How effective are topical herbal therapies for treating osteoarthritis?

Clinical question: 
How effective are topical herbal therapies for treating osteoarthritis?
Bottom line: 
Arnica gel probably improved symptoms as effectively as a gel containing non-steroidal anti-inflammatory drugs, but with no better (and a possibly worse) adverse event profile. Comfrey extract gel probably improved pain, and capsicum extract gel probably would not improve pain or function at the doses examined in this review. Although patches containing the Chinese herbal mixtures FNZG (Fufang Nanxing Zhitong Gao) and SJG (Shangshi Jietong Gao) probably slightly improved pain and function more than placebo, there was uncertainty in the clinical applicability of these results because these interventions were tested over seven days only.
Caveat: 
This review was compromised by some poorly designed clinical trials that were underpowered and inadequately blinded. The quality and/or quantity of current scientific evidence of effectiveness were insufficient for all the products. Generally, high tolerance of the herbal medicinal products was demonstrated; however, caution is warranted in interpreting safety due to the small sample size in some of the studies
Context: 
Before extraction and synthetic chemistry were invented, musculoskeletal complaints were treated with preparations from medicinal plants. They were either administered orally or topically. In contrast to the oral medicinal plant products, topical agents act in part as counterirritants or are toxic when given orally.
Review CD#: 
CD010538
PEARLS No: 
402
Date: 
September, 2013
Authored by: 
Brian R McAvoy