You wince, reaching for that jar on the top shelf. Or maybe it’s a dull ache that’s been nagging you after your weekend tennis game. That familiar, unwelcome shoulder pain. It’s something I see a lot in my practice. When you come in, and we’re trying to figure out what’s going on with that shoulder, one of the things we might do is a simple in-office check called the O’Brien test. It’s also sometimes called the active compression test, and it gives us some good clues.
So, What Exactly is This O’Brien Test?
Think of your shoulder – it’s a busy place, a really complex joint. The O’Brien test helps us zoom in on a couple of specific areas: your acromioclavicular (AC) joint and your labrum.
Let me break those down a bit:
- Your AC joint is where your collarbone (the clavicle, to be precise) meets the top, outer part of your shoulder blade (that’s the acromion). Problems here could be a separation in the joint or just wear and tear on the cartilage.
- Your labrum is a special kind of cartilage. Picture it like a little rubber bumper or gasket that lines the rim of your shoulder socket (the glenoid). It’s super important for keeping the main ball-and-socket joint of your shoulder stable – where the ball of your upper arm bone (the humerus) fits into that socket.
The O’Brien test is particularly helpful if we suspect a tear in the top part of that labrum. You might hear this called a SLAP tear, which is a bit of an acronym for Superior Labrum, Anterior to Posterior. It just means a tear at the top, running from front to back.
Besides these, the test can also help us consider if other common shoulder culprits, like a rotator cuff tear or shoulder impingement syndrome, are less likely.
Who Does the O’Brien Test?
It’s not just us family doctors! You might have this test done by:
- Athletic trainers, especially if it’s a sports-related injury.
- Orthopedists (they’re the specialists for bones and joints).
- Physical therapists, who are fantastic at diagnosing and treating these kinds of issues.
How We Do the O’Brien Test in the Clinic
Alright, let’s walk through it. It’s pretty simple, and you don’t need to do any special prep. You can be sitting or standing.
Here’s what I’d ask you to do:
- First, you’ll raise your arm straight out in front of you, so it’s parallel to the floor (that’s 90 degrees), keeping your elbow straight.
- Then, bring that arm slightly across your body, just a little bit (about 10 to 15 degrees).
- Next, you’ll turn your arm inward, so your thumb points down towards the floor. Your elbow will naturally point outwards. This is called pronation.
While you’re holding this position, I’ll gently press down on your arm. Your job is to resist me and try to push your arm upwards. We’ll note if this causes any pain.
Then, we repeat, but with a little twist:
- Same starting position – arm at 90 degrees, elbow straight, slightly across your body.
- This time, you’ll rotate your arm the other way, so your palm faces up towards the ceiling. Your elbow will now point towards the floor. This is called supination.
Again, I’ll gently press down, and you’ll resist.
What Does a “Positive” O’Brien Test Mean?
So, what are we looking for? An O’Brien test is considered “positive” if you feel pain in that first position (thumb down), and then – this is key – that pain is less or gone in the second position (palm up).
The location of the pain gives us more clues:
- If you feel the pain deep inside your shoulder, it might point towards a labral tear. Sometimes, with a labral tear, you might even hear or feel a little click during the test.
- If the pain is more on the surface, right at the top of your shoulder, that could suggest an issue with your AC joint instead.
Is the O’Brien Test Always Right?
Now, it’s important to know that the O’Brien test is a helpful piece of the puzzle, but it’s not the whole picture. Sometimes, people with perfectly healthy shoulders might feel a twinge during the test. Weird, right? That’s why we don’t rely on it alone. We combine its findings with your story of how the pain started, what makes it worse, a full physical exam of your shoulder, and sometimes, other investigations.
What Happens After the Test?
You’ll know the results of the O’Brien test right away. From there, we’ll chat about what it might mean in your specific situation. Depending on what we find, and how things are looking, I might suggest:
- Imaging tests like an X-ray, CT scan, or an MRI to get a better look inside your shoulder. These can show us bones, cartilage, and other soft tissues.
- Blood tests, though less common for this specific test, might be ordered if we suspect something like gout or rheumatoid arthritis could be contributing to shoulder pain generally.
- In some cases, an orthopedist might recommend a shoulder arthroscopy. This is a minimally invasive procedure where a tiny camera is used to look directly inside your shoulder joint. It can be used for both diagnosis and repair.
We’ll discuss all the options and decide on the best next steps for you.
Take-Home Message: Understanding Your Shoulder and the O’Brien Test
Here’s what I’d really like you to remember:
- The O’Brien test is a quick, hands-on way for us to check for certain types of shoulder pain, especially problems with the labrum (like a SLAP tear) or the AC joint.
- It involves specific arm movements while your doctor applies gentle resistance.
- Pain in the first position (thumb down) that improves in the second position (palm up) is a “positive” test.
- Where you feel the pain can give clues – deep pain often points to the labrum, while top-of-the-shoulder pain might indicate the AC joint.
- It’s a useful tool, but it’s usually part of a bigger diagnostic picture, often combined with your history and other exams or tests to get a full understanding of your O’Brien test results and what’s causing your shoulder discomfort.
You’re not alone in this. Shoulder pain is common, and we have ways to figure it out and get you on the road to feeling better.
