A 41-year-old man presented with a 2 weeks history of progressive right ankle pain and inability to bear weight. There was no medical history of trauma, infection or predisposing factors for osteonecrosis. Physical examination revealed mild tenderness along the tarsal bones and slight impairment in full range of ankle movement.
Plain radiographs were unremarkable. MR imaging demonstrated bone marrow oedema in the talus, navicular and cuneiform bones along with a small joint effusion (Fig. 1,2). The contrast enhanced fat suppressed T1-w MR images showed intense enhancement in the above mentioned oedematous areas as well as slight synovial enhancement (Fig. 3). The imaging findings together with the clinical presentation and the medical history suggested the diagnosis of transient bone marrow oedema syndrome. The patient was treated conservatively with oral analgesics and instructions for weight bearing protection. Three months after initial presentation and following complete resolution of clinical symptoms, the patient presented with a new pain syndrome involving the ipsilateral knee joint. MR imaging revealed bone marrow oedema in the medial femoral condyle (Fig. 4). An additional MR imaging study of the ankle and foot showed almost complete resolution of findings with some residual marrow oedema in a cuneiform bone (Fig. 5). Based on MR imaging studies, the diagnosis of regional migratory osteoporosis (RMO) was suggested. The patient followed the same treatment scheme as for the original presentation. The diagnosis of RMO was established after complete resolution of clinical symptoms and patient's full recovery 6 months post initial presentation.
RMO was first described by Duncan et al. and is a bone disorder characterised by migrating arthralgia to other joints or within the same joint. Patients usually present with arthralgia of a single lower appendicular skeleton joint with no remote history of trauma, predisposing factors for osteonecrosis, infection and neoplasia. Clinical findings at physical examination are usually mild and include tenderness, joint effusion and swelling with no significant restriction in the range of joint motion. However the clinical symptoms and the MR imaging findings are more profound than the clinical examination. Plain radiography is insensitive initially and can show localized osteopenia in the juxtarticular bone if taken 3-6 weeks after the onset of the symptoms. Bone scintigraphy has high sensitivity in demonstrating increased uptake of radionuclide tracer in the involved bone but lacks specificity. Thus MR imaging is the imaging study of choice for initial patient evaluation as well as follow up of improvement or investigation of future joint attacks. Bone marrow oedema with indistinct borders, exhibiting decreased signal intensity on T1-w and increased signal intensity on STIR and fat suppressed T2-w images is the characteristic imaging finding and along with the patient's history and the migrating nature of the disease can suggest the diagnosis. According to the literature, the typical patterns of migration are either sequential from a proximal to a distal joint (e.g. hip to knee and then to ankle) or secondary, symmetrical involvement of the contralateral, same anatomical joint (e.g. hip to hip, knee to knee etc). Migration within the same joint (e.g. from the lateral femoral condyle to the medial one) is another typical pattern of the disease course. In our case it must be pointed out that a reverse pattern of distribution from a peripheral lower appendicular skeleton joint towards a more central weight bearing joint occured. The repeated knee arthralgia occurred 3 months after the initial presentation, in keeping with the reported observation that the time interval between the initial joint attack and the second joint involvement usually occurs within 2–12 months period. The aetiology of RMO is still under investigation. Theories of a combination of systemic osteoporosis with minor traumatic events and embiomechanical changes in local joint loading seem to explain enough of the disease course, but further studies are needed to investigate the exact pathophysiology, which may affect the treatment planning.
Regional migratory osteoporosis
Based on the provided MRI images and the patient’s clinical symptoms in the right ankle region, the following findings are observed:
Combining the patient’s age, clinical symptoms, and MRI findings, the most likely diagnosis is
Regional Migratory Osteoporosis (RMO).
The characteristic features include the appearance of bone marrow edema and pain in one joint or a localized region, followed by migration to another joint after several months. The patient initially presented with ankle symptoms and later developed knee joint bone marrow edema, consistent with the typical clinical course of RMO. Ongoing imaging follow-up can further confirm the disease progression and assess the treatment response.
Treatment Strategy:
Rehabilitation and Exercise Prescription (FITT-VP Principle):
During rehabilitation, closely monitor pain and swelling. If significant discomfort occurs, adjust the exercise intensity or pause training and seek specialist advice.
This report is a reference analysis based on currently available information and does not replace an in-person consultation or professional medical advice. If you experience any discomfort or have questions, please seek medical attention promptly for an accurate diagnosis and individualized treatment plan.
Regional migratory osteoporosis
