A severe case of enthesopathy mimicking intertrochanteric fractures on Tc-99m MDP scan

Enthesopathy or enthesitis refers to inflammation at the sites of ligamentous and tendinous insertions onto bone. Clinically, this manifests as pain, with or without swelling, at the entheses. The most common site of involvement is the calcaneum where the Achilles tendon and plantar fascia are inserted. Other sites include the fingers, toes, symphysis pubis, ischium, iliac crest, and femoral trochanters. Radiologically, enthesopathy is suggested by the development of erosions and reactive new bone formation. Classic appearances of plantar fasciitis on a Tc-99m MDP bone scintigram are well known but there is a paucity of similar information in other areas affected by this condition. The authors describe a case of severe enthesopathy, which mimicked intertrochanteric fractures on the bone scan. The typical bone tracer distribution, including involvement of other areas, and a normal contemporaneous radiograph were helpful to exclude trauma.