At what point can a patient with osteoarthritis (OA) of the knee consider Monovisc (hyaluronic acid) injections?

Timing and Appropriateness of Monovisc Injections for Knee Osteoarthritis

Monovisc (hyaluronic acid) injections should only be considered after exhausting first-line treatments including exercise, weight loss, physical therapy, acetaminophen, NSAIDs, and intra-articular corticosteroid injections, though current guidelines conditionally recommend against their use due to limited evidence of benefit. 1, 2

Treatment Algorithm Before Considering Monovisc

First-Line Treatments That Must Be Tried First

• Land-based exercise (aerobic and/or resistance training) is the foundational treatment for knee OA 2
• Weight loss for overweight patients with knee OA 1, 2
• Physical therapy with documented trial of at least 3 months 2, 3
• Acetaminophen up to 3g daily in divided doses for adequate duration 1, 2
• Oral NSAIDs if acetaminophen fails to control symptoms 1, 2
• Topical NSAIDs, particularly for patients ≥75 years old 2
• Knee bracing when biomechanically appropriate 1, 2

Second-Line Treatment Before Hyaluronic Acid

• Intra-articular corticosteroid injections should be tried before considering hyaluronic acid, as they have stronger evidence for short-term pain relief (typically <4 weeks) 1, 2, 4
• Corticosteroids are particularly indicated for acute flares, especially when accompanied by joint effusion 1

Current Guideline Position on Monovisc

Evidence Against Routine Use

• The 2019 American College of Rheumatology/Arthritis Foundation conditionally recommends against intra-articular hyaluronic acid injections for knee OA due to limited evidence of benefit 1, 2, 3
• When limited to high-quality trials with low risk of bias, the effect size of hyaluronic acid compared to saline approaches zero 2
• The American Academy of Orthopaedic Surgeons does not support routine use due to inconsistent treatment response 3

When It May Be Considered (Despite Conditional Recommendation Against)

The conditional recommendation against allows for use in specific circumstances through shared decision-making: 1

• After documented failure of all first-line nonpharmacologic therapies 1, 3
• After documented inadequate response to topical and oral NSAIDs 1, 3
• After documented failure of intra-articular corticosteroid injections 1, 3
• In patients who want an alternative to no treatment when other options are exhausted 1
• Recognition that benefit is limited and largely due to contextual effects (placebo response) 1

Age and Patient Selection Considerations

• Patients should typically be over 50 years old according to medical necessity criteria 3
• Younger patients (under 50) should exhaust more conservative options before considering viscosupplementation 3
• Most clinical trials excluded severe OA (Kellgren-Lawrence grade 4), suggesting use in mild-to-moderate disease 1

Practical Timing Details

If Proceeding Despite Guidelines

• Monovisc is given as a single injection (unlike traditional HA requiring 3-5 weekly injections) 5, 6
• Symptom relief may begin within 2 weeks if effective 5
• Duration of effect is approximately 6 months (27 ± 7 weeks) when successful 6, 7
• Repeat injection series can be considered when pain returns to baseline severity (resting VAS >45mm) 7

Important Caveats and Safety Concerns

Potential Harms

• Recent evidence suggests corticosteroid injections may accelerate OA progression more than HA or no injection 8
• HA injections were associated with decreased OA progression compared to corticosteroids over 2 years in one high-quality study 8
• Minor adverse events include local pain and swelling lasting a few days 6, 7
• Severe allergic reactions are extremely rare 6

Documentation Requirements

• Complete documentation of failed conservative treatments is essential before considering HA 3
• Document inadequate response to each prior treatment modality 3
• Insurance coverage may require meeting specific criteria including age >50 and documented treatment failures 3

The Guideline Contradiction

There is notable tension in the evidence: while the 2019 ACR/AF guidelines conditionally recommend against HA 1, 2, older EULAR guidelines from 2003 listed it as a symptomatic treatment option 1, and recent research shows potential structure-modifying effects 8. The most recent and authoritative guideline (2019 ACR/AF) should guide practice, meaning HA should generally not be used unless all other options have failed and the patient understands the limited evidence. 1, 2