Can Hymovis (hyaluronic acid) injections be administered into a knee that has undergone total knee replacement (TKR) surgery?

Hymovis Injections in Total Knee Replacement

Hymovis (hyaluronic acid) injections are not recommended for knees that have undergone total knee replacement surgery, as there is no evidence supporting their use in prosthetic joints and potential risks exist. 1

Rationale for Not Using Hyaluronic Acid in Replaced Knees

Hyaluronic acid injections like Hymovis are specifically designed to treat osteoarthritis by providing lubrication and shock absorption in natural knee joints where cartilage has deteriorated. However, in a total knee replacement:

• The natural joint surfaces are replaced with prosthetic components (metal and polyethylene)
• The original osteoarthritic surfaces that would benefit from viscosupplementation are no longer present
• The mechanism of action of hyaluronic acid is not applicable to artificial joint surfaces

Evidence Against Use in Prosthetic Joints

Current clinical practice guidelines do not support the use of hyaluronic acid injections in prosthetic joints:

• The 2019 American College of Rheumatology/Arthritis Foundation guidelines only discuss hyaluronic acid injections in the context of natural joints with osteoarthritis 1
• The 2020 VA/DoD Clinical Practice Guideline only recommends considering viscosupplementation for natural knee joints with inadequately controlled osteoarthritis pain 1
• No clinical guidelines mention or support the use of hyaluronic acid products in prosthetic joints

Potential Risks

Injecting any substance into a prosthetic joint carries risks that outweigh potential benefits:

• Infection risk: Any intra-articular injection introduces infection risk, which is particularly serious in a prosthetic joint where it could lead to prosthetic joint infection requiring revision surgery 1
• Lack of efficacy: Hyaluronic acid is designed to supplement natural synovial fluid and interact with natural joint tissues, not prosthetic materials
• Waste of resources: Using an expensive treatment without evidence of benefit represents poor resource utilization

Alternative Approaches for Pain in Prosthetic Knees

For patients experiencing pain in a knee with total knee replacement, more appropriate options include:

1. Evaluation for prosthesis complications: Assess for loosening, infection, or mechanical issues
2. Physical therapy: To strengthen supporting muscles and improve joint function
3. Oral analgesics: Following appropriate guidelines for pain management
4. Corticosteroid injection: May be considered in specific circumstances after consultation with the orthopedic surgical team 1

Important Considerations for Corticosteroid Injections in Prosthetic Joints

If pain management is needed in a prosthetic joint:

• Corticosteroid injections should only be performed after consultation with the orthopedic surgical team 1
• A retrospective study showed a 0.6% infection rate in prosthetic knees receiving corticosteroid injections (1 infection per 625 injections) 1
• Strict screening for prosthetic infection should be performed before considering any injection 1

Conclusion

Hymovis or other hyaluronic acid injections should not be administered into knees that have undergone total knee replacement. The treatment has no established efficacy in prosthetic joints, carries potential risks, and is not supported by clinical evidence or guidelines. Patients experiencing pain in a prosthetic knee should be referred back to their orthopedic surgeon for appropriate evaluation and management.