Osteitis Pubis

Osteitis pubis (OP) is the non-infectious inflammation of the pubic symphysis. It can be caused by childbirth, suprapubic surgery, athletic activities, trauma, and rheumatologic disorders. Osteitis pubis is a self-limiting process, which resolves without treatment. NSAIDS are the treatment of choice, but symphyseal injection of steroids and anesthetics may also be performed.

Radiographs will show sclerosis and lysis around the pubic symphysis (usually 1 month following onset of symptoms) and widening of the pubic symphysis (greater than 1 cm). Stability of the joint can be assessed by taking radiographs with the patient alternating standing on each foot (flamingo views). The joint is considered unstable if there is more than 2 mm of cephalad translation of the superior pubic ramus.

MRI will show bone marrow edema spanning the pubic symphysis, symphyseal fluid, and peripubic soft-tissue edema.

The main differential consideration is osteomyelitis. Bone destruction may be seen in active osteomyelitis. Bony bridging and symphyseal ankylosis may be seen in both OP and osteomyelitis. The two entities are differentiated based on clinical grounds, but biopsy and culture may be required for definitive diagnosis.

References

• GibbonWW and Hession PR. Diseases of the pubis and pubic symphysis: MR imaging appearances. AJR Am J Roentgenol 1997;169(3):849–853.
• Allen KL and Fried GW. Osteitis Pubis. eMedicine. Jul 28, 2009.