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Two Fingers, Bent Knuckles, and a Fist Check Nobody Should Skip.
Most people wear an ulnar or radial gutter splint for about 3 to 6 weeks after a hand fracture, full-time at first, then weaned as the bone settles. Heavy gripping and contact sport usually wait until 8 to 12 weeks.
An ULNAR GUTTER splint holds the ring and little fingers. A RADIAL GUTTER splint holds the index and middle fingers. Both hold the knuckles bent around 70 to 90 degrees, the finger joints straight and the wrist tilted slightly back.
The knuckles are held BENT on purpose. It’s the position that stops them stiffening while the bone heals.
If you’re reading this, you’ve probably got a splint on the side of your hand, fingers set at a slightly odd angle, and a doctor who said “see you in a week”. You’re wondering if the angle is right, how long this lasts, and whether you can work.
Here’s what goes wrong if this is handled badly. A rotated fracture that’s missed in the first week or two heals rotated, and then fixing it means breaking the bone again. And knuckles held straight for weeks can take months to bend fully again…long after the X-ray looks perfect.
What is a gutter splint?
Your hand has five long bones in the palm, the metacarpals, one under each finger. The ring and little finger metacarpals sit on the outside edge of the hand (the ulnar side). The index and middle sit on the thumb side (the radial side). A gutter splint is a U-shaped trough that cradles one side of the hand and the two fingers on that side.
- Ulnar gutter splint: ring and little fingers, along the little finger edge of the hand and forearm.
- Radial gutter splint: index and middle fingers, with a cut-out so the thumb stays free.
- The ER version is often a fiberglass or cast slab held on with a bandage. A hand therapist usually swaps this for a lighter, custom thermoplastic splint that fits closer and can be adjusted as the swelling drops.
What position should a gutter splint hold?
This is the part that decides how stiff you’ll be at the end.
- Two fingers, not one. A fractured metacarpal is held with its neighbor, so the fingers can’t pull against each other.
- Knuckles (MCP joints) bent, around 70 to 90 degrees. The ligaments at the sides of the knuckles are at their longest in this position. Held straight for weeks, they shorten and the knuckle can be slow to bend again.
- Finger joints (PIP and DIP) straight. The front of the middle joint shortens if it’s held bent, so it’s held straight instead.
- Wrist tilted slightly back, around 20 to 30 degrees, which relaxes the tendons pulling on the fracture.
- Thumb and the other two fingers free to move.
Knuckles bent, finger joints straight. Get that wrong and the stiffness outlasts the fracture.
If your splint holds the knuckles flat and straight, ask why. Sometimes there’s a specific surgical reason. Often it’s just how the slab was rushed on in a busy ER.
What fractures need an ulnar or radial gutter splint?
- Ulnar gutter: boxer’s fractures (the neck of the little finger metacarpal), ring and little finger metacarpal shaft fractures, and fractures at the base of those fingers.
- Radial gutter: index and middle finger metacarpal fractures and some finger fractures.
- After surgery for the same fractures (pins, plates or screws), once the wound allows.
The first rule of boxer’s fracture…nobody admits they punched a wall. (I’ve heard “I fell” a LOT. The walls rarely get the credit they deserve.) The splint doesn’t care how it happened. Your surgeon does, though, for one reason in the red flags below.
Rotation: the check that matters most
Before and after the splint goes on, make a gentle fist.
If the injured finger crosses over or under its neighbor, the fracture has rotated. A splint won’t correct that, and it needs a surgical opinion.
This is where the window is tightest. In the first week or two, a rotated fracture can usually be lined up or fixed in place. Once the bone has knit, that window is SHUT: correcting it means cutting the healed bone and resetting it. Same finger, a much bigger operation.
How long do you wear a gutter splint?
Your surgeon’s dates come first. A conservative timeline for a stable fracture treated in a splint:
- Weeks 0 to 3: splint on full time, including at night. Move the free fingers, thumb, elbow and shoulder every day. Hand raised above your heart to control swelling.
- Weeks 3 to 4: often out of the splint for gentle bending and straightening exercises, back in between sessions. Only when your clinician says so.
- Weeks 4 to 6: splint weaned, light use, tendon glides. Many people still wear it at night and in crowds.
- Weeks 6 to 12: grip strengthening. Heavy work and contact sport usually return between 8 and 12 weeks, once the fracture is solid and grip is back.
A broken bone in the hand is clinically sticky by about 3 to 4 weeks, but it keeps gaining strength for months. The X-ray often looks less healed than the bone really is at 6 weeks, and that’s normal.
Many stable boxer’s fractures now heal well with a shorter spell of support, buddy taping or a hand-based metacarpal fracture brace. Your clinician decides based on the angle and rotation. The little finger tolerates a fair bit of angle. The index and middle tolerate far less.
What exercises can I do in a gutter splint?
The fingers OUTSIDE the splint are your job from day one. They stiffen just from sitting next to an injury.
- Free-finger fist. Make a full fist with the free fingers, then straighten them fully. 10 times.
- Thumb touches. Touch the thumb tip to the tip of each free finger, then slide it down to the base. 10 rounds.
- Elbow and shoulder. Bend and straighten the elbow, lift the arm overhead. 10 each. An arm held still to protect a hand gets stiff surprisingly fast.
- How often: every 1 to 2 hours while you’re awake, little and often.
- Inside the splint: nothing unless your therapist has shown you. From around week 3 to 4 you may be given gentle knuckle bending and tendon glides out of the splint.
How do I look after a gutter splint?
- Keep it dry. A plastic bag sealed with tape for the shower, arm held out of the spray. A wet fiberglass or cast slab softens skin and loses shape.
- Don’t take it off unless you’ve been told you can. A thermoplastic splint is often removable for washing later on, but only when your clinician says the fracture is ready.
- Check the skin daily where the edges sit, especially over the bump at the base of the little finger and along the edge of the hand.
- Loosen nothing, trim nothing. If the straps feel tight, raise the hand first. If they still feel tight, get it adjusted.
- Sleep with the hand on a pillow for the first week or two.
Can I work or drive in a gutter splint?
- Desk work: usually within a few days, typing with the free fingers and the other hand.
- Driving: not while the splint stops you gripping the wheel firmly. The test is whether you could control the car in an emergency. Check with your insurer.
- Light manual work: often around 6 weeks.
- Heavy manual work, gym, contact sport: usually 8 to 12 weeks. A protective splint for sport is sometimes used for a few weeks after that.
What happens after the splint comes off?
Most people expect the hand to feel normal the day the splint comes off. It won’t. Expect stiff knuckles, a weak grip and a slightly puffy back of the hand for a few weeks.
- Knuckle bending is the priority. Getting the knuckles to bend fully is easier in the first few weeks out of the splint than months later.
- A lump on the back of the hand over the fracture is often the healing bone. It usually shrinks over months.
- A dropped knuckle after a boxer’s fracture is common and usually doesn’t affect function.
- Grip comes back last. See stiff hand after a cast or splint if the fingers aren’t loosening.
A hand therapist checks rotation and position, molds the splint to the safe position, adjusts it as swelling drops, and decides when exercises out of the splint can start. See what a hand therapist does.
Get it checked today if
- A cut over the knuckle from a punch that hit teeth. Go to the ER. Mouth bacteria in a knuckle joint can cause a serious infection within a day or two. See bites to the hand.
- A finger crosses another when you make a fist.
- Numbness, or fingers that turn pale, blue or cold.
- Pain rising sharply instead of settling, or the splint feels much too tight even with the hand raised.
Get it checked if
- The splint has slipped so the knuckles are no longer bent.
- A red or sore pressure spot under the splint.
- The knuckles still won’t bend fully 3 to 4 weeks after the splint comes off.
- Pain over the fracture that’s no better at 6 weeks.
Two fingers held together, knuckles bent, and a fist check for rotation.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. A finger that crosses its neighbor when you make a fist needs to be seen this week, not at the end of the splint.
Part of: Hand, wrist and elbow splints: which one, why and how long
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.