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The Repair That Fails Quietly, by a Few Degrees at a Time
Most extensor tendon repairs in the hand and fingers take about 12 weeks to recover: 4 to 6 weeks protected in a splint, light use from weeks 6 to 8, strengthening from week 8, and full heavy use around week 12. Fingertip and middle-joint injuries often need 6 to 8 weeks of splinting. The main risk isn’t the tendon snapping. It’s a finger that slowly stops straightening all the way.
The tendons on the back of your hand and fingers straighten them. Cut one and it gets repaired, and the recovery looks nothing like a flexor tendon repair, even though people assume it’s the mirror image.
Flexor repairs fail loudly. The tendon ruptures and the finger stops bending.
Extensor repairs usually fail quietly, as a lag. The finger bends fine, looks fine, works fine…and just doesn’t quite straighten all the way. Ten degrees. Then twenty.
Nobody notices it happening, which is exactly the problem. By the time someone points at it, the tendon has often healed at that length, and the degrees it lost don’t come back with exercise.
What’s actually happening in there
Flexor tendons are thick round cords. Extensor tendons are thin flat ribbons, sitting directly under the skin with almost nothing between them and the bone underneath.
Two consequences follow from that, and they run in opposite directions.
First, there’s less tendon to stitch into. An extensor repair holds less well than a flexor repair of the same quality, so it needs protecting.
Second, a flat ribbon lying against bone with barely any tissue between them sticks to that bone readily. Protect it too well and it scars down flat, and a tendon glued to bone can’t slide.
Then there’s the geometry. Extensor tendons have very little slack in the system. A repair that heals even a few millimeters longer than it started…because it stretched slightly, or a stitch loosened, or scar filled a gap…costs you degrees of straightening permanently.
There’s just no margin, space or reserve to absorb it.
(That’s the extensor lag. Not a failure of effort. A few millimeters of length, converted into a finger that won’t flatten on a table.)
Where the cut was changes everything
Extensor injuries get grouped by level, called zones, and the zone dictates the plan. Your surgeon’s notes or your hand therapist will tell you which one you had. The full zone map is in extensor tendon injuries by zone.
- Over the fingertip joint: that’s mallet finger, usually splinted rather than stitched. The end joint is held straight continuously for 6 to 8 weeks.
- Over the middle knuckle: the central slip, and the risk of boutonnière deformity if it isn’t handled properly. The middle joint is usually protected straight for about 6 weeks, sometimes with carefully limited motion.
- Over the back of the hand and the big knuckles: the classic repair territory, and the zone that responds well to modern early-motion splinting.
- At the wrist and forearm: multiple tendons in tight compartments, higher adhesion risk, longer rehab. The wrist is usually splinted too.
Ask which zone yours was. Two people with “an extensor tendon repair” can be on completely different protocols and both be correct.
What splint will I wear, and for how long?
The old approach was straightforward: splint everything straight for weeks, protect the repair completely, then start moving. It protected the repair well and produced a lot of stiff fingers.
Modern practice for many of these leans on controlled early motion instead, and one splinting idea in particular is worth understanding because it looks strange.
A relative motion splint holds the repaired finger’s big knuckle slightly HIGHER than its neighbors…a small yoke across the back of the hand, nothing else. That tiny difference in position takes tension off the repaired tendon while letting you use the hand almost normally. More in relative motion yoke splints.
It looks far too casual for someone who’s just had a tendon repaired. It works because the mechanics are doing the protecting rather than the immobilization.
A flexor repair is protected by holding still. An extensor repair is protected by position, so it can keep moving.
Which splint you get depends on the zone and the surgeon. What doesn’t vary: it goes on early, it stays on, and the exercises get done daily.
- Hours: full-time, day and night, for the protected phase. It comes off only when your therapist says it can, for skin care or specific exercises.
- Weeks: typically 4 to 6 weeks full-time for hand and big-knuckle repairs, 6 to 8 weeks for mallet and central slip injuries, then weaned over the following 2 weeks.
- The rule: if the splint comes off for a wash, keep the finger STRAIGHT and supported on a flat surface. One unguarded bend in week 2 can stretch a repair that took an hour to stitch.
Extensor tendon repair recovery week by week
Your surgeon and hand therapist set your protocol. Their dates beat mine.
- Weeks 0 to 2: splinted, elevated, wound care. Controlled movement only as your protocol allows. Stitches out around day 10 to 14.
- Weeks 2 to 4: still splinted full-time. Swelling managed, gentle scar care begins once the wound has fully healed. Movement inside the splint as prescribed.
- Weeks 4 to 6: splint weaning often begins for hand-level repairs. This is when any lag becomes visible, and it’s the point to escalate rather than accept.
- Weeks 6 to 8: active straightening work, scar management, light functional use. Still no resistance.
- Weeks 8 to 12: strengthening. Gripping returns. Full fist with the wrist bent is usually the last movement to come back.
- Months 3 to 6: full use. Scar softens, remaining stiffness slowly improves.
Exercises after extensor tendon repair
Do only what your therapist has cleared for your zone and your week. Doing the week 8 exercises in week 3 is how repairs stretch.
- In the splint (protected phase): the movements your protocol allows, usually gentle active bending and straightening within the splint’s limits. Typically 10 reps, every 1 to 2 hours while awake.
- Flat hand lifts (once cleared): hand flat on a table, lift the repaired finger straight up off the surface and hold 5 seconds. 10 reps, 3 to 4 times a day. This works the straightening muscle without stretching the repair.
- Partial then full fist: start with a gentle half-fist and progress toward a full fist over weeks, as cleared. Forcing a full fist early is the classic way to stretch a repair and create a lag.
- Scar massage: once the wound has fully healed, firm small circles over the scar, a few minutes, 2 to 3 times a day. Keeps the tendon gliding under the skin. See scar management after hand surgery.
- Strengthening (usually from week 8): light putty or a soft ball, building gradually over weeks 8 to 12.
If the finger is straightening well but won’t bend into a fist by around week 8, the tendon may be stuck. That’s the stiffness side of the trade, and it’s worth reading stiff hand after a cast or surgery.
How to check for an extensor lag at home
The thing to watch for, weekly: lay the hand flat on a table and see whether that finger goes down as flat as its neighbors. A gap that’s growing rather than shrinking between weeks 4 and 8 is the signal to get seen, not to wait for the next scheduled appointment.
A hand therapist measures the same thing with a goniometer: how far the finger straightens on its own versus how far it straightens when pushed. If it straightens fully when pushed but not on its own, that difference IS the lag.
Here’s the window:
- Open (weeks 0 to 6): a lag spotted now can often be pulled back by going back into a straight splint for a few more weeks.
- Closing (weeks 6 to 12): the tendon is maturing at whatever length it’s at. Re-splinting can still help, but less each week.
- Shut (past about 3 months): the length is set. A small lag often doesn’t bother daily life much. A large one that does is a conversation with your surgeon about further surgery. The goal changes, not the effort.
When can I work, drive and use my hand normally?
- Desk work: often within 1 to 2 weeks, typing one-handed or carefully around the splint, if your surgeon agrees.
- Light manual work: usually from around week 8, once the splint is off and no resistance restrictions remain.
- Heavy manual work: around 12 weeks, sometimes longer for wrist and forearm repairs. See returning to work after a hand injury.
- Driving: not while the splint stops you gripping the wheel firmly. Usually once the splint is off and you could control the car in an emergency, often 6 to 8 weeks.
- Sport and gym: about 12 weeks for gripping and contact sport. Push-ups and planks load the back of the hand, so they wait too.
Call your surgeon today if
- The finger suddenly drops or can’t straighten at all, especially after a pop or a slip. That can be a rupture, and a quick repair beats a late one.
- Increasing redness, heat, throbbing, discharge, or a fever.
- The wound opens, or you can see tendon.
- The splint causes numbness, a white or blue fingertip, or a painful pressure spot that doesn’t ease when you loosen the strap.
Get it checked if
- The finger sits lower on the table than its neighbors, and the gap is growing between weeks 4 and 8.
- The finger straightens well but still won’t bend into a fist by week 8.
- Swelling and stiffness are getting worse rather than better after week 3.
- A firm, tender lump in the scar that’s limiting movement.
Extensor repairs rarely snap. They stretch quietly. Check it flat on the table every week.
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. Follow your own surgeon’s and therapist’s protocol over anything here.
Part of: Recovery after hand, wrist and elbow surgery: every week-by-week guide
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.