Is a combination of hyaluronic acid and Kenocart (diclofenac) effective for osteoarthritis treatment?

Combination of Hyaluronic Acid and Kenocart (Diclofenac) for Osteoarthritis

Based on the most recent and highest quality evidence, I do not recommend the combination of hyaluronic acid and diclofenac (Kenocart HEXA) for osteoarthritis treatment, as the 2019 American College of Rheumatology/Arthritis Foundation guidelines conditionally recommend against intra-articular hyaluronic acid injections due to lack of efficacy when limited to low-risk-of-bias trials. 1

Why This Combination Is Not Recommended

Hyaluronic Acid Lacks Proven Efficacy

• When meta-analyses are limited to trials with low risk of bias, the effect size of hyaluronic acid injections compared to saline approaches zero. 1, 2, 3
• The number needed to treat is 17 patients, meaning 16 patients receive no benefit for every 1 patient who does. 3, 4
• Earlier guidelines from 2000 suggested modest benefits, but these were based on industry-sponsored trials with higher risk of bias. 1

Limited Evidence for Combination Therapy

• Only one small preliminary study (62 patients) examined hyaluronic acid combined with diclofenac for knee osteoarthritis, showing some improvement in pain scores at 6 months. 5
• This single study is insufficient to overcome the strong evidence against hyaluronic acid monotherapy, and no major guidelines recommend this combination. 1, 2, 3
• The study was not powered to demonstrate superiority over standard treatments and lacked long-term follow-up. 5

What You Should Use Instead

First-Line Treatments (Start Here)

• Land-based exercise programs (aerobic and/or resistance training) with effect sizes ranging from -0.58 to 1.05 for pain reduction. 2, 4
• Weight loss for overweight patients with knee osteoarthritis. 2, 4
• Physical therapy with structured rehabilitation protocols. 2, 4
• Oral NSAIDs (including diclofenac taken orally) when not contraindicated. 2, 4
• Topical NSAIDs as an alternative with fewer systemic side effects, particularly for patients ≥75 years old. 2, 4
• Acetaminophen up to 3g daily in divided doses for additional pain control. 2, 4

Second-Line Treatment (When First-Line Fails)

• Intra-articular corticosteroid injections are strongly recommended with Level 1B evidence, providing effective short-term pain relief (effect size 1.27 over 7 days) for up to 3 months. 1, 2, 3, 4
• Corticosteroids can be repeated as needed for symptom flares. 3

When Conservative Management Fails

• Joint replacement surgery should be considered for patients with refractory pain and radiological deterioration when conservative management has failed. 3, 4

Critical Pitfalls to Avoid

Do Not Use These Treatments

• Avoid oral narcotics including tramadol, as they cause notable increase in adverse events without consistent improvement in pain or function. 3, 4
• Do not proceed with arthroscopic debridement or partial meniscectomy for primary osteoarthritis, as it provides no benefit and delays definitive treatment. 3, 4
• Do not use hyaluronic acid as "bridge therapy" when the patient has already failed appropriate conservative management. 3, 4

Important Context About Guideline Evolution

• More recent high-quality guidelines from 2019-2025 have reversed previous recommendations for hyaluronic acid based on rigorous meta-analyses limited to low-risk-of-bias trials. 1, 2, 3, 4
• The apparent benefits reported in older studies (2000-2001) were restricted to studies with higher risk of bias, often industry-sponsored. 1, 6
• While hyaluronic acid may provide several months of benefit compared to several weeks with corticosteroids, this is offset by slower onset of action and the requirement of 3-5 weekly injections with associated logistical and cost issues. 1, 4

Shared Decision-Making Exception

• In clinical practice, if a patient has exhausted all other options (nonpharmacologic therapies, topical and oral NSAIDs, and intra-articular steroids), hyaluronic acid may be considered through shared decision-making that recognizes the limited evidence of benefit. 1
• However, this should not be the default approach, and the combination with diclofenac lacks sufficient evidence to recommend over standard treatments. 1, 5