Why your Thumb matter: Thumbs play a key role in your grip!

Have you ever realized how difficult it is for the hand to function when there is functional loss of the thumb? Ever try to do basic tasks, such as getting dressed, typing, or holding dinnerware without every using the thumb? Now try to do much more complex tasks like shooting a weapon, catching or throwing a ball, or playing sports in general. As it turns out, when there is loss of thumb function, there is about a 40% functional loss of the entire hand(1). That is almost half of the hands function.  When we consider that as humans, we use our hands to manipulate our environment, the thumb has contributed to our development over our existence.

As a high school freshman, trying out for the varsity softball team, I learned what life is like without functional use of my left thumb. The lesson a young softballer learns as she is learning to catch and throw is when the ball is above the waist, “fingers up” and when the ball is below the waist, “fingers down”. During a day at practice, I was in the pitching/catching cage. As I sat in my catcher’s crouch behind home plate prepared for the next pitch, the pitcher pitched a slightly wild ball in my direction. As I preceded to “dig the ball”, my glove hand was palm down, thumb down. Either a poor split-second decision, freak accident, or my level of experience, the ball bounced off the gym floor, and contacted my thumb causing an excruciating hyperextension injury known as gamekeepers’ thumb or skiers thumb. This eventually led to a lot of athletic tape, bracing, and learning how to catch without movement of my thumb joint.

The thumb is a unique feature on the hand. More specifically the carpometacarpal joint (CMCJ) of the thumb is what allows us to access full opposition of our hand’s dexterity.(2)  The CMC joint is described as a saddle joint meaning it has a joint surface that is convex in one dimension while concave in another dimension. This distinction allows for what is described as two degrees of freedom. That means we can access different ranges of motion that then facilitate different types of grips needed for daily life. That may be gripping a key, holding a round tube, holding a coffee cup, or even a sewing needle. The thumb is what permits the unique experience of each of these examples. The thumb also is comprised of the metacarpophalangeal joint (MCPJ), allowing for less motion but still contributes to our ability to hold items, and the interphalangeal joint (IPJ).

Gamekeepers Thumb, also known as Skiers Thumb, is an injury to the ulnar collateral ligament of the thumb. As was the case with me, it can occur due to direct trauma or force to the thumb either from a direct impact or an awkward fall onto the thumb(4). This injury does tend to be seen at a greater risk in the male population, with an injury rate of about 60%. Thumb injuries account for about 2.7% of all NBA game related injuries with Ulnar Collateral Ligament (UCL) or Radial collateral ligament(RCL) being the most frequently injured.(3) Regarding the rates specifically to women, there is a higher rate of hand and wrist injuries in women’s ice hockey, field hockey, and gymnastics.(5) Wrist, hand and thumb injuries can also be seen in those in the elderly population who have sustained a fall.  

As with any injury, there are surgical and non-surgical approaches. In a study conducted by Holderread BM et al, they found that players who underwent surgical intervention, not only were athletes able to return to sport in a reasonable amount of time, it also did not affect the players career length. In cases when surgical options are not necessary a person can do well with four to six weeks of bracing that allows for rest of the injured thumb. In my case, I completed a non-surgical period however given the nature of the injury, I still wore a brace under my catcher’s glove to prevent re injury.

Of note, these exercises are just examples. If you have a hand or thumb injury, please consult with an Occupational Therapist, Physical Therapist, or an individual who specifically is skilled in the anatomy and function of the hand and who can help guide you in what may be most appropriate for you and your hand or thumb injury.

1)     Thumb Interphalangeal joint flexion

2)     Thumb Metacarpophalangeal flexion

3)     Grip strength exercises

4)     Upper extremity range of motion exercises(shoulder, elbow, wrist and fingers)

References

1.     Flatt AE. Our thumbs. Proc (Bayl Univ Med Cent). 2002 Oct;15(4):380-7. doi: 10.1080/08998280.2002.11927870. PMID: 16333469; PMCID: PMC1276642.

2.     Neumann, DA. Kinesiology of the Musculoskeletal System: Foundation for Rehabilitation. 3rd ed.

3.     Return to Sport and Performance After Thumb Metacarpophalangeal Joint Collateral Ligament Surgery in the National Basketball AssociationBrendan M Holderread, MD1; Jordan Jafarnia, B.S.1; Brian M Phelps, MD1; Mark Perrin, B.S.1; Joshua D. Harris, MD2; Shari R Liberman, MD11Houston Methodist Hospital, Houston, TX; 2Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, TX

4.     Sources: Madan, S. S., Injury to Ulnar Collateral Ligament of Thumb. Orthopaedic Surgery. 2014;6:1–7; Mandhkani M, et al. Rupture of the ulnar collateral ligament of the thumb – a review. Int J Emerg Med. 2013; 6: 31. doi: 10.1186/1865-1380-6-31PMCID: PMC3765347

5.     Simpson AM, Donato DP, Veith J, Magno-Padron D, Agarwal JP. Hand and Wrist Injuries Among Collegiate Athletes: The Role of Sex and Competition on Injury Rates and Severity. Orthop J Sports Med. 2020 Dec 15;8(12):2325967120964622. doi: 10.1177/2325967120964622. PMID: 33403205; PMCID: PMC7745597.