Transient osteoporosis

Last revised by Joshua Yap on 25 May 2023

Transient osteoporosis is a self-limited condition characterized by reparative bone remodeling, which can affect all weight-bearing joints, being most common in the femoral head (see transient osteoporosis of the hip). 

Typical symptoms are pain with sudden onset in the affected joint, gait disturbance, and limited range of motion. Regional migratory osteoporosis is a specific form of the disorder, in which the transient osteoporosis migrates between joints 1,2

In only 20% of cases, osteopenia becomes visible after a delay of 4-8 weeks following symptom onset 1.

MRI is the modality of choice. Features include:

  • high T2/PDFS signal similar to bone marrow edema without a necrotic core 1

  • subchondral fracture lines: found in up to 49% of cases 3

  • sparing sign (sparing of the medial bone marrow of the femoral head by bone marrow edema): found in 88% of patients, disappears towards the later stages of the disease 3

On bone scans the affected area shows increased radiotracer uptake (cf. osteonecrosis which demonstrates focal photopenia) 1

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