The Hidden Risk: Undersurface Labral Tears in Baseball Pitchers

Following up on my last post about the subscapularis muscle, I'm diving deeper into another part of the shoulder that's crucial for throwers: the labrum. Specifically, I want to talk about undersurface labral tears—a sneaky injury that can completely derail a pitcher's season if it goes unnoticed.

The Labral Landscape: It's Not Just SLAP Tears

When most people think about labral tears, they immediately jump to SLAP tears. But there's a whole world of labral pathology out there: Bankart tears, posterior labrum tears, and the ones I really want to focus on today—undersurface tears.

Here's the thing about baseball pitchers: every time they throw, they're putting massive distraction forces through their shoulder. The humeral head is literally being pulled away from the socket, and it's the labrum—especially the superior and posterior parts—that has to resist all that tension. When that system breaks down, you get tears that can develop so gradually the pitcher doesn't even realize what's happening.

Why These Tears Are So Hard to Catch

I've seen this countless times: a pitcher comes in complaining of vague shoulder discomfort, nothing too dramatic. Maybe it's just a dull ache in the back of their shoulder, or they feel like something's "not quite right" when they throw.

The problem? Undersurface labral tears are masters of disguise. They don't always cause sharp pain or obvious instability like SLAP and Bankart tears. Instead, they can mimic internal impingement, rotator cuff irritation, or even just general shoulder fatigue. This is why imaging and advanced diagnostics are so important when dealing with throwers who have ambiguous posterior shoulder pain.

Diagnosis: What Actually Works

Traditional MRI arthrograms are still your best bet, with about 80–85% accuracy. But I've been following some research on deep learning models that can identify these subtle patterns even on standard MRIs—no contrast needed. This could be a game-changer for early detection.

For physical exams, no single test gives you a definitive answer. I like using what researchers call the "3-Pack": O'Brien's active compression test, resisted throwing position, and bicipital palpation. When you combine these with the uppercut test, your accuracy goes way up.

The Mechanics Behind the Injury

During the late cocking phase of pitching, the humeral head experiences distraction forces that can exceed 1,000 Newtons. The posterior-superior labrum bears the brunt of this load. Over thousands of throws, this creates a "peel-back" mechanism where the biceps-labral complex gets subjected to torsional and tensile forces simultaneously.

If a pitcher has GIRD (glenohumeral internal rotation deficit) or scapular dyskinesis, they're setting themselves up for trouble. These conditions change normal mechanics and put even more stress on an already vulnerable structure.

I know this firsthand—during my playing career, I developed a labral tear from bony growth that formed on my humeral head. The constant throwing motion had created bone spurs that eventually tore my labrum, ending my collegiate baseball career. It's a harsh reminder of how these seemingly small mechanical issues can snowball into career-ending injuries if left unchecked.

My Treatment Philosophy: Rehab First, Surgery as a Last Resort

I'm a big believer in trying conservative treatment first, especially for undersurface tears. A focused rehab plan that hits posterior capsule stretching, scapular control, and smart strengthening usually works better than jumping straight to surgery.

When surgery becomes necessary, precision is key. SLAP repairs have inconsistent return-to-play success in throwers, so biceps tenodesis is increasingly used. The goal is restoring stability without compromising the range of motion essential for throwing.

What I Want You to Remember