Dens fractures in the elderly continue to haunt modern health care. These injuries are especially prevalent in this more frail patient population; they can present following seemingly trivial trauma; and, with the dramatic growth of the geriatric sector of our general population, it is reasonable to assume that the incidence of these injuries will increase. Moreover, dens fractures in the elderly are extremely challenging to treat, and are associated with a high incidence of morbidity and mortality regardless of whether operative or nonoperative treatment is used. Although certain patient characteristics (age, female sex, osteoporosis, and senility) have been linked to dens fractures in general, their association with specific upper cervical spine anatomic abnormalities has yet to be determined.

Shinseki et al. investigated potential associations between advanced degenerative changes in the atlanto-dens joint and dens fractures in the elderly. They are not the first to do so. In 1942, Olssondescribed arthrosis of the median facet of the atlas and the dens process, which he reported could cause pain and limit neck motion. Almost fifty years later, Genez touted thin-section, high-resolution computed tomography (CT) with reconstruction as the best way to depict atlanto-dens osteoarthritis and recognized that the physiological abnormalities associated with these changes had yet to be described. Several years later, in a consecutive series of 500 patients who had undergone CT to rule out brain or paranasal sinus disorders, Zapletal et al.determined that degenerative aberrations of the atlanto-dens joint are present in a substantial percentage of individuals and these changes demonstrate a linear progression with increasing age.

However, it was Lakshmanan et al.who first suggested a potential relationship between advanced degenerative changes in the atlanto-dens joint and dens fractures in the elderly. These authors reviewed CT scans of twenty-three patients with a dens fracture who were greater than seventy years of age. In each patient, the extent of degenerative changes was analyzed for all five of the joints involved in upper cervical spine motion (the two atlanto-occipital joints, the two lateral atlanto-axial joints, and the median atlanto-dens joint). In this cohort, atlanto-occipital joint changes were noted in eight patients and lateral atlanto-axial joint degeneration was also noted in eight patients; however, twenty patients demonstrated atlanto-dens degeneration, and all twenty-three patients had diffuse degeneration of the facet joints in the subaxial cervical spine. The authors suggested that there was a strong relationship between upper cervical spine osteoarthritis and dens fractures in the elderly that warranted further exploration.

In the present article, Shinseki et al. make a compelling case for a possible relationship between the nature and extent of the age-related degenerative changes that occur at the atlanto-dens joint and dens fractures in the elderly. In a single-institution series of trauma patients fifty-five years of age or older who had cervical CT, they compared the atlanto-dens degenerative changes in a group of fifty-six patients with a dens fracture with a randomly selected control group of 736 patients without a dens fracture. They specifically analyzed three degenerative parameters: intraosseous cysts, synovitis, and joint space narrowing.

The prevalence of intraosseous cysts and synovitis in the 736 patients without a dens fracture was 16.4% (121 patients) and 4.2% (thirty-one patients), respectively. The prevalence of cysts and synovitis rose significantly as age increased from fifty-five years to greater than eighty years (from 11.2% to 24.6% for cysts, and from 1.5% to 9.5% for synovitis), and both of these increases were significant (p < 0.0001). A cyst was detected in thirty-six (64.3%) of the fifty-six patients with a dens fracture, and synovitis was detected in fourteen (25.0%); the rates of both cysts and synovitis in the dens fracture group were both significantly higher than those in the control group (p < 0.0001). Atlanto-dens interval narrowing was present in twenty-eight (50%) of the patients with a dens fracture and 330 (44.8%) of the patients in the control group. Multivariate analysis of age, cysts, synovitis, and joint space narrowing demonstrated that patients with a dens fracture were almost eight times more likely to have a cyst and five times more likely to have synovitis.