Knee

ONGENITAL KNEE DISLOCATION

Congenital knee dislocation is a rare condition, occurring in approximately 1 in 100,000 live births. The exact cause is unknown. Although it is rare, early diagnosis and treatment are crucial for recovery. Signs of congenital knee dislocation in a newborn include hyperextension of the knee (bending backward beyond the normal range), inability to bend the knee, and the foot reaching towards the mouth or shoulder. This condition can be detected before birth through ultrasound imaging, as it may be visible while the baby is still in the womb. Other associated conditions may include hip dislocations and foot deformities. There are three types of this condition based on the severity of the deformity:

• Type 1: Caused by stiffness and loss of elasticity in the quadriceps muscle, located in the front of the thigh (between the hip and knee joints). The knee can move close to a normal range of motion. Treatment involves gentle bending of the knee.
• Type 2: Partial knee dislocation at birth. The lower end of the femur (thigh bone) and the upper end of the tibia (shin bone) remain partially in contact. The knee can only extend fully.
• Type 3: Complete dislocation of the knee at birth. The upper end of the tibia is positioned in front of the lower end of the femur, and the knee cannot bend. The bones are not in contact, and the quadriceps muscle is shortened, stiff, and malformed.

Diagnosis

When evaluating the patient, additional conditions should be investigated, as congenital knee dislocation may occur alongside musculoskeletal or internal organ abnormalities. It can affect one or both knees and may be part of a group of congenital anomalies known as syndromes. Muscle and nerve disorders may also be present. The knee may slide abnormally backward in the womb, remaining in this position due to muscle-nerve diseases that cause reduced movement or excessive joint laxity. This leads to shortening, stiffness, and structural abnormalities of the quadriceps muscle. Diagnosis is confirmed through physical examination and X-rays of the knee.

Treatment

Gentle manipulation of the knee is performed to gradually bend it, and the leg is placed in a cast with the knee bent. The cast is replaced approximately weekly, with each new cast allowing further bending until the knee reaches 90 degrees of flexion. If the successive castings are not effective, surgery is performed under anesthesia to lengthen the quadriceps tendon, reposition the knee, and apply a cast for stabilization.