Spinal pseudoarthrosis following osteoporotic vertebral fracture: prevalence, risk factors, and influence on patients’ activities of daily living 1 year after injury

PURPOSE: To investigate the prevalence and risk factors and influence of pseudoarthrosis on activities of daily living (ADL) of patients with osteoporotic vertebral fracture (OVF). METHODS: Spinal pseudoarthrosis is defined as the presence of a cleft in the vertebral body on a lateral X-ray image in the sitting position at 1 year after admission. Of the total 684 patients treated for OVF between January 2012 and February 2019 at our institution, 551 patients (mean age, 81.9 years; a male-to-female ratio, 152:399) who could be followed up to 1 year were included in this study. Prevalence, risk factors, and influence of pseudoarthrosis on the ADL of patients as well as fracture type and location were investigated. Pseudoarthrosis was set as the objective variable. Total bone mineral density, skeletal muscle mass index, sex, age, history of osteoporosis treatment, presence of dementia, vertebral kyphosis angle, fracture type (presence of posterior wall injury), degree of independence before admission, history of steroid use, albumin level, renal function, presence of diabetes, and diffuse idiopathic skeletal hyperostosis were set as explanatory variables for multivariate analysis of the influence of pseudoarthrosis on the walking ability and ADL independence before and 1 year after OVF. RESULTS: In total, 54 (9.8%) patients were diagnosed with pseudarthrosis 1 year after injury (mean age, 81.3 ± 6.5 years; male-to-female ratio, 18:36). BKP was performed in nine patients who did not develop pseudoarthrosis after 1 year. In the multivariate analysis, only the presence of posterior wall injury was significantly correlated with the presence of pseudoarthrosis (OR = 2.059, p = 0.039). No significant difference was found between the pseudarthrosis group and the non-pseudarthrosis group in terms of walking ability and ADL independence at 1 year. CONCLUSIONS: The prevalence of pseudoarthrosis following OVF was 9.8%, and its risk factor was posterior wall injury. The BKP group was not included in the pseudoarthrosis group, which may have led to an underestimation of the prevalence of pseudoarthrosis. SUMMARY: The prevalence, risk factors, and influence of spinal pseudoarthrosis on patients’ ADL following osteoporotic vertebral fracture (OVF) were investigated. Pseudoarthrosis occurs in 9.8% 1 year after the injury in patients with OVF. Posterior wall injury was the risk factor of pseudoarthrosis.