Proximal femoral intra-capsular osteoid osteoma in a 16-year-old male with epiphyseal periostitis contributing to Cam-type deformity relating to femoro-acetabular impingement

Intra- and juxta-articular osteoid osteoma in children and adolescents

BACKGROUND

Osteoid osteoma (OO) is a common benign tumor in children and adolescents, but intra-and juxta-articular OO is rare and difficult to diagnose. The purpose of this study is to investigate the distinctions between intra- and juxta-articular OO, trying to avoid delaying diagnosis and optimize treatment strategies.

METHODS

Thirty patients diagnosed with OO in the intra- and juxta joint at our institution who underwent surgical resection were included. Clinical and epidemiological factors, preoperative radiograph parameters, including computed tomography (CT), magnetic resonance imaging (MRI), and bone scan, were documented. The outcomes of the involved extremity were evaluated at the final follow-up.

RESULTS

Mean age at diagnosis, interval time, and follow-up time was 8.37±3.79 years old, 4.67±5.88 months, 3.57±2.18 years, respectively. Factors identified to be significantly associated with intra- and juxta-articular OO including pain with activity (P=0.004) and abnormal range of motion (P=0.00). The factor of abnormal range of motion (P=0.03) also influenced the existence of complications. Six children had a secondary operation to cure the recurrence.

CONCLUSIONS

It is essential for clinicians and radiologists to be aware of the atypical clinical and radiographic features of intra- and juxta-articular OO, as the delayed diagnosis can lead to unnecessary pain and further complications after surgeries. The pain with activity and abnormal range of motion is helpful to identify the location of OO. The persistently abnormal range of motion also significantly leads to complications. The open surgeries to resect the nidus in juxta-articular OO were effective.

A rare case of osteoblastoma in the femoral head combined with cam-type femoroacetabular impingement: A case report

Osteoblastoma is a relatively rare benign bone-forming tumor accounting for less than 1% of all bone tumors. This report describes a patient with an osteoblastoma in the femoral head complicated by coexistence of femoroacetabular impingement. A 25-year-old male rugby football player complained of severe right hip pain after an injury during rugby practice. The pain became progressively worse despite resting from sports activity and rehabilitation for 4 months. The image inspection revealed bone tumor complicated by cam-type femoroacetabular impingement and a labral injury. Hip arthroscopic surgery was planned using a navigation system and a three-dimensional model for both complete debridement and cam resection. The tumor was resected by open surgery using a posterior approach. The bone tumor was diagnosed histopathologically as an osteoblastoma. The patient’s symptoms improved markedly after surgery, with no evidence of local tumor recurrence or hip arthritis 1 year later.

Osteoid osteoma of the hip: imaging features

Osteoid osteoma (OO), a small bone tumor relatively common in young subjects, frequently involves the hip. In addition to typical findings, we emphasize unsuspected clinical and imaging features including painless OO causing limping gait, non-visibility of totally mineralized nidus, absence of hyperostosis or adjacent edema, and recurrence at distance from the initial location. We also discuss the option of medical treatment for some cases of deep hip locations.

Clinical presentation of intra-articular osteoid osteoma of the hip and preliminary outcomes after arthroscopic resection: a case series

Intra-articular osteoid osteoma (IAOO) of the hip is a relatively rare diagnosis, but one that can closely mimic symptomatic presentation of femoroacetabular impingement (FAI). Although there are multiple case reports of osteoid osteoma (OO) in the hip, we present the largest case series of hip IAOO treated with hip arthroscopy and discuss limited patient-reported outcomes after treatment with hip arthroscopy. We retrospectively identified patients diagnosed with IAOO of the hip with confirmatory computed tomography, magnetic resonance imaging or biopsy diagnoses of OO. We analyzed lesion location, main presenting symptoms, symptom duration and treatment undertaken. For the patients who underwent hip arthroscopy for treatment of their IAOO, we reviewed patient-reported outcome scores when available.

Forty patients with confirmed IAOO were identified. Thirteen underwent excision with hip arthroscopy. The most common presenting symptom was groin pain. In limited patients who had pre- and post-operative outcome scores, we found significant improvements in modified Harris Hip Score (mHHS), Hip Outcome Score-Activity of Daily Living (HOS-ADL) and international Hip Outcomes Tool (iHot33) scores. Compared with patients undergoing hip arthroscopy for FAI alone, baseline mHHS, HOS-ADL, Hip Outcome Score–Sport-Specific Subscale and iHot33 scores were almost identical. We found that the presenting symptoms of hip IAOO closely mimic symptomatic FAI, including groin pain and anterior hip pain, so it is important to keep IAOO of the hip in the differential diagnosis of hip pain. Based on our experience, arthroscopy can be an effective treatment option for excision of intra-articular OO and is especially effective in patients with concomitant FAI in treating both pathologies.

Progressive femoroacetabular impingement after complete excision of osteoid osteoma in adolescents: a report of two cases

This article highlights that the long-term and serial follow-up of adolescents with osteoid osteoma should be considered, even after complete excision of the nidus owing to the possibility of the delayed onset or progression of femur head and neck deformities or osteoarthritis. It is important to recognize the sequelae of osteoid osteomas, such as bone edema and new bone formation, which can alter the normal anatomy of the proximal femur. We report two cases of osteoid osteoma in the proximal femur, which showed progressive hypertrophy of the femoral neck after excision of the nidus and subsequent cam-type femoroacetabular impingement (FAI), requiring additional osteochondroplasty procedures. Even though hip pain was relieved immediately after excision of the nidus in both cases, cam-type FAI developed during postoperative follow-up of 18 months (case 1) and 6.5 years (case 2). Hip pain subsided within 1 month of osteochondroplasty, and the full range of motion of the hip joint was achieved and was being maintained after postoperative follow-up of 1 year (case 1) and 6 months (case 2).

Osteoid Osteoma of the Femoral Neck: Use of the Half-Moon Sign in MRI Diagnosis

OBJECTIVE

Osteoid osteoma is a benign bone tumor that is commonly located in the proximal femur. Although CT is helpful in the diagnosis of osteoid osteoma, patients in whom the clinical presentation of the tumor is atypical are first referred to undergo MRI, which yields a high percentage of false-negative or inconclusive results. We sought to explore the association between a half-moon sign of bone marrow edema and the presence of osteoid osteoma of the femoral neck.

SUBJECTS AND METHODS

The MRI examinations of 11 consecutive patients with osteoid osteoma (group 1) were prospectively included in the study. In addition, 950 consecutive hip MRI examinations of 485 patients were retrospectively analyzed for the presence of bone marrow edema of the femoral neck, with 19 patients identified as having bone marrow edema resulting from causes other than osteoid osteoma (group 2). Patients in both study groups were evaluated for the presence of the half-moon sign.

RESULTS

The half-moon sign of bone marrow edema was significantly associated with the presence of osteoid osteoma (p < 0.0001), having been seen on the MR images of all 11 patients in group 1 and only one of 19 patients in group 2. MRI examination was therefore 94.7% specific and 100% sensitive for the detection of osteoid osteoma, with positive and negative predictive values of 91.7% and 100%, respectively.

CONCLUSION

The half-moon sign is an MRI finding that is highly specific and sensitive for an accurate diagnosis of osteoid osteoma of the femoral neck.

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

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.

Collar-type osteophyte of the femur in young adults: is it a harbinger of intra-articular osteoid osteoma?

Variable clinical and radiological findings for intra-articular osteoid osteoma (OO) of the hip joint make its diagnosis difficult. Because radiographs commonly do not identify the nidus, MR imaging becomes the second line of study. However, because the appearance varies, findings on MR images can be confusing. We found "collar type osteophyte" of the femur i.e. an osteophyte rim around the femoral neck, to be a conspicuous finding of intra-articular OO. Here, this feature will be emphasized and intra-articular OOs will be discussed, with a review of the literature.