Incidence of pubic bone marrow oedema in Australian rules football players: relation to groin pain.

OBJECTIVES To examine the relation between the clinical features of groin pain and groin magnetic resonance imaging (MRI) appearances in a group largely comprising elite Australian Rules football players. The incidence of bone marrow oedema and other MRI findings in the pubic symphysis region was noted. The relation between a past history of groin pain and these other MRI findings was also examined. METHOD In a prospective study, 116 male subjects (89 footballers, 17 umpires, 10 sedentary men) were examined before history taking and groin MRI. The clinical history was not known to the examiner (GMV) and radiologists (JPS, GTF). Clinical evidence of groin pain and examination findings were correlated with the presence of increased signal intensity within the pubic bone marrow. A past history of groin pain was correlated with the presence of other MRI findings such as cyst formation, fluid signal within the pubic symphysis disc, and irregularity of the pubic symphysis. RESULTS Fifty two athletes (47 footballers, five umpires) had clinical features of groin pain with pubic symphysis and/or superior pubic ramus tenderness. A high incidence of increased signal intensity (77%) within the pubic bone marrow was identified in this group. There was an association between this group of athletes and the MRI finding of increased signal intensity (p<0.01). There was also an association between a past history of groin pain and the presence of other MRI findings (p<0.01). CONCLUSIONS Athletes with groin pain and tenderness of the pubic symphysis and/or superior pubic ramus have clinical features consistent with the diagnosis of osteitis pubis. The increased signal intensity seen on MRI is due to pubic bone marrow oedema. An association exists between the clinical features of osteitis pubis and the MRI finding of pubic bone marrow oedema. A high incidence of pubic bone marrow oedema was also noted. Degenerative features visualised by MRI, such as subchondral cyst formation, were associated with a past history of groin pain. A stress injury to the pubic bone is the most likely explanation for these MRI findings and may be the cause of the clinical entity osteitis pubis.