Case of Multiple Insufficiency Fractures in a Patient with Rheumatoid
Friel R, Gardiner PV, Armstrong DJ, McDonald S, O’Longain D
Altnagelvin Hospital (Western Health and Social Care Trust) Northern Ireland
A 64 year old lady with a 15 year history of RF +, ACPA -ve rheumatoid arthritis treated with Methotrexate and Sulfasalazine presented with increasing pain in her feet and knees with tenderness in her heels and MTPJs with normal CRP/ESR.
Initially had x-rays of both feet and knees which showed abnormality in left calcaneus. She then had updated ankle x-rays (fig1) which were suspicious for calcaneum stress fractures. Following this she had MRI of both ankles and bone scan confirming multiple insufficiency fractures bilaterally involving calcaneus, proximal and distal tibia and fibula, and midfoot bones (fig2,3).
DEXA results T-score hip-0.7 and spine -1.5. VitD 46, CCa 2.21, ALP 78, prolactin normal, ANA -ve, TFTs normal. Seen by orthopaedics and treated with air cast boots. Reviewed at osteoporosis clinic. Crosslaps P1NP and Beta-CTX checked.
Treated initially with 3 months of teriparatide with symptomatic improvement. Follow-up MRI indicates some improvement to initial fractures and also some stress fractures not previously identified. Further treatment with Zolendronic acid subsequently arranged with a view to repeat MRI in 3-6 months.
Lower limb stress fractures in rheumatoid patients are not uncommon. This may be related to periarticular osteopenia, abnormal foot stress due to persistent synovitis and limb deformity, steroid use and methotrexate osteopathy. Other risk factors for fracture including osteomalacia and generalised osteoporosis were not present in our patient. Multiple stress fractures are likely underdiagnosed as feet are not included in DAS28 and are difficult to identify on plain x-ray and may need MRI or bone scanning to confirm.
Stress fractures should be considered in rheumatoid patients presenting with sudden/persistent pain in the lower limb.