"Pruning shears vary in size, cutting mechanism, extra features, and ease of use. So how do you select teh one that's best for you? The first step is to understand some of the terms used to describe types of pruners.
Ratchet or gear-type pruners use a mechanism similar to a car jack that multiplies hand strength, making pruning cuts easier. They're recommended for gardeners whose hand strength has been diminished by arthritis or carpal tunnel syndrome. Ratchet pruners can be anvil or bypass type."
As seen in Organic Gardening Magazine Dec 2011/Jan 2012 Issue