Osgood-Schlatter disease occurs when there is irritation to the top, front portion of the shin bone (tibia) where the tendon attached to the kneecap (patella) meets the shin bone. It occurs when there is an increased amount of stress placed upon the bones where the tendons attach. This is most often the result of increased activity levels by an adolescent athlete.
Our musculoskeletal system is made up of bones and surrounding soft tissue structures, including muscles, ligaments (which connect bone to bone), and tendons (which connect muscle to bone). These structures all play a role in helping us move.
During adolescence our bodies grow at a rapid rate. As our bodies develop, our bones are growing longer. Throughout this phase, our growth plates (epiphyseal plates) are susceptible to injury. A growth plate is the site at the end of a bone where new bone tissue is made and bone growth occurs. Females typically experience the most rapid growth between approximately 11 to 12 years of age, and males typically experience this growth surge between approximately 13 and 14 years of age. Males experience OS more frequently than females, likely due to an increased rate of sports participation.
Structures in our body might become irritated if they are asked to do more than they are capable of doing. Injuries can occur in an isolated event, but OS disease is most likely the cumulative effect of repeated trauma. OS is most frequently experienced in adolescents who regularly participate in running, jumping, and “cutting” (rapid changes in direction) activities.
When too much stress is present (ie, from rapid growth) and when the body is overworked (ie, either too much overall volume of exercise, or too much repetition), the top of the shin can become painful and swollen. As this condition progresses, the body’s response to bone stress can be an increase in bone production; an adolescent may begin to develop a boney growth that feels like a bump on the front of the upper shin.
OS can start as mild soreness, but can progress to long-lasting pain and limited function, if not addressed early and appropriately.