Bone scintigraphic findings of os trigonum: A prospective study of 100 soldiers on active duty

PURPOSE: To determine the clinical significance of an increased uptake of 99mTc methylene-diphosphonate (Tc-MDP) in the os trigonum region seen on bone scintigrams of soldiers on active duty. PATIENTS AND METHODS: Radionuclide whole-body skeletal imaging and physical examination of the foot were carried out in 100 consecutive soldiers on active duty referred for evaluation of suspected stress-injury of the lower limbs, back pain, and different skeletal trauma. Lateral radiographs of the foot were performed in those with increased uptake of Tc-MDP at the site of os trigonum. Radiographic, scintigraphic, and clinical findings were correlated. RESULTS: Among 200 feet, 27 (13.5%) showed an increased uptake of Tc-MDP in the os trigonum region. The right side was affected in six patients, the left side in 11 and five patients had bilaterally increased uptake. On X-rays, 31 of 44 feet showed the os trigonum. Only 10 of these 27 feet (37%) had a symptomatic os trigonum. CONCLUSIONS: Our results suggest that increased uptake of Tc-MDP in the os trigonum region is a frequent finding among active soldiers and is of limited value in detecting symptomatic os trigonum.