Being diagnosed with osteoarthritis (OA) at an early age is not uncommon and there is a strong link between severe joint damage and OA. Most young adults who develop OA have previously suffered a joint injury, in most cases a knee injury. The knee is especially susceptible to injuries within several sports and the relationship between knee injury and OA is therefore what has been studied the most. Common serious knee injuries are anterior cruciate ligament injuries and meniscus injuries. About half of those who seriously injure their knee proceed to develop so-called post-traumatic OA.  Why this happens is still unclear as OA is a complex disease where several different factors play a role in the development of the condition.

Risk of injury amongst young athletes

Serious knee injuries are common in young athletes, especially tears to the anterior cruciate ligament. An ACL tear usually occurs as the result of a knee rotation. In several sports such as football, basketball, and alpine skiing, where there are quick changes in direction and pivoting, the foot risks getting stuck while the rest of the body turns. When this happens, the anterior cruciate ligament may completely or partially tear. Several structures in the knee are often damaged at the same time, such as the menisci, other ligaments, and cartilage. Non-athletes may also suffer an ACL tear as a result of a sudden knee rotation in normal day-to-day activities. However, this is quite uncommon.

Half of all injuries can be avoided

An ACL tear has been proven to increase the risk of future knee OA sixfold amongst young adults. Per year, approximately 3000 people under the age of 45 in Sweden suffer from knee OA as a result of a previous joint injury. It is estimated that around 50% of all cruciate ligament injuries in sports could have been avoided with regular injury prevention training.  Nevertheless, if you are unlucky enough to suffer a serious knee injury, it is important to focus on knee rehabilitation to minimize the risk of developing OA or other knee problems later in life.

Meniscus tears associated with ACL tears

Another serious knee injury that many young people are seen to suffer from as a result of trauma to the knee, is a tear to the meniscus. The mechanism of injury of a meniscus tear is similar to an ACL tear, i.e. a sudden rotation of the knee joint. It is thus not uncommon for the meniscus to also tear in conjunction with an ACL tear. About half of all those who injure their ACL also injure the meniscus in the same knee.

Meniscus tears in older adults

Older individuals may also suffer a meniscus tear but this is usually due to the degeneration of the meniscus and not severe knee trauma. With age, the meniscus weakens and degenerates and may even tear as a result of an awkward movement of the knee. A meniscus tear in older adults may be a sign of early-stage OA.

Injuring the hip - less common, but possible

Although rare, young adults who have previously suffered a hip injury may proceed to develop hip OA. A hip injury can cause the edge of the cartilage surrounding the hip joint (the labrum) to tear. A tear to the hip labrum can be compared to a meniscus injury in the knee.

Hip impingements are also associated with an increased risk of hip problems such as OA later in life.  Hip impingement may for example occur in individuals who have played a lot of sports at a young age. Constant movement of the legs during sports activity can over time cause hip impingement.