The first step out of bed is the diagnosis.

PRP FOR PLANTAR FASCIITIS

The first steps out of bed are the tell. Plantar fasciitis announces itself as a sharp pain under the heel that eases after a few minutes of walking and returns after any period of sitting. Most cases resolve within a year. This page is about the ones that do not.

Not fasciitis, and not really a heel spur

Like the tendons elsewhere on this site, chronic plantar heel pain is degenerative rather than inflammatory. Tissue shows collagen disarray, increased ground substance and neovascular ingrowth at the fascia’s origin on the calcaneus — fasciosis, not fasciitis. The distinction is not pedantry: it explains why anti-inflammatories and rest so reliably fail to fix it.

The heel spur is a similar misunderstanding. Spurs are common in people with no heel pain and absent in plenty of people with severe pain. The spur is a consequence of chronic traction, not the source of the symptom, and removing it is rarely the answer.

The study that separates the spur from the pain

If you want one piece of evidence for why this page keeps insisting the spur is not the diagnosis, it is this one. Investigators compared 100 patients who had painful plantar fasciitis against an age- and sex-matched control group — and every person in both groups had a radiographically confirmed heel spur. Same finding on the film, one group in pain and one group not.

What separated them was body mass. Mean BMI was 35.2 in the painful group against 30.9 in the pain-free group, and on multivariable regression obesity carried an odds ratio of 2.675. Spur size mattered too, above about 5.3 mm. The authors' conclusion is the sentence worth taking away: the presence of a heel spur alone did not account for the symptoms.

It is a comparative study rather than a randomized trial, and it cannot tell you which came first. What it does establish is that the thing on your X-ray is present in people whose heels do not hurt, and that the difference between those two states is at least partly systemic.

Newer work points the same way from the treatment side. A prospective cohort followed more than 2,900 adults with chronic plantar heel pain and compared the 92 who happened to be taking semaglutide for diabetes or weight management against the rest. The semaglutide group reported substantially better pain scores, and — the part that is hard to explain away as reporting bias — their plantar fascia thickened more slowly on imaging, by 0.25 mm per year. That is an observational signal supported by a 30-patient pilot, the authors call for a randomized trial, and we are not going to describe it as more than that. It is also not a treatment offered here for heel pain. What it illustrates is the thesis of this whole site: move the terrain and a structural measurement moves with it. What we measure.

Why it persists

The plantar fascia is dense, largely avascular connective tissue — poor perfusion is built into the anatomy, which is the mechanical half of the story.

The biological half: insulin resistance and glycation stiffen the fascia and reduce its ability to absorb the tensile loads walking imposes, and chronic low-grade inflammatory signaling keeps the tissue in a degradative state. Plantar heel pain is markedly more common in people with obesity and with type 2 diabetes, and the usual explanation — more weight on the foot — is only part of it. The tissue itself is different tissue.

The social driver is unavoidable and rarely discussed: you cannot rest a foot. Nurses, teachers, warehouse staff, anyone on hard floors for a shift will re-load the fascia thousands of times a day regardless of what any clinician advises. That is why this condition disproportionately persists in people who cannot sit down at work.

What PRP contributes

The case is the same as other stalled repairs: place a concentrated growth-factor signal into degenerate, poorly perfused tissue, fenestrate it to convert a chronic lesion into an acute one, and let a loading program organize what follows.

Plantar fasciitis has a reasonable comparative literature against corticosteroid, and it follows the pattern seen at the elbow: steroid better early, PRP equal or better from three months and holding at a year. It matters more here than elsewhere, because corticosteroid injection into the plantar fascia carries two specific risks — fat pad atrophy, which is permanent and leaves you with less natural cushioning than you started with, and fascial rupture. Neither is common, both are consequential, and they are the reason repeat steroid injections into a heel are a poor idea.

What else causes heel pain

• Baxter’s neuropathy — entrapment of the first branch of the lateral plantar nerve, producing burning rather than sharp first-step pain
• Calcaneal stress fracture — pain on squeezing the heel from both sides, worse with continued impact, and a reason not to inject
• Fat pad atrophy — deeper, more central, often in older patients or after previous steroid injections
• Tarsal tunnel syndrome — numbness and burning into the sole
• Inflammatory enthesitis — bilateral heel pain in a younger patient with back stiffness needs a rheumatological opinion, not an injection

The six-month line

Most plantar heel pain resolves. That single fact does more to decide candidacy than anything else on this page, and it is the reason the honest answer for someone three months in is usually to wait and keep doing the boring things.

Past six months the arithmetic changes. Pain that has outlasted stretching, night splints, orthotics and time is no longer a condition running its course; it is a repair that has stalled, and that is a different problem with a different answer. Add a fascia thickened on ultrasound with the typical degenerate appearance, and a steroid injection that helped briefly — helpful diagnostically, and not something to repeat, given what repeated steroid does to a fat pad and to the fascia itself — and the case is made.

Four things argue against it. A conservative trial that never genuinely happened, because most of those people get better without any of this. A suspected calcaneal stress fracture, until imaging clears it. Fat pad atrophy, where there is no stalled repair to restart and the heel simply has less padding than it used to. And a nerve entrapment being treated as though it were fascia, which the differential above sets out and which no injection into the fascia will touch.

The other requirement is the loading program afterward. It is not negotiable here for the same reason it is not negotiable in the Achilles: the biology restarts the repair and the load organizes it.

Treatment and what follows

One ultrasound-guided injection into the degenerate origin, occasionally repeated at six weeks. A regional block is used because this is one of the more uncomfortable injections on this site — the plantar fascia is dense and richly innervated, and there is no point pretending otherwise.

• Days 1–4 Expect it to be worse. Limit standing where you can.
• Weeks 1–3 Calf and fascia loading begins — the fascia is continuous with the calf mechanically, and a tight gastrocnemius drives fascial strain.
• Weeks 3–12 Progressive loading, commonly heel raises with the toes extended over a towel, which loads the fascia through the windlass mechanism.
• Ongoing Footwear and floor surface matter more than most people are told. So does calf flexibility, indefinitely.

When the heel does not settle

Re-examine the diagnosis first — the differential list above accounts for a meaningful share of non-responders. Then ask whether the loading happened and whether the calf was addressed. Shockwave therapy is a reasonable next step with its own evidence base, and surgical release is a last resort with mixed results.

Why the first steps are the worst

The pattern is so consistent it is nearly diagnostic, and it has a mechanical explanation. Overnight the ankle rests in plantarflexion and the fascia shortens. Whatever disorganized repair tissue formed during the day contracts into that shortened position. The first weight-bearing step abruptly re-lengthens the fascia and tears through that immature tissue, which is the sharp pain you feel — and then it settles, because after a few dozen steps the tissue has given way and the fascia is at length again.

This is also why night splints help some people: holding the ankle at neutral prevents the overnight shortening, so there is less to tear through in the morning. It is a mechanical fix for a mechanical problem, and it is worth trying before anything involving a needle.

What else is worth doing, ranked honestly

Most plantar heel pain resolves without injection, and it is worth being direct about what carries the evidence, because an injection offered before these have been tried is an injection offered too early.

• Calf and fascia loading. The single most useful intervention. High-load strength work outperforms stretching alone in comparative trials.
• Footwear and surface. Unglamorous and frequently decisive, particularly for anyone standing on concrete through a shift.
• Night splints. Effective for the morning pain specifically, poorly tolerated by many people, worth a trial.
• Orthotics. Reasonable short-to-medium term benefit; prefabricated devices perform comparably to custom ones in most studies.
• Shockwave therapy. A real evidence base for recalcitrant cases, and a sensible alternative or sequel to injection.
• Weight and glycemic management. Slow, unpopular, and acting directly on the tissue quality rather than on the symptom.

PRP belongs after that list, not instead of it. Anyone who offers it first is skipping the part that works for most people.

What people ask about heel pain

Are orthotics or PRP the better option?

Orthotics first, always — they are cheaper, reversible and often sufficient. PRP is for what remains after them. How we assess candidacy.

Why not another cortisone injection?

Fat pad atrophy and fascial rupture are real risks that accumulate with repeat injections. PRP compared with cortisone.

Does the heel spur need removing?

Almost never. Spurs are common in pain-free feet. PRP compared with surgery.

How long does recovery take?

First change around six weeks, the real answer at three months. Recovery timeline.

Related reading

• Achilles tendinopathy
• How PRP works
• PRP compared with cortisone
• Risks and side effects

Dense tissue on a weight-bearing surface produces a harder few days.