Why Plantar Fasciitis Becomes Chronic and Hurts With the First Step in the Morning — What Stem Cell Conditioned Media Local Injection Aims to Repair at the Enthesis2026.07.05
Have you ever taken the first step out of bed in the morning and felt a sharp, stabbing pain in your heel? The pain may ease a little over the next few dozen steps, only to return in the evening after long sitting or a long walk. Many people leave it hoping “it will resolve on its own,” only to end up living with it for months, sometimes years. This is plantar fasciitis. This article, from the perspective of Dr. Moriwaki at AVAN TOKYO Ginza, organizes what a local injection of stem cell conditioned media can and cannot aim to do for this chronic heel pain.
Key Points
・Most cases of plantar fasciitis are not acute inflammation but chronic degeneration (tendinosis) at the fascial enthesis.
・Steroid injections offer short-term pain relief, but repeated use risks fascial rupture and atrophy of the heel fat pad.
・A local injection of stem cell conditioned media targets the repair environment at the enthesis, but it is not a cure-all and individual response varies.
・Injection alone is not enough: stretching, insoles, weight management, and load review form the foundation.
・Objective evaluation should be done over weeks to months; if response is poor, orthopedic re-evaluation is needed.
The Mechanism Behind Morning First-Step Pain in Plantar Fasciitis
A Fan-Shaped Connective Tissue Sheet From the Heel to the Arch
The plantar fascia is a tough sheet of connective tissue that fans out from the heel bone (calcaneal tuberosity) to the base of the toes. During walking and running it absorbs ground impact and supports the arch of the foot. Long hours of standing, running, flat feet or weight gain, and reduced flexibility with age gradually build up microscopic injuries at the fascial attachment site — especially on the calcaneal side. These micro-injuries are the starting point of chronic heel pain.
“Degeneration” Rather Than “Inflammation” Drives Chronicity
This condition used to be understood as “inflammation of the fascia (fasciitis).” Recent histological studies, however, show that the chronic-stage enthesis contains few obvious inflammatory cells; disorganized collagen fibers, abnormal neovascularization, and degeneration (fasciosis) dominate. Morning first-step pain occurs because the fascia shortens during sleep and is suddenly stretched on standing, triggering repeated micro-injuries. This is also why treatments that merely “suppress inflammation” tend not to lead to fundamental recovery.
What a Local Injection of Stem Cell Conditioned Media Aims to Do for Plantar Fasciitis
How the Axis of Action Differs From Steroid Injection
Steroid injection has traditionally been the most-used injection for chronic heel pain. It offers strong short-term analgesia, but repeated use is known to risk atrophy of the heel fat pad, fascial rupture, and skin depigmentation, so orthopedic practice generally limits it to a few sessions. For related joint and enthesis conditions, the Japanese Orthopaedic Association website is a useful reference.
A local injection of stem cell conditioned media, by contrast, targets the cellular environment of the degenerated enthesis itself. The diverse growth factors, cytokines, and exosomes contained in conditioned media have been reported at the basic-research level to send repair-directed signals to tendon tissue in terms of neovascularization, fibroblast activation, and extracellular matrix metabolism. That said, large-scale comparative trials verifying its effect on human plantar fasciitis remain limited. Statements like “the tendon will definitely regenerate” cannot be made. It is more honest to position it as an alternative or complementary option to existing therapies.
“Where to Inject” and “How Many Sessions” Change the Meaning
What matters in local injection is precisely delivering the media to the calcaneal enthesis and the medial degenerated portion of the fascia — the actual source of pain — under ultrasound guidance. Simply “injecting somewhere around the heel” cannot be expected to work. In our clinic we determine injection sites while confirming fascial thickening and hypoechoic areas on ultrasound. As a guideline we design 2–3 sessions at 1–2 month intervals, and evaluate objectively using pain scores, changes in first-step pain, and continuous walking distance.
What to Confirm Before Considering Treatment
Heel Pain Has Multiple Causes
It is dangerous to assume that “first-step morning heel pain” always equals plantar fasciitis. Calcaneal stress fractures, tarsal tunnel syndrome, Achilles enthesopathy, and systemic rheumatic diseases such as ankylosing spondylitis can present with heel pain as an initial symptom. Especially in young men with bilateral heel pain or long-lasting morning stiffness, differential diagnosis in orthopedics and rheumatology is needed before treating it as fascial pain. For our general approach to joint and local conditioned media injections, please also see this page about stem cell conditioned media joint injection.
Injection “Alone” Cannot Complete Treatment
The foundation of treatment is conservative therapy: calf and plantar fascia stretching, arch-supporting insoles, weight control, and — for runners — reviewing training volume and running surface. A local injection of conditioned media is an option we consider when these conservative measures have plateaued, or when patients want to avoid repeated steroid injections. Relying on injection alone while neglecting conservative therapy makes evaluation ambiguous and raises the risk of recurrence.
Frequently Asked Questions
Q. How many local injections are needed for plantar fasciitis to work?
Response varies individually, but in most cases one session is not enough. We typically design 2–3 injections at 1–2 month intervals. Evaluation is done not immediately after treatment but over weeks to months, given the time tendon repair requires. If response is poor, we consider continuation, modification, or orthopedic re-evaluation.
Q. Can steroid injection and stem cell conditioned media injection be combined?
Generally we avoid mixing them in the same period and separate them by purpose and timing. Steroids may be chosen for acute severe pain when short-term relief is needed, but because repeated use raises the risk of fascial rupture, conditioned media is chosen to target the repair environment of the enthesis in the chronic phase.
Q. How painful is the procedure and how long is the downtime?
The sole has thick skin and abundant nerve endings, so even with local anesthesia there is some pain during injection. Discomfort or swelling may remain for 1–2 days after treatment, so prolonged standing and intense exercise should be avoided. Daily walking is fine, but it is safer to reintroduce loading gradually over the first week.
Q. Who is this local injection not suited for?
Yes, careful assessment is needed for people with poorly controlled diabetes, active infection or dermatitis around the injection site, high bleeding risk on anticoagulants, or during pregnancy. If enthesitis due to a rheumatic disease is the background, systemic control in internal medicine or rheumatology takes priority first.
Q. Can surgery for plantar fasciitis be avoided?
Surgical release (fasciotomy) is considered only in refractory cases that do not improve with any conservative therapy over 6–12 months or longer. A local injection of conditioned media should be positioned as part of conservative therapy, not as a “last resort to avoid surgery.” It cannot be guaranteed that surgery can be avoided in every case.
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Supervising physician: Shin Moriwaki, MD
Member, Japan Society of Aesthetic Surgery (JSAS) / Member, American Academy of Aesthetic Medicine
ECFMG Certificate holder
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