Can 300 Patients Be Wrong?
Based on a retrospective (looking back) study of 300 patients with carpal tunnel syndrome, this study showed a direct link between the number of trigger fingers a person had and the risk of carpal tunnel syndrome. In fact, they found that patients with more than one trigger finger were three times more likely to develop carpal tunnel syndrome in the same hand as someone with only one trigger finger.

Hand surgeons have noticed for a long time that many patients with trigger finger often had carpal tunnel syndrome first. They naturally wondered if there was a direct connection between trigger finger and carpal tunnel syndrome.

And according to this study, 41 per cent of the patients with multiple trigger fingers also had carpal tunnel syndrome. Only 16 per cent with single trigger finger presentation had carpal tunnel syndrome. And as the number of trigger fingers increased (from one finger to four), the incidence of carpal tunnel also increased.

Risk factors for carpal tunnel have been studied and written about. The most common risk factor for carpal tunnel syndrome is diabetes. Now we can add trigger finger to that list.

Once the link between multiple digit trigger fingers was established, the authors turned their attention to the possible reasons for this connection. The carpal tunnel is created by the wrist bones forming an arch around the soft tissues of the wrist (e.g., around the ligaments, nerves, blood vessels, fascia, tendons).

Anything that decreases the space in the tunnel for these soft tissues can put pressure on the median nerve resulting in wrist and hand pain, numbness, and tingling common symptoms of carpal tunnel syndrome. It may be that thickening of the synovium (fluid and lining around the tendons) that causes trigger finger is a contributing factor to carpal tunnel syndrome.

Patients with trigger finger also have thickening of the fibrous cartilage around the pulley system that helps the flexor tendons move the fingers. This pathologic change in the anatomy may help explain why carpal tunnel syndrome follows the formation of trigger fingers.

In conclusion, there is evidence that multiple trigger fingers increase the risk for and rate of carpal tunnel syndrome. Other studies have also linked carpal tunnel release surgery with trigger finger. More study is needed to understand the pathoanatomic relationship between trigger finger, carpal tunnel syndrome, and carpal tunnel release.
Lauren E. Wessel, BSE, et al. Epidemiology of Carpal Tunnel Syndrome in Patients with Single Versus Multiple Trigger Digits. In The Journal of Hand Surgery. January 2013. Vol. 38A. No. 1. Pp. 49-55.