Clinical and imaging features of intra-articular osteoid osteoma in the femoral neck / 中华放射学杂志

ABSTRACT

Objective To evaluate the clinical and imaging characteristics of osteoid osteoma in femoral neck and to improve diagnostic accuracy of this disease.Methods Twenty-one patients (18 males and 3 females,age,7-26 years,median age,13 years) with pathologically proven osteoid osteoma of the femoral neck were retrospectively analyzed for their clinical profile and radiologic features.CT and X-ray examinations were performed in all patients,10 of them pefformed post-contrast CT scan and 4 of them performed MRI examinations.Results Nineteen patients had hip pain (pain worse at night in 11,and 8 received salicylates treatment with good response),and 2 patients only with intermittent claudication.The duration ranged from 2 months to 54 months (median duration 12 months).X-ray Nidus was seen on plain film in 10 cases,18 cases showed different degrees of bone sclerosis of the nidus.CT Nidus was demonstrated in all cases.Among them,8 were intracortical,6 were subperiosteal,7 were endosteal.Twenty cases showed different degrees of bone sclerosis of the nidus-extra-articular anteromedial cortical surface of the femur neck.Nineteen cases showed vascular groove sign.MRI Nidus was seen in 4 cases.Bone sclerosis was low signal on all sequences.Three cases had joint effusion,4 cases had bone marrow edema,and 2 cases had synovial thickening.Conclusions Although osteoid osteoma of femoral neck has non-specific clinical features,the radiographic findings are usually typical.The nidus of osteoid osteoma is often located within the joint.Bony sclerosis occurs at the area of extra-articular anteromedial cortical surface of the femur neck.CT examination remains an optimal method to identify the nidus.