JSES - 2026-08-01 - Journal Article
Radiographic assessment of medial elbow stability.
Gressl M, Zendeli F, Fritz B, Wieser K, Borbas P
Topics
Key Takeaway
Valgus stress radiography at 60° flexion with a Telos device (50 N load) detects significant ulnohumeral joint gapping after MCL and common flexor tendon transection, with supination reducing measurable laxity compared to pronation and neutral rotation.
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Summary
This cadaveric study evaluated whether standardized Telos valgus stress radiography (50 N) at 0°, 30°, and 60° flexion in neutral, supination, and pronation could detect ulnohumeral gapping after sequential MCL and common flexor tendon release. Joint gapping increased significantly after both MCL transection and combined flexor tendon release versus intact state across most positions (P < .05), except at 30° flexion in supination. Laxity was greatest at 60° flexion, and supination reduced detectable gapping compared to pronation and neutral rotation, implicating dynamic stabilizer contribution.
Key Limitation
The sample size of only 6 cadaveric elbows is critically insufficient to establish diagnostic thresholds or statistically validate positional protocols for clinical implementation.
Original Abstract
BACKGROUND
Diagnosing simple valgus instability of the elbow currently involves time- and cost-intensive imaging modalities such as magnetic resonance imaging or magnetic resonance arthrography. Previous studies have demonstrated that stress radiography represents an alternative diagnostic tool for such conditions. The aim of this study was to investigate whether standardized valgus stress radiography can identify soft-tissue lesions of the medial elbow.
METHODS
A telos stress device (telos GAIII/E; telos Arzt- und Krankenhausbedarf GmbH, Woelfersheim-Bernstadt, Germany) was used to apply 50 N of valgus stress to 6 cadaveric elbows during static radiographic imaging. Forearm flexor and extensor tendons were loaded with 25 N and 20 N, respectively. Ulnohumeral joint spaces (mm) were measured with the joint in the intact state (M1), after transection of the medial collateral ligament (M2) and after release of the common flexor tendon (M3). Imaging was repeated in 0°, 30°, and 60° flexion with the forearm in neutral rotation, supination, and pronation in each position.
RESULTS
Mean joint gapping was increased in all groups representing ligament- and/or tendon-deficient joint conditions compared with the intact (stressed) state (group M1). The absolute difference in ulnohumeral joint gapping after common flexor tendon transection compared with the uninjured state was statistically significant (P < .05) in all positions but not in 30° flexion and supination. Medial joint laxity was greater in 60° than 0° or 30° flexion. Joint spaces were greater in pronation and neutral rotation compared with supination.
CONCLUSION
Telos stress radiographic imaging can be used to detect large ligamentous injuries at the medial elbow. Dynamic joint stabilization might affect the detection of medial collateral ligament injuries. Stress radiographic imaging at the elbow should involve examination of the joint at flexion angles of 60°.