Osteoarthritis of the sternoclavicular joint: is clavicular length a risk factor?

Osteoarthritis (OA) is the most prevalent disorder of the Sternoclavicular Joint (SCJ), with a reported lifetime prevalence of approximately 50%, yet it is rarely observed in individuals under the age of 35. When symptomatic, it manifests with pain and swelling. Although OA is strongly age-related, the influence of biomechanical factors - such as clavicular length - remains unknown. In this retrospective case-control study, computed tomography (CT) scans of adult polytrauma patients admitted to our hospital between 2012 and 2014 were evaluated. OA was defined radiologically by the presence of osteophytes, subchondral cysts, or cortical sclerosis, and a score from 0 to 6 was assigned according to the severity of these changes. Medial-most and lateral-most points of the clavicle were used to determine clavicular length. The x-, y-, and z-coordinates of these two points were extracted from the DICOM metadata and clavicular length was calculated as the distance between these two points using 3D geometry. A total of 334 SCJs from 167 patients (36% female, mean age 48.5 ± 20.5 years) were analyzed. Mean clavicular length was shorter in the group with OA (144 ± 11 mm vs. 150 ± 12 mm, p < 0.001, right; 146 ± 11 mm vs. 153 ± 11 mm, p < 0.001, left). Age and clavicular length were independent risk factors on multivariate regression model. The logistic model showed a robust discriminative ability with the area under the curve being 90% (right) and 91% (left). Adjusted odds ratios were 0.93 (right) and 0.92 (left). Mean clavicular length showed a decreasing trend with increasing OA scores (p = 0.01). Our findings suggest that shorter clavicles are associated with a higher prevalence of sternoclavicular joint osteoarthritis, demonstrating an inverse correlation between clavicular length and the severity of the radiological signs of degeneration. Prospective studies are warranted to further investigate the clinical implications of clavicular shortening and its potential role in the development of SCJ osteoarthritis.