The Size of the Radial Tuberosity is Not Related to the Occurrence of Distal Biceps Tendon Ruptures: A Case-Control Study.

INTRODUCTION Hypertrophic changes at the radial tuberosity have traditionally been related to distal biceps tendon degeneration and rupture. From supination to pronation of the forearm, the space available for the distal biceps tendon between de lateral ulna and radial bicipital tuberosity (RBT) decreases by almost 50%. A hypertrophic change at the radial tuberosity further reduces this space with impingement of the distal biceps tendon as a result. The purpose of this study was to evaluate whether the size of the RBT plays a role in the pathophysiology of distal biceps tendon ruptures. MATERIALS AND METHODS Twenty-two consecutive patients with a surgically proven distal biceps tendon rupture were matched to controls, in a 1:1 ratio. The size of the RBT was expressed as a ratio of the maximum diameter of the radius at the RBT to the diameter of the diaphysis just distal to the RBT (RD ratio), measured on standard radiographs of the elbow. The RD ratio of patients and matched controls were compared. RESULTS The mean RD ratio in control group was 1.25 and not significantly different from the mean 1.30 in the group of patients with a distal biceps tendon rupture. Each 0.1 point increase in RD ratio results in an estimated 60% increase of the rupture odds, which was not significant either. CONCLUSION Based on the RD ratio on conventional radiographs of the elbow, there was no significant difference in RBT size between patients with a distal biceps tendon rupture and matched controls without biceps tendon pathology.