Legg-Calve-Perthes disease is a childhood hip disorder that occurs when the blood supply to the ball part of the thigh bone (femoral head) is disrupted. This causes the bone tissue to die, leading to its collapse and deformity. The femoral head then regenerates itself, but often not as round and smooth as it should be, which can lead to hip problems in later life.

The disease is named after three doctors who independently described it: Arthur Legg, Jacques Calve, and Georg Perthes. It typically affects children between the ages of 4 and 10, more commonly boys than girls. Symptoms may include limping, pain in the hip or knee, reduced range of motion in the hip, and muscle wasting. Treatment often involves rest, physical therapy, and sometimes surgery to realign or reshape the femoral head.

Bone lengthening is a surgical procedure that involves cutting and then gradually stretching the bone apart, allowing new bone to grow in its place. This process is also known as distraction osteogenesis. The goal of bone lengthening is to increase the length of a bone, either to improve function or to correct a deformity.

The procedure typically involves making an incision in the skin over the bone and using specialized tools to cut through the bone. Once the bone is cut, a device called an external fixator is attached to the bone on either side of the cut. The external fixator is then gradually adjusted over time to slowly stretch the bone apart, creating a gap between the two ends of the bone. As the bone is stretched, new bone tissue begins to grow in the space between the two ends, eventually filling in the gap and lengthening the bone.

Bone lengthening can be used to treat a variety of conditions, including limb length discrepancies, congenital deformities, and injuries that result in bone loss. It is typically performed by an orthopedic surgeon and may require several months of follow-up care to ensure proper healing and growth of the new bone tissue.

The femoral head is the rounded, ball-like top portion of the femur (thigh bone) that fits into the hip socket (acetabulum) to form the hip joint. It has a smooth, articular cartilage surface that allows for smooth and stable articulation with the pelvis. The femoral head is connected to the femoral neck, which is a narrower section of bone that angles downward and leads into the shaft of the femur. Together, the femoral head and neck provide stability and range of motion to the hip joint.

Osteotomy is a surgical procedure in which a bone is cut to shorten, lengthen, or change its alignment. It is often performed to correct deformities or to realign bones that have been damaged by trauma or disease. The bone may be cut straight across (transverse osteotomy) or at an angle (oblique osteotomy). After the bone is cut, it can be realigned and held in place with pins, plates, or screws until it heals. This procedure is commonly performed on bones in the leg, such as the femur or tibia, but can also be done on other bones in the body.

The hip joint, also known as the coxal joint, is a ball-and-socket type synovial joint that connects the femur (thigh bone) to the pelvis. The "ball" is the head of the femur, while the "socket" is the acetabulum, a concave surface on the pelvic bone.

The hip joint is surrounded by a strong fibrous capsule and is reinforced by several ligaments, including the iliofemoral, ischiofemoral, and pubofemoral ligaments. The joint allows for flexion, extension, abduction, adduction, medial and lateral rotation, and circumduction movements, making it one of the most mobile joints in the body.

The hip joint is also supported by various muscles, including the gluteus maximus, gluteus medius, gluteus minimus, iliopsoas, and other hip flexors and extensors. These muscles provide stability and strength to the joint, allowing for weight-bearing activities such as walking, running, and jumping.