Background Posture abnormalities such as scoliosis may cause injuries among athletes. Symmetrical posture is important for athletes to make their body balance and sturdy. Symmetrical posture allows athletes to reach high performance during training and competition. Long periods of injuries may damaged cartilage tissue and induce osteoarthritis in the knee joints. However, the effect of posture abnormalities among athletes especially scoliosis on osteoarthritis remain unknown. Therefore, we aim to identify the effect of scoliosis among athletes on secondary osteoarthritis in the knee joint.

Methods Analytic cross-sectional design has been used for this study. 92 athletes with scoliosis were chosen by random sampling technique in National Sport Hospital of Indonesia. The data were analysed with Chi-Square, Fisher test and Prevalence Ratio.

ResultsThe risk factors of secondary osteoarthritis in scoliosis athletes were not age, gender and type of sport, but Cobb’s angle and curve shape of scoliosis. Scoliosis may lead asymmetrical shape of the spine and malalignment. Asymmetrical load distribution on the cartilage could be the underlying factor that may lead to osteoarthritis of the knee joint. Higher degree of scoliosis may increase the risk of cartilage damage and osteoarthritis. S-curve may increase the risk of osteoarthritis in the knee joint.

Conclusion Secondary osteoarthritis among athletes may be caused by scoliosis that were characterised by Cobb’s angle and curve shape of scoliosis. Athletes with moderate Cobb’s angle degree have 7.5 times increased risk for secondary osteoarthritis compared with mild Cobb’s angle. In addition, athletes with “S” curve of scoliosis have 3.2 times increased risk for secondary osteoarthritis compared with athletes with “C” curve of scoliosis.