A 20 year old footballer presents with generalized ankle and foot pain following return to function after a period of disuse for treatment of navicular stress fracture.
MRI demonstrates diffuse patchy osseous high T2 signal throughout the involved foot with relative paucity of soft tissue oedema. Focal stress injuries were present at the diaphyses of 3rd and 4th metatarsals, with associated periosteal reaction. Screw fixation of the previous navicular fracture is noted.
Disuse osteoporosis refers to the process by which there is loss of bone mass after prolonged immobilization – such as that required to heal some fractures. The process is thought to be related to loss of mechanical stress leading to altered osteoclast and osteoblast activity. The changes are often visible as osteopaenia on standard radiographs, though this typically taking at least 8 weeks to develop. The osteopaenic bone is weaker and more prone to fracture and stress injuries.
Disuse osteopaenia is asymptomatic unless a secondary fracture has occurred. At this point the patient will describe pain and focal tenderness, particularly with load bearing.
Disuse osteoporosis following fracture treatment is often unavoidable as the fracture requires immoblisation to heal. In some cases, however, medication may be used to help reduce the severity of the condition (eg bisphosphonates, calcitonin, vitamin K2).
Following return to function, the bone stock will recover – though the time this takes is generally much longer than the time for the bone loss to occur in the first place. The recovery can be helped by early ambulation and graded rehabilitation. If the return to use is too early or too heavy, however, the patient is at risk for overuse injuries such as those demonstrated here.
Abreu, M et al. Bone Marrow MR Imaging Findings in Disuse Osteoporosis. Skeletal Radiol. 2011 40:571-575.
Takata, S. Yasui, N. Disuse Osteoporosis. J Med Invest. 2001, August; 48:147-156.
Nardo, L et al. Bone Marrow Changes Related to Disuse. Eur Radiol. 2013, Dec; 23(12): 3422-3431