Three-dimensional measurement of proximal radioulnar space during active forearm pronation

• Published in: Journal of biomechanics Vol. 113; p. 110120
• Main Authors: Matsuki, Keisuke, Sugaya, Hiroyuki, Takahashi, Norimasa, Tokai, Morihito, Ueda, Yusuke, Hoshika, Shota, Hamada, Hiroshige, Banks, Scott A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 02.12.2020; Elsevier Limited
• Subjects: Adult; Biomechanical Phenomena; Bones; Computed tomography; Dimensional measurement; Distal biceps rupture; Elbow; Fluoroscopic imaging; Fluoroscopy; Forearm; Forearm - diagnostic imaging; Forearm rotation; Humans; Humerus; Hypertrophy; Image registration; Kinematics; Male; Middle Aged; Model-image registration techniques; Pronation; Proximal radioulnar space; Radius - diagnostic imaging; Rotation; Software; Statistical analysis; Supination; Three dimensional models; Ulna; Ulna - diagnostic imaging; Forearm rotation; Model-image registration techniques; Proximal radioulnar space; Distal biceps rupture; Elbow
• ISSN: 0021-9290; 1873-2380; 1873-2380
• DOI: 10.1016/j.jbiomech.2020.110120

Distal biceps tendon ruptures have been reported to be associated with narrowing of the proximal radioulnar space. There have been no studies that three-dimensionally measured the distance between the bicipital tuberosity and the proximal ulna during active motion. The purpose of this study was to three-dimensionally measure the proximal radioulnar space during active forearm pronation in healthy subjects. Five healthy volunteers (10 forearms) were recruited for this study. They consisted of all males with a mean age of 37 years (range, 34–46 years). Lateral fluoroscopy of forearm rotation from maximum supination to maximum pronation was recorded for both forearms. Three-dimensional forearm kinematics were determined using model-image registration techniques with fluoroscopic images and CT-derived bone models, and the closest distance between the bicipital tuberosity and the proximal ulna was computed at each 30° increment of radial axial rotation relative to the distal humerus. The distance between the bicipital tuberosity and the proximal ulna decreased with pronation, reaching a minimum value at 90° of radial rotation (average 4.6 ± 1.3 mm), then increased with further rotation to maximum pronation (P = 0.004). The clearance between the proximal radioulnar space and the distal biceps tendon is very small (<1mm). Hypertrophy of the bicipital tuberosity or tendon can induce impingement and lead to tendon rupture.