- Written By: Shelby Miller
- Edited By: W. Everett
- Last Modified Date: 06 April 2012
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Copyright Protected:
2003-2012 Conjecture Corporation
Alternately known as the tibial tuberosity, the tibial tubercle is a bony protrusion on the anterior, or front, part of the top of the tibia bone in the lower leg, which forms a small bump roughly an inch (2.54 cm) below the kneecap. It serves as a point of attachment for the patellar ligament, which originates above the kneecap as the suprapatellar tendon, where the quadriceps femoris muscles insert, and then continues past the patella, or kneecap, to attach to the tibial tubercle. Both the patella and the tibial tubercle are visible through the skin at the knee joint. Furthermore, the entire chain of quadriceps, tendons, patella, ligament, and tibia acts as a lever to extend the leg at the knee through the contraction of the quadriceps muscles.
Because the tibial tubercle is an end-point for the chain of muscles, tendons, and bones involved in knee extension, a chain activated during movements ranging from cycling to jumping, injuries to this bony point are possible, though uncommon. One type of injury to the tibial tubercle is known as an avulsion fracture. An avulsion is a bone fracture in which a fragment of bone breaks off from the main body of the bone — in this case the tubercle is split from the tibia.
This particular avulsion, which is most common in male adolescents, tends to occur following an extension of the knee joint during the push-off or landing phase of a jump. The injury happens where the ligament attaches to the tibial tubercle, as the forces causing the extension on the knee joint, which pull upward on the ligament, are greater than the forces holding the bone together. Outside forces, such as a high-impact landing, are usually more responsible for a tibial avulsion than internal forces, such as a very powerful quadriceps muscle contraction, due to built-in neurological reflexes that prevent a muscle from excessively lengthening during extension.
To treat a tibial avulsion, orthopedic experts recommend immobilizing, elevating, and icing to treat swelling. In many cases, rest and immobilization via a cast or splint are sufficient to heal the injury. When the tibial tubercle breaks away entirely from the tibia bone, however, surgery may be required to reattach the piece of bone using screws. Recovery from surgery may take up to six months, with more healing time recommended prior to returning to sports. In the case of mild fractures, as little as four weeks of immobilization followed by light therapy may be indicated.
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Izzy78
Post 5 |
@stl156 - I actually just found this article after reading something about Osgood - Schlatters disease, which affects the tibial tubercle. The article I was reading didn't do a very good job of explaining what the tubercle was.
The disease (which is more of a syndrome) usually happens to youngsters who are going through growth spurts. What happens is that when a kid grows quickly, their bones aren't quite as solid as they will eventually be, and when they are playing, the ligament pulls at the bone and causes the avulsion mentioned in the article.
Usually the child will be given the treatments described in the article, but there can be pain for several months afterward. As far as I could tell, there is no genetic reason that causes the disease. It is simply that boys play in rougher, more physical sports than girls at that age.
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stl156
Post 4 |
I am just curious: does anybody know what the article says that adolescent boys are the most likely to have the avulsion.
Are they predisposed to it, or does it just mean that boys are more active and tend to get injured more often? |
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jcraig
Post 3 |
@TreeMan - Good question. I've actually had a tibial plateau fracture, so I think I should be able to explain it.
If you feel your knee, the tibial tubercle is the slightly protruding part (about an inch down like the article says). As I understood it when I was injured, the plateau is actually the top of the tibia bone where it joins with the femur. I assume it got it's name, because on an X-ray, the top of the bone looks almost flat.
It was about 10 years ago that I hurt my knee, but I know the doctors talked about the tibial plateau and explained it as the top of the bone. I hope that clears things up. |
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TreeMan
Post 2 |
I have heard the term "tibial plateau" before. I always thought that this was the raised part that was below the knee. Is the plateau the same thing as the tubercle, or is there some type of subtle difference? |
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matthewc23
Post 1 |
I never realized there was a name for that little piece of bone that stuck out there by your knee.
What I don't understand is exactly how a tibial avulsion happens. The article mentions that it could occur after landing on a jump, but what is the force that causes the injury? Is it like the ligament is "glued" to the bone, and it is held on so tightly that it pulls the tibial tubercle away from the rest of the bone? Could someone please correct me if I am wrong.
If that is actually the case, it sounds extremely painful. |
