Imaging Studies
Radiography
Anteroposterior (AP) and lateral radiographs are used to classify the ligamentous injury into one of five types in accordance with the schema developed by Louis et al (see Presentation).
Other imaging modalities
Other methods of diagnosis, such as stress radiography, magnetic resonance imaging (MRI), [8] arthrography, and ultrasonography (US), [9] also have been used to aid in diagnosing Stener lesions, with varying accuracy. Further research is warranted to establish the accuracy of these modalities. [10, 11, 12, 13, 14, 15, 16]
Melville et al, in a retrospective study aimed at characterizing the appearance of surgery-proven displaced UCL tears on US, determined that two US findings—the absence of UCL fibers and the presence of a heterogeneous masslike abnormality proximal to the first MCP joint—were 100% accurate in differentiating displaced from nondisplaced full-thickness tears of the thumb UCL. [17]
The so-called tadpole sign on US has been described as representing a Stener lesion. [18]
Milner et al used extremity MRI to assess UCL injury and measure the degree of ligament displacement, which they then correlated with clinical outcome; planned surgical intervention was reserved for patients with a Stener lesion. [19] They were able to generate a four-stage treatment-oriented classification of these injuries, as follows:
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Type 1 (partial and minimally displaced UCL tears (type 1) - Typically healed with immobilization alone
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Type 2 (tears displaced < 3 mm) - Typically healed by immobilization alone
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Type 3 (tears displaced >3 mm) - Failed immobilization and required surgery in 90% of cases
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Type 4 (Stener lesion) - Failed immobilization and required surgery in all cases
In a systematic review and meta-analysis, Qamhawi et al evaluated the diagnostic accuracy of US (nine studies; 315 thumbs) and MRI (six studies; 107 thumbs) for diagnosing Stener lesions of the thumb. [20] Both modalities showed high diagnostic accuracy in detecting these lesions. Pooled sensitivity was 95% for US and 93% for MRI; pooled specificity was 94% for US and 98% for MRI. The authors suggested that US could serve as a first-line imaging modality in this setting
In a systematic review and meta-analysis focusing on the use of US to diagnose UCL injuries (17 studies; 597 injuries), Raheman et al found US to have excellent diagnostic accuracy for Stener lesions. [21] Estimated pooled sensitivity and specificity were 0.96 and 0.90, respectively. The area under the curve (AUC) for Stener diagnosis with US was 0.98. The authors suggested that US could be employed in the diagnostic work-up of UCL injuries, with MRI being reserved for ambiguous cases.
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Displacement of the ulnar collateral ligament by the adductor aponeurosis during hyperabduction of the thumb.
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Stress view of ulnar collateral ligament.
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Ruptured ulnar collateral ligament.
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Completed repair using suture anchors for fixation.
