Osteo-Proliferative Lesions of the Phalanges on Radiography: Associations with Sex, Age, and Osteoarthritis.

Objectives: The effects of aging such as osteophyte formation, acral shape changes, cortical tunneling, and bone porosity as well as enthesophytes can be studied in the X-rays of hands. However, during the interpretation of radiographs of the hands, misinterpretation and false-positive findings for psoriatic arthritis often occur because periosteal proliferations of the phalanges are overinterpreted and too little is known about enthesophytes of the phalanges in this area. Method: It included a total of 1153 patients (577 men, 576 women) who presented themselves to the emergency department and received a radiography of their right hand to exclude fractures. The Osseographic Scoring System was used in a modified form to record osteophytes and enthesophytes. A linear regression model for periosteal lesions was computed with age, sex, osteophytes, and global diagnosis as covariables. The inter-reader agreement was assessed using ICC (two-way mixed model) on the sum scores of osteophytes and periosteal lesions. Results: Overall, men exhibited more periosteal lesions, demonstrated by a higher mean sum score of 4.14 vs. 3.21 in women (p = 0.008). In both sexes, the second and third proximal phalanx were most frequently affected by periosteal lesions, but the frequencies were significantly higher in men. The female sex was negatively associated with an extent of periosteal lesions with a standardized beta of −0.082 (p = 0.003), while age and osteophytes were positively associated with betas of 0.347 (p < 0.001) and 0.156 (p < 0.001), respectively. The distribution of osteophytes per location did not differ between men and women (p > 0.05). The inter-reader agreement was excellent for periosteal lesions with ICC of 0.982 (95%CI 0.973−0.989, p < 0.001). Conclusions: Special care should be taken not to confuse normal periosteal changes in aging with periosteal apposition in psoriatic arthritis.