An apophysis is a type of growth plate at the end of the bone to which a tendon or ligament attaches to. Growth plates are areas of growing tissue near the ends of bones. They are mainly located at each end of long bones, such as the femur in younger people. Growth plates allow us to grow, and as long as the growth plates are active, or “open”, children will continue to grow taller.
Once a person is done growing, the growth plates fuse, or “close”, and are replaced by solid bone. Therefore, the apophysis, as well as other growth plates, are the weakest link in the musculoskeletal system and are prone to injury from direct trauma or repetitive stress.
Apophysitis is an inflammation or stress injury to the areas on or around growth plates in children and adolescents. Apophysitis is usually caused by repetitive overuse activities like running, jumping, and throwing, but can also occur as an acute injury with a fall or rapid, powerful movement. Generally, apophysitis can present anywhere in the body where a muscle or tendon attaches to an area of bone where a growth plate is located. The most common types of apophysitis are:
- Osgood Schlatter’s disease – Also known as “jumper’s knee”, Osgood Schlatter’s disease is a condition that happens when a tendon in the knee pulls against the top of the shinbone. This causes pain in the knee and the upper shin. Osgood-Schlatter disease is also referred to as osteochondrosis, which is a group of disorders of the growth plates that occur when a child is growing rapidly. Doctors aren’t sure as to what causes osteochondrosis, however, the disorders do seem to run in families.
- Sinding-Larson-Johansson syndrome (SLJ) – This is an injury directly to the growth plate where your patella (kneecap) attaches to your patellar tendon, the tendon that connects your kneecap to your shin bone (tibia). SLJ is also an injury to the tendon at the spot where the tendon leaves the patella, which is the inferior pole of your kneecap.
- Iselin’s disease – Iselin’s disease is a painful inflammatory condition of the apophysis of the 5th metatarsal (foot bone), where one of the leg muscles inserts. This condition is most often seen in physically active children between the ages of 8-13 years of age.
- Sever’s disease – Also known as “calcaneal apophysitis”, this condition is a painful inflammation located in the heel that results from a dramatic growth spurt in younger pre-teen patients. The inflammation comes about due to an abrupt growth when the heel bone grows at a faster rate than surrounding muscles and tendons which become overstretched and tight.