P136 Methotrexate osteopathy - clinical and radiological characteristics in a case series of twenty-one patients

Abstract

Abstract Background/Aims Methotrexate osteopathy was originally described in the 1980s as a combination of bone pain, osteoporosis and insufficiency fractures in paediatric patients receiving high-dose methotrexate for leukaemia. Since then, cases of insufficiency fractures in patients on long-term, low-dose methotrexate for rheumatic disease have been sporadically reported as methotrexate osteopathy. This case series aims to characterise the clinical and radiological features of this poorly defined condition. Methods Patients were identified by searching the MRI reports of rheumatology patients in NHS Lothian for the term ‘insufficiency fracture’ and asking consultant rheumatologists to submit cases where methotrexate osteopathy was suspected. Patient demographics, clinical and radiological features were analysed. Results We identified 21 patients with insufficiency fractures taking long-term methotrexate. The mean age at presentation with methotrexate osteopathy was 66.9± 9.5 years. 20 of the patients (95%) were women. 18 of the patients (86%) had rheumatoid arthritis. The average BMI of the cohort was 25.7± 5.4. The average duration of methotrexate use was 7.5± 4.5 years. The most common sites of fracture were the calcaneus (12 patients, 57%) and the metaphysis of the distal tibia (13 patients, 62%). Other frequent fracture sites included the proximal tibia, talus, and distal femur. 13 of the patients (62%) had more than one fracture and 12 (57%) had bilateral fractures. 12 of the patients (57%) required an MRI to identify the fracture and there was an average delay of 4.8± 4.0 months between the initial presenting symptoms and imaging confirming a fracture. Osteoporosis was found in 12 of the 15 patients (80%) who had a DEXA scan, with an average T-score of -2.23± 1.14 for the spine and -2.64± 0.78 for the femoral neck. 14 of the 21 (66.6%) patients received antiresorptive osteoporosis treatment. Only 2 of the patients (9.5%) were on long-term steroids at the time of diagnosis. Conclusion Methotrexate osteopathy should be suspected in patients on long-term methotrexate with unexplained pain in the lower limbs. There are often multiple, bilateral fractures which most commonly affect the distal tibia and calcaneus. Fractures may not be visible on X-ray, and pain from the fractures may mimic synovitis, causing a delay in diagnosis. A high index of suspicion and detailed imaging with MRI is often required to identify insufficiency fractures associated with methotrexate osteopathy. If the condition is suspected, a detailed fracture risk assessment should be organised, and the cessation of methotrexate considered. Disclosure A.T. Merriman: None. J. Foley: None. J. Golla: None. E. McRorie: None. B. Hauser: None.