@article {Kim2460, author = {Tae-Jong Kim and Tae-Hwan Kim and Jae-Bum Jun and Kyung-Bin Joo and Wan-Sik Uhm}, title = {Prevalence of ossification of posterior longitudinal ligament in patients with ankylosing spondylitis.}, volume = {34}, number = {12}, pages = {2460--2462}, year = {2007}, publisher = {The Journal of Rheumatology}, abstract = {OBJECTIVE: To determine the prevalence of ossification of the posterior longitudinal ligament (OPLL) in patients with ankylosing spondylitis (AS). METHODS: A cross-sectional radiological examination was performed in patients diagnosed with AS. A bone and joint radiologist screened and confirmed the cervical radiographs of these patients. A review of the medical records was also conducted to investigate the relationship between the clinical manifestations and the actual expression of OPLL in patients with AS. RESULTS: Among 544 patients with AS, 470 (86.4\%) were men and 96.1\% were HLA-B27-positive. The mean age was 34.3 +/- 9.3 years and mean disease duration was 12.4 +/- 7.2 years. After reviewing the cervical radiographs, OPLL was found in 19 patients (3.5\%; 95\% CI 1.9, 5.0). The mean age of these 19 patients was 39.9 +/- 10.7 years, and the male to female ratio was 18:1. Interestingly, a statistically significant number of patients who expressed OPLL were older (p = 0.007). However, we were unable to determine whether OPLL was significantly associated with AS disease duration, peripheral arthritis, anterior uveitis/iritis, HLA-B27, anterior atlantoaxial subluxation, diffuse idiopathic skeletal hyperostosis, or other paraspinal ligament disorders. CONCLUSION: Our study showed that the frequency of OPLL in Korean patients with AS was 3.5\%, which was considerably lower than previously reported values (15.5\% in 103 Mexican AS). We were able to determine that OPLL in AS was associated with older age.}, issn = {0315-162X}, URL = {https://www.jrheum.org/content/34/12/2460}, eprint = {https://www.jrheum.org/content/34/12/2460.full.pdf}, journal = {The Journal of Rheumatology} }