Injury patterns following simple elbow dislocation: radiological analysis implies existence of a pure valgus dislocation mechanism

Abstract

Introduction The aim of the present study was to analyze the injury pattern and thus the dislocation mechanism after simple elbow dislocation using radiographs and magnetic resonance imaging (MRI) data sets. Materials and methods The MRI data sets of 64 patients with a mean age of 44 years (18-77 years) were analyzed retrospectively. The inclusion criteria for the study were (1) radiograph with confirmed simple elbow dislocation, (2) low-energy trauma, (3) MRI of the affected elbow ≤ 3 weeks after trauma. The dislocation direction was determined using radiographs. The integrity of the lateral collateral ligament complex (LCLC), common extensor origin (CEO), anterior capsule (AC), medial collateral ligament (MCL), and common flexor origin (CFO) as well as the joint congruity were assessed based on MRI. Results 34 patients (53%) had a posterolateral, 26 patients (41%) a posterior, and 4 patients (6%) a posteromedial dislocation. LCLC and AC were affected in 64 out of 64 patients (100%). MCL was affected in 58 patients (91%). CEO were affected in 25 patients (39%) and the CFO in 20 patients (31%). In 11 patients (17%) the injury pattern was more pronounced medially than laterally (MCL, CFO, LCLC), with 2 of these patients exhibiting only a partial LCLC tear. All cases with joint incongruency (n = 12, 19%) showed CEO and/or CFO involvement. Conclusions Simple elbow dislocation leads to a very heterogeneous spectrum of soft tissue injury pattern. A small proportion of patients showed medially pronounced injury patterns. These findings strongly indicate existence of a "reversed Horii circle" with an underlying valgus mechanism (medial force induction) originating and continuing from medial to anterior.

Variant of the terrible triad of the elbow, a CASE report with a review of the literature

“…In 1992, O'driscoll carried out a detailed study of the dislocation process, concluding that supination stress coupled with valgus stress led to the rupture of the lateral collateral ligament and the posterolateral part of the capsule, ending in dislocation. Based on these findings, Horii and Odriscoll developed a theory of the “Horii circle”, similar to Mayfield's diagram for the carpus, in which soft tissue damage occurs from lateral to medial [ 10 ]. Three stages are then described (defined by the spectrum of instability for O'driscoll) [ 11 ]: Stage 1: Partial or complete rupture of the lateral collateral ligament = posterolateral subluxation Stage 2: Rupture of the anterior and posterior soft tissues = complete dislocation of the elbow (pronated forearm stabilizes the elbow by action of the LLU) Stage 3 is subdivided into three categories: 3A: Associated with a fracture of the radial head and coronoid/anterior fascicle of the LLI intact: no subluxation during the varus/valgus test 3B: The medial ligament complex is ruptured/the elbow is unstable even after reduction.…”

Posterior Translation of the Radial Head in Magnetic Resonance Imaging of Lateral Epicondylitis

“…The posterior translation of the radial head was measured in T2- or T2-weighted sagittal images following a method described in a previous study 9 (Fig. 1 ).…”

“…A full tear was defined as a tear showing no continuity with the attachment of the lateral epicondyle of the humerus. 2,7,8 The posterior translation of the radial head was measured in T2-or T2-weighted sagittal images following a method described in a previous study 9 (Fig. 1).…”

Abordaje de las luxaciones simples de codo en el servicio de emergencias

“…El método diagnóstico por excelencia. Se debe realizar en proyección anteroposterior y lateral para confirmar la luxación y descartar la presencia de fracturas asociadas (16). Puede estar presente la existencia del signo de la almohadilla grasa posterior (signo radiográfico donde se visualiza la presencia de una media luna brillante en la fosa del olecranon) (ver figura 6).…”

“…línea radiocapitelar (en proyección lateral se traza una línea imaginaria a través del centro del cuello del radio pasando por el centro del cóndilo lateral del húmero); si hay presencia de luxación, esta línea no atraviesa el cóndilo (16).…”