If you felt a sudden snap, pop or blow to the back of your ankle and cannot push off properly or stand on tiptoe on that leg, you may have ruptured your Achilles tendon. Go to an urgent treatment centre or A&E the same day. Ruptures are missed in a meaningful proportion of first presentations, and early treatment gives better results.
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Most Achilles pain is tendinopathy — a gradual breakdown in the tendon structure from repeated loading, causing pain and stiffness that build over weeks. A smaller number of people have a partial or complete tear. The distinction matters, because a disrupted tendon needs different loading advice and a longer recovery than one that is degenerate but intact. Ultrasound can tell them apart.
The Achilles is the thickest and strongest tendon in the body. It joins the two calf muscles — gastrocnemius and soleus — to the heel bone, and it transmits the force that lifts your heel off the ground every time you walk, run or climb stairs. During running it handles loads of several times body weight.
It has one significant vulnerability. Around two to six centimetres above the heel bone there is a stretch with a relatively poor blood supply. This is where mid-portion tendinopathy usually develops and where most ruptures happen.
Achilles problems fall into two locations, and they behave differently:
The commonest cause by far is tendinopathy: the tendon collagen fibres lose their orderly structure, ground substance and small blood vessels increase, and the tendon thickens and becomes painful. It is usually driven by a change in load — starting running, increasing distance too quickly, changing footwear or surface, or returning to sport after a break.
Other causes to be aware of:
Some medications matter here. Fluoroquinolone antibiotics such as ciprofloxacin are associated with tendon injury and rupture, sometimes weeks after the course. Tell your clinician if you have taken one recently.
| Tendinopathy | Complete rupture | |
|---|---|---|
| Onset | Gradual, over weeks | Sudden, during a specific movement |
| What it felt like | Ache that built up | A snap, pop, or being kicked from behind |
| Walking | Possible, though sore | Possible but with an obvious limp and weak push-off |
| Standing on tiptoe on that leg | Usually possible | Usually not possible |
| The tendon itself | Thickened and tender | A palpable gap may be felt |
| What to do | Book an assessment | Same-day urgent care |
A word on why this matters: some people can still walk after a complete rupture, because other muscles compensate. Being able to walk does not rule out a rupture. The clinical test used is the calf squeeze — with the patient lying face down and the foot hanging over the edge, squeezing the calf normally makes the foot point downwards, and no movement suggests rupture. Even that test has limits: if the small plantaris tendon is intact, the foot may still move.
Ultrasound is well suited to the Achilles. The tendon is superficial, so image quality is high, and it can be scanned while the ankle moves.
A scan can show:
Ultrasound performs well for confirming rupture and, importantly, for locating it and measuring the gap — information that helps decide between bracing and surgery.
Most patients we scan for Achilles pain have tendinopathy rather than a tear. That is the expected finding and usually the reassuring one.
The reason we look carefully for a partial tear anyway is that it changes the advice. A tendon that is degenerate or inflamed, but with its fibres intact, can generally be loaded progressively — that loading is the treatment. A tendon with genuinely disrupted fibres is a different proposition: the load management and the recovery advice both need to change, because the structure is not just irritated, it is discontinuous in part.
That distinction is difficult to make from examination alone, and it is the specific question worth putting to a scan when someone Achilles pain is not behaving as expected.
Describes a general pattern across the patients we scan, not any individual case.
Loading exercises are the main treatment for tendinopathy. Progressive calf strengthening — commonly heel drops and heel raises, progressed over time — has the strongest evidence. The programme differs for mid-portion and insertional problems: exercises that take the heel below the step help mid-portion tendinopathy but often aggravate insertional pain, where the range is kept flatter. This is a good reason to have the diagnosis confirmed before starting.
Load management. Reduce the aggravating activity rather than stopping altogether. Rest alone tends to leave the tendon weaker and no less painful.
Footwear and orthotics. A small heel raise reduces strain on the tendon and can help in the early stages. Stiff-backed shoes often aggravate insertional pain.
Time. Achilles tendinopathy is slow. Three to six months of consistent work is typical, and some cases take longer. That is normal, not failure.
What to be cautious about. Corticosteroid injection directly into the Achilles tendon is generally avoided because of the risk of weakening it further and precipitating rupture. Injections around the tendon or into an inflamed bursa are sometimes used, but the decision is a specialist one — see ultrasound-guided injections for how guidance affects placement.
Rupture management. Complete ruptures are treated either with functional bracing or with surgery. Many UK centres now manage most ruptures non-operatively, with outcomes comparable to surgery and fewer complications. That decision belongs to an orthopaedic team, and is influenced by the size of the gap between the tendon ends — which is one of the things a scan measures.
Suspect a rupture if the pain came on suddenly, you felt or heard a snap, and you cannot stand on tiptoe on that leg. Being able to walk does not rule it out. This needs same-day assessment, not a scheduled scan.
No. For tendinopathy, complete rest usually makes things worse in the medium term. Reduce the activities that provoke pain and begin progressive loading under guidance.
Typically three to six months of consistent loading work. Insertional problems often take longer than mid-portion ones. Slow improvement is expected.
Often yes, at reduced volume, if pain stays low during and after the run and settles by the next morning. Pain that worsens over subsequent days means the load is too high. Get a plan from a physiotherapist rather than guessing.
Not for every case. A scan is worth having if a tear is suspected, if the diagnosis is unclear, if pain has not improved after a proper period of rehabilitation, or if you need to know the state of the tendon before increasing your training.
Injecting corticosteroid directly into the Achilles risks weakening it and increasing the chance of rupture. It is generally avoided. Injections around the tendon or into a bursa are occasionally appropriate and are a specialist decision.
An Achilles and ankle ultrasound is £235. You receive instant verbal results at the appointment from the consultant performing your scan, with the written report following within 24 hours.
Related reading: tennis elbow versus golfer’s elbow applies the same tendinopathy reasoning in the upper limb, and our guide to MSK ultrasound sets out what the scan assesses. We also offer foot ultrasound and the full range of MSK ultrasound scans. Call 020 3633 4902 to book or to discuss whether a scan is the right next step.
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