![]() MRI not only reveals the size and location of the avulsed lesser tuberosity fragment, but can also provide important assessment of the integrity of the subscapularis tendon. The fracture is often not visible on AP x-rays. ConclusionĪvulsion fractures of the lesser tuberosity are unusual injuries that should be suspected in an adolescent athlete who presents with chronic pain and focal anterior tenderness. A trial of conservative treatment may be undertaken, but displaced fracture fragments and surrounding fibrosis may have to be excised to restore full strength and pain free throwing ability in the adolescent athlete. (5a) Marrow edema is visible at the fracture site (arrow) on the coronal fat suppressed T2 weighted image.īecause the majority of cases of lesser tuberosity avulsion present with malunion or delayed union, continued pain and weakness with internal rotation frequently results. ![]() Images below are from an MRI on another patient who presented three months after being tackled while throwing a football. It can be visulized on axillary x-rays, but is best seen on MRI, which also assesses the integrity of the subscapularis tendon. Physical exam may reveal tenderness over the anterior aspect of the shoulder, weakness in internal rotation, increased passive external rotation, or a positive lift-off test.ĭelayed union of the lesser tuberosity fracture is common at presentaton, and the fracture is often not visible on AP x-rays. 11Īffected patients most often present with a history of chronic shoulder pain. In these patients, the stress upon the lesser tuberosity from contraction of the subscapularis tendon is maximal as the thrower transitions from the fully abducted cocking phase to the internal rotation of the acceleration phase. However, it may also present, as in this case, as a chronic overuse injury in throwing athletes. 10 The injury most commonly occurs with forced external rotation during abduction, and can be seen in contact sports such as football or wrestling. ![]() ![]() 1-9 It is thought that in such cases the recently fused lesser tuberosity of the adolescent is the point of weakness, rather than the subscapularis tendon insertion. Isolated fractures of the lesser tuberosity of the humerus are uncommon, with only a few pediatric cases reported. Isolated avulsion fracture of the lesser tuberosity. (2a) Axial proton density and (2b) Sagittal T1-weighted images demonstrate corticated ossifications (arrows) medial to the lesser tuberosity of the humerus, abutting the undersurface of the subscapularis tendon (arrowhead). ![]()
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