What is the role of hyaluronic acid (HA) injections in treating osteoarthritis (OA)?

Hyaluronic Acid Injections for Osteoarthritis

Hyaluronic acid injections are not recommended for routine use in osteoarthritis treatment due to inconsistent evidence of benefit in high-quality studies and potential for harm. 1, 2

Current Guideline Recommendations

• American Academy of Orthopaedic Surgeons (2022): Recommends against routine use of hyaluronic acid in patients with knee osteoarthritis. Despite common usage, the evidence from 17 high-quality and 11 moderate-quality studies does not consistently support its efficacy. 1

• American College of Rheumatology/Arthritis Foundation (2020):

  • Conditionally recommends against hyaluronic acid injections for knee and first CMC joint OA 1
  • Strongly recommends against hyaluronic acid injections for hip OA 1
  • Notes that when limited to trials with low risk of bias, the effect size compared to saline injections approaches zero 1

Efficacy Considerations

• The number needed to treat (NNT) for hyaluronic acid is 17 patients, suggesting some patients may benefit, but current evidence cannot identify which specific subgroups 1

• Best results may be seen in:

  • Patients with mild to moderate knee OA
  • Those without active joint effusion
  • Patients over 60 years with functional impairment 2

• Effects are generally:

  • Slower in onset but potentially longer-lasting than corticosteroid injections
  • May provide pain relief and functional improvement for up to 6 months 2, 3

Clinical Context for Use

Despite recommendations against routine use, hyaluronic acid injections may still be considered in specific clinical scenarios:

• When patients have failed other interventions including:

  • Nonpharmacologic therapies
  • Topical and oral NSAIDs
  • Intraarticular corticosteroid injections 1, 2

• As part of shared decision-making when other alternatives have been exhausted 1

Administration Considerations

If used, typical administration includes:

• Course of 3-5 weekly injections
• Common formulations range from 20-48 mg per injection
• Intra-articular injection using aseptic technique 2

Safety Profile

• Common adverse events: joint swelling and arthralgia
• Serious adverse events are rare 2
• Repeated courses appear to be safe 2

Important Caveats

• Industry-sponsored studies show more positive results than publicly funded research, raising concerns about publication bias 1
• Higher molecular weight products may provide better pain relief compared to lower molecular weight preparations 2, 4
• Combination with other treatments (corticosteroids, PRP) may show better results than HA alone, but requires further research 3
• Oral hyaluronic acid has been studied but with limited evidence of efficacy 5

In summary, while hyaluronic acid injections remain widely used in clinical practice, current high-quality evidence and guidelines do not support their routine use in osteoarthritis management. They should be considered only after failure of first-line treatments and with appropriate patient counseling about the limited evidence for benefit.