| Part 1. | | | | that viscosupplements performed as well or better |
| It's remarkable that rooster combs have provided | | | | than NSAIDS. However, design issues of the studies |
| the source of a frequently used treatment for | | | | make interpretation somewhat difficult. It must be |
| osteoarthritis (OA) of the knee. Through a | | | | pointed out that adverse events were noted in both |
| combination of research and serendipity, | | | | treatment groups. Not surprisingly, systemic therapies |
| viscosupplements- a type of lubrication treatment for | | | | (NSAIDS) had more systemic side effects and HA |
| OA of the knee- originally derived from rooster | | | | therapies had more local adverse events. |
| combs, are widely used by both rheumatologists as | | | | One question that clinicians often wonder about is, |
| well as orthopedic surgeons. But do they really work? | | | | "What about corticosteroid injections?" How do they |
| This two part article discusses the evidence in the | | | | compare? These preparations are used to reduce |
| medical literature. | | | | pain and inflammation, especially in acute knee |
| Viscosupplements are compounds that have been | | | | osteoarthritis flare-ups and are relatively fast-acting |
| created to mimic the effects of normal synovial fluid. | | | | However, there are shortcomings. They include: |
| Synovial fluid is the lubricating liquid present in normal | | | | Duration of efficacy may not last |
| joints that permits gliding and also helps with | | | | Frequent injections (more than 3 per year) may |
| cushioning. Synovial fluid is produced by cells that line | | | | cause cartilage damage |
| the joints and is essential for proper nourishment of | | | | Local adverse effects |
| the cartilage that caps the ends of long bones. At | | | | Post-injection flares of pain |
| low levels of shear force (standing and walking for | | | | Skin atrophy |
| instance), synovial fluid's primary effect is a lubricating | | | | Osteonecrosis (dead bone) |
| one. At high levels of shear force (running and | | | | Studies have evaluated the effects of |
| jumping), synovial fluid has a more shock absorbing | | | | viscosupplements vs intraarticular glucocorticoids. |
| function. | | | | These include the following studies: |
| The major component of synovial fluid is a substance | | | | [Leardini G, et al. Clin Exp Rheumatol. 1991; 9: 375-381 |
| called hyaluronic acid. (HA). All synthetic | | | | (both equivalent until day 28 when divergence |
| viscosupplements also have HA as their major | | | | favored Hyalgan)] |
| component. In this article I will use the term | | | | [Caborn D, et al. J Rheum. 2004; 31:333-343 (both |
| viscosupplement and HA interchangeably. | | | | worked @ 1-4 weeks post injection; Synvisc better |
| The first question is do these compounds work for | | | | @ 5-13 weeks post injection)] |
| osteoarthritis (OA) of the knee? As with any | | | | [Tekeoglu I, et al. J Rheumatol and Medical Rehab. |
| treatment, there is the possibility of negative studies. | | | | 1998; 9: 220-224. (For first 4 weeks Orthovisc and |
| Viscosupplementation is no exception. Lo concluded | | | | methylpredsolone acetate similar; @ 5-13 weeks post |
| that HA products have only a small effect compared | | | | injection, Orthovisc better)] |
| with placebo (Lo GH, et al. JAMA. 2003; 290: | | | | Most studies show this divergence of effect |
| 3115-3121). Brandt stated that HA and placebo | | | | occurring at 5-13 weeks post injection. |
| produce similar results (Brandt KD, et al. Arthritis | | | | (Raynauld JP, et al. Osteoarthritis and Cart. 2002; 10: |
| Rheum. 2000; 43: 1192-1203). And Karlsson posited | | | | 506-517). This is an interesting study from Canada |
| that neither of two HA products did better than | | | | where they looked at the difference between usual |
| placebo at 26 weeks (Karlsson J, et al. Rheumatol. | | | | care, meaning all the things you would do for a knee |
| 2002; 41:1240-1248). | | | | OA patient except viscosupplementation versus |
| However, the majority of studies have | | | | another group where viscosupplementation was |
| demonstrated that there is a significant effect. But | | | | added. And they found that the usual care group + |
| how well do they work? The interpretation of how | | | | visco supplementation did better. |
| effective these preparations are has been difficult | | | | So what about repeating treatment? This was one |
| because of a number of factors. These include: | | | | study that looked at patients receiving 5 injections of |
| Global use of these compounds with different | | | | viscosupplement every 6 months for a total of 25 |
| measuring instruments and techniques in the research | | | | injections. While the results showed that good safety |
| studies; | | | | and positive outcomes, design issues made this study |
| Single versus multi-center studies | | | | a bit difficult to interpret. (Scali JJ. Eur J Rheumatol |
| Varying inclusion and exclusion criteria | | | | Inflamm. 1995; 15: 57-62). |
| Different statistical outcome measurements | | | | One important bit of information that we can glean |
| Other study design issues | | | | from many of these studies, regardless of |
| And comparisons have been made to treatments | | | | viscosupplement used, is that the period of maximum |
| other than placebo. Two studies looked at | | | | onset of relief is @ 5-13 weeks post injection. |
| viscosupplements compared with non-steroidal | | | | Part 2 of this series will discuss more about what the |
| anti-inflammatory drugs (NSAIDs). (Altman RD, et al. J | | | | medical literature can tell patients about "rooster |
| Rheum. 1998; 25:2203-2212; Adams ME, et al. | | | | comb" treatments. |
| Osteoarthritis and Cart. 1995; 3: 213-216). They found | | | | |