Ultrasonographic detection of thumb ulnar collateral ligament injuries: a cadaveric study

Ten fresh-frozen cadaveric thumbs were utilized to determine whether ultrasound is a useful tool for diagnosing ruptures of the ulnar collateral ligament. The integrity of the ulnar collateral ligament was evaluated by ultrasound and confirmed by dissection. Partial ruptures were produced by gentle manual loading in four of the cases and were all correctly diagnosed by ultrasound. Six complete ruptures occurred secondary to forceful loading and were diagnosed as torn in five of them. Ultrasound correctly determined the presence of an iatrogenic Stener's lesion in one specimen and an intra-articular displacement in another. In the laboratory setting, repeated clinical stress examinations of the ulnar collateral ligament can lead to iatrogenic displacement of the ligament edges. Diagnostic ultrasound is a useful, noninvasive tool for assessing the extent of rupture of the ulnar collateral ligament.