Morphology of the radial head: A reverse engineering based evaluation using three-dimensional anatomical data of radial bone

Abstract

The proximal part of the radius has a complex shape and dimension that cannot be precisely determined by standard roentgenogram for real three-dimensional anatomical shape which is important for prosthesis design. This study presents a method by which computer tomography (CT) images are combined with the reverse engineering technique to obtain and analyse the three-dimensional inner and outer geometry of the proximal radius. The three-dimensional models were reconstructed from CT images obtained from 40 radial bones and approximated with two- and three-dimensional fitting algorithms based on reverse engineering methods. The mean total length of the radius was 240.0 mm [standard deviation (SD) = 17.3]. The radial head in this study is more likely to be circular with an average diameter of 20.5 mm (SD = 1.9). The outer diameter of the radial neck averages 14.7 mm (SD = 1.0). The thickness of the radial head averages 12.9 mm (SD = 1.4). The intramedullary canal diameter of the radial neck averages 7.4 mm (SD = 1.4). The depth of the fossa at the articular surface averages 1.5 mm (SD = 0.4).

Anatomical Parameters of Radial Head: An Aid for Prosthesis Design

“…None of the previous studies have measured depth of radial head on dry bone. They mainly measured depth with the of computer tomography [4,9,10]. Depth of radial head in the present study (1.74 mm) was within range of previous studies (1.5-2.4mm).…”

The applicability of the mayo clinic congruent radial head plate: cadaveric study

“…In the remaining cases, in which there is a clear mismatch between the plate and proximal radius morphology, the plate should be correctly bent according to the morphology of each radius. Considering that previous studies showed no difference in morphometric aspect between the left and right radii [22][23][24][25], a radiograph of the contralateral radius may guide the surgeon to bend the plate or to select the most appropriate plate, in order to improve plate congruency and the anatomical reconstitution of the safe zone in each patient. In keeping with this, in the clinical setting, we started to perform a contralateral radiograph before operating on patients with comminuted fractures and, at present, we are very satisfied with this new approach.…”

“…The anatomical landmarks of the safe zone have been investigated in a few studies [16][17][18]. Further studies analyzed the morphometric aspects of the proximal radius including the diameters of radial head and neck, neck length, radial head height, articular surface depth, radial head-neck angles, and neck-shaft angle [19][20][21][22][23][24][25][26][27]. These investigations were aimed at analyzing the morphometric aspects of the proximal radius to design well-performing radial head prostheses, while none of them were focused on the morphology of the safe zone in order to improve the accuracy of radial head osteosynthesis.…”

Reference Points for Radial Head Prosthesis Size

“…8 The suggestion to insert the largest prosthesis that will fit may be suitable in the biomechanics laboratory 7 but is not appropriate clinically, particularly in patients with associated el- bow ligament injuries in whom the instability of the elbow easily will accommodate the insertion of a thick, oversized prosthesis. Studies of the size and shape of the radial head [17][18][19][20][21][22] have focused on the anatomic features of the native radial head for the purposes of prosthesis design. 20,21 The excised radial head is available in patients who have arthroplasty for acute fractures for appropriate sizing of the prosthetic head but original radial length is hard to estimate and restore, especially in more comminuted fractures.…”