Osteoporotic Vertebral Deformity: Radiological Appearances and Their Association With a History of Trauma and the Risk of Further Fragility Fracture.

I read the recent article by Lentle et al with great interest. This article is significant in that it clarified that morphometric vertebral deformity (VD) is not associated with increased further osteoporotic fracture risk. Although these morphometric VDs have long been considered not to be true fracture by some authors, solid evidence had been lacking. On the other hand, these morphometric VDs have been over-called as osteoporotic vertebral fracture (OVF) by other investigators. In our experience, consistent with other publications and also that shown in Figure 1 of Lentle et al’s work, morphometric VDs often involve multiple adjacent vertebrae appearing similarly deformed, while fractural deformities tend more often to be singular appearing as a distinct loss of expected shape (as compared to adjacent vertebrae). In our interpretation of spine radiographs, morphometric VDs are generally regarded as degenerative changes and ignored for the purposes of osteoporotic risk assessment. Lentle et al classified suspected fractures into morphometric VD and mABQ (modified algorithm–based qualitative)-VDs which are VDs coexisting with endplate and/or cortical fractures (ECF). We reported that there is another category of radiological VDs which do not have ECF. These radiological VDs have a high risk of developing ECF and thus can turn into mABQVD during follow-up. In our MsOS(Hong Kong) study for elderly women, of radiological VDs with 25% to 33% measured height loss at baseline, 74% of them turned to fractures which meet mABQ criteria during 4 years’ follow-up, and the progression of radiological VD severity is associated with an increasing probability of meeting mABQ-VD criteria during follow-up. Lentle et al argue against the diagnosis of wedge-shaped OVF. Vertebral fracture can occur among osteoporotic patients in 3 possible scenarios: (1) with minimal energy trauma which is often not noted or not recalled, (2) with distinct low-energy trauma which is defined as forces equivalent to a fall from a standing height or less, and (3) with high-energy trauma (these being much less common and not, by definition, OVF). Osteoporotic vertebral fractures in epidemiological studies and clinical screenings commonly appear as concave deformities which more often associated with minimal trauma. However, OVFs have varied appearances, and at least a portion may be similar to traumatic fracture and be wedge-shaped particularly when a distinct low-energy trauma event had been involved. Sugita et al classified vertebral fracture in osteoporotic patients into 5 types: swelled-front, bow-shaped, projecting, concave, and dented, with the first 3 types having a poorer prognosis with a higher incidence of late collapse and showing an intravertebral cleft during follow-up. In their cases, swelled-front-type, bow-shaped-type, and projecting-type fractures accounted for 58.3% of total fractures, while the concave type counted for 32.1%. Indeed, Sugita et al noted that concavetype fractures mostly occurred without specific trauma, whereas swelled-front-type fractures resulted from recognizable accidents. Since concave OVFs are more often found without a history of notable trauma, they are likely to be associated with even more compromised bone strength and higher future fracture risk than those wedge-shaped OVFs.