Why Hyaluronic Acid Injections Delay Knee Replacement and Reduce Costs in Knee Osteoarthritis

For many patients, total knee arthroplasty (TKA) is ultimately an effective solution. However, surgery is not always desired or appropriate, particularly for patients who wish to delay joint replacement because of work demands, caregiving responsibilities, age, or personal preference. This creates a substantial “treatment gap” between failed conservative care and surgery.

At Sports Health Northwest in Portland, Oregon, we offer intra-articular hyaluronic acid (HA) injections as part of a comprehensive, nonsurgical approach to knee OA. These injections are performed under ultrasound guidance, improving accuracy and patient comfort while minimizing procedural pain and complications. A key question for patients and the healthcare system alike is whether HA injections meaningfully reduce costs and delay the need for knee replacement.

How hyaluronic acid injections work: 

Hyaluronic acid is a naturally occurring component of normal synovial fluid. In
osteoarthritic knees, both the concentration and molecular weight of endogenous HA are reduced, leading to diminished lubrication, increased friction, and heightened inflammation. Viscosupplementation aims to restore these properties. Injected HA improves the viscoelastic behavior of joint fluid, enhancing shock absorption and lubrication. It also appears to have biologic effects, including modulation of inflammatory mediators, inhibition of cartilage-degrading enzymes, and improved chondrocyte function. These mechanisms help explain why HA injections tend to provide more durable symptom relief than corticosteroid injections, particularly beyond the first 6–8 weeks.

What does the evidence say about delaying TKA?

Historically, the role of HA injections has been controversial, with earlier guidelines questioning their clinical value. More recent large-scale analyses, however, suggest a more nuanced picture.
A 2025 evidence summary published by the American Academy of Family Physicians reported that intra-articular HA injections delayed TKA by approximately 299 to 370 days, with some patients who received multiple courses delaying surgery by several years [1]. Importantly, about 84% of patients receiving HA injections did not undergo TKA within two years, suggesting a meaningful delay for a substantial subset of patients.

Large database studies have shown mixed results, with some analyses noting higher overall costs in patients who eventually proceed to surgery after injections. However, these findings may reflect selection bias, as patients receiving injections often have more severe symptoms or are intentionally trying to defer surgery due to medical or social factors [2]. When viewed from a patient-centered perspective, delaying surgery—even if it remains inevitable—can be highly valuable.

Cost considerations for patients and the healthcare system:

From a cost standpoint, HA injections can be impactful. By reducing reliance on
NSAIDs, corticosteroid injections, and opioid medications, HA therapy may lower
downstream medication-related risks and expenses [1]. For individual patients, delaying surgery by even one to two years can translate into hundreds to thousands of dollars in avoided out-of-pocket costs, lost wages, and recovery-related expenses. At a population level, modest delays in TKA across millions of patients could represent billions of dollars in healthcare savings, particularly as knee replacements are increasingly performed in younger patients who face higher lifetime revision risks.

Safety and tolerability:

Hyaluronic acid injections have a strong safety profile. Adverse events are typically mild and localized, such as transient swelling or soreness at the injection site. Serious complications are rare. Compared with some high–molecular weight formulations, standard HA products are associated with lower rates of post-injection inflammatory flares, making them well tolerated for most patients.
Using ultrasound guidance, as we do at Sports Health Northwest, further enhances safety by ensuring accurate intra-articular placement and reducing procedural discomfort.

What patients can expect after injection:

Patients should understand that HA injections are not immediate pain relievers like corticosteroids. Symptom improvement often begins gradually over several weeks, with benefits lasting three to six months or longer in appropriate candidates. HA works best when combined with other evidence-based strategies such as targeted physical therapy, weight management, bracing, and activity modification.

Bottom line:

Hyaluronic acid injections are not a cure for knee osteoarthritis, and they will not
eliminate the need for knee replacement in every patient. However, current evidence supports their role in reducing pain, improving function, delaying TKA, and potentially lowering overall healthcare costs in selected patients [1]. When delivered accurately with ultrasound guidance and integrated into a comprehensive care plan, HA injections remain a valuable option for patients seeking to stay active and postpone surgery while maintaining quality of life.

Sources:
1. Intra-articular hyaluronic acid injections for knee osteoarthritis-AAFP (...). AAFP.
(2025).
2. Analysis of the cost and efficacy of intra-articular knee injections. Journal of the
American Academy of Orthopaedic Surgeons: Global Research & Reviews.
(2022).

Author

David Westerdahl MD FAAFP RMSK Sports Medicine Physician and owner Sports Health Northwest, Inc.