Written by Zita Sham, Principal Physiotherapist at Phoenix Rehab, AHPC A1302159H.Clinically reviewed by Louise Yow, Principal Physiotherapist & Director, AHPC A1300363H.Last reviewed 1 November 2026.
The sprain was months ago. The swelling went weeks ago. So why does the outside of the ankle still ache behind the bone, and why did it click on the stairs down to the platform this morning?
Pain behind the outer ankle bone that outlasts a sprain is often not the ligament at all. It is one of the two peroneal tendons that run behind that bone, whose job is to stop the ankle rolling. This page covers what they are, how to tell tendonitis from a tear from a tendon that slips, how long each takes, the signs that mean a doctor first, and what to do when it will not settle.
What is a peroneal tendon injury?
The peroneal tendons, peroneus longus and peroneus brevis, run behind the outer ankle bone and pull the foot outward to stop the ankle rolling. An injury ranges from tendonitis, an irritated and thickened tendon, to a split tear, usually in peroneus brevis, to subluxation, where the band holding the tendons in their groove tears and they flick over the bone.1
Key takeaways
- The peroneal tendons run behind the outer ankle bone and stop the ankle rolling. They are loaded hard in the same twist that sprains the ankle.
- Tendonitis comes on gradually and usually settles over weeks with progressive loading. A split tear, or a tendon that slips over the bone, does not knit back on its own.
- A tendon you can see or feel flick over the ankle bone needs a doctor’s opinion. Scans and surgical decisions are theirs.
- Pain that outlasts a sprain is tested by pressing along the tendon and resisting the foot turning out, against the other side. It is not read from how the sprain felt.
- Rest settles the ache. Loading rebuilds the tendon, and balance training retrains the ankle to catch itself.
First, the signs that mean a doctor, not this page
- Call 995 if the foot below the injury is cold, white or blue, or the ankle is visibly out of shape after a fall.
- Go to the emergency department now if you could not take four steps straight after the injury, or the bone itself is tender at the back edge of either ankle bone or at the bony point halfway along the outer edge of the foot. Those are the signs that call for an X-ray.
- See a doctor the same day if the ankle is hot, red and swollen with a fever, or one calf is swollen and tender on its own.
- See a doctor soon if you can see or feel a tendon flick over the outer ankle bone, the ankle keeps giving way, or the pain has not eased after four to six weeks of sensible care.
None of these? Then the rest of this page is for you.
Where it hurts tells you which tendon
| Where | What it usually points to | Who checks it |
|---|---|---|
| Behind and just below the outer ankle bone, along a cord you can feel | Peroneus brevis, the tendon most often torn | A physiotherapist tests it. A doctor orders imaging if a tear is suspected |
| The outer edge of the foot, halfway along, sometimes into the sole | Peroneus longus, which dives under the foot to the arch | The same |
| A flick or snap over the ankle bone when you turn the foot out, which you may be able to see | Subluxation. The retinaculum that holds the tendons in their groove has torn | A doctor, usually a foot and ankle surgeon |
| A bony point on the outer mid-foot, bruised after a twist | The base of the fifth metatarsal, where brevis attaches. It can fracture | A doctor and an X-ray first |
Tendonitis, a tear, or a tendon that slips?
You cannot tell them apart by how much it hurts. Tendonitis builds over weeks, is worst starting out and eases once warm. A split tear usually follows a sprain, aches behind the bone for months, and hurts when the foot is turned out against resistance. Subluxation announces itself: a flick or snap over the bone, sometimes with a click you can hear.1
Tears are commonly missed at first, because they are read as a sprain that has not settled.2 That is why the tests below matter more than the label you were given in the first week. Imaging, when it is needed, is an ultrasound or MRI that a doctor orders.
How long does a peroneal tendon injury take to heal?
Tendonitis typically settles over six to eight weeks on a loading program, longer if it has been there for months. A split tear does not knit back together. Many ankles are made strong and steady around it with strengthening, and a surgeon decides whether repair is needed when they are not. A tendon that keeps slipping out of its groove needs a surgeon’s opinion, because the retinaculum does not tighten on its own. After any repair, the surgeon’s protocol sets the timeline, usually in months.
Can you walk on it?
With tendonitis, usually yes. Walking on flat ground within comfort is part of the recovery. What to stop until it has been tested: uneven ground, trails, hills, and the sport that set it off. If you could not take weight through it straight after a twist, that is the emergency department sign above, not a walking question.
Why the sprain healed and the ankle did not
The thinking goes: it was a sprain, sprains take time, give it time.
At week ten you are still stepping off the bus with the other foot first. You take the flat route round the hawker centre because the broken pavement makes the ankle flinch. You have not run on a Sunday since the sprain. Then you roll it again, lightly, on the stairs down to the MRT platform, and the whole thing starts over.
That pattern has a reason. The ligament on the outside of the ankle heals in weeks. The peroneal tendons are the cord that catches the ankle before it rolls, and the twist that tore the ligament loaded them hard too. Swelling is the first thing to leave. The strength and reaction speed of the tendon are the last things to come back, and they come back only when they are trained. Rest settles the ache and leaves the tendon as weak as it was the day the swelling went down. In trials, balance and strength training after an ankle sprain lowered the rate of re-sprain compared with no exercise.4
Has anyone pressed along the tendon behind the ankle bone, tested you turning the foot out against resistance, and timed how long you can stand on that leg with your eyes shut, against the other side? If not, nobody yet knows whether this is a tendon that needs loading, a tear that needs a scan, or a retinaculum that needs a surgeon. The race in January does not care which.
Physiotherapy for a peroneal tendon injury or tear
Finding the real problem is half the battle. Treating it is the other half.
At the Assessment & Treatment, a physiotherapist asks how it started, in your words, then tests the things a sprain rarely gets tested for: tenderness along the course of each tendon, pain and strength when you turn the foot out against resistance, single-leg balance with eyes open and shut, how many single-leg heel raises each side can do, and whether the tendon stays in its groove. If the tests point to a tear or a tendon that is slipping, we tell you and write to your doctor. Scans and surgical decisions are theirs. Physiotherapists do not order imaging.
If the tests point to a split tear, physiotherapy does not try to heal the split. It strengthens the peroneals and the ankle around it, retrains balance, and tracks whether the ankle stops giving way. Most peroneus brevis split tears managed this way do not need surgery; the ones that keep giving way or keep swelling go to a surgeon for an opinion.
If it is the tendon that needs training, most of the 45 minutes is treatment: hands-on work for the calf and ankle, a loading program for the peroneals that starts at a level the tendon can take and is measured up at each review, balance retraining, and taping or a footwear change while it settles. Progressive loading, not rest, is what tendons respond to in trials.3 You leave knowing which stage you are in, what is limiting the ankle, and a written plan.
More on physiotherapy for ankle pain, the ankle sprain that started it, and the peroneal tendonitis exercises we build the loading program from. Every appointment is one to one with your physiotherapist for the full 45 minutes, at five clinics: Orchard, Tampines, Serangoon, Tanjong Pagar and Jurong East. Bring any scan report you have.
Questions about peroneal tendon injuries
How do I know if my peroneal tendon is torn?
You cannot tell from pain alone. A tear is suspected when an ache behind the outer ankle bone outlasts a sprain by weeks, the tendon is tender along its length, and turning the foot out against resistance hurts or feels weak. It is confirmed by an ultrasound or MRI that a doctor orders.
Can a torn peroneal tendon heal on its own?
A split in the tendon does not knit back together. The ankle can often be made strong and steady around it with a strengthening and balance program, and a surgeon decides whether repair is needed when it cannot.
What is the difference between peroneal tendonitis and a tear?
Tendonitis is an irritated, thickened tendon that builds up over weeks, hurts most starting out and eases once warm. A tear is a split in the tendon fibers, usually after a sprain, with a persistent ache behind the bone and pain when the foot is turned out against resistance. The two are told apart by testing and, where needed, imaging.
Can you walk with a peroneal tendon injury?
With tendonitis, usually yes, on flat ground within comfort. Stop uneven ground, hills and the sport that set it off until the tendon has been tested. If you could not take weight through the ankle straight after a twist, see a doctor for an X-ray first.
What is peroneal tendon subluxation?
The peroneal tendons sit in a groove behind the outer ankle bone, held by a band called the superior peroneal retinaculum. If that band tears, usually in a forceful twist, the tendons can flick over the bone when the foot turns out. You may feel or see the snap. It is a decision for a doctor, usually a foot and ankle surgeon.
Four months after the sprain and the outside of the ankle still aches on the platform stairs? Get Assessed & Treated, and leave knowing whether it is the tendon, what it can take today, and what the next stage asks of it.
Sources: 1. Davda K, Malhotra K, O’Donnell P, Singh D, Cullen N. Peroneal tendon disorders. EFORT Open Rev. 2017;2(6):281-292. 2. Dombek MF, Lamm BM, Saltrick K, Mendicino RW, Catanzariti AR. Peroneal tendon tears: a retrospective review. J Foot Ankle Surg. 2003;42(5):250-258. 3. Cardoso TB, Pizzari T, Kinsella R, Hope D, Cook JL. Current trends in tendinopathy management. Best Pract Res Clin Rheumatol. 2019;33(1):122-140. 4. Doherty C, Bleakley C, Delahunt E, Holden S. Treatment and prevention of acute and recurrent ankle sprain: an overview of systematic reviews with meta-analysis. Br J Sports Med. 2017;51(2):113-125.
Also on this site: the page on eversion ankle injuries covers the less common sprain to the inside of the ankle.
Where are you with this right now?
1. It is settling on its own
Most injuries and most flare-ups settle over weeks with sensible load management and a return to normal movement. Improvement is judged over a month, not over a day, and good days and bad days inside that are usual. If you are doing more this month than last, and sleeping better, it is behaving the way it should. You do not need us for this, and we would rather say so.
2. It has stopped improving
You have adapted without noticing. The other side takes the load, you plan movements you used to make without thinking, and you have quietly dropped things you used to do.
What our patients say
Google reviews from our clinics in Singapore.
Pain is the first thing to leave. Movement and strength are the last things trained back, and most people stop before that part is done. That is the gap worth measuring, and it is not measured by how you feel on the day.
The Stalled Recovery Review is three appointments over three weeks with the same therapist, because what a joint does under load cannot be read in one visit. The first finds what is limiting it. The next two measure how it responds. $690, nett, no GST, which is three appointments at $230.
3. You have had surgery, or you have a date
Recovery after an operation has a shape, and knowing which stage you are in tells you whether you are on it. If you had surgery on the ankle, see the Ankle Ligament Reconstruction Recovery Program or the Ankle Fracture Surgery Recovery Program. For a peroneal tendon repair on its own, or any other operation, see all the recovery programs, hand and physiotherapy.
All of it runs on the same four stages. The Phoenix Recovery Protocol explains what each stage works on and what you have to meet to move up. No referral needed to start.
Next step
Find out which stage you are in
Pain is the first thing to leave. Movement and strength are the last things trained back, and most people stop before that part is done. One Assessment and Treatment is a single 45-minute appointment at $230, nett, no GST. Your therapist finds what is actually limiting you, treats it in the same appointment, and you leave with your current stage and a written plan.
Prefer to phone? Each of our five clinics has its own number on the clinics page. No referral needed to book.
Related reading
Where we are
Clinics across Singapore
ORCHARD
400 Orchard Road #12-12
Orchard Towers, S238875
NS22 Orchard MRT
Physiotherapy and hand therapy in Orchard →
WhatsApp 8800 1830TAMPINES
9 Tampines Grande #01-20
Asia Green, S528735
EW2DT32 Tampines MRT
Physiotherapy and hand therapy in Tampines →
WhatsApp 8780 9608SERANGOON
265 Serangoon Central Drive #04-269
S550265 · Lift C only
NE12CC13 Serangoon MRT
Physiotherapy and hand therapy in Serangoon →
WhatsApp 8892 4121TANJONG PAGAR
10 Anson Road #02-77A
International Plaza, S079903
EW15 Tanjong Pagar MRT
Physiotherapy and hand therapy in Tanjong Pagar →
WhatsApp 8227 7074JURONG EAST
2 Venture Drive #02-02
Vision Exchange, S608526
NS1EW24 Jurong East MRT
Physiotherapy and hand therapy in Jurong East →
WhatsApp 8242 7340