Achilles tendonitis treatment: what it is, and what to do when it’s not healing

You’ve done the stretches and the heel drops, and it still hurts. That’s common. Here’s what Achilles tendonitis is, why it stalls, and how a Foot and Ankle Surgeon decides what comes next.

What is Achilles tendonitis?

Achilles tendonitis is irritation and wear in the large tendon at the back of your ankle, usually from overuse. You may also hear “tendinopathy,” a word for damage from long-term strain.^[5]

Symptoms include morning pain and stiffness, pain with activity that is worse the next day, a thickened tendon, and pain in shoes. Causes include doing too much too soon, a change of shoes, tight calves and a bony bump on the heel.^[5] It’s common in athletes and in middle-aged people who are overweight.^[6]

Why the tendon degenerates. Under a microscope, a long-painful tendon looks different. Its collagen fibers lose their orderly pattern, new small blood vessels and pain-sensing nerves grow in, and inflammatory cells gather.^[7] Researchers describe this as a healing response that has failed.^[6] At the heel bone, pressure from a bony prominence can add soft, mucus-like breakdown and calcium deposits.^[8] In our view, that’s why a stubborn tendon behaves less like a strain and more like damaged tissue that has stopped repairing itself.

Midportion or insertional: which type do you have?

	Midportion	Insertional
Where it hurts	More than 2 cm above the heel attachment[1]	Within 2 cm of the attachment[1]
Typical findings	Tiny tears, swelling, thickening[5]	Bone spurs, sometimes a Haglund’s bump[5,1]
12-week eccentric program satisfactory	89%[2]	32%[2]

Why is my Achilles tendonitis not healing?

Many people recover with exercise, which is why it comes first.^[1] But the failure rates are real, and they point to surgery as the answer for a defined group.

• Exercise has limits. On a 12-week program, 15 of 34 inactive patients (44%) did not improve, and neither did 18 of 45 athletes.^[9,10] The Dutch guideline reports 23% to 37% still having symptoms up to 10 years later.^[1]
• Insertional pain is harder. After other care had failed, only 7 of 25 people (28%) were recovered or much improved four months into eccentric exercise.^[11] One review estimates that 10% to 30% with insertional pain need surgery.^[12]
• The wrong exercise can keep it irritated. Deep stretches and heel drops squeeze an insertional tendon against the bone. Our Achilles tendonitis stretches guide shows what to change.
• Bone can keep rubbing. A Haglund’s bump presses on the tendon, and exercise can’t remove it.^[5]

What is the treatment for Achilles tendonitis?

1. Load the tendon. Do progressive calf strengthening for at least 12 weeks.^[1] Our heel-drop guide has the programs.
2. Add on at three months. Results are mixed. Shockwave beat eccentric exercise in one 50-person insertional trial, while a 2026 review of nine trials found no clinically meaningful gain over sham.^[11,13] PRP (platelet-rich plasma) showed no benefit over placebo.^[14] A steroid injection added to exercise improved scores at six months in one trial, yet the guideline urges caution.^[15,1]
3. Consider surgery at six months. That’s the point named by the Dutch guideline and the American Academy of Orthopaedic Surgeons.^[1,5] In our view, it’s also the point to stop repeating what failed and treat the damaged tissue itself.

How do Tenex and TenJet treat Achilles tendonitis?

Both remove damaged tendon tissue through a tiny cut, guided by ultrasound. Tenex uses an ultrasonic tip; TenJet uses high-pressure saline.^[3,16] Our Tenex and TenJet guide covers how they work. At the Achilles, one Tenex team worked in a clinic procedure room with local numbing only, through a cut of about 5 mm, and no patient needed opioid pain medicine.^[17] Patients typically spend two weeks in a walking boot, and most were released to full activity by 3 to 4 months.^[3]

What the studies report:

• 56 people, midportion or insertional: pain fell from 6.1 by about 3 points and function rose 25 points at one year.^[3]
• 34 people, insertional: moderate or severe pain fell from 68% to 15%, and all 14 with recorded work status were back at work by 12 weeks.^[17]
• 25 people, insertional, ultrasound-guided microresection: 84.6% success, counting two repeat procedures, at about 16 months.^[18]
• An older small-cut tendon procedure, not Tenex or TenJet: 77% of 39 runners reported good or excellent results about 17 years later.^[19]
• A randomized trial of a related procedure: radiofrequency microtenotomy (a heat-based wand) against physical therapy in 38 people with midportion pain. Pain went from 7.2 to 1.0 versus 5.9 to 3.1 at two years, significantly lower with the procedure. MRI showed no difference between groups.^[20] It isn’t Tenex or TenJet, but it’s the closest randomized evidence of a tendon procedure outperforming therapy.

How do small-incision procedures compare with open Achilles surgery?

Open surgery works. In 465 insertional operations, 89.6% had good or excellent results, with an average complication rate of 18.3%.^[12] Where smaller approaches have been compared with it, they recovered faster or had fewer complications:

Comparison	Smaller approach	Open surgery
Insertional, camera-guided: back to daily activities[4]	6.75 weeks	22.45 weeks
Haglund’s, camera-guided: complications[21]	4.1%	15.5%
Insertional, small-incision heel bone cut: unrestricted walking[22]	7.1 weeks	13.2 weeks
Insertional, small-incision heel bone cut: wound problems[22]	None	26.7%
Midportion: complications (a trend, not firm)[23]	5.3%	10.5%

Final pain and function scores were often similar.^[4,22,23]

None of those studies tested Tenex or TenJet, and we found no comparative study of either at the Achilles. At the elbow, Tenex and open surgery gave similar results in a small retrospective study.^[24] A 2023 review of 12 comparative studies of ultrasound-guided needle tenotomy reported the same outcomes as surgical tenotomy in two studies, with PRP and steroid effects fading over time.^[25]

So the sourced case is this: a 5 mm cut under local numbing, with favorable single-group results and early walking. If it falls short, researchers using the older small-cut procedure noted it did not stand in the way of later surgery.^[26]

Who is a poor candidate for Tenex or TenJet?

• A large Haglund’s bump or heavy calcium. In the 2026 study, these went with 13 to 14 points less improvement in function.^[3] Open surgery that removes the bump may suit you better. See Haglund’s deformity.
• Widespread tendon disease. With the older small-cut procedure, researchers advised that formal open exploration may be preferable for diffuse or multi-nodular disease.^[26]
• A tight calf that stretching hasn’t changed. Calf lengthening may fit instead.^[5]
• More than half the tendon damaged. This can call for a tendon transfer.^[5]

What are the limits of this evidence?

No randomized trial has tested Tenex or TenJet at the Achilles.^[3,27] In the 2026 study, 76% of the 39 who answered were satisfied, but 46% still called their symptoms unacceptable, and most kept some pain at one year.^[3] We found no published TenJet results at the Achilles; its data come from the elbow and the hip, and the hip study was sponsored by its maker.^[28,16] In a randomized trial of 36 Achilles patients, a radiofrequency wand matched open decompression at six months, and those surgeons stopped using it.^[29] A lead Tenex researcher has consulted for the company.^[30] Complications were 0.7% across 289 procedures, but small reports describe Achilles ruptures, a blood clot and worsening pain, and one called the complications similar to other Achilles surgery.^[30,31] Some insurers call Tenex investigational.^[27] Please call our office at 908-215-5953 to inquire about your insurance.

How we decide

Dr. Efe Ozturk is a Foot and Ankle Surgeon and podiatrist who offers both Tenex and TenJet. We examine the tendon, use X-ray and in-office ultrasound, and check that the first steps had a fair trial. Then we lay out the options side by side: Tenex, TenJet, calf lengthening, or open surgery through our Center for Lower Extremity Surgery (external site). See our Achilles tendon care page. We see patients in Lyndhurst, Paramus and Millburn, NJ.

Common questions

Can Achilles tendonitis heal on its own?

Don’t count on it. A network review of 29 trials advised against wait-and-see for midportion pain, because active treatments did better at three months.^[32]

How long does Achilles tendonitis take to heal?

Recovery can take months to years.^[1] After Tenex, most people in one study were released to full activity by 3 to 4 months.^[3]

How does Tenex compare with a PRP or cortisone shot?

That hasn’t been tested at the Achilles. At the elbow, Tenex and PRP gave similar results in 62 patients.^[33] In the 2023 review, steroid shots gave faster but temporary relief, while tenotomy relief came slower and lasted.^[25]

When to see a Foot and Ankle Surgeon or podiatrist