Clinical and radiological features and skeletal sequelae in childhood intra-/juxta-articular versus extra-articular osteoid osteoma

Abstract

Background: To compare the clinical and radiological features of intra-/juxta-articular osteoid osteoma and extra-articular osteoid osteoma in skeletally immature patients, paying special attention to the skeletal complications.

Methods: Osteoid osteoma in 34 children (22 boys and 12 girls, mean age 10.4 years) was dichotomized according to the location of the nidus as intra-/juxta-articular (11 children) or extra-articular (23 children). The following features were compared: diagnostic delay, typical symptoms, synovitis and limited range of joint motion, response to treatment, typical radiographic findings, and skeletal complications.

Results: Eight of the 11 children with intra-/juxta-articular osteoid osteoma presented with synovitis in the involved joint, which led to a delayed diagnosis for a median 9.5 months. Pain disappeared in all children with surgical or medical interventions, but at the mean 4.9-year follow-up evaluation, skeletal abnormalities around the joint were noted in 5 children (4 proximal femur and 1 distal humerus) with intra-/juxta-articular osteoid osteoma, 2 of whom required subsequent surgeries for limited hip motion caused by femoroacetabular impingement and limited range of elbow motion, respectively. In contrast, typical clinical and radiological features were observed more often in extra-articular osteoid osteoma, and only 1 child showed overgrowth of the tibia, which did not have clinical significance.

Conclusions: Intra-/juxta-articular osteoid osteomas in growing children exhibit different clinical and radiological features from extra-articular lesions. Skeletal abnormalities mainly develop in intra-/juxta-articular osteoid osteoma, and these may lead to permanent skeletal sequelae.

Figure 1

A 9.7-year-old girl with a juxta-articular osteoid osteoma of the proximal femur with involvement of the hip joint. (A) Axial CT image of the right femoral neck shows a prominent bony hypertrophy (arrowheads) around the nidus (arrow). (B) Coronal CT image demonstrates a nidus just above the lesser trochanter of the femur (arrow). Note the widening of the femoral neck and hypertrophy of the femoral head compared with the contralateral normal side. (C) Axial contrast-enhanced T1-weighted MR image with fat suppression shows synovial hypertrophy with effusion. The head-neck offset is not clear.

Figure 2

A 14.1-year-old boy with an intra-articular osteoid osteoma of the olecranon fossa with involvement of the elbow joint. (A, B) Anteroposterior (A) and lateral (B) radiographs show hypertrophic deformation around the left elbow joint. (C, D) Coronal (C) and axial (D) CT images demonstrate the nidus (arrow) at the olecranon fossa. (E) Sagittal T2-weighted MR image with fat suppression shows a heterogeneous intermediate signal intensity of distal humerus with a high signal intensity around the elbow joint indicating bone marrow edema with synovitis.