Introduction Pubic-related groin pain can affect young athletes and pubic apophysitis is a potential cause of pain. We aimed to describe the maturation of the pubic symphysis in adolescent football players on x-ray.

Materials and Methods 105 anteroposterior radiographs of healthy adolescent male football players between 12 and 24 years old were used to develop the Maturing Adolescent Pubic Symphysis (MAPS) classification. Our understanding and radiological scoring of the symphyseal joint was developed in 6 rounds. The final MAPS-classification items were scored in random order by two experienced observers, blinded for the age of the participant. The inter-observer reliability was examined using weighted kappa (κ).

Results We developed a classification system with clear definitions and a pictorial atlas. We divided the joint into three regions: the superior corners, the upper and the lower regions of the joint line. The superior corners were classified as rounded, squared or beaked. The upper region of the joint line: round or straight. The lower region of the joint line: straight, diagonal, or in between. Inter-observer reliability was moderate to almost perfect: superior region: κ = 0.70 (95% CI 0.60 - 0.79), upper region of the joint line: κ = 0.89 (95% CI 0.86 - 0.92), lower region of the joint line: κ = 0.65 (95% CI 0.55 - 0.75).

Conclusion The MAPS-classification is reliable and can be used to assess the maturation of the pubic symphysis joint. Maturation starts at the superior corner, followed by ossification of the joint line from superior to inferior.