Ultrasonography of lateral elbow pain through a weighted varus flexion position contributes to detect minor instabilities

Abstract

Background

Recent evidence indicates that lateral elbow pain may not stem solely from extra-articular or tendon-related sources, but rather be part of a multifactorial process that also involves intra-articular factors. Therefore, diagnosis of minor elbow instability is often delayed, waiting for conservative measures to assess the problem. A timely diagnosis could help achieve better patient care. While ultrasound (US) stress tests have been instrumental in evaluating joint instability across various anatomical sites, their role in diagnosing minor instability of the lateral elbow remains unexplored. The aim of this study is to assess the presence of lateral joint opening in a functional position using dynamic varus-stressed US in patients with clinically suspected atraumatic minor instability.

Materials and methods

Patients with suspected minor instability were compared to a control group with nonpathologic elbows. Eligible patients underwent varus stress US of the elbow with 70° of flexion of the elbow and a 3 kg weight fixed to the wrist. The presence of lateral widening and its increase were documented and compared between the groups. The test was named Highlight Elbow Lateral Pathology with UltraSound (HELP US). Sixty-five elbows were evaluated in this study. There were 35 patients in the case group (80% male, mean age 47 years) and 30 healthy controls (77% male, mean age 49 years).

Results

The mean lateral elbow joint width was 26.7% in the pathological group, meanwhile, in the control arm, the mean lateral elbow joint width increase was 3.2%. The groups had a significant difference in the widening of the lateral elbow during the HELP US test (P < .01). Within the cases, a total of 17 patients (48%) had a history of previous corticosteroid injections. The mean lateral elbow joint width increase was 27%, showing no difference with those patients who showed no history of previous corticosteroid injections.

Conclusions

The HELP US test can detect changes in the lateral elbow compartment and can depict lateral elbow articular space widening. This is a valid diagnostic tool and should be implemented in evaluating all patients complaining of lateral elbow pain. The HELP US test could help physicians screen for a timely diagnosis of minor instability and speed up the request for second-level imaging studies to those patients that effectively require it the most.