Ross Hauser, MD; Danielle Matias, PA-C; Demi Foster, APRN

You may recognize the pattern: tightness at the back of the ankle initially settles, then returns when you resume walking, running, or climbing stairs. Rest, shoe inserts, a boot, physical therapy, or an injection may have helped for a while. Eventually, the discussion turns to whether you have a tendon tear and whether surgery is necessary.

We want to preserve the useful questions within that experience. What exactly is injured? Why do symptoms keep returning? What can rehabilitation accomplish? When does a partial tear need a different approach? What does the research actually show about prolotherapy, platelet-rich plasma, and cell-based treatment?

This article addresses chronic tendon pain, insertional and midportion disease, partial tears, complete ruptures, imaging, nonsurgical care, surgery, and recovery. A complete acute rupture requires prompt assessment and a rupture-specific treatment plan. It should not be treated as another episode of chronic tendinopathy.

Understanding the Achilles tendon and the terms in your diagnosis

The Achilles tendon connects the calf muscles to the heel bone. It transmits force when you push off, rise onto your toes, walk uphill, run, or jump. A problem here can affect both comfortable walking and more demanding athletic activity.

Tendinopathy is the clinical term for a painful tendon disorder associated with impaired function. “Tendinitis” emphasizes inflammation; “tendinosis” emphasizes degenerative tissue changes. These labels do not, by themselves, establish the amount of damage or identify the best treatment. Chronic disease is more complex than a simple progression from inflammation to a tendon with no inflammatory activity.

Insertional tendinopathy involves the attachment at the heel. Midportion tendinopathy involves the tendon above the attachment. A partial tear disrupts some fibers; a complete rupture disrupts the tendon’s continuity. These distinctions are consistent with a contemporary review of Achilles tendinopathy, which describes the roles of mechanical loading, inflammation, and metabolic factors. (1)

Symptoms may include morning stiffness, tenderness, a thickened or nodular tendon, and pain with activities that load the calf–Achilles unit. A sudden sharp change, new weakness, or a pop deserves reassessment rather than an assumption that the usual tendon pain has simply flared.

Why do symptoms start or return?

Sometimes symptoms follow a noticeable increase in activity: more running, a new exercise program, hills, or a return to sport after reduced activity. In other cases, the onset is gradual. A period of rest may reduce pain without restoring the ability to tolerate the previous workload.

The surface and type of activity can change tendon demand. In a laboratory study of 18 healthy runners, treadmill running produced higher modeled Achilles loads than overground running under the study conditions. This does not prove that treadmills cause tears or that all runners should avoid them. It illustrates why a change in training can matter even when the distance appears unchanged. (2)

Running on sand, changing footwear, and moving abruptly to more demanding activity are also relevant details to describe. We should not use a surface label alone to decide what caused an injury. Nor does every painful Achilles tendon indicate underlying ankle instability.

Is the surrounding ankle involved?

The original clinical discussion considered whether a tendon might be compensating for a problem elsewhere in the ankle. This remains a useful question when examination findings support it. It is a possible contribution in selected patients, not an established explanation for every Achilles disorder.

Pain at the back of the ankle can also involve the retrocalcaneal bursa or posterior impingement. An os trigonum is an accessory bone behind the ankle that can be relevant to pain with certain movements; its presence on imaging does not automatically make it the pain source. Our heel bursitis article explains bursal symptoms, steroid concerns, and Haglund’s deformity in greater detail.

Is it tendinopathy or a partial tear?

A partial tear can be mistaken for worsening tendinopathy. A review of the limited literature emphasized a sharp onset of pain, difficulty fully loading the tendon, and weakness with heel raises as findings that deserve attention. A history of an intratendinous corticosteroid injection may be relevant, but does not diagnose a tear on its own. (3)

This distinction changes the discussion about exercise. A painful but intact tendon and a partially torn tendon may need different initial loading restrictions. The same review described conservative care using heel elevation, temporary avoidance of stretching, and staged loading, with surgery considered for persistent problems. The evidence was sparse; it should not be converted into a universal home-treatment protocol. (3)

For the reader, the useful question is whether a new symptom pattern has been evaluated adequately. Continuing a familiar exercise solely because it was once prescribed may be inappropriate after a new injury.

Protection and loading are parts of different recovery stages

We distinguish temporary protection after a tear from prolonged avoidance of all tendon loading. A partial tear may initially require reduced strain, followed by a staged return to strengthening. This differs from the exercise discussion for an intact tendon with chronic pain. The diagnosis and stage of recovery determine which approach applies. (3)

Is an MRI necessary? What can ultrasound show?

An MRI can show the location and extent of a tear, tendon changes, and associated abnormalities. Ultrasound can assess tendon structure dynamically and show surrounding tissue. Both can be useful when the diagnosis is uncertain or a tear is suspected. (4)

Imaging is not required in every straightforward presentation of tendinopathy. The 2024 clinical practice guideline specifically addresses midportion Achilles tendinopathy, including diagnosis, examination, imaging, and physical therapy. Its scope should not be extended automatically to complete ruptures or insertional disease. (5)

An abnormal scan does not measure pain or strength directly. Likewise, a scan that appears improved does not establish that the tendon is ready for sprinting or jumping. The practical issue is whether imaging answers a question that changes diagnosis or care.

Video: Ultrasound diagnosis and Prolotherapy treatments for Achilles tendon problems

In this video, Danielle Steilen-Matias explains ultrasound findings in Achilles tendon problems. The images help readers distinguish tendon thickening and abnormal tissue appearance from the idea that all posterior heel pain is bursitis.

The video also illustrates that tendon abnormalities can involve both the heel attachment and tissue farther above it. Identifying the location helps explain why a bursa-focused diagnosis may not account for all symptoms.

The video describes the clinic’s perspective on injection treatment. The research below separates that perspective from what controlled studies have established. Ultrasound findings alone cannot predict treatment success.

Insertional and midportion problems need different rehabilitation considerations

For chronic tendon pain, rehabilitation aims to improve tolerance of load. Exercises can involve calf strengthening, heel raises, and progression toward the activities a person wants to resume. “Eccentric” loading means the calf–tendon unit is lengthening while producing force, as during controlled lowering from a heel raise.

The tendon insertion also experiences compression against the heel as the ankle bends upward. A 2025 randomized trial of 42 people with insertional tendinopathy found better outcomes at 12 and 24 weeks with lower-compression rehabilitation. That program limited dorsiflexion during exercise, avoided calf stretching, and included heel lifts. (6)

The important distinction is the location of disease. Deep heel drops below a step should not be assumed appropriate for a painful insertion merely because they are associated with Achilles rehabilitation.

Equinus, calf tightness, and heel spurs

Equinus describes limited upward ankle movement. Calf flexibility and ankle motion may be relevant to the assessment, but an irritable insertion should not automatically be stretched aggressively.

Tendon thickening, calcification, and heel spurs may coexist with symptoms. They should not be described as proof that the tendon intentionally built a stabilizing structure. Haglund-related compression and the surrounding bursa are discussed in our companion heel bursitis article.

Anti-inflammatory medication and physical therapy

Pain relief and rehabilitation benefit are different outcomes. In a randomized trial of 69 people with early Achilles tendinopathy, adding a seven-day course of naproxen to a rehabilitation program did not improve outcomes compared with placebo plus the same rehabilitation. Symptoms improved over time without measurable structural imaging changes. (7)

This does not mean anti-inflammatory medicines never help symptoms. It means this trial did not show an additional rehabilitation benefit from that short course. It also illustrates why feeling better and seeing a different tendon image need not occur together.

Rest, a boot, massage, or manual techniques may form part of an individual treatment history. If relief is temporary, the question becomes how activity tolerance is being rebuilt and whether the diagnosis remains correct. Failure of one rehabilitation program does not prove that all exercise will fail.

Does shockwave therapy help?

Shockwave treatment delivers acoustic energy to the affected region. Radial and focused approaches differ in how energy is delivered; they should not be classified simply as treatments for chronic versus acute disease.

A retrospective cohort of 87 patients with symptoms persisting despite exercise compared radial treatment with combined radial and focused treatment and reported functional gains. Its design cannot establish superiority over rehabilitation alone. (8)

A randomized trial of 119 patients with insertional tendinopathy found no additional overall pain or function benefit at 24 weeks from radial shockwave added to eccentric exercise compared with sham shockwave plus exercise. (9)

The diagnosis, protocol, and comparison treatment matter. These studies do not support promising that shockwave will resolve every difficult Achilles problem.

Prolotherapy for chronic Achilles tendinopathy

Dextrose prolotherapy uses a dextrose-containing injection intended to stimulate a local tissue response. Proposed repair and pain-modulating mechanisms provide a rationale for research; they do not prove complete tendon restoration in an individual.

Our 2016 systematic review examined dextrose prolotherapy across chronic musculoskeletal conditions and reported supportive findings for some applications. It included different study designs and diagnoses. It should be read as background evidence rather than a definitive Achilles tear or bursitis trial. (10)

The relevant treatment target must be specified. Midportion tendon disease, insertional disease, a partially torn tendon, a painful bursa, and documented ligament instability are different findings. They should not be grouped into one injection success rate.

Early reports and different injection targets

Early reports published in 2005 and 2007 examined subcutaneous injections, meaning injections beneath the skin. A later systematic review discussed this early literature and its methodological limitations. These approaches differ from injections placed within the tendon. We should not combine their results as though they tested the same treatment. (11)

The 2007 ultrasound-guided pilot study

A pilot study enrolled 36 people with chronic Achilles symptoms. Thirty-two patients, representing 33 tendons, completed the treatment successfully; this wording describes completion, not a cure rate. The study reported reduced pain and some improved ultrasound findings after ultrasound-guided dextrose injections. Participants received an average of four treatments, with a range of two to eleven. Among 30 patients available for later telephone follow-up, 20 reported no symptoms, nine mild symptoms, and one moderate symptoms. There was no control group, so improvement cannot be attributed to the injections alone. (12)

The 2010 insertional and midportion study

A larger observational study included 99 patients with 108 symptomatic tendons: 86 midportion and 22 insertional. Pain at rest, during daily activity, and during sport improved in both groups, and some ultrasound abnormalities decreased. The median number of treatment consultations was five, with substantial variation between patients. Follow-up averaged approximately 29 months. The study had no untreated or rehabilitation-only comparison group. It supports further investigation but does not establish a standard number of injections or show that every tear healed. (13)

The randomized Achilles study

A small trial compared eccentric exercise, prolotherapy, and their combination for Achilles tendinosis. Forty-three participants began treatment. All groups improved, with faster improvement in some outcomes in the prolotherapy-containing groups and broadly similar longer-term outcomes. It concerned midportion tendinopathy, not complete rupture or isolated bursitis. (14)

What the 2015 lower-limb review established

A systematic review assessed eight studies involving several conditions, including Achilles tendinopathy, plantar fasciopathy, and Osgood–Schlatter disease. It found limited support for improvements in pain and function, with generally poor study quality. Pooling these different diagnoses into an Achilles success percentage would be misleading. No adverse events were reported in the included studies, but small studies and incomplete reporting cannot establish that a procedure has no risks. (11)

The 2017 study of tears within the tendon

A case series followed 43 patients with tears within the Achilles tendon. Thirty returned questionnaires: the reported 70% was the response rate, not a treatment success rate. Treatment combined a dextrose injection, four to six weeks in a boot, and progressive rehabilitation. Pain and function scores improved, but there was no control group to separate these contributions. (15)

Follow-up ultrasound was available for 26 patients at an average of about five weeks, not five months. Seven tears were no longer visible; this did not establish restored tendon strength. One patient with a previous deep vein thrombosis developed another clot during the treatment period. The study cannot determine which part of care caused improvement or the complication. Improvement also did not mean everyone returned to their previous sporting level. (15)

The review published online in 2017 and in print in 2018

Another review examined both sclerotherapy and prolotherapy, which are different interventions. It included 18 articles in its qualitative analysis; 13 human studies assessed pain or satisfaction, and six entered the meta-analysis. Most reported favorable findings, but study quality was limited. The often-cited “12 of 13” describes positive studies across these approaches, not a patient cure rate or 13 trials of dextrose alone. One serious and two minor adverse events were reported. The authors called for stronger randomized studies and longer follow-up. (16)

The 2024 review of randomized tendon studies

A review included 20 randomized trials involving 1,136 participants across sports-related tendon conditions. Only one trial concerned the Achilles tendon. Protocols and comparison treatments varied, and the search ended in July 2021. Its 2024 publication date does not mean it incorporated newly conducted 2024 trials. Favorable results across several diagnoses cannot establish an Achilles-specific cure rate. (17)

The newer study published in 2025

A retrospective study reviewed 132 patients with nontraumatic Achilles tendinopathy. It reported symptom resolution within 12 months in 98 patients, or 74.2%, and improvement after one treatment in 71, or 53.8%. No adverse events were reported. Records dated from 2014–2017, there was no comparison group, and patients lost to follow-up were excluded. These limitations prevent attributing all improvement to prolotherapy or treating the results as proof of safety. (18)

The 2026 review of prolotherapy and paratenon stripping

A newer review discusses dextrose prolotherapy and a separate intervention involving tissue around the tendon, called paratenon stripping. Preliminary results were encouraging, but small studies and a lack of large randomized comparisons leave the approach’s role unsettled. A combined procedure’s results cannot be attributed to dextrose alone. This is a review, not a new efficacy trial. (19)

Research for plantar heel pain is a separate question

For patients with pain beneath the heel as well as Achilles symptoms, a 2026 plantar-fasciitis review found different short- and intermediate-term results for dextrose and steroids. Steroids performed better at one month; dextrose improved foot function more at three months, without a significant pain difference then. This is indirect evidence for a different structure. (20)

PRP for Achilles tendinopathy: why the evidence appears conflicting

PRP concentrates platelets and associated signaling proteins from a patient’s blood. It is different from dextrose prolotherapy and is not a stem-cell product. PRP should not be described as glue that physically joins torn tendon ends. Proposed biological effects and restoration of tendon continuity are different claims.

Laboratory and rat research examined how PRP affected tendon-derived cells and experimental rupture repair. Such findings provide biological plausibility, not proof that standard human PRP injections reconnect torn tendons. (21)

A retrospective study of 73 patients with 83 non-insertional Achilles tendons reported satisfaction for 91.6% of tendons and no ruptures. Without a comparison group, these observations cannot establish treatment effectiveness or rupture prevention. (22)

A larger randomized trial of 240 patients found that one PRP injection did not improve midportion tendon-related function at six months compared with a sham procedure. Injection discomfort, swelling, and bruising occurred. (23)

We preserve both the encouraging observational findings and the less favorable randomized evidence. Different preparations and schedules may be worth investigating, but the negative trial does not prove that additional injections would work. Nor can symptoms after one treatment establish that a patient received an inadequate treatment course.

What do before-and-after tendon images mean?

The clinic ultrasound illustration shows a change in tendon appearance in an individual case. It should remain clearly identified as a case illustration. A darker area becoming lighter is not proof of complete regeneration, normal mechanical strength, or elimination of rupture risk.

The reader’s useful distinction is between an imaging change, reported pain relief, and the ability to perform progressively demanding activities. None should be substituted automatically for the others.

Diabetes and other factors that may affect outcomes

A 2024 retrospective case-control study compared 60 people with diabetes or prediabetes with 60 controls who had Achilles or patellar tendinopathy and received PRP. Outcomes were less favorable in the diabetes/prediabetes group. There was no sham-treatment comparison, and the population included two tendon diagnoses. The findings do not establish that PRP fails in everyone with diabetes. (24)

This preserves an important individual factor in the treatment discussion: two people with a similar scan may not have the same health background or recovery. Baseline function, metabolic health, and the desired activity level matter when interpreting outcomes.

Can cell-based treatments repair Achilles tendon damage?

Cell-based tendon treatments remain an area of investigation. Bone marrow aspirate concentrate contains a mixture of cells and other components; adipose-derived stromal vascular fraction, or SVF, is also a mixed cell preparation. Neither should be treated as equivalent to every laboratory stem-cell product.

A small randomized study enrolled 44 people with non-insertional tendinopathy and compared adipose-derived SVF with PRP. Both groups improved; some early outcomes favored SVF, while later scores did not significantly differ. There was no placebo group, follow-up was six months, and imaging findings did not correlate with clinical findings. This cannot establish complete tendon regeneration or a benefit for acute rupture. (25)

Animal experiments involving cells, PRP, or combinations remain relevant to the scientific rationale. However, their cell preparations, injury models, and treatment conditions differ from human clinical care. A result in a surgically injured animal tendon is not a demonstrated treatment effect for a person with chronic Achilles pain.

We should not present cell-based injections as a proven escalation after unsuccessful PRP, or promise that they will prevent surgery or reconnect a complete rupture. Availability and regulatory status depend on the exact product and preparation; an experimental study is not evidence that the same product is offered by this clinic.

Complete Achilles rupture: surgery or nonsurgical care?

A sudden pop, abrupt loss of push-off strength, or a new inability to walk normally needs prompt assessment. A complete rupture is not simply severe tendinopathy.

Some acute ruptures are managed surgically; others undergo structured nonsurgical care using protection, positioning, and rehabilitation. “Nonsurgical” does not mean an injection alone, unrestricted activity, or waiting without a plan.

A major randomized trial assigned 554 patients to nonsurgical treatment, open repair, or minimally invasive surgery. At 12 months, patient-reported and performance outcomes were similar. Re-rupture occurred in 6.2% of the nonsurgical group and 0.6% of each surgical group; nerve injuries were more frequent with surgery, particularly the minimally invasive approach. These tradeoffs belong in the decision. (26)

A smaller 2024 study comparing 12 surgically and 12 nonsurgically treated patients found a surgical advantage in one jump test but no difference in several other hop and jump measures. Weakness, calf atrophy, and tendon elongation remained relevant despite preserved performance on some tests. This was a small retrospective cohort with a prospective assessment, not proof that the options are identical for every patient. (27)

Does PRP improve healing after a rupture?

A small human tissue study compared biopsies from 10 PRP-treated and 10 control patients and found differences in early tissue organization and healing markers. Tissue findings do not establish better walking, strength, or return to sport. (28)

The PATH-2 randomized trial included 230 adults with acute rupture managed nonsurgically. Adding PRP did not improve muscle–tendon function or patient-reported outcomes compared with placebo at 24 weeks. Early biological findings therefore should not be presented as a proven clinical benefit. (29)

Surgical choices for persistent insertional disease

Surgery for chronic insertional tendinopathy differs from repair of a new complete rupture. Depending on the findings, it may involve removing diseased tendon tissue, addressing the bursa or a bony prominence, and repairing or reattaching the tendon. Tendon-sparing approaches, partial or complete detachment, and augmentation procedures have different indications. A surgical review emphasized that no single technique is a universal gold standard. (30)

The useful question is which abnormality an operation is intended to address and what recovery it requires. Our heel bursitis article retains the specific discussion of Haglund’s deformity and endoscopic calcaneoplasty.

PRP during or after surgery

A prospective comparison of 30 patients undergoing Achilles rupture repair found no superior clinical and functional outcomes from adding PRP. This was a small study with alternating allocation, rather than a large concealed randomized trial. (31)

An older retrospective series of 26 patients compared PRP alone with surgery plus PRP and reported improvements in both groups. Without randomization or a surgery-without-PRP control, it could not establish that PRP caused improvement or that the approaches were equally effective. (32)

What about dilution and treatment delivery?

Preparation, placement, and delivery are legitimate research questions. A cadaveric knee-arthroscopy study examined dilution of an injected substance by residual irrigation fluid. That finding should not be used to explain away negative Achilles PRP results: it involved a different anatomical setting and did not test Achilles treatment efficacy. (33)

The same boundary applies to favorable laboratory and animal studies of growth factors after tendon repair. They help explain why clinical trials are performed; they do not determine whether an individual surgical patient benefits.

Immobilization, movement, and recovery after rupture repair

Protection and progressive movement serve different purposes at different stages of healing. A randomized postoperative trial compared functional weight-bearing in an orthosis with initial non-weight-bearing cast care. Functional mobilization affected early healing markers and ankle motion, but did not improve longer-term heel-rise outcomes. It used a protected protocol, not unrestricted early activity. (34)

This is why the phrase “early movement helps healing” needs context. It is not permission to abandon a brace, stretch a healing repair, or resume sport early. Recovery decisions should follow the rupture-specific plan.

A re-tear does not always mean another immediate operation

A retrospective study reviewed 390 primary repairs, including 20 re-ruptures occurring during the subacute postoperative period. Those re-ruptures were managed with casting and bracing. Some earlier outcomes were worse, but measured outcomes were comparable by 12 months. The paper was published online in December 2023 and appeared in a 2024 journal issue. (35)

This preserves a useful option for selected patients: repeat surgery is not inevitable. It does not justify self-managing a suspected re-tear or delaying reassessment. The timing, tendon findings, and circumstances determine whether that study applies.

Summary video: tendon thickening and the surrounding ankle

In the existing Danielle Matias video, a patient’s symptomatic Achilles tendon appears substantially thicker than the other side on ultrasound. The discussion illustrates why a bigger tendon does not necessarily mean a stronger tendon, and why the surrounding ankle may warrant attention.

The proposed contribution of ankle instability should remain identified as a clinical possibility. It is not established by thickness alone. The video also distinguishes the demands of comfortable household walking from a return to hiking or basketball; those are different functional goals.

We retain a broad treatment discussion because patients often arrive with several diagnoses and a long history of attempted care. The key distinctions are between insertional and midportion disease, tendinopathy and partial tear, and a chronic painful tendon and a complete acute rupture.

The newer prolotherapy literature adds promising observations, but stronger Achilles-specific comparative research remains needed. PRP findings are mixed, with important randomized trials showing no benefit for the tested midportion and acute-rupture protocols. Cell-based treatment should be described with its specific evidence and limitations.

An accurate explanation should identify the diagnosis, the expected outcome, and the limits of the treatment being considered. Pain, scan appearance, strength, and return to activity should each be described honestly.

This article is for patient education and does not replace an individual medical evaluation, diagnosis, or treatment plan.

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