Citation, DOI & article data
Bone infarction is a term used to refer to osteonecrosis within the metaphysis or diaphysis of a bone. Necrosis is a type of cell death due to irreversible cell injury, which can be recognized microscopically by alterations in the cytoplasm (becomes eosinophilic) and in the nucleus (swelling, pyknosis, karyorrhexis, karyolysis). Bone infarction is a result of ischemia, which can lead to destruction of bony architecture, pain, and loss of function 1. Bone infarctions have numerous causes and have fairly distinctive imaging features on conventional radiography, CT and MRI.
Medullary infarct is a fairly equivalent term to bone infarct but is less frequently used. The term may also be applied to some cases involving the epiphysis, but should not be used to describe subchondral osteonecrosis, in which case avascular necrosis (AVN) is preferred.
Whilst serpiginous sclerosis is a classic feature, radiographic findings can vary. In cases where radiographic findings are inconclusive, MRI is usually definitive 11.
Infarction begins when blood supply to a section of bone is interrupted. Once an infarct is established, a central necrotic core develops which is surrounded by a hyperemic ischemic zone. With time collagen granulation tissue becomes layered around the necrotic core. The demarcation between the normal surrounding marrow, the ischemic zone, and the necrotic core accounts for many of the radiographic appearances of bone infarcts.
Due to the smaller diameter of terminal vessels and the lack of collateral vascularization, convex articular surfaces are affected the most. Impairment of blood flow may be caused by vascular compression, trauma, vessel occlusion by nitrogen bubbles (caisson disease) or rigid sickle cells (sickle cell anemia). The mechanism of ischemia and necrosis in other non-traumatic osteonecroses is not yet fully understood 1.
Rarely, bone infarcts can undergo cystic degeneration or liquefaction as bone marrow necroses 4.
General causes of osteonecrosis include:
- caisson disease
- hemoglobinopathies, e.g. sickle cell disease 2
- connective tissue disorders
- renal transplantation
- corticosteroid excess (both endogenous and exogenous)
- Gaucher disease
- Behçet disease 9
The above list applies to both bone infarct and subchondral avascular necrosis. Some conditions are more likely to lead to one over the other: sickle cell disease and Gaucher disease very commonly cause bone infarcts and less commonly cause subchondral avascular necrosis.
General features include:
- serpiginous border
- often symmetrical and/or multiple
There is a significant delay between the infarct onset and development of radiographic signs. Classic description is of medullary lesion of sheet-like central lucency surrounded by shell-like sclerosis with a serpiginous border. Discrete calcification and periostitis may also be seen.
CT features are similar to those seen on plain film. Again, onset of the infarct frequently precedes radiographic features by several months 12. The typical appearance is regions of patchy or serpiginous sclerosis surrounding a central metadiaphyseal lucency.
An important feature in differentiating bone infarct from other medullary lesions is that the central signal usually remains that of normal marrow. The marrow is not replaced.
- serpiginous peripheral low signal due to granulation tissue and, to a lesser extent, sclerosis
- peripheral rim may enhance post gadolinium
- central signal usually that of marrow
- acute infarct may show ill-defined non-specific area of high signal
- double-line sign: hyperintense inner ring of granulation tissue and a hypointense outer ring of sclerosis
- absence of a double-line sign does not exclude bone infarct
- central signal usually that of marrow
- will also show double-line
- edema obscured by susceptibility
- no uptake (cold spot/photopenia) where blood supply absent
- mildly increased uptake at periphery during the acute phase
Treatment and prognosis
- Bone infarcts may occasionally dedifferentiate to a tumor such as 5-7:
General imaging considerations include:
- 1. Fondi C & Franchi A. Definition of Bone Necrosis by the Pathologist. Clin Cases Miner Bone Metab. 2007;4(1):21-6. PMC2781178 - Pubmed
- 2. Saito N, Nadgir R, Flower E, Sakai O. Clinical and Radiologic Manifestations of Sickle Cell Disease in the Head and Neck. Radiographics. 2010;30(4):1021-34. doi:10.1148/rg.304095171 - Pubmed
- 3. Robert Branstetter (Publisher), Salvador Beltran (Drawings). Orthopaedics. (2004) ISBN: 9780721629209 - Google Books
- 4. Hermann G, Singson R, Bromley M, Klein M, Springfield D, Abdelwahab I. Cystic Degeneration of Medullary Bone Infarction Evaluated with Magnetic Resonance Imaging Correlated with Pathologic Examination. Can Assoc Radiol J. 2004;55(5):321-5. - Pubmed
- 5. Abdelwahab I, Klein M, Hermann G, Springfield D. Angiosarcomas Associated with Bone Infarcts. Skeletal Radiol. 1998;27(10):546-51. doi:10.1007/s002560050435 - Pubmed
- 6. Desai P, Perino G, Present D, Steiner G. Sarcoma in Association with Bone Infarcts. Report of Five Cases. Arch Pathol Lab Med. 1996;120(5):482-9. - Pubmed
- 7. Torres F & Kyriakos M. Bone Infarct-Associated Osteosarcoma. Cancer. 1992;70(10):2418-30. doi:10.1002/1097-0142(19921115)70:10<2418::aid-cncr2820701007>3.0.co;2-e - Pubmed
- 8. Domson G, Shahlaee A, Reith J, Bush C, Gibbs C. Infarct-Associated Bone Sarcomas. Clin Orthop Relat Res. 2009;467(7):1820-5. doi:10.1007/s11999-009-0744-7 - Pubmed
- 9. Oktayoglu P, Cevik F, Tahtasiz M et al. Bilateral Knee Pain Associated with Bone Infarction in a Patient with Behcet's Disease. Case Rep Rheumatol. 2012;2012:539310. doi:10.1155/2012/539310 - Pubmed
- 10. Blacksin M, Finzel K, Benevenia J. Osteomyelitis Originating in and Around Bone Infarcts: Giant Sequestrum Phenomena. AJR Am J Roentgenol. 2001;176(2):387-91. doi:10.2214/ajr.176.2.1760387 - Pubmed
- 11. Munk P, Helms C, Holt R. Immature Bone Infarcts: Findings on Plain Radiographs and MR Scans. AJR Am J Roentgenol. 1989;152(3):547-9. doi:10.2214/ajr.152.3.547 - Pubmed
- 12. Barakat E, Guischer N, Houssiau F, Lecouvet F. The "Birth of Death": MRI Step-By-Step Reveals the Early Appearance of a Bone Marrow Infarct. Acta Radiol Open. 2019;8(3):2058460119834691. doi:10.1177/2058460119834691 - Pubmed