Methods: We analyzed data from 45 patients with T2OFs and 79 with sub-axial fractures, all aged ≥75 years. Hounsfield unit (HU) values at C2–C4, the prevalence of ankylosis, and degenerative changes were assessed via computed tomography. We performed sex-specific analysis and logistic regression to identify factors associated with T2OF. In addition, we used the Swedish Fracture Registry (SFR) to analyze the prevalence of spinal ankylosis among Swedish patients with T2OFs and sub-axial fractures. Results: Among patients with T2OFs, in comparison with those with sub-axial fractures, spinal ankylosis was less prevalent (2.2% vs. 31.6%, p<0.001), HU values were lower (p<0.05), atlanto-occipital degeneration was less prevalent (p=0.009), and facet joint degeneration was more prevalent (p=0.03). Logistic regression revealed that atlanto-occipital degeneration (odds ratio, 0.33; p=0.02) and spinal ankylosis (odds ratio, 0.06; p=0.01) were negative predictors of T2OF. Sex-specific analysis revealed that HU values were lower for women with T2OFs (p<0.05) and ankylosis was less prevalent among men with T2OFs (p<0.001) than among sex-matched patients with subaxial fractures. The SFR confirmed that ankylosis was less prevalent among patients with T2OFs (3.3%) than among those with sub-axial fractures (28.3%, p<0.0001). Conclusions Spinal ankylosis and atlanto-occipital degeneration are significant risk factors for T2OF. According to sex-specific analysis, spinal ankylosis was less prevalent among men with T2OFs than among those with sub-axial fractures, whereas C2–C4 HU values were significantly lower in among women with T2OFs.

Methods: We evaluated 758 lateral cervical radiographs. One medical student and one spine surgeon (i.e., measured ×2 within 4 weeks) independently measured the parameters obtaining 5,850 values. Standard error of measurement (SEm) and minimum detectable change (MDC) were calculated for each parameter. The accuracy and reliability of the Cobb angle measurements were calculated for the different types of angles: cervical lordosis, prosthesis angle, segmental angle with two bone surfaces (SABB), and segmental angle with one bone and one metal surface. Reliability was determined with intraclass correlation coefficient (ICC). Results: SEm was 1.8° and MDC was 5.0° for the Cobb angle, with an intraobserver/interobserver ICC of 0.958/0.886. All the different subtypes of Cobb angles had an ICC higher than 0.950, except SABB (intraobserver/interobserver ICC of 0.922/0.716). The most accurate and reliable measurement was for KLT. Conclusions This study provides normative data on SEm and MDC for Cobb angles, T1S, KLT, OCI, and cSVA in cervical lateral radiographs. Reliability was excellent for all parameters except SABB (e.g., good).