The tibial tuberosity is the bony protrusion at the top of the tibia bone in the lower leg. It is located just underneath the kneecap and can be easily felt with the hand. Several important ligaments and cartilage structures are connected to the protrusion to provide stability, cushioning, and flexibility to the knee during physical activity. Acute or chronic injury to the area can result in significant leg pain and stiffness. If the bone and surrounding structures are damaged, medications, physical therapy, or surgery may be needed.
The tibia is the larger of two bones in the lower leg, and it is responsible for bearing weight and absorbing force when jumping, turning, and stopping. The tibial tuberosity, which is connected to the knee by the ligamentum patellae, aids in the joint's ability to bend and straighten. In infancy, the tuberosity is primarily composed of cartilage and other types of soft tissue that gradually ossify throughout early childhood. A growth plate underneath the bump allows the tibia to fully develop and the protrusion to become solid bone by adulthood.
Problems with this part of the tibia are almost exclusive to children and adolescents, since the bone is most susceptible to injury while it is still developing. A chronic childhood disorder called Osgood-Schlatter disease can occur if frequent strain is placed on the lower legs. Children who play high-intensity sports such as basketball, football, and tennis constantly put stress on their knees, which can cause this part of the bone to swell. Osgood-Schlatter disease typically results in chronic pain, tenderness, and loss of flexibility.
A young person's tibial tuberosity can also be fractured due to a bad fall or blunt trauma to the leg. Fractures are typically very painful and swelling underneath the knee can be severe. It is possible for an adult to suffer a fracture as well, but it is much less common.
An individual who has pain and swelling under the knee should be evaluated by a medical proessional. Osgood-Schlatter disease can often be managed by limiting physical activity, taking anti-inflammatory medications, and wearing a supportive knee brace. Fractures typically require leg casts and up to six months of rest. Surgery may be necessary if the bone is severely fractured or if the ligamentum patellae is damaged. Children and adolescents who are treated for fractures often need to attend physical therapy sessions during recovery. With effective treatment, most people are able to overcome leg problems entirely by adulthood.