Complex regional pain syndrome and bone marrow oedema syndrome: family ties potentially closer than expected

Abstract

Complex regional pain syndrome (CRPS) and bone marrow edema syndrome (BMES) are two rare conditions that are still being discussed. They are generally considered as two distinct entities, yet they share similarities such as a homogeneous bone marrow edema is also often found in the early phase of CRPS. We present the case of a 41-year-old man with CRPS after a foot fracture followed by the development of painful BMES of the ipsilateral knee and hip a few weeks later. The search for another pathology was negative. After pamidronate infusions, the evolution was spectacular: the disappearance of hip pain at 1 month and more than 50% reduction in knee and foot pain at 2 months. At final follow-up (1 year), the patient was asymptomatic. This case reinforces the idea of a possible link between CRPS and BMES probably through similar trabecular bone involvement. Imaging remains useful in diagnosis of CRPS.

Keywords: musculoskeletal and joint disorders; musculoskeletal syndromes; pain; rehabilitation medicine.

Figure 1

The bone scintigraphy, late-bone phase, showing uptake of the tracers to the three sites concerned: hip, knee and foot.

Figure 2

Upper part: standard X-ray showing diffuse osteopenia of the ankle, knee and hip. Lower part: the MRI showed a diffuse, homogeneous T2 hypersignal, without clear delimitation or cartilage damage, of the ankle and tarsal bones, femoral condyles, and head and neck of the femur.

Figure 3

Evolution of the Brief Pain Inventory interference (blue) and severity (red) subscales over time.