The Thumb Test: A Simple Physical Examination Maneuver for the Diagnosis of Symptomatic Posterior Shoulder Instability

• Published in: Arthroscopy techniques (Amsterdam) 2022-09, Vol.11 (9), p.e1613-e1616
• Main Authors: Boileau, Pascal, Van Steyn, Peter M., Czarnecki, Michael, Teissier, Sylvain, Gasbarro, Gregory, Galvin, Joseph W.
• Format: Article
• Language: English
• Subjects: Technical Note
• ISSN: 2212-6287; 2212-6287
• DOI: 10.1016/j.eats.2022.05.007

Posterior shoulder instability is becoming increasingly recognized in young active patient populations. Diagnosing posterior instability can be challenging because patients commonly present with a complaint of pain without a history of a dislocation or subluxation event. Additionally, a posterior labral tear is not always clearly visualized on advanced imaging studies. As such, physical examination is critical to the diagnosis. We report a simple physical examination maneuver for the diagnosis of symptomatic posterior shoulder instability. The thumb test attempts to replicate a posterior bone block procedure, helping to re-establish stability and relieve pain. The examiner places his or her thumb over the posterior glenohumeral joint line while the patient actively forward elevates the affected arm overhead. Improvement in pain and stability with this maneuver is diagnostic for symptomatic posterior shoulder instability. This test augments current physical examination maneuvers to assist with correctly diagnosing posterior shoulder instability. Video 1 Thumb test in a patient with a symptomatic posterior labral tear in the right shoulder with posterior shoulder instability. The patient has pain and dynamic posterior humeral head translation with active forward elevation and then shows improvement in pain and stability with the thumb test.