Part 2.
In Part 1, I began a discussion on whether ?rooster comb? treatments work for osteoarthritis (OA) of the knee. I remarked at the beginning of part 1, how amazing it was that rooster combs have provided the source of a frequently used treatment for osteoarthritis (OA) of the knee. Through a combination of research and serendipity, viscosupplements- a type of lubrication treatment for OA of the knee- originally derived from rooster combs, are widely used by both rheumatologists as well as orthopedic surgeons. The major component of these viscosupplements is a substance called hyaluronic acid (HA). I use the term ?viscosupplements? and HA interchangeably.
First, let?s revisit the potential mode of action of HA briefly:
? HA may increase viscosity and viscoelasticity of synovial fluid
? HA may reduce the degradation of hyaluronon and other key components of cartilage and synovium (lining of the joint)
? Direct analgesic effect on nerve impulses and nerve sensitivity
? HA has effects on the inflammatory (and immune) process
There also appear to be effects of hyaluronic acid on immune function. These include inhibitory effects on lymphocytes and macrophages, cells that drive the inflammation process.
Are there differences among HA products? From the Cochrane review, here is the answer
(Bellamy N, et al Cochrane Database Syst Rev. 2005; 2: The Cochrane Collaboration. John Wiley and Sons)?
?Few randomized head-to-head comparisons of different viscosupplements and readers should be cautious? in drawing conclusions regarding the relative value of different products.? So the answer is that there may be differences in effects but it is unclear as to what they are.
Storage is also not a real difference since none require refrigeration.
My experience in using a number of these products is this: Individual products work for individual patients. Some people will respond to one and not another
The frequency of administration does vary:
3 injections one week apart (Orthovisc, Synvisc, Euflexxa)
5 injections one week apart (Hyalgan, Supartz)
How often are the different viscosupplements administered? at least as far as the product recommendations are concerned?
Duration of relief from the product inserts state:
? Euflexxa 12 weeks
? Orthovisc 26 weeks
? Supartz 26 weeks
? Hyalgan 26 weeks
? Synvisc 26 weeks
Personally, I feel that patients should get at least 6 months of relief; otherwise it probably isn?t worth doing.
What about side effects? Here is what was seen in clinical trials across all types of HA products:
? Injection site pain/edema (2.5-23%)
? Joint swelling (0.7-13%)
? Generalized joint pains (up to 17.8%)
? Pseudoseptic joint ? a swollen painful joint that has the appearance of an infected joint? but isn?t. This complication may be more common with some viscosupplements than others
? Gastrointestinal complaints (variable)
An interesting question that has been raised is that there appears to be an increased risk of knee effusion (fluid accumulation) after HA injection and pseudoseptic reactions in patients receiving cross-linked preparations (eg., Synvisc) vs. non cross linked preparations. Some have wondered whether the cross-links predispose to immunogenic responses that might be responsible for these severe knee effusions that are sometimes seen. It?s an interesting observation that needs more investigation.
This is an important point I want to make. Some time back, Doug Jackson, an eminent orthopedic surgeon, studied the accuracy of needle insertion during the course of knee joint injection. What he found was amazing and disturbing. Roughly 7-29% of the time, needle insertion was inaccurate! This may also explain the pain and effusion that occurs following viscosupplementation injection. More importantly, it tells physicians that either ultrasound or fluoroscopy are required for accuracy.
This is another interesting study. (Waddell DD, et al. Journal of Managed Care Pharmacy; March 2007, Vol. 13, No. 2, Pg 113-121). In a large orthopedic practice over a six-year period, they evaluated the possibility of delaying total knee replacement.
A total of 863 patients ? 1,187 knees- that had grade 4 changes (Grade 4 is bone on bone) were studied. They determined that viscosupplementation- in this case using Synvisc- delayed last-resort surgery by about 2 years. And using survival analysis, delayed total knee replacement for approximately 3.8 years. This is very interesting and valuable information that suggests the possibility of at least some disease modification with HA.
HA is contraindicated:
? patients with known hypersensitivity to hyaluronan products
? injection through an infected or inflamed area of skin
Caution in patients who have:
? allergy to bird proteins, feathers, or egg products since most HA products are made from chicken products. The exception is Euflexxa which is synthesized in a different manner.
? severe inflammation in the knee joint to be treated
Other joints where viscosupplementation has been used include
? Hip
? Shoulder
? Ankle
? Jaw (TMJ)
? Base of the thumb (CMC)
As far as future possibilities for viscosupplementation (and other therapies) in OA, there are many. They are:
? Block cartilage degradation
? Restore cartilage and synovial homeostasis
? Stop disease progression
? Reverse damage
Conclusions:
? HA works as a class, particularly with weight-bearing pain at 5-13 weeks.
? No major safety concerns.
? HA comparable to systemic therapies with fewer systemic adverse events (side effects) but more local adverse events.
? More prolonged effect than injecting steroids.
? The medical literature supports the use of HA in the treatment of knee OA
Author Bio
Nathan Wei, MD FACP FACR is a rheumatologist and Director of the Arthritis and Osteoporosis Center of Maryland. He is a Clinical Assistant Professor of Medicine at the University of Maryland School of Medicine. For more info: Arthritis Treatment
