Don’t Mistake Greater Trochanteric Pain Syndrome for Hip Osteoarthritis — Dr. Moriwaki Clarifies the Gluteus Medius/Minimus Tendon Enthesopathy and the Role of Stem Cell Conditioned Media Peri-Articular Injection2026.07.20

“When I lie on my side, the outside of my hip aches badly enough to wake me up,” “When I stand up from a chair, I feel a sharp pain just beside the hip” — complaints like these are often lumped together as hip osteoarthritis, but in reality they are frequently due to greater trochanteric pain syndrome (GTPS). Previously called “trochanteric bursitis,” this condition is now understood as primarily an enthesopathy of the gluteus medius and minimus tendons at the greater trochanter, rather than isolated bursal inflammation. Degeneration inside the joint and degeneration outside the joint at the tendon insertion produce pain through different mechanisms and call for different treatment approaches. In this column, Dr. Moriwaki lays out how to avoid mistaking greater trochanteric pain syndrome for hip osteoarthritis, and where a peri-articular injection of stem cell conditioned media might fit — honestly delineating both indications and limits.

Key Points of This Article

・Greater trochanteric pain syndrome is chronic pain on the lateral hip (over the greater trochanter), driven primarily by enthesopathy of the gluteus medius/minimus tendons

・Hip OA pain is mainly in the groin and anterior thigh, while greater trochanteric pain syndrome shows a pinpoint tender spot on the outside — the location of the pain is the first branching point

・Tendon insertions have poor blood supply and are slow to heal, so an anti-inflammatory-only mindset is insufficient

・A peri-articular injection of stem cell conditioned media can be considered as an option that both calms inflammation at the trochanteric enthesis and supports tissue repair signals

・Active infection, extensive tendon tearing, or poorly controlled systemic disease are contraindications; concurrent exercise therapy is a prerequisite

What Is Greater Trochanteric Pain Syndrome? — From “Trochanteric Bursitis” to an Updated Understanding

Greater trochanteric pain syndrome refers to chronic pain around the greater trochanter, the bony prominence on the outside of the hip. Previously known as “trochanteric bursitis,” the pain was thought to arise solely from inflammation of the bursa between the trochanter and the skin. However, more recent MRI, ultrasound, and pathological studies have made clear that the principal source of pain is not the bursa itself but the enthesopathy of the gluteus medius and minimus — collectively called the “gluteal tendons” — at their insertion onto the greater trochanter. Tendon degeneration, microtears, and impaired repair become chronic, with reactive bursitis layered on top, prolonging the pain.

Typical Complaints

・Wakes up in pain within tens of minutes of lying on the affected side

・Sharp lateral pain when standing up from a chair or climbing stairs

・Fatigue on the lateral hip after long walks, with pain building in the later half

・Clear point tenderness on pressing the greater trochanter with a finger

These patterns overlap in part with the classic presentation of hip osteoarthritis (groin pain at the start of walking or after long walks), but also differ decisively. In the exam room, asking “where does it hurt?” and watching where the patient places their finger becomes the first key piece of information for differential diagnosis.

Distinguishing from Hip Osteoarthritis — Read the “Location” and Provocation Tests

Greater trochanteric pain syndrome and hip osteoarthritis sound similar and share the domain of hip-region pain. But whether the source is “inside the joint” or “outside the joint” changes the differential thinking completely.

The Location of Pain Differs

In hip osteoarthritis, the source is the joint itself — cartilage, labrum, bone — so patients tend to report pain in the groin (inguinal region) or anterior thigh. In greater trochanteric pain syndrome, the problem lies in the tendons and bursa on the outside of the joint, so pressing on the greater trochanter (the bony prominence that touches the floor when lying on your side) produces a localized tender point, and patients experience the pain as “a single spot on the outside.” Where the patient’s hand lands — groin or trochanter — is why an initial direction for differential diagnosis becomes visible.

Provocation Tests and Imaging

When pain at the trochanter is provoked by resisted hip abduction, single-leg stance, or side-lying on the affected side, gluteal tendon enthesopathy is suggested. Plain X-ray showing joint space narrowing, osteophytes, or femoral head deformity strongly favors hip osteoarthritis, and MRI can evaluate intratendinous signal change at the trochanter, partial tears, and bursal fluid collection. The two conditions often coexist, so rather than framing it as “one or the other,” it matters clinically to read “which is the dominant pain generator.” General information about joint disease is also available at the Japanese Orthopaedic Association website.

Why “Peri-Articular Injection” for GTPS? — Positioning Stem Cell Conditioned Media

Because the central problem in greater trochanteric pain syndrome is the enthesopathy of the gluteus medius/minimus tendons, the treatment target is not “inside the joint” but “around the joint” — specifically the tendon insertion at the trochanter and the reactive bursa. It is here that peri-articular injection of stem cell conditioned media comes into view as an option.

Difference from Local Steroid Injection

Local steroid injection has long been used for trochanteric pain and is known to provide short-term analgesia. However, repeated steroid injections at a tendon insertion have been noted to increase risks of tissue weakening and rupture, so caution is required with repetition. Stem cell conditioned media is a fluid containing growth factors, cytokines, and exosomes secreted by cells; it works on the tendon’s microenvironment through both anti-inflammatory signals and tissue repair signals (TGF-β, IGF-1, FGF, etc.), so its axis of action differs from steroids.

What Can Be Expected, and What Cannot Be Overstated

What a peri-articular injection of stem cell conditioned media can target is the layer of “calming the inflammation cycle at the tendon insertion and supporting a repair-friendly environment.” Cases with extensive tendon tears, active local infection, or poorly controlled systemic disease are contraindications. On the evidence ladder, the majority of data come from case reports and observational studies; there is no basis for concluding that comparative trials have clearly outperformed hyaluronic acid or steroids — that current state must be shared honestly. Individual variability is real, and the design does not fit the mindset of “cure by injection alone.”

Treatment Design — Not to End with Injection Alone

Greater trochanteric pain syndrome cannot be handled with injections alone. Given the underlying functional decline of the gluteus medius/minimus, exercise therapy — strengthening the hip abductors, single-leg balance, and core stability — forms the foundation. In daily life, patients are asked to avoid lying on the affected side (a pillow between the knees can help), reduce leg-crossing, and avoid prolonged adducted standing. Please see our page on joint injections with stem cell conditioned media for our clinic’s basic approach and indications.

Being labeled with greater trochanteric pain syndrome does not automatically mean an injection is required. Many patients improve with exercise therapy and modification of daily-life movements. The peri-articular injection of stem cell conditioned media is properly positioned as an option for cases where “conservative treatment has been carried out properly but pain persists and tendon degeneration continues.”

Frequently Asked Questions

Q. Can greater trochanteric pain syndrome and hip osteoarthritis coexist?

Yes, coexistence is not uncommon. When both intra-articular degeneration and lateral gluteal tendon disorder generate pain simultaneously, we determine which is the dominant source through examination and imaging, then decide the treatment priority. When both contribute, we carefully design how to combine intra-articular and peri-articular approaches.

Q. How many peri-articular injections of stem cell conditioned media are typically needed?

Because tendon insertion repair takes time, an induction phase with a few injections at somewhat shorter intervals, followed by a maintenance phase with longer intervals based on response, is a common two-phase design. However, frequency and interval must be individualized to severity, age, and activity level — there is no one-size-fits-all answer. Effect is judged along three axes: pain, range of motion, and daily activities.

Q. Steroid injections gave me relief but the pain came back — how should I think about the next step?

Because tendon degeneration underlies greater trochanteric pain syndrome, the anti-inflammatory effect of steroids often does not resolve the root problem in the tendon. Repeated dosing is also of concern for tendon tissue, so this may be the stage to build back exercise therapy and consider a different axis of action, such as peri-articular injection of stem cell conditioned media.

Q. Can I exercise or bathe on the day of, or the day after, the procedure?

On the day of the procedure, please avoid strenuous exercise, prolonged walking, alcohol, and long soaks in hot baths. From the next day, gradually return to daily activities while watching your pain response, and consult your physician individually about the timing of resuming exercise therapy.

Q. What should be reconsidered when the effect is limited?

When several injections produce little improvement in pain or range of motion, the diagnosis itself is re-examined. We reassess — through imaging and examination — whether another condition (progression of hip OA, sacroiliac pain, lumbar radicular pain, infection, etc.) is the dominant source, and if needed switch to orthopaedic re-evaluation or an alternative treatment.

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Supervising Physician: Shin Moriwaki, MD

Member, Japan Society of Aesthetic Surgery (JSAS) / Member, American Academy of Aesthetic Medicine

ECFMG Certificate

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