If you’ve been told your knee osteoarthritis is “just wear and tear” and that you’ll need to manage it with pain medication until you’re ready for a replacement, you’re not alone — and you may not have heard the full story. Over the past two decades, a small but growing body of clinical research has examined a procedure called dextrose prolotherapy: injecting a concentrated medical sugar solution into and around an arthritic knee joint to stimulate healing. The results have been consistently surprising.

Here’s a plain-language look at the three most important clinical trials on this treatment, what they found, and why the findings matter.

What Is Dextrose Prolotherapy?

Prolotherapy (short for proliferative therapy) involves injecting an stimulant solution — most commonly, a form of concentrated glucose (Dextrose) — into damaged or lax connective tissue. The idea is that Dextrose triggers a healing response: repair cells are recruited to the area, collagen is deposited, and the targeted structure — a ligament, tendon attachment, or joint capsule — becomes stronger and more stable.

For knee osteoarthritis specifically, researchers have theorized that much of the pain and dysfunction isn’t solely from cartilage loss, but also from ligament laxity — looseness in the stabilizing structures around the joint that causes abnormal movement, increased stress on cartilage, and chronic pain signaling. Prolotherapy, in this view, addresses a root mechanical cause rather than just masking symptoms.

The Foundational Trial: Reeves & Hassanein (2000)

Reeves KD, Hassanein KM. Randomized Prospective Double-Blind Placebo-Controlled Study of Dextrose Prolotherapy for Knee Osteoarthritis with Ligament Laxity. Alternative Therapies in Health and Medicine. 2000. PMID: 10710713

Before this study, prolotherapy existed largely in the realm of anecdote. Reeves and Hassanein changed that by conducting one of the first randomized, double-blind, placebo-controlled trials of dextrose prolotherapy for knee osteoarthritis — a genuinely rigorous design that was rare in this field at the time.

The trial enrolled patients with knee OA, including people with and without measurable ACL (anterior cruciate ligament) laxity. Participants received either dextrose prolotherapy (10–25% concentration, injected at periarticular sites including ligaments, the joint capsule, and tendon attachments) or placebo injections, over multiple sessions.

What They Found

The results were notable on multiple fronts:

  • Pain dropped by roughly 40% in the dextrose group compared to placebo,  a clinically meaningful reduction, not just a statistical blip.
  • Knee flexion range of motion improved by about 14 degrees, representing approximately a 27% gain. Better range of motion suggests improved joint mechanics, not just pain tolerance.
  • Most strikingly, ACL ligament stability improved by 55% in the dextrose group, as measured objectively by a KT-1000 arthrometer, a device that quantifies how much the shin bone slides forward relative to the thigh bone (anterior-posterior displacement). This is an objective ACL mechanical measurement, not a patient questionnaire. It’s hard to fake.

Preliminary blinded radiographic readings also suggested improvement in OA severity on imaging, though this was a secondary finding.

Why It Mattered

This study proposed something that challenged the dominant cartilage-centric model of osteoarthritis: that ligament insufficiency and periarticular instability are significant contributors to OA pain, and that treating those structures — not just the joint surface — can produce real improvement. That idea has since become more mainstream as OA has been reframed as a whole-joint disease.

Reeves & Hassanein (2000) became the foundational reference point for every prolotherapy-for-OA study that followed.

Confirming the Findings: Rabago et al. (2013)

Rabago D, et al. Dextrose prolotherapy for knee osteoarthritis: a randomized controlled trial. Annals of Family Medicine. 2013.

More than a decade later, David Rabago and colleagues at the University of Wisconsin designed a larger, more comprehensive test. Their trial enrolled 90 adults with at least three months of symptomatic knee OA, recruited from community and university clinics.

What made this study particularly rigorous was its three-arm design: participants were randomized to dextrose prolotherapy injections, blinded saline placebo injections, or a structured at-home exercise program. This allowed researchers to ask not just “does prolotherapy beat nothing?” but “does it beat an active comparator?”

The Protocol

The prolotherapy arm received both extra-articular (periarticular) and intra-articular injections — a more comprehensive approach than targeting the joint space alone. Injections were given at weeks 1, 5, and 9, with optional additional sessions at weeks 13 and 17 for patients who needed them. All groups were followed for 52 weeks.

Baseline characteristics — age, sex, BMI, and radiographic OA severity (Kellgren-Lawrence scale) — were similar across groups, with one noted exception: the saline group had a longer pre-treatment pain duration. Follow-up analyses adjusted for baseline scores, age, sex, and BMI to account for any residual imbalance.

The WOMAC index (Western Ontario and McMaster Universities Osteoarthritis Index) is a widely used patient-reported outcome measure designed to assess the severity of osteoarthritis, most commonly of the knee and hip.

What it measures:

It captures three core symptom domains:

  • Pain (5 items) — pain during activities like walking, stair climbing, and at rest
  • Stiffness (2 items) — joint stiffness after waking or after sitting/lying down
  • Physical function (17 items) — difficulty with daily tasks such as descending stairs, rising from a chair, bending, and walking on flat surfaces

How it measures:

Patients self-report their experiences over the past 48 hours (or past week, depending on the version). Each item is rated on either a 5-point Likert scale (none / mild / moderate / severe / extreme) or a 100mm visual analog scale (VAS), depending on the version used. Scores are summed within each subscale and can also be combined into a total score. Higher scores indicate greater pain, stiffness, and functional limitation.

Key strengths:

  • It is disease-specific (focused on OA rather than general health)
  • Sensitive to clinically meaningful change over time, making it valuable for tracking treatment outcomes in both clinical practice and research

What They Found

At 52 weeks, 50% of prolotherapy patients achieved the MCID of a 12-point change in the WOMAC score, compared with 30% of saline-treated patients and 24% of exercise participants. Myhealthtoolkit

In summary, the prolotherapy group showed roughly double the improvement of the control groups on the WOMAC composite score (15.3 vs. ~7.6–8.2 points),

A Cleaner Replication: Sit et al. (2020)

Sit RWS, et al. Intra-articular dextrose prolotherapy for knee osteoarthritis: a randomized controlled trial. Annals of Family Medicine. 2020.

The most recent of the three landmark trials came from Hong Kong, where Rudolf Sit and colleagues enrolled 76 adults aged 45–75 with knee OA from outpatient clinics. Their design was simpler and more streamlined than Rabago’s — deliberately so.

The Protocol

Participants received either 25% dextrose intra-articular injections or normal saline, at weeks 0, 4, 8, and 16 — four injections total, targeting only the joint space (no periarticular injections). Follow-up ran to 52 weeks.

The primary outcome was WOMAC pain at one year. Secondary outcomes included WOMAC composite score, VAS knee pain, physical function tests, stiffness, and EuroQol-5D quality of life.

What They Found

Within-Group WOMAC Composite Improvement

The within-group improvement in WOMAC composite scores was 20.9 points for the DPT group and 9.4 points for the saline group — meaning the prolotherapy group improved more than twice as much from their own baseline. The DPT group’s improvement exceeded the predefined minimal clinically important difference (MCID) of 12 points, while the saline group’s improvement did not. Annals of Family Medicine

This trial is often cited as one of the cleaner prolotherapy studies because its simple two-arm, blinded design makes the comparison straightforward and hard to argue with.

Putting It Together: How the Three Trials Compare

Study Design Participants Injection Approach Follow-Up
Reeves & Hassanein (2000) Dextrose vs placebo Not specified Periarticular Not specified
Rabago et al. (2013) Dextrose vs saline vs exercise 90 Extra + intra-articular 52 weeks
Sit et al. (2020) Dextrose vs saline 76 Intra-articular only 52 weeks

The Rabago protocol was the most treatment-intensive — combining periarticular and intra-articular injections with up to five sessions. Sit’s protocol was more minimalist and easier to replicate in a clinical setting. Both arrived at similar conclusions.

What the Evidence Suggests — and What It Doesn’t

Taken together, these three randomized controlled trials consistently show that dextrose prolotherapy for knee osteoarthritis produces:

  • Meaningful pain reduction relative to placebo or saline
  • Improved WOMAC scores (pain, function, and stiffness)
  • Better knee range of motion
  • Objective gains in ligament stability (Reeves & Hassanein)
  • Sustained benefit at one year
  • No serious adverse events in any of the three trials.

The Bigger Picture

These trials represent a quiet shift in how some researchers and clinicians think about knee osteoarthritis, prolotherapy positions the joint’s surrounding connective tissue — ligaments, capsule, tendon attachments — as important targets for intervention.

The idea that stabilizing the joint can reduce pain isn’t radical; it aligns with well-established biomechanical principles and with the broader recognition of OA as a whole-joint disease. What’s notable is that dextrose prolotherapy appears to achieve this stabilization in a measurable, objective way — not just through patient-reported outcomes, but through instruments like the KT-1000 arthrometer.

Prolotherapy and larger trials would strengthen the evidence base. But for patients and clinicians looking for non-surgical options for knee OA, the existing RCT evidence is more robust than many assume.

For further reading, see the primary sources

  1. Reeves KD, Hassanein KM. Randomized Prospective Double-Blind Placebo-Controlled Study of Dextrose Prolotherapy for Knee Osteoarthritis with Ligament Laxity. 2000.
  2. Rabago D, et al. Dextrose prolotherapy for knee osteoarthritis: a randomized controlled trial. Annals of Family Medicine. 2013.
  3. Sit RWS, et al. Intra-articular dextrose prolotherapy for knee osteoarthritis: a randomized controlled trial. Annals of Family Medicine. 2020.