Risk factors, treatment options and prevention methods for knee osteoarthritis in sports

The need to better address such a prevalent condition
Osteoarthritis (OA), the breakdown and eventual loss of articular cartilage, is the most common musculoskeletal disease and is characterized by joint pain, tenderness and limitation of movement. OA, which occurs most frequently in the knee, serves as a major strain on the quality of life for young athletes and older people, and the number of people affected by it is increasing due to the growing age of the population. It’s apparent that the condition must be better understood and approached with effective prevention and management strategies to reduce its rates. A review was therefore performed to evaluate the relationship between sports and OA, and to summarize some recommended prevention and treatment options.

Who is most at risk for developing knee osteoarthritis?
While old age increases risk, with symptomatic knee OA occurring in 10-38% of people 60 or older, the three strongest risk factors for knee OA are high body mass index (BMI), excessive stress to the knee, and previous knee injury. Many sporting activities can lead to knee OA, but the likelihood of it occurring depends on the intensity, frequency and level of involvement in the sport. Moderate exercise has a low risk level, but sports that include high intensity and direct joint impact from contact with other participants increase risk, and repetitive impact and twisting loads to the knee are associated with joint degeneration. More importantly, athletes who’ve sustained a knee ligament tear (usually ACL), meniscal injury or fracture involving articular surfaces are particularly at a higher risk, with some studies claiming those athletes are five times more likely to develop OA. Therefore, athletes should be aware of their sport’s risk factors, and should seek effective treatment and complete rehab from any prior ACL or meniscus injury to decrease their risk.

Conclusive evidence is lacking on effectiveness of most available treatments
Certain treatments aim to stop knee OA in its tracks before it fully develops, but their effectiveness is questionable. Microfracture is a minimally invasive procedure that creates small holes in the bone to stimulate cartilage growth, and is usually the first choice for patients with previously untreated cartilage defects. Literature on the procedure, however, is minimal and inconclusive, requiring more in-depth studies. Mosaicplasty and mesenchymal stem cell (MSC) transplantation are additional procedures that have recently emerged, but are in the early stages and require further research. Autologous chondrocytes implantation (ACI), an arthroscopic procedure used to regenerate cartilage, has shown more promise, with one study reporting 88% of patients experiencing good-to-excellent results. Once knee OA does occur, for patients who don’t obtain sufficient pain and functional improvement from rehabilitation and pharmacological treatment, surgical treatments are considered. High tibial osteotomy (HTO), which may avoid the progression of OA, and total knee arthroplasty (TKA), recommended for older athletes, are two common procedures, but literature on their relationship to sports is lacking. Physical therapy and non-surgical procedures should therefore be focused on first, and if surgery is deemed necessary as a last resort, an educated decision should be made.

How to prevent knee OA in sports
Prevention methods must take the three prominent risk factors mentioned above into account, and adhering to the following guidelines is a logical choice for athletes and those administering care. One study claims that avoiding squatting, kneeling and carrying heavy loads has been associated with a reduction of 15-30% in knee OA prevalence. Since high BMI is a major risk factor, weight reduction is also heavily recommended for those at risk for knee OA. Weight reduction reduces not only the symptoms and progression of knee OA, but also the risk of acquiring it. Some figures claim maintaining the BMI at 25 kg/m2 or below would reduce OA in the population by 27-53%. Due to the high-risk nature of certain sports and those who have suffered knee injuries in the past, prevention programs for athletes at risk should be implemented into athletic workouts, and athletes with prior injuries should be especially careful to prevent the development of knee OA. Neuromuscular training programs to prevent ACL injuries have also been shown to reduce the prevalence of knee OA by 14-25%. Knee OA will continue to be an important issue of concern, but by spreading knowledge of risk factors and taking simple steps to prevent it from occurring, rates can hopefully begin to decrease while better treatment strategies are established.

Summarized by Greg Gargiulo

As reported in the Feb. 11 edition of the British Journal of Sports Medicine