Radial head volume measurements using quantitative three-dimensional computed tomography images for radial head deformation following missed Monteggia lesions.

Background: In chronic radial head dislocation cases, the radial head may enlarge and become dome-shaped. To date, there is no validated tool to quantify radial head deformation and predict its influence on surgical outcomes. This study assesses the potential value of volume and surface calculations obtained by quantitative three-dimensional computed tomography scanning (Q3DCT) in the workup for a corrective surgery in pediatric patients with missed Monteggia lesions.

Material And Methods: Ten consecutive pediatric patients with a missed Monteggia lesion were included (2012-2020). The volume and articular surface size of the radial head were calculated using Q3DCT, and a three-dimensional reconstruction of the articular surface relief was depicted in a heat map. The head-neck ratio was calculated and compared to Q3DCT data of missed Monteggia patients and their age-/sex-matched controls.

Results: The radial head volume and radial articular surface size did not differ significantly between patients with missed Monteggia lesions and age-/sex-matched controls (volume 1487 mm vs. 1163 mm,  = .32; articular surface size 282 mm vs. 236 mm,  = .33). Optically, heat maps of the articular surface of missed Monteggia patients did not differ notably from control heat maps. A higher head-neck ratio correlated to a larger radial head volume (Pearson r = 0.73;  = .2).

Discussion And Conclusion: Q3DCT may be an interesting tool in the preoperative workup of pediatric missed Monteggia lesions. Prospective research with larger cohort sizes and data that compares the affected side to the contralateral elbow is needed to assess its true clinical potential.