Pisiform Fractures: The Tiny Wrist Bone That Can Cause Big Trouble

Your wrist has eight small carpal bones, and the pisiform is the smallest one, a literal pea-sized bone sitting on the pinky side of your wrist, right in that crease you see when you flex your hand. It’s easy to ignore until it breaks. When it does, it hurts like hell and can be a real pain to diagnose and treat.

How It Usually Happens

You’ll find when looking for pisiform fracture info that it almost always comes from direct force to the base of your palm. The classic story is falling on an outstretched hand (FOOSH injury), getting hit with a stick or puck in hockey, punching something (or someone) in martial arts, or even a dashboard impact in a car crash. Because the pisiform sticks out a little and is only loosely attached by ligaments, it takes the full brunt of the blow.

You’ll know pretty quick something’s wrong: sharp pain on the little-finger side of the wrist, worse when you grip or try to bend the wrist toward the pinky (ulnar deviation). The area swells and gets brutally tender right over that little bump.

Who Gets Them

• Contact-sport athletes (hockey, football, lacrosse, MMA)
• Racquet-sport players (tennis, squash – repetitive stress plus occasional smashes into the ground)
• Gymnasts (constant impact on vault, bars, floor)
• Anyone who falls on their hand – skateboarders, cyclists, the occasional drunk person on ice
• Manual laborers who use the heel of the hand as a hammer (yes, that happens more than you’d think)

Why They’re Easy to Miss

Standard wrist X-rays often don’t show the pisiform well because it overlaps with other bones. Doctors have to order special views (like the “carpal tunnel” view or a 30–45° supinated oblique) to see it clearly. If they only do the usual PA and lateral, the fracture can hide in plain sight. That’s why a lot of these get called “wrist sprains” at first and only show up weeks later when the patient is still hurting.

If there’s any doubt, a CT scan is the gold standard. MRI is rarely needed unless they’re worried about ligament damage to the nearby ulnar nerve or TFCC.

Treatment: Most of the Time It’s Simple

About 85–90% heal fine without surgery:

• Short-arm cast or removable splint for 4 to 6 weeks (keep the wrist in slight flexion and ulnar deviation so the flexor carpi ulnaris tendon doesn’t pull on the bone)
• Ice, NSAIDs, and rest from gripping or impact
• Once the cast is off – hand therapy to get motion and grip strength back

When Surgery Is Needed

• Big displacement (>2–3 mm)
• Non-union after 3 months of casting
• Ongoing pain from pisiform instability is irritating the ulnar nerve

The operation is usually straightforward: pisiform excision (they just take the whole bone out). Sounds dramatic, but you honestly don’t need it. The flexor carpi ulnaris tendon still works fine, and grip strength comes back to normal in almost everyone. Recovery from surgery is actually faster than waiting for a stubborn fracture to heal most people are back to sports in 6–12 weeks.

Pisiform fractures are uncommon, frequently missed at first, and a little annoying, but the vast majority get better with a few weeks in a cast. If yours hurts exactly where that little pea bone lives and isn’t getting better after a week or two, ask your doctor for the right X-ray views or a CT. Catch it early and you’ll save yourself months of unnecessary pain.