Osgood-Schlatter Disease (OSD) is a common condition causing pain and swelling just below the knee, specifically where the patellar tendon attaches to the shinbone at the tibial tuberosity. While OSD is widely recognized as a condition of youth, adults experiencing knee pain often wonder if this ailment can affect skeletally mature individuals. True OSD is impossible in adulthood, but the residual effects of the condition can certainly cause significant, recurring symptoms.
Understanding Osgood-Schlatter in Youth
The underlying mechanism of OSD is traction apophysitis, a type of overuse injury. This condition occurs during the rapid growth phases of adolescence, typically affecting males aged 10 to 15 and females aged 8 to 14. During these periods, bones often lengthen faster than the surrounding muscles and tendons, which increases tension on the knee joint structures.
The patellar tendon connects the quadriceps muscle to the shinbone and pulls repeatedly on the growth plate (physis) at the tibial tuberosity. Because the growth plate is made of weaker cartilage before it hardens into bone, this chronic, repetitive stress causes microtrauma, inflammation, and pain. This cycle of tension and irritation links OSD intrinsically to the period of skeletal immaturity and active growth. The pain usually resolves naturally once the growth plate fuses with the rest of the tibia, generally occurring between the ages of 14 and 18.
When Juvenile Symptoms Persist into Adulthood
True Osgood-Schlatter Disease, as defined by inflammation of an open growth plate, cannot develop in an adult because skeletal maturity has been reached and the growth plate has closed. However, symptoms that feel identical to the juvenile condition can persist or recur in up to 10% of patients who had OSD as adolescents. This adult pain is not a new case of OSD but a consequence of the structural changes left behind by the disorder.
The most common reason for persistent adult pain is the non-union of the tibial tubercle, which results in the formation of a persistent bone fragment known as an ossicle. During the adolescent phase, the repeated pulling of the patellar tendon can cause small pieces of cartilage and bone to partially separate from the main tibia. If this fragment fails to completely fuse back into the bone when the growth plate closes, it remains as a separate, painful ossicle embedded within the patellar tendon.
This residual bony prominence and the embedded ossicle can cause chronic irritation, especially with activities that put pressure on the knee, such as kneeling or direct impact. The ossicle can rub against the bursa (a fluid-filled sac that cushions the joint) or the tendon itself, leading to chronic inflammation and localized tenderness. Consequently, the adult patient experiences pain localized to the tibial tuberosity, mimicking the original OSD symptoms even decades after skeletal maturation.
Treatment and Distinguishing Adult Knee Pain
Management of persistent adult OSD symptoms focuses first on conservative measures similar to those used in youth, aimed at reducing inflammation and mechanical stress. This approach includes using nonsteroidal anti-inflammatory drugs (NSAIDs) to manage pain and swelling. Physical therapy is also a cornerstone of conservative treatment, focusing on stretching and strengthening the quadriceps and hamstring muscles to reduce the chronic tension placed on the patellar tendon.
If conservative treatments fail to provide relief over several months, especially when a prominent ossicle is the source of pain, surgical intervention may be considered. This procedure typically involves the excision of the non-united ossicle and debridement of any associated inflamed soft tissue or bursa. Surgery is reserved for severe, refractory cases and treats the residual structural problem rather than an active growth plate issue.
Adults experiencing pain at the tibial tuberosity must seek a clear diagnosis, as the symptoms can be easily confused with other adult knee conditions. A physician must differentiate residual OSD from several other issues, including:
- Patellar tendinopathy, often called “jumper’s knee,” which involves inflammation of the patellar tendon but not the growth plate.
- Chronic infrapatellar bursitis, which is inflammation of the bursa sac located directly over the bony prominence.
- Other potential causes of pain, such as a stress fracture of the tibia or, rarely, a tumor.