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The Finger That Bent Sideways… and Stayed Fat
A sprained collateral ligament in a finger usually takes 3 to 6 weeks to stop hurting in normal use, about 3 months before it’s strong enough to trust in sport, and 6 to 12 months before the swelling fully settles. Most are treated with buddy taping and early movement, not surgery.
A collateral ligament sprain is a tear of one of the two ligaments running down the SIDES of a finger joint. It happens when the finger is forced sideways rather than backwards. Most of them sit at the middle joint, the PIP.
So here you are. A fat middle joint, a finger that won’t quite make a fist, and a handshake that makes you wince. It’s been weeks.
These take far longer to settle than people are told. A swollen, stiff PIP joint at three months is the normal course, not a sign anything went wrong.
The mistake is not the injury. It is being splinted too long for it.
Hold a PIP joint still in a rigid splint for weeks and it can lose a chunk of its bend that takes months of work to get back. Sometimes it never fully does. A slightly loose ligament rarely bothers anyone. A stiff middle joint bothers you every time you grip.
What is a finger collateral ligament injury?
Every finger joint has two collateral ligaments, one on each side, like the hinges on a door. They let the joint bend and straighten but stop it bending sideways. Force the finger sideways and one of them stretches or tears.
Ball sports, mostly.
- A basketball or volleyball catching the finger at an angle.
- A hand caught in a jersey.
- A fall where the finger snags.
The radial collateral ligament, on the thumb side of the finger, is the one usually injured, because the force typically comes from the outside.
It overlaps heavily with what people call a jammed finger, and with PIP sprains more generally. The distinguishing feature is the direction: sideways instability rather than pain on bending.
How do I know if I tore a ligament in my finger?
- Pain on ONE side of the joint. Press along both sides of the middle joint. The sore side is the injured ligament.
- Swelling around the whole joint within hours, often with bruising by the next day.
- Pain when the finger is pushed sideways, away from the sore side.
- A finger that feels wobbly when you pinch or grip something narrow, like a pen or a key.
Bending and straightening is usually possible, just sore and limited by swelling. A finger that can’t straighten at all, or sits crooked, is a different story. See the red flags at the end.
How is it diagnosed and graded?
Testing is done with the joint held at about 30 degrees of bend, comparing against the same finger on the other hand. Testing it straight gives a false sense of stability because other structures take over.
- Grade 1. Stretched, not torn. Tender over one side, stable when stressed. Full movement, just painful.
- Grade 2. Partial tear. Tender, some sideways give, but a definite firm endpoint.
- Grade 3. Complete tear. Opens up sideways with no endpoint, often with a visible angle when stressed.
X-ray matters here for one reason: a ligament can pull a fragment of bone off with it. An avulsion involving more than about a third of the joint surface, or one that is displaced, is a different problem from a soft tissue tear. The X-ray also checks that the joint is sitting centered, not partly out of place. Ultrasound or MRI is rarely needed.
The grade changes very little about the first six weeks. It changes a lot about whether a surgeon needs to see it.
How long does a finger collateral ligament sprain take to heal?
Grade 1 sits at the quick end of these ranges, grade 3 at the slow end. Your doctor’s or therapist’s dates beat mine.
- Days 0 to 5. Taped, elevated, iced for 10 to 15 minutes a few times a day if it helps. Gentle bending starts almost immediately.
- Weeks 1 to 3. Taped during activity, free movement otherwise. Do not immobilize a PIP joint in a rigid splint for weeks. Stiffness is a bigger enemy than looseness here.
- Weeks 3 to 6. Tape only for sport or risky tasks. The ligament is knitting but still weak, so no sideways testing.
- Weeks 6 to 12. Normal use. Sport returns with taping.
- Months 3 to 12. Swelling, morning stiffness and the ache in cold weather fade slowly.
Do I need a splint, or just buddy tape?
Grades 1 and 2, the vast majority: buddy taping to the neighboring finger, on the side of the injured ligament, so the neighbor blocks the sideways force.
- Two loops of tape, one around the segments below the middle joints and one around the segments above them. Never across the joint creases, or the joint can’t bend.
- A strip of gauze or foam between the fingers so the skin doesn’t go soggy and split.
- Change it daily, or whenever it’s wet.
- How long: 3 to 6 weeks for daily activity, then for sport until about 3 months. See buddy taping: when it helps and when it harms.
Grade 3: still usually treated without surgery in the fingers, often with 2 to 3 weeks in a protective finger splint, then the same taping progression. Surgery is reserved for a large displaced bony avulsion, a joint that won’t stay in place, or a ligament trapped outside the joint.
The thumb is the exception to all of this. A complete tear of the ulnar collateral ligament at the thumb’s knuckle, skier’s thumb, often needs surgical repair because the torn end flips outside a tendon and can never reattach. Different rules entirely.
Exercises for a sprained finger ligament
Start in the first few days, within comfort. Mild ache during the exercise is fine. Pain that lingers for hours afterwards means ease off.
- Gentle fist. Bend all fingers into a fist as far as comfortable, then straighten them fully. 10 reps, 4 to 5 times a day.
- Middle-joint blocking. Support the injured finger just below the middle joint with your other hand. Bend ONLY the middle joint. Hold 3 seconds, 10 reps, 4 to 5 times a day.
- Full straighten. Rest the hand palm-down on a table and actively lift and straighten the finger fully. Hold 5 seconds, 10 reps. Losing straightening is the sneaky one.
- Leave it out: wiggling it sideways to “test” it, cracking it, or forcing it with the other hand.
By week 3 the finger should bend close to its neighbor. If it doesn’t, read stiff fingers after a splint or injury before another month goes by.
Why is my finger still swollen months later?
Not instability. Swelling and stiffness. That’s what actually bothers people afterwards.
- Spindle-shaped swelling around the joint lasting 6 to 12 months, sometimes longer.
- Permanent mild thickening of the joint in some people.
- A few degrees of lost movement at the extremes.
- Aching in cold weather for the first year.
This is the information most people are missing, and it is why they start googling at month four convinced something has been missed.
Compression with a self-adherent wrap, wound firmly but not tight from the fingertip down, plus elevation and consistent gentle motion, do more for the swelling than anything else. See swelling after a hand injury.
(It’s the sitcom that keeps getting renewed for another season. Each morning the swelling’s back. Each month there’s a bit less of it.)
When can I play sport, drive and go back to work?
- Desk work and typing: usually within days, taped.
- Driving: once you can grip the wheel firmly and control the car in an emergency. For grade 1 and 2, usually within the first week or two.
- Manual work: taped, often 1 to 3 weeks for grade 1 and 2, and 4 to 6 weeks for grade 3.
- Ball sports: buddy taped, often 1 to 3 weeks for grade 1, 3 to 6 weeks for grade 2, and 6 to 8 weeks or longer for grade 3. Keep taping for sport until about 3 months.
- Gym, climbing, grappling: narrow grips and finger-only holds load the sides of the joint, so they come back last. See the gym after a hand injury.
Which window are you in?
Name the window, find where you are in it, act while it’s open.
- Weeks 0 to 3, OPEN: get moving. Immobilization beyond this is where the stiffness comes from.
- Week 6, CLOSING for bony injuries: displaced bony avulsions need fixing before this. After it, the fragment has healed in the wrong place.
- Months 3 to 6: movement is largely settled; swelling is not. A joint still stiff at this point is harder to shift, and usually needs a splint plus therapy rather than more waiting.
- Month 12: final appearance.
Everyone wants to know when the finger will look normal again. The honest answer is that it mostly will, about a year later, and slightly thicker than its neighbor forever.
What a hand therapist does differently
- Grades it properly, stressed at 30 degrees and compared with the other hand.
- Tapes it to the right neighbor, on the right side, with the loops off the joint creases.
- Measures the bend and straighten in degrees each visit, so stiffness is caught at week 3, not month 4.
- Makes a short-term finger splint for a grade 3, and gets you out of it on time.
- Checks the middle joint straightens fully, because a missed tendon injury on the back of the joint turns into a permanently bent finger.
Get it checked today if
- The finger sits crooked or at an angle at rest.
- The joint went out of place, even if it popped back in. See PIP fracture-dislocation.
- You can’t actively straighten the middle joint fully. A torn tendon on the back of the joint can drift into a boutonniere deformity if it’s missed.
- There’s a cut or wound over the joint.
- The fingertip is numb, pale or cold.
Get it checked if
- It’s still wobbly sideways and painful at 2 weeks.
- The finger isn’t bending close to its neighbor by week 3, or it’s moving less than it was last week.
- The middle joint is slowly drifting into a bend.
- Swelling is increasing after week 3 instead of slowly easing.
- You still need the tape for everyday tasks at 6 weeks.
Tape it, move it, and give the swelling a year. Splint it stiff and you’ll be fixing a different problem.
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’s wobbly sideways or won’t straighten deserves an X-ray and a proper look, not another week of tape.
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.