Clinical features of methotrexate osteopathy in rheumatic musculoskeletal disease: A systematic review

There is growing evidence from case reports that methotrexate (MTX) therapy may impair bone metabolism in individual patients leading to low bone mass, atraumatic stress fractures and immobilizing bone pain - referred to as 'MTX osteopathy'. However, the clinical features, risk factors and treatment options of this condition are still elusive.

A systematic review was conducted according to PRISMA guidelines. Two databases (MEDLINE, Embase) were searched for published cases of MTX osteopathy in patients with rheumatic musculoskeletal diseases (RMD). Data from the included publications were extracted and descriptive statistical analysis was performed.

We report data from 32 studies describing 80 adult RMD patients with stress fractures in MTX osteopathy. Most cases were found in elderly women with longstanding RMD, especially rheumatoid arthritis (72.5%). MTX osteopathy commonly presented as stress fracture of the distal tibia (51.3%), calcaneus (35.0%) and proximal tibia (27.5%), mimicking arthritis in some cases. Although a majority of the patients met the densitometric criteria for osteoporosis (58.1%), typical osteoporotic fractures (e.g., vertebral fractures) were rarely seen. Patients frequently suffered from bilateral (55.0%), multiple (71.3%) and recurrent fractures (25.0%). Fractures mainly occurred at low to moderate doses of MTX therapy (45.0%). It should be noted that half (48.8%) of the patients did not receive systemic steroid therapy for at least 3 years.

Low-dose MTX therapy in RMD may result in atraumatic stress fractures of the lower extremity that can mimic arthritis. MTX osteopathy is characterized by a pathognomonic type of stress fractures with band- or meander-shaped appearance along the growth plate.