Hook of Hamate Fractures: The Tiny Wrist Bone Taking Down Big League Athletes
⌚️ read time: 4.6 minutes
My dad used to call them ‘the swinging sticks’ sports. It’s not hard for most of us to draw similarities between sports like baseball, hockey, and golf.
But did you know these sports also share a specific type of wrist fracture? One that can seem so very insignificant but end up altering professional athletes’ careers?
If you’re skeptical, just ask MLB superstar Mike Trout about his ‘hook of hamate’ fracture — this is the same injury that sidelined him for a significant portion of the 2023 season (and playoffs).
What's this ‘Hook of Hamate’?
As you may recall, when we say the ‘wrist,’ we are actually referring to a complex arrangement of eight small bones that hang out between your forearm bones (radius and ulna) and hand bones (metacarpals). One of these wrist bones, the hamate, has a little hook-shaped projection (like a tiny coat hook) that sticks out into your palm. Notice this hook in red in the animation below.
Source: BodyParts3D made by DBCLS
This little hook might seem insignificant, but it's actually quite important.
From my previous articles explaining carpal tunnel syndrome, you may remember that this hook is actually one of the sidewalls of the carpal tunnel (see image below) and serves as the attachment point for the big thick transverse carpal ligament (in orange in the image below) that forms the roof of the carpal tunnel. My full description of carpal tunnel anatomy is in this article here.
But here's the catch – the hook of hamate is a little more fragile than we might like.
How Does It Break?
This injury is particularly common in sports requiring a tight grip on something that can deliver a sudden impact. AKA ‘swinging sticks’ sports.
Think about:
A baseball player fouling off a pitch (that vibration has to go somewhere)
A golfer hitting the ground hard behind the ball (I know all your golf swings are perfect, but let’s imagine for a moment)
A hockey player practicing a slapshot over and over
This is exactly what happened to Mike Trout (video here). It’s a freak accident and looks like nothing more than any other foul tip. But as you can see, he gets a shock of immediate pain through the wrist when that hook breaks off.
Why It's Tricky to Diagnose
The symptoms of a hook of hamate fracture are generally pretty straightforward. Patients will usually tell a story of pain after an impact, as in the examples above, that persists in the palm. This pain typically worsens with gripping activities.
Another subtle finding with this fracture is weakness in the pinky and ring finger. Again, if you remember our carpal tunnel anatomy from previous articles, the tendons that flex our fingers (in blue in the image below) when we grip do this function by sliding through the carpal tunnel. As you might imagine, tendons sliding past a broken bone…hurts! Pain with this motion can lead to weakness.
Notice the vertical (green) hook projection on the hamate bone in the image I drew below, drawn as a cross-sectional image of the carpal tunnel with the palm at the top of the image.
But in reality, this weakness is not only due to pain with this motion. It also comes from a natural lever effect. The flexor tendons curve around this anchor of bone on their way to flexing the fingers, resulting in greater strength than would be present with just a straight-line pull.
Anatomy is smart…we find these built-in mechanical advantages all over the hand and wrist. So cool!
Unfortunately, this also explains the most dramatic finding associated with an undiagnosed hook of hamate fracture. The jagged edges of the fracture can actually wear away and even fully cut the tendons of the ring and small finger if this goes unrecognized/untreated for too long. NOT GOOD.
Imaging these fractures can be tricky. On standard wrist x-rays, this fracture can be extremely difficult to see. The way we position the wrist for x-rays doesn’t line up the hook to be viewed appropriately. So it requires a high level of suspicion on the part of the doctor.
When I suspect this particular fracture, (patient has persistent palm pain over the ulnar base of the hand, especially with gripping) I get a special x-ray called a "carpal tunnel view" (and my staff all groan in unison — it’s a difficult x-ray to perform). In many cases, I even get a CT scan.
These special tests are much better at revealing the exact location of the injury and whether the fracture has displaced at all. Both location and displacement are crucial for deciding how best to treat a hook of hamate fracture.
Treatment: To Fix or Remove
Wait, Dr. G, did you really just say remove?
Unlike most broken bones where we automatically think "let's either fix it surgically or cast it" with hook of hamate fractures, we often actually remove the broken piece entirely!
I know what you're thinking — "Wait, we can just remove part of a bone?"
Yes.
And here's why: This particular fragment has a notoriously poor blood supply (sound familiar from my previous article on scaphoid fractures?). Which means it often doesn't heal well even if we try to fix it.
There are some nuances here based on exactly where along the hook that the hamate fractures. But suffice it to say that cast immobilization, or even surgery, are not a guarantee that this bone will heal.
For this reason, many athletes (especially professionals who have contracts to play for) opt for removal of the fragment and return to play as soon as 3-4 weeks later. It’s not always that quick, but it certainly can be when everything goes well.
The biggest concerns we have regarding hook of hamate excision surgery include nerve dysfunction (a very important nerve lies right across the hook of hamate), occasional persistent dull palm pain, and a theoretical (though never proven) small loss of grip strength.
Not a zero-risk surgery but it is fairly low-risk.
Takeaways:
Don't ignore persistent palm pain, especially if you're a golfer or baseball player
Regular X-rays often miss this injury – special views may be needed
Several treatment options exist depending on fracture pattern, but many athletes choose to have the bone removed for the fastest recovery
Remember, while this might be a small bone, it can cause big problems if ignored. Even superstars like Mike Trout aren't immune to its effects. Sometimes the smallest things in our body can have the biggest impact on our game.
And remember, if you're experiencing persistent pain with gripping activities, don't try to play through it – get it checked out. Just like your slicing golf swing, this is a problem that usually won't fix itself!
