"The classic clinical presentation is a history of non-traumatic joint pain, which peaks at 2 months and then resolves, with the subsequent presentation of pain in another joint between 2-11 years later 1,2. They can also present with an insufficiency fracture."
"The aetiology is unclear 1,3 with the relationship to transient osteoporosis of the hip, bone marrow oedema syndrome and osteonecrosis debated 2. Joint involvement is variable although most commonly is proximal-to-distal; more than one joint can be involved at once and intra-articular migration (e.g. one femoral condyle then another) can also occur 1."