The sometimes development of arthritis at the base of the thumb – the 1st carpometacarpal or 1st CM joint near the wrist – is the price humans pay for having a thumb that can be apposed to other fingers. The base of the first metacarpal bone rotates with respect to the wrist bones to allow this apposition. However this is not a fully developed joint, lacks durability, and overuse of the hand by any repetitive manual tasks (carpentry, golf, guitar, frequent texting etc) can cause painful arthritis of this joint. While we have good success treating arthritis of this joint with PRP (platelet rich plasma) most patients can be treated by a simple activity modification regimen based on the so-called “simian grip.”. This refers to the fact that other primates either have smaller thumbs which they use much less often than humans or in the case of some, like the spider monkey, do not have a functional thumb at all. Instead of wrapping their thumb around objects they grip, they use only their four fingers to encircle objects. This mode of use works well for almost all activities in humans as well. In patients with mild to moderate thumb (1st CM) arthritis, in most cases the discomfort will go away completely or at least substantially such that no other treatment is needed by employing this simian grip method. It is important also though to discontinue use of any pain killers or anti-inflammatory medicines because they mask pain and can also interfere with healing.
The picture above shows the hand of a spider monkey illustrating the lack of a thumb. These amazing primates spend most of their time gripping the branches of trees, climbing, swinging etc. with near perfect grip – without the use of a thumb. So if you have arthritis at the base of your thumb near your wrist, try imitating our closest evolutionary relatives – primates – and only use your thumb when you need to – and not at all for painful activities. This method alone without drugs, injections, or surgery is our go-to treatment method for this common problem and can provide good short and long term relief. If it doesn’t provide sufficient relief, PRP usually works well. Since medications are counter-productive, and there is really not a good surgical option for this problem: there is all the more reason to try the simian grip at the first sign of a problem. And next time you’re at a zoo or animal sanctuary check out the grip mechanics of any primates you see there – you’ll be amazed at how well a thumbless grip can work.