Intra-articular Osteoid Osteoma Research Articles

Hip preservation in crisis: total hip replacement for osteoid osteoma-induced degeneration in a young adult

Osteoid osteoma is a small, benign tumor known for causing severe pain, especially at night. Intra-articular osteoid osteomas are rare and often misdiagnosed due to overlapping symptoms with other joint disorders like osteoarthritis or synovitis. These tumors require advanced imaging for accurate diagnosis and may necessitate surgical intervention when conservative treatments fail. A 22-year-old female presented with a four-year history of left hip and loin pain, initially treated with NSAIDs. Her symptoms progressively worsened, leading to imaging studies that revealed a sclerotic lesion in the hip joint. A biopsy confirmed osteoid osteoma, and due to the extent of joint damage, total hip replacement (THR) was performed. Postoperative recovery was excellent, with full functional restoration and no complications. This case illustrates the diagnostic and therapeutic challenges of intra-articular osteoid osteomas. THR proved to be a successful treatment in restoring function and alleviating pain, underscoring the need for early diagnosis and individualized surgical management in advanced cases.

Intra-articular Osteoid Osteomas: Imaging Manifestations and Mimics.

Osteoid osteoma (OO) is the third most prevalent benign bone neoplasm in children. Although it predominantly affects the diaphysis of long bones, OO can assume an intra-articular location in the epiphysis or the intracapsular portions of bones. The most common location of intra-articular OO is the hip joint. The presentation of intra-articular OOs often poses a diagnostic enigma, both from clinical and radiologic perspectives. Initial symptoms are often vague and nonspecific, characterized by joint pain, stiffness, and limited range of motion, which frequently contributes to a delayed diagnosis. Radiographic findings range from normal to a subtle sclerotic focus, which may or may not have a lucent nidus. In contrast to their extra-articular counterparts, intra-articular lesions have distinct features at MRI, including synovitis, joint effusion, and bone marrow edema-like signal intensity. While CT remains the standard for identifying the nidus, even CT may be inadequate in visualizing it in some cases, necessitating the use of bone scintigraphy or fluorine 18-labeled sodium fluoride PET/CT for definitive diagnosis. Radiologists frequently play a pivotal role in suggesting this diagnosis. However, familiarity with the unique imaging attributes of intra-articular OO is key to this endeavor. Awareness of these distinctive imaging findings of intra-articular OO is crucial for avoiding diagnostic delay, ensuring timely intervention, and preventing unnecessary procedures or surgeries resulting from a misdiagnosis. The authors highlight and illustrate the different manifestations of intra-articular OO as compared with the more common extra-articular lesions with respect to clinical presentation and imaging findings. ©RSNA, 2024 Supplemental material is available for this article.

Multimodality Imaging of a Patient with Intra-Articular Osteoid Osteoma: A Case Report

Multimodality Imaging of a Patient with Intra-Articular Osteoid Osteoma: A Case Report

Primary intraosseous papillary intralymphatic angioendothelioma of the distal femoral epiphysis: a case report with literature review.

Papillary intralymphatic angioendothelioma (PILA) is an exceptionally rare metastasizing soft tissue tumor. It tends to arise in the subcutaneous tissues of distal extremities in children. Only four intraosseous PILA cases have been reported until now in English language literature. We present a case of PILA arising in the distal femoral epiphysis of a 50-year-old female patient. It started as a relentless pain in her left knee. A plain radiography revealed a radiolucent area in the left internal femoral condyle. Computerized tomography revealed a 1-cm lytic lesion with a sclerotic rim. Magnetic resonance images showed a significant bone marrow edema signal focused on a 1-cm subchondral lesion suggestive of an intraarticular osteoid osteoma. Histologically, the tumor contained vascular channels covered by a single endothelial layer with intraluminal papillary endothelial structures lined with hobnail cells. Immunohistochemically, the cells were positive for ERG, CD31, and D2-40. The tumor underwent cryoablation and 6months later, after local recurrence or tumor persistence, a wide tumor resection was referred. After 7years of follow-up, the patient displayed neither local recurrence nor distant metastases. Primary intraosseous PILAs are exceedingly rare tumors that should be considered in the differential diagnosis of vascular bone tumors.

Olecranon fossa osteoid osteoma excision through arthroscopy: surgical technique.

In the elbow joint, occurrences of intra-articular osteoid osteoma are uncommon. We detail the case of a 21-year-old male who experienced pain, inflammation, and a restricted ability to move his elbow. For a few months, the diagnoses was missed and the patient was treated for idiopathic synovitis. After a contrast MRI, the tumor was revealed. During an arthroscopic examination of the elbow, a distinct red lesion was observed after the removal of the pale reactive bone in the olecranon cavity. This was subsequently removed in its entirety with the aid of a specialized bone tool. Histopathology confirmed the diagnosis of osteoid osteoma. Remarkably, the individual reported alleviation from the symptoms just a day following the operation and regained full range of motion 5weeks after the surgery. This case underscores the efficacy of arthroscopy in addressing intra-articular osteoid osteoma, with a focus on accurately pinpointing the lesion.

CT-guided radiofrequency ablation of painful intra-articular osteoid osteoma in children: Is there a concern for cartilage damage?

To evaluate the safety and efficacy of computed tomography-guided percutaneous radiofrequency ablation (PRFA) in the management of uncommon and technically challenging intra-articular osteoid osteoma in children. From December 2018 to September 2022, 16 children with intra-articular osteoid osteoma, including ten boys and six girls, were treated at two tertiary centers with percutaneous CT-guided RF ablation using a straight monopolar electrode. The procedures were carried out under general anesthesia. Post-procedural clinical outcomes and adverse events were assessed through clinical follow-up. Technical success was achieved in all of the participating patients. Clinical success with relief of symptomatology throughout the period of follow-up was achieved in 100% of the patients. No persistence or recurrence of pain occurred during the follow-up period. No immediate or delayed adverse effects were observed. PRFA is shown to be technically feasible. Clinical improvement can be achieved with a high rate of success in the treatment of children with difficult-to-treat intra-articular osteoid osteomas.

Intra-Articular Osteoid Osteoma of the Hip: An Observation and the Review of the Literature

Osteoid osteoma is a common benign bone tumor that affects young adults and has a typical clinical and radiographic presentation in long bones. However, when it appears in unusual intra-articular locations, the clinical symptomatology is then atypical and can lead to misdiagnosis constituting a diagnostic challenge for clinicians and causing delay in management. We present the case of a girl of 16 years with an osteoma osteoid intra-articular right hip involving the femoral head. This unusual location was the cause of unexplained pain and a delay in diagnosis of 20 months after the onset of symptoms, as the initial Magnetic Resonance Imaging (MRI) examination could not identify the lesion. The tomodensitometry is in this indication the most specific examination which made it possible to evoke the diagnosis of osteoid osteoma. Once the diagnosis is made, given the complexity of the location, it makes it difficult to access radio-guided techniques. The open surgical excision allowed healing with complete disappearance of pain. After complete surgical excision of the tumor, histopathological examination confirmed the final diagnosis of intra-articular osteoid osteoma. No recurrence was observed.

Intra-articular osteoid osteoma: report of two cases

骨样骨瘤是一种良性骨肿瘤，常见于长骨骨干，具有特征性的临床和放射学表现。关节内骨样骨瘤少见，通常累及髋部，很少累及肘部。由于肿瘤位于关节内，会产生关节僵硬、疼痛和活动能力下降等类似于关节炎的临床表现。骨样骨瘤的典型放射学表现是沿着长骨骨干以小的溶骨灶为中心的丰富的骨硬化，而关节内骨样骨瘤的影像学特征通常不典型，因此常导致诊断延误。本文报道2例临床诊断为关节炎的肘关节内骨样骨瘤，探讨其临床影像学、组织学、免疫表型及分子特征，为诊断提供帮助。.

Osteoid Osteoma Mimicking Arthritis

Intra-articular osteoid osteoma may simulate arthritis, due to the intra-articular presence of prostaglandin, which leads to synovitis, joint effusion, pain, and high local temperature. Also, intra-articular osteoid osteoma may present with minimum or no cortical thickening. Therefore, a high suspicion is needed for a correct and early diagnosis. Perfusion weighted imaging, such as dynamic contrast-enhanced imaging, can aid in the localization of the tumor nidus, seen as an early arterial-phase focal enhancement after the gadolinium injection, with fast washout, as a result of its hypervascularity.

Midterm Clinical, Radiological, and Functional Results of Arthroscopic Excision of Osteoid Osteoma of the Hip Joint: a Case Series.

We aimed to evaluate the midterm functional and clinical outcomes of the patients who underwent arthroscopic excision of hip osteoid osteoma (OO). We reviewed records of patients diagnosed with intra-articular hip OO, treated with hip arthroscopic excision procedure, and a minimum of 1-year postoperative between 2011 and 2020. Clinical outcomes were assessed range of motion (ROM) pre and postoperatively, and functional outcomes were evaluated with a modified Harris hip score (modified HHS) and Visual analog scale test. All patients were assessed by hip radiography, and three radiological measurements, including lateral center-edge angle (LCEA), alpha angle, and Tönnis angle, were measured. These parameters were compared with unaffected hips. Fifteen (5 female and 10 male) patients were included in the study, with a mean age of 32.6 ± 12.7 (range 12-53). The average postoperative follow-up period was 59.1 ± 28 (range 13-106) months. The functional and clinical scores were significantly improved at the final visit compared to the preoperative values. No differences were found between the operated and unaffected sides with respect to the radiological parameters. The preoperative alpha was significantly higher on the operated side than on the unaffected side (p = 0.007). In this study, within an average of 5years after surgery, hip arthroscopy provided successful clinical outcomes in the treatment of OO of the hip joint without recurrence. The modified HHS, VAS, and HOS values improved significantly at the final follow-up; 14 of 15 patients had satisfactory outcomes after hip arthroscopy for hip OO. Prognostic Level IV study.

Intraarticular osteoid osteoma of the knee misdiagnosed as meniscal tear: a case report

Intraarticular osteoid osteoma of the knee misdiagnosed as meniscal tear: a case report

Role of percutaneous CT-guided radiofrequency ablation in treatment of intra-articular, in close contact with cartilage and extra-articular osteoid osteomas: comparative analysis and new classification system.

We investigated procedural safety, technical and clinical outcomes of the percutaneous image-guided radiofrequency ablation (PRFA) of intra-articular (IA), intra-articular close to cartilage (IACC), and extra-articular (EA) osteoid osteomas (OO). We proposed a new radiologic classification for osteoid osteoma depending on the degree and location of sclerosis which may correlate with technical failure and/or difficulties. According to the inclusion criteria, we enrolled consecutive patients who were referred to the investigation center from June 2018 to January 2022. After clinical and CT imaging features were suggestive for the diagnosis of OO, all the patients were treated by percutaneous CT-guided RFA with a standardized technique. Biopsy of the lesion was not performed in all patients. A retrospective analysis was conducted to assess the procedure's technical, primary clinical, and secondary clinical successes, recurrence rate, and complications. We classified all the OOs according to a new proposed classification of the site and the amount of sclerosis. A total number of 55 patients were enrolled in our study according to the inclusion criteria. The mean age of the enrolled patients was 24.07 ± 14.71years (ranges from 7 to 57years). The M/F ratio was roughly 2:1. The mean follow-up was 20.18 ± 12.60months (ranges from 2 to 44months). EA group included 36 patients, IA included 5 and IACC included 14 patients. Technical success was achieved in all cases of IA and IACC groups. Technical success in the EA group was 97.22% (1 technical failure). Primary clinical success was 100%, 92.85%, and 91.66% for IA, IACC, and EA groups, respectively. Accordingly, the recurrence rate was 5.88% in EA, and 7.14% in IACC, while no recurrence occurred in the IA group. No complications occurred. The secondary success rate of the 3 cases of recurrence was 100%. PRFA proved to be a safe procedure with a high rate of success for OO treatment even in intra-articular lesions in close contact with cartilage. This study showed that the results in terms of technical and clinical success are comparable for IA OO, IACC OO, and EA OO, even if the recurrence rate was higher in EA OO. Our proposed new classification of the degree and location of sclerosis may correlate to technical failure, but further studies with a larger number of patients are needed for validation.

IMAGING FINDINGS OF OSTEOID OSTEOMAS IN CHILDREN AND ADOLESCENTS, CT VERSUS MRI: A SINGLE CENTER EXPERIENCE

Objective: To analyze osteoid osteomas of the pediatric age group, assess the distribution of lesions, and radiological findings, and compare the ability of Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) in detecting the tumor.Material and Methods: Forty-four lesions of osteoid osteoma in children and adolescents were retrospectively analyzed using hospital files and institutional picture archiving and communication systems. Age, gender, treatment choices, modality used for diagnosis, tumor site, location within the bone, presence of calcified nidus, perilesional reactive sclerosis, cortical thickening, perilesional bone marrow edema, and joint effusion were documented.Results: Twenty-nine males and 15 females with a median age of 15.00 (range: 4-18 years) were included in the study. All of the lesions were located in the appendicular skeleton. No axial skeletal involvement was found. Forty out of 44 lesions were located in the long bones. One was localized in the patella, 2 of them in the talus and 1 in the calcaneus. Thirty-four out of forty long bone involvement were in lower extremities. Six cases were located intraarticularly and joint effusion was seen in the involved joint. CT was available in all patients and MRI was available in 18 patients. CT was the first choice of cross-sectional imaging modality in 35 patients, and MRI was the first choice in 9 patients. MRI was successful in only 56% of the cases in characterizing osteoid osteomas. CT was accurate to characterize all osteoid osteoma lesions.Conclusion: CT is more successful than MRI in detecting and characterizing osteoid osteomas. Intraarticular osteoid osteoma must be kept in mind in differential diagnosis, evaluating joint synovitis in children and adolescents.

Intra-articular Osteoid Osteoma of the Olecranon Fossa

Osteoid osteomas are benign primary bone lesions characterized by a central nidus with surrounding reactive sclerosis, classically presenting as worsening nocturnal pain relieved by non-steroidal anti-inflammatory medications (NSAIDs). These most commonly occur in intracortical bone and the diaphysis of long bones. As a rare entity, intra-articular osteoid osteomas present unusually, often resulting in a delayed or incorrect diagnosis. We present a case of an intra-articular osteoid osteoma, emphasizing the importance of MRI in aiding diagnosis in this atypical location.

Comparison of arthroscopy versus percutaneous radiofrequency thermal ablation for the management of intra- and juxta-articular elbow osteoid osteoma: case series and a literature review

BackgroundToday, intra-articular and juxta-articular osteoid osteomas are treated with arthroscopy and radiofrequency thermal ablation. However, for the case of an elbow joint, arguments are made for the use of a minimally invasive technique to be the optimal choice. This study aims to analyse our experiences of arthroscopically treated elbow osteoid osteomas and to compare it with the published results of both techniques.MethodsThe retrospective study analyses the patients who underwent elbow arthroscopy ablation of an elbow osteoid osteoma at a single institution from January 2014 until March 2020. Clinical and diagnostic features, success and treatment failure rates, complications and tumour recurrence rates were all compared to 13 studies of intra-articular elbow osteoid osteoma arthroscopic ablation and 15 studies involving radiofrequency thermal ablation of intra-articular osteoid osteoma within different joints.ResultsFour males and two females, with a mean age of 19.3 years, were encompassed. All the patients had immediate postoperative pain relief and improved range of motion. No tumour recurrences were observed during a median of 21.7 months. The literature review yielded 86.4% success rate, 68.2% successful biopsies, one minor complication and no recurrences following the arthroscopic ablation of an elbow osteoid osteoma; while radiofrequency thermal ablation of an intra-articular elbow osteoid osteoma yielded 96.3% success rate, 33.3% successful biopsies, no complications and 3.7% recurrence rate.ConclusionsOur results are consistent with the published literature proving that arthroscopic ablation is an efficient method with low treatment failure rates and no recurrences in treating intra- and juxta-articular elbow osteoid osteomas. Advantages of arthroscopic ablation stem from the ability to visualise and safely deal with the lesion and the joint’s reactive changes resulting in high biopsy rates, no recurrences and better postoperative elbow’s range of motion. Still, the technique selection should be personalised considering the medical expertise of every institution.

Arthroscopic removal as an effective treatment option for intra-articular osteoid osteoma of the knee.

BACKGROUNDIntra-articular osteoid osteoma (iaOO) can be found in 5.2% up to 10% of cases. They may cause non-specific symptoms, mimicking degenerative or traumatic pathologies. If iaOO is left untreated, it may lead to severe muscle atrophy, tenderness, swelling, and limited range of motion. Therefore, surgical treatment is recommended. The main goal of surgical treatment is complete removal or destruction of iaOO.AIMTo evaluate the efficiency of arthroscopic removal of iaOO of the knee in our cases and cases available in the literature.METHODSAnalysis of available hospital records of four patients with iaOO of the knee treated by arthroscopic removal from August 2005 to December 2015 at our Department was performed. All patients had a diagnosis of iaOO confirmed by histopathologic analysis. Additional literature review of cases of iaOO of the knee available on PubMed and Google Scholar was made. All cases of iaOO of the knee treated by arthroscopic or arthroscopically assisted removal were reviewed in order to further evaluate the efficiency of the method.RESULTSThe average age of patients included in our study was 23.2 (range 16-37) years. The average duration of the symptoms prior to surgery was 14.2 (range 6-24) months. All of the patients had persistent knee pain. Three patients reported worsening of pain during the night, while two reported worsening of pain during activity. Three patients reported alleviation of pain on non-steroidal anti-inflammatory drugs (NSAIDs), while one patient reported partial alleviation of pain on NSAIDs. No intraoperative complications were noted, and the postoperative period was uneventful in all patients. The patients reported immediate pain relief in the postoperative period. No recurrence of the disease was noted in any of the patients during the follow-up period of at least 24 mo. The literature review revealed 14 cases with an average age of 27.6 (range 16-48) years and onset of symptoms 27.7 (range 6-108) months prior to surgery, with recurrence of the disease noted in a single case.CONCLUSIONArthroscopic removal is an efficient treatment method that allows excision of iaOO that is neither insufficient nor excessive, thus avoiding disease recurrence while obtaining adequate material for histopathologic analysis.

Arthroscopic Excision of Intra-Articular Osteoid Osteoma of the Hip: A Case Series

1) To identify the clinical features of intra-articular osteoid osteoma (OO) of hip, 2) to evaluate the clinical effect of arthroscopic excision for intra-articular OO.3) to summarize the characteristics of revision cases of hip OO and the revision surgery under arthroscopy on these cases. We retrospectively reviewed the data of 25 patients who underwent arthroscopic excision of hip OO. The case series included 10 patients who underwent revision surgery. Lesion location, presenting symptoms, and symptom duration were analyzed; postoperative improvement was assessed using the modified Harris Hip Score (mHHS) and international Hip Outcomes Tool (iHot-12) scores. We examined the reasons for need of revision surgery and the characteristics of OO progression after the first surgery. The most common presenting symptom was groin pain that was relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). Varying degree of limitation of range of motion (ROM) was present in all patients. The osteosclerosis around the tumor nest in CT scan is a characteristic radiographic feature in this disease. However, the classic radiographic feature was only apparent on plain x-rays in 2 out of 25 patients. As a kind of efficient radiological method, MRI can help in distinguishing OO from femoroacetabular impingement (FAI), as the latter is characterized by a large effusion and bone marrow edema at the atypical site of impingement. For the patients who had only one arthroscopic resection, the mean mHHS and iHot-12 scores were 70.30 ± 9.06 (51-86) and 75.07 ± 7.69 (57-88), respectively. At last follow-up, the mean scores were 98.30 ± 2.15 (94-100) and 97.76 ± 2.04 (94-100). respectively (Table 3). For revision cases, the mean mHHS and iHot-12 scores were 68.55 ± 3.77 (60-72) and 67.88 ± 5.39 (56-76), respectively. At last follow-up, the mean scores were 97.11 ± 2.47 (94-100) and 95.22 ± 1.78 (94-100). respectively. In the present study, 24 of 25 patient (96%) reached the MCID of mHHS and 21 of 22 patients (95.2%) reached the MCID of iHot-12. Among the revision patients, the most common misdiagnosis at first surgery was FAI. Another feature is that a wrong diagnosis or incomplete intra-articular OO resection can stimulate the tumor and cause an inflammatory reaction and rapidly progressive OA, necessitating prompt revision surgery for complete removal. The degree of joint degeneration was related to the time since the first operation. OO of the hip joint typically presents with pain and limited joint activity. Misdiagnosis as FAI or synovitis is common and so that patient who has limit ROM, night pain and can be relieved by NASIDs should be suspected OO, and more advanced radiological evaluation, such as CT scan, should be performed. Arthroscopic excision appears to be an effective method for the treatment of OO of the hip joint. IV, case series.

A CT-free protocol to treat osteoid osteoma of the hip region in childhood and adolescence by percutaneous drilling and by hip arthroscopy.

It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment.In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography. 10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases. All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV). Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

CT-guided radiofrequency ablation of osteoid osteoma: established concepts and new ideas.

Osteoid osteoma is a painful benign bone tumour of children and young adults with characteristic clinico-radiological features depending upon the location of the lesion. Intraoperative visualisation of the nidus is difficult and therefore curative surgery is often associated with excessive bone removal, significant perioperative morbidity and potential need of bone grafting procedures. With advancement in cross-sectional imaging and radiofrequency ablation (RFA) technology, CT-guided RFA has emerged as the treatment of choice for the osteoid osteoma. This procedure involves accurate cannulation of the nidus and subsequent thermocoagulation-induced necrosis.Multidisciplinary management approach is the standard of care for patients with osteoid osteoma. Appropriate patient selection, identification of imaging pitfalls, pre-anaesthetic evaluation and a protocol-based interventional approach are the cornerstone for a favourable outcome. Comprehensive patient preparation with proper patient position and insulation is important to prevent complications. Use of spinal needle-guided placement of introducer needle, namely, "rail-road technique" is associated with fewer needle trajectory modifications, reduced radiation dose and patient morbidity and less intervention time. Certain other procedural modifications are employed in special situations, for example, intra-articular osteoid osteoma and osteoid osteoma of the subcutaneous bone in order to reduce complications. Treatment follow-up generally includes radiographic assessment and evaluation of pain score. Dynamic contrast-enhanced MRI has been recently found useful for demonstrating post-RFA healing.

Secondary radiological findings of osteoid osteoma as muscular atrophy and synovitis in paediatric and adult patients

PurposeDiagnosis of osteoid osteoma may be delayed if secondary radiological findings such as muscle atrophy, oedema in peripheric soft tissue and bone marrow, joint effusion, or synovitis are more severe than the lesion itself. In this article, the purpose was to demonstrate secondary radiological findings of osteoid osteoma in both paediatric and adult patients. This study is one of the very few with such a large case series.Material and methodsRadiological images of 152 patients were reviewed retrospectively. Peri-nidus sclerosis, periosteal reactive bone formation, bone marrow and soft tissue oedema, presence of synovial effusion, muscular atrophy in the affected extremity, osteopaenia, and posture deterioration were noted.ResultsMost of the lesions (87.5%) were localised in lower extremity bones. Among all the patients, 56% had extra-articular (65% in paediatric patients) and 44% had intraarticular (69% in paediatric patients) osteoid-osteoma. In 44% of the patients, synovial effusion was presented. In 89.4% of these, osteoid osteoma was localised in the joint. Of the 97 patients who had osteoid osteoma in lower extremities or pelvic bones, 73% had muscular atrophy. In 6% of them muscular atrophy was severe, and they had posture-gait disorder with accompanying osteopaenia. In 48% of the patients, there was reactive periosteal bone formation around the nidus.ConclusionsSecondary radiological findings, such as muscular atrophy, synovitis, posture-gait deterioration, and reactive bone formation in a patient with continuous pain that is relieved by anti-inflammatory drugs may point to an osteoid osteoma.