MR debunks common views on causes of groin pain

MR findings show that commonly diagnosed causes of groin pain in soccer and rugby players - conjoint tendinitis and osteitis pubis - are far less common than believed, according to a pair of papers presented Thursday.

The studies are significant because the two conditions usually require surgery. The conjoint tendinitis diagnosis, dubbed Gilmore's groin, has been particularly controversial.

Dr. Francis W. Smith of the University of Aberdeen in the U.K. analyzed groin pain in 127 male athletes aged 11 to 30, 90% of them footballers (soccer players). In half of the cases (63), MR images revealed no abnormality. There were 19 cases of osteitis pubis, nine stress fractures, five adductor muscle tears, 10 cases of inflammation of the small rotator muscles of the hip, and four cases of ilio-psoas tendinitis. The remaining 11 cases had various other findings, but none showed evidence of conjoint tendinitis, although 25 of the athletes went on to surgery.

Smith used offset coronal T2-weighted and STIR and transverse T1- and T2-weighted images obtained on a 0.2T open scanner.

Smith, who also advises sports teams, said he has seen a number of cases in which surgery is performed, yet months later, the groin pain continues.

He concluded that conjoint tendinitis is often overdiagnosed and that careful MR examination is advisable for athletes suffering from groin pain. Using offset coronal T2-weighted and STIR sequences, which are especially good at visualizing stress fractures and adductor muscle tears, adds important information when imaging the pelvis for groin pain, Smith said.

A study conducted at the University of Dublin used MR sequences to image 70 athletes with groin pain. The researchers looked for isolated adductor dysfunction, isolated osteitis pubis, and combinations of the two.

Although osteitis pubis is commonly blamed for groin pain, adductor dysfunction, identified by an accessory cleft sign, was found in 54 of the 70 cases, said Dr. Patricia Cunningham, the lead researcher. In each case, the side of the cleft sign corresponded with the side of the groin pain.

Osteitis pubis was found in just 12 patients. Four of the patients had normal scans, while 20 patients showed signs of both pathologies.

The images were obtained on a 1.5T scanner using a body coil with coronal and axial T1- and STIR-weighted tissue excitation.

The researchers concluded that adductor dysfunction appears to precede the development of osteitis pubis. Isolated osteitis pubis as a cause of groin pain is uncommon, they said.