Cervical spine involvement in psoriatic arthritis.

UNLABELLED: The clinical and radiographic manifestations of cervical spine involvement in psoriatic arthritis remain incompletely described. Only one case-control study has been reported.
OBJECTIVE: To conduct a case-control study of the clinical and radiographic manifestations of cervical spine involvement in psoriatic arthritis. PATIENTS AND METHODS: 30 psoriatic arthritis patients (mean age, 53.3 years (21-78); sex ratio, 1; mean disease duration, 80.4 months (12-204); and mean Ritchie's index, 9.3 (2-30)) were compared with 30 controls with common low back pain (mean age, 53.8 years (21-78)). Each patient underwent a physical examination, completed a questionnaire on function, underwent cervical spine radiography (anteroposterior and lateral views and views in flexion and extension). All radiographs were evaluated by an independent observer.
RESULTS: Patients were more likely than controls to have neck pain (22/30 (73%) vs 8/30 (26%) P < 0.001). Among subjects with neck pain, the time pattern was more likely to be inflammatory in the patients than in the controls (14/22 vs 1/8, P < 0.001). Functional impairment and pain severity were significantly greater in the patients. On radiographs, facet joint abnormalities (osteophytes, joint space loss, sclerosis) were significantly more common (P < 0.01) in the patients, particularly at C3-C4 and C4-C5. Also more common in the patients were signs of spondylitis (7 vs 0) and of facet joint arthritis (7 vs 2). No subjects had syndesmophytes. Three (10%) patients had anterior C1-C2 subluxation with an atlas-dens interval greater than 4 mm. Within the patient group, no correlations were found between clinical patterns and radiographic findings.
CONCLUSION: Our data confirm that psoriatic arthritis frequently involves the cervical spine, with the facet joints being a preferred target, and can cause anterior C1-C2 subluxation.