Humero-ulnar synostosis is a rare congenital condition in which the humerus (upper arm bone) and ulna (forearm bone) fuse together. This fusion can cause the elbow to become stiff and limit the range of motion in the arm. It can also cause the arm to be shorter than the other arm. Treatment typically involves surgery to separate the fused bones and restore normal range of motion.

The most common symptoms of humero-ulnar synostosis include:

-Limited range of motion in the elbow joint
-Pain and Stiffness in the elbow joint
-A visible bump or lump on the elbow joint
-Decreased strength in the arm
-Decreased sensation in the arm
-Deformity of the elbow joint

Humero-ulnar synostosis is a rare condition caused by the fusion of the humerus and ulna bones in the arm. The exact cause of this condition is unknown, but it is believed to be caused by a combination of genetic and environmental factors. Possible causes include:

1. Genetic mutations: Certain genetic mutations can cause the bones to fuse together.

2. Trauma: Traumatic injuries to the arm can cause the bones to fuse together.

3. Infection: Infections in the arm can cause the bones to fuse together.

4. Radiation therapy: Radiation therapy used to treat cancer can cause the bones to fuse together.

5. Congenital abnormalities: Certain congenital abnormalities can cause the bones to fuse together.

1. Surgery: Surgery is the most common treatment for humero-ulnar synostosis. During the procedure, the surgeon will remove the fused bone and replace it with a prosthetic implant. The implant will help to restore the normal range of motion in the elbow joint.

2. Physical Therapy: Physical therapy can help to strengthen the muscles around the elbow joint and improve range of motion.

3. Splinting: Splinting can help to keep the elbow in a position that will help to reduce pain and improve range of motion.

4. Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) can help to reduce pain and inflammation.

1. Genetic predisposition
2. Previous trauma to the elbow
3. Prolonged immobilization of the elbow
4. Infection
5. Inflammatory conditions
6. Neuromuscular disorders
7. Congenital anomalies

At this time, there is no known cure for humero-ulnar synostosis. Treatment typically involves surgical intervention to correct the deformity and restore range of motion. Medications may be prescribed to manage pain and inflammation.