Ambiguity of the radiographs around the elbow joint: Anatomical variant versus degenerative changes

Abstract

Introduction: Interpretation of traumatological radiographs of the region of the elbow joint may come with many challenges. Aside from traumatological avulsions and fractures, we can also identify other entities such as persistent epiphysis, aseptic necrosis, osteochondritis dissecans, calcific bursitis, synovial chondromatosis, and other degenerative changes. It is also necessary for all these pathological conditions to be differentiated from the anatomical variants. Material and Methods: We performed a retrospective analysis of patients admitted to our clinic between 2010 and 2020 for arthroscopic treatment of chronic elbow joint stiffness. We evaluated the radiographs of their elbow joints for the presence of accessory ossification. If present, these cases were then sorted by previously defined criteria into groups according to the kind of anatomical variant and degenerative changes. On the basis of these data, we performed a statistical analysis. Results: We analyzed 39 limbs in 39 patients (12 women and 27 men). The average age was 40.9 years (span 16–74). The exclusion criteria did not exclude any patient. Accessory ossifications were present in 78.4% (29/37) of patients, and all three criteria for accessory bone were fulfilled by two patients. Discussion and Conclusion: This sample of patients suffering from joint stiffness due to degenerative changes around the elbow joint enabled us to prove the usefulness of the criteria for differentiating degenerative changes from accessory bones. We were also able to validate the hypothesis that in a sample of patients suffering from elbow stiffness, the dominant cause of the stiffness should be the degenerative changes, while the accessory bones prevalence should not differ significantly from their prevalence in the healthy population. Our analysis showed that the seemingly ovoid intra-articular loose bodies do not appear on the radiographs as regularly shaped and can be differentiated from accessory bones. In order to avoid the wrong interpretation of elbow radiographs, it is necessary to be aware of this issue. Our study validates the three previously defined criteria as means to diagnose accessory bones with a high specificity. The intra-articular loose bodies macroscopically seemed ovoid and regular. Nevertheless, they do not appear as regularly shaped on radiographs and do not, therefore, fulfill the criteria of accessory bones.