joint's soft tissues), MPFL reconstruction (reconstruction of the crucial ligament stabilizing the patella), and realignment of the quadriceps or extensor mechanism.

After skeletal maturity (when bones stop growing), if necessary, a tibial tubercle osteotomy (cutting and repositioning the prominent part of the shin bone) can be performed. For select patients with severe trochlear dysplasia, trochleoplasty (reconstruction of the femur's groove) is considered. If significant angular or rotational deformities of the femur or tibia are present, a corresponding femoral or tibial osteotomy may also be required.

Importance of a Holistic Approach

Experts believe that considering congenital patella dislocation as merely common recurrent patellar instability would be an error. A systematic evaluation of the extensor mechanism, trochlear dysplasia, lower limb rotational alignment, and overall deformity is crucial before planning treatment. In the right patient, at the right time, correcting structural deformities can significantly help improve knee function, reduce pain and instability, and prevent future degradation of the patellofemoral joint.

For such complex cases, the treatment plan should be individualized by a pediatric orthopedic surgeon or a specialized knee specialist, as the nature and severity of the deformity can vary in each patient.