Radial Pronation Angle

Abstract

Introduction Congenital proximal radioulnar synostosis (CPRUS) is a relatively rare forearm deformity that is characterized by a fixed pronated forearm of varying severity. The osseous synostosis between the proximal part of the ulna and the radius can be seen on the X-ray images in most cases. Many researchers have attempted to identify methods to measure the disease severity to guide in the treatment of CPRUS. However, to describe the overall deformity, the use of multiple indicators is essential, and some of these measurements require special software or need to be conducted on cadavers. Objective The aim of the current study was to introduce the radius pronation angle (RPA), a novel radiological evaluation index of CPRUS, and analyze the relationship between the RPA and the severity of the deformity. Methods Three-dimensional models of 43 CPRUS forearms (19 left forearms and 24 right forearms) of 32 patients (23 males and 9 females; average age was 6 years 8 months; range, from 1.5 to 27 years) treated at Beijing Ji Shui Tan Hospital during 2016 to 2019 were reconstructed using a computer-assisted technique. The special flexed posterior-anterior views of the X-ray image (the f-PA view) of the forearms were obtained, and the forearm rotation angle and the ulnar inner rotation angle were measured on each forearm. The RPA was measured on the f-PA view, and the lengths of the osseous synostosis, ulna, and the radial head were measured on the computed tomography scan images using the multiplanar reconstruction function. The Pearson index was analyzed between the RPA and the other measurements. Results The RPAs were correlated with the forearm rotation angle, ulnar inner rotation angle, relative length of the osseous synostosis, and the relative length of the radial head (P < 0.05). Conclusions The RPA can be measured quickly and easily on the f-PA view of the X-ray image and can be used as a reliable indicator of the severity of CPRUS.

Observation on the effect of reconstruction of the forearm rotation function with an external fixator in the treatment of congenital radioulnar synostosis

“…Until Kanaya adjusted the approach using free vascularized fascia-fat graf to ll in the space between the divided radius and ulna and then reset the radial head by osteotomy at the proximal radius, the outcomes were satisfactory[18]. However, it has been reported in the literature that in addition to the proximal radioulnar synostosis, patients with CRUS also suffer from ulnar and radial deformities, soft tissue abnormalities and a high rate of redislocation of the radial head, so the results of fusion zone separation and reconstruction are still not perfect and the restoration of forearm rotational function is still a challenge for orthopedic surgeons [9,19,20].…”

Normative Data of Ulnar Length in Pediatric Indian Population

“…This is likely due to the inclusion of soft tissue when using a segmometer as opposed to a direct bone measurement. 29,30 The specific limitation of the study is the nonuniform sample size leading to potential bias due to sampling error. The major drawbacks with normative data are difficulty in determining to what extent data from a population could be applied to determine individual normative data.…”

“…This is likely due to the inclusion of soft tissue when using a segmometer as opposed to a direct bone measurement. 29 30…”

Quantitative Analysis of Deformity in Digital Model of Congenital Radioulnar Synostosis

“…Congenital radioulnar synostosis (CRUS) is a rare congenital deformity of the upper extremity, which usually presents as a pronation deformity of the forearm, and can be bilateral or unilateral. 1 , 2 , 3 This disease may cause difficult experiences for affected children in participating in activities like perineum sanitation and using utensils, thus leading them to develop a variety of psychological problems as they grow up. In severe cases, the patient cannot complete movements, such as carrying a bowl and writing, which affect the patient's daily life, work, social activities, and hobbies.…”