Knee Joint Viscosupplementation

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October 2019

BULLET POINTS – VISCOSUPPLEMENTATION, CURRENT CONCEPTS-SAFETY AND EFFICACY

Dr. Kiran Kharat

Senior Consultant Orthopaedic Surgeon

Founder Director Dept. of Arthritis and Joint Replacement, Ruby Hall Clinic and Birla Hospitals.

·      Recent research that demonstrates that the synovium actually functions as a syncytium, almost as an organ.

·      Synoviocytes actually communicate with one another through gap junctions.

·      In osteoarthritic synovium there is a phenotypic change that occurs when a joint becomes arthritic- synovial cells communicate to each other more frequently.

·      Interleukin (IL)-1 beta elaborates matrix metalloproteinases (MMPs)-inflammatory mediators- that are at the forefront of the damage of cartilage in osteoarthritic joints.

·      Original concept of viscosupplements was to actually substitute or replace a more normal rheologic product, such as a viscosupplement with a higher molecular weight, higher viscosity, and higher elasticity, to provide all of those normal functions back!

·      They may actually restrict pain-triggering molecules and enhance normal hyaluronic acid (HA) production from synovial sites.

·      HA interferes with this process by suppressing MMPs. It binds at CD44 receptor sites. It acts as a gap junction inhibitor. And the molecular weight of this HA may actually contribute to the inhibitory effect of IL-1 beta. 

·      Disease-modifying capabilities.

·      A meta-analysis, which was a collection of approximately 20 studies comparing placebo to a viscosupplement- viscosupplementation trumped over placebo in terms of clinical efficacy.

·      All viscosupplements are made from purified HA, either from avian or bacterial fermentation sources.

·      Cross-link purified HA molecules to get a hylan. Hylan A is designated as roughly a fluid type of material, slightly higher viscosity and elasticity.

·      Cross-link them further to get a gelatinous product called hylan B-hylan G-F 20, or hylan gel factor 20.

·      It seems to work better in earlier-grade OA and improves patient-assessed pain, is generally well tolerated, with a very low rate of complications and good, long-term efficacy. Importantly, there are no systemic adverse events.

·      The disadvantage of viscosupplementation is that patients with long-term and/or severe-grade OA may respond less. And, there may be some local adverse events, including injection site erythema, joint diffusion, swelling, warmth, even some arthralgias -- but these tend to be self-limited.

·      Elderly patients across the OA spectrum. Younger patients with mild to moderate OA to the knee but are not yet ready for a surgical intervention.

·      In late-stage Kellgren-Lawrence 4 OA to the knee, it can be useful to delay total knee replacement. First-line treatment in patients with comorbidities taking multiple medications to avoid adverse events associated with other types of systemic anti-arthritic drugs, such as the anti-inflammatories.

·      In patients who cannot take anti-inflammatories at all because of GI or renal disease or unstable hypertension.

·      Offered to patients who are too young for total knee replacement or in patients who have a medical contraindication for total knee replacement when their OA is really quite advanced.

·      HA derivatives are effective and safe with regard to both placebo and other anti-inflammatory use.

·      Viscosupplementation tends to be more effective, have a greater magnitude of impact over steroid, and certainly lasts a longer period of time.

·      Use of the viscosupplement can also reduce the use of secondary rescue medications- like anti-inflammatories- concept of local treatment for local disease and thus the reduction of systemic adverse events.

·      Can certainly delay the need for surgical intervention in particular for total knee replacement.

·      Cross-linked HAs with higher molecular weight had better therapeutic effect compared with noncross-linked HA derivatives.

·      In a meta analysis Lower molecular weight and higher molecular weight HA produced the same results -- all of the viscosupplements were effective for decreasing symptoms of OA of the knee, such as pain, swelling, and stiffness.

·      Many studies show repeat treatment certainly can be effective in the management of OA.

·      No systemic side effects.

·      Hypersensitivity reactions are less than 1%. Fifty percent of flare reactions are immediate, spontaneously resolve without treatment in 3 weeks.

·      The risk of strong, transient delayed reactions occurs only in about 0.3% of patients. Patients recover well and benefit from the procedure, even in these stronger severe reactions. 

·      Placement of any kind of viscosupplement in a nonprotected environment -- outside of the joint, into the tissues -- can certainly cause a significant inflammatory reaction.

·      Using a longer needle to truly penetrate the capsule -- the fat pad -- and get into the joint. 

·      No strenuous activities should be performed on the day of the injection. An ice pack to the knee for several hours during the course of the day can reduce inflammation. Elevating the knee to relieve pressure can also be helpful.

·      50% of normal activity be resumed on the day of the injection and then, following that, a gradual increase in activity.

·      Viscosupplementation, characterized as local treatment for a localized disease, is really a very important tool in the armamentarium of treatment of OA of the knee.

·      It works on different levels to improve synovial health, with increasing the viscoelasticity within the joint. It blocks pain mediators, it nourishes chondrocytes, and it may significantly reduce inflammation.

·      The efficacy of viscosupplements can exceed 80%. It can certainly delay total knee replacement, even in patients afflicted with very severe OA.

·      There are no significant systemic adverse events. And, events generally occur in a very low percentage of patients, even locally. The local events are mostly mild to moderate and are easily managed with symptomatic treatments.

Dr. Kiran Kharat

www.jointreplacementexpert.in

kiran.kharat@gmail.com

Senior Consultant Joint Replacement Surgeon

OPD at Ruby Hall Clinic, Main and Wanowarie

Birla Hospital, Columbia Asia Hospital

Admission and operating rights also at Jupiter, Inamdar Hospitals