Reliability of Magnetic Resonance Imaging Signs of Posterolateral Rotatory Instability of the Elbow

• Published in: The Journal of hand surgery (American ed.) Vol. 40; no. 7; pp. 1428 - 1433
• Main Authors: Hackl, Michael, MD, Wegmann, Kilian, MD, Ries, Christian, MD, Leschinger, Tim, MD, Burkhart, Klaus Josef, MD, PhD, Müller, Lars Peter, MD, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2015
• Subjects: Adult; Aged; Arthroscopy; chronic instability; Contrast Media; diagnosis; Elbow instability; Elbow Joint - physiopathology; Elbow Joint - surgery; Female; Humans; Image Interpretation, Computer-Assisted; Joint Instability - physiopathology; Joint Instability - surgery; Magnetic Resonance Imaging - methods; Male; Middle Aged; MRI; Orthopedics; Physical Examination; PLRI; Reproducibility of Results; Retrospective Studies; diagnosis; Elbow instability; chronic instability; MRI; PLRI
• ISSN: 0363-5023; 1531-6564
• DOI: 10.1016/j.jhsa.2015.04.029

Purpose To evaluate radiographic signs of posterolateral rotatory instability (PLRI) on magnetic resonance imaging (MRI). The goal was to establish objective radiographic criteria to aid in the diagnosis of PLRI. Methods The MRI scans of 60 patients were evaluated retrospectively. Two study groups were compared. Group 1 (n = 30) consisted of unstable elbows in which PLRI was confirmed by clinical examination and arthroscopy. Group 2 (stable; n = 30) served as the control group. Patients in group 2 had transient epicondylitis without clinical suspicion of instability. Joint incongruity was analyzed for sagittal views through the radial head and the coronoid tip and for coronal and axial views. Interobserver and intra-observer reliability were evaluated. Results In the sagittal view through the radial head, average radiocapitellar incongruity differed significantly between groups 1 and 2. In addition, mean ulnohumeral incongruity in an axial view through the motion axis of the distal humerus showed significant differences between groups. Sagittal views through the tip of the coronoid and coronal views did not reveal significant differences in patients with unstable elbows compared with the control group. Conclusions The current study provides useful MRI criteria indicative of PLRI when combined with physical examination. Cutoff points of 1.2 mm for radiocapitellar incongruity (sagittal view) and 0.7 mm for axial ulnohumeral incongruity (axial view) are suitable to screen for PLRI. Radiocapitellar incongruity greater than 2 mm and axial ulnohumeral incongruity greater than 1 mm are highly suspicious of elbow instability. Type of study/level of evidence Diagnostic IV.