Radiocapitellar incongruity of the radial head in magnetic resonance imaging correlates with pathologic changes of the lateral elbow stabilizers in lateral epicondylitis.

Yeun Soo Kim,Sung Taeck Kim,Kyoung Hwan Lee,Hyun Sik Gong,Joong Mo Ahn,Markus Geßlein

doi:10.1371/journal.pone.0254037

Yeun Soo Kim, Sung Taeck Kim + Show 4 more

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https://doi.org/10.1371/journal.pone.0254037

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Abstract

ObjectivePost-traumatic posterolateral rotatory instability (PLRI) can be shown as radiocapitellar incongruity or posterior translation (PT) of the radial head in magnetic resonance imaging (MRI). We aimed to evaluate whether PT correlated with pathologic changes of lateral elbow stabilizers in patients with lateral epicondylitis.Materials and methodsIn MRIs of 160 patients with lateral epicondylitis, we measured PT of the radial head in the sagittal images. We qualitatively graded five lesions of the lateral elbow structures that included common extensor tendon (CET) lesion (grade 1–3), lateral collateral ligament complex (LCLC) insufficiency (grade 0–2), and absence or presence of bone marrow signal change, osteochondral lesion, and calcification. We analyzed whether the PT correlated with pathologic changes of the lateral elbow stabilizers and evaluated the diagnostic value of the PT for severe lesions.ResultsThe average PT was 1.9 mm. The PT correlated with both the CET lesion (p < 0.001) and LCLC insufficiency (p < 0.001). The optimal cutoff values of the PT for grade 3 CET lesion and grade 2 LCLC lesion were 2.6 and 2.8 mm, respectively. When potential PLRI was defined as the PT of > 3.4mm as suggested for post-traumatic PLRI, 21 patients had potential PLRI. The positive predictive values of the PT > 3.4mm were 76% for grade 3 CET lesions and 67% for grade 2 LCLC insufficiency.ConclusionThis study demonstrates that PT of the radial head correlates with pathological changes of the lateral elbow stabilizers. As radiocapitellar incongruity is easy to measure quantitatively, it can be used for screening potential PLRI in patients with lateral epicondylitis.

Highlights

Lateral epicondylitis, recently called lateral epicondylopathy, is known to be caused by chronic overuse of the lateral forearm muscles, especially the extensor carpi radialis brevis, which arises from the lateral epicondyle of the humerus [1]
This study demonstrates that posterior translation (PT) of the radial head correlates with pathological changes of the lateral elbow stabilizers
As radiocapitellar incongruity is easy to measure quantitatively, it can be used for screening potential Posterolateral rotatory instability (PLRI) in patients with lateral epicondylitis

Summary

Introduction

Recently called lateral epicondylopathy, is known to be caused by chronic overuse of the lateral forearm muscles, especially the extensor carpi radialis brevis, which arises from the lateral epicondyle of the humerus [1]. Posterolateral rotatory instability (PLRI) of the elbow usually occurs as a result of trauma, in which the ulna and radius rotate posterolaterally against the humerus. This kind of instability can be present in patients with lateral epicondylitis, resulting from a degenerative change of the lateral stabilizers as well as from iatrogenic injury from steroid injection or surgical debridement [2,3,4,5]. The diagnosis of lateral epicondylitis is usually made from physical examination and taking a history, magnetic resonance imaging (MRI) can be helpful for evaluating other causes of pain and the extent of the lesion for surgical treatment. MRI findings of lateral epicondylitis include degenerative changes or tears of the common extensor tendon (CET) origin and lateral collateral ligament complex (LCLC) [9, 10]

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