Mike Trout, the face of the MLB, suffered a tear of the ulnar collateral ligament (UCL) of the thumb. This ligament should not be confused with the UCL of the elbow, which is what needs to be repaired in Tommy John surgery. The UCL of the thumb can be sprained, torn, and sometimes even avulsed from its insertion site, which is on the proximal phalanx of the thumb. The injury typically occurs in a couple different types of athletes, including volleyballers, skiers and baseball players, as they suffer a fall on an outstretched hand, and in the case of baseball players – sliding into a raised base.
Damaging the UCL of the thumb leads to instability MCP joint of the thumb – which is the joint closer to the base of the thumb. This then translates to pain, swelling, and extensive bruising over the MCP joint. Spraining or tearing of the UCL leads to weakness when trying to pinch, grasp, throw, and when trying to squeeze things.
With an UCL injury, there is a weakened ability to grab objects, like a baseball player trying to bat, pitch or throw a ball across the diamond. Performing simple tasks like tying one’s shoes or holding a piece of paper can be very challenging with a UCL injury. The thumb is vital to our everyday lives; try living without it for more than 5 minutes, it is nearly impossible.
The injury typically occurs from either forced abduction or hyperextension of the proximal phalanx of the thumb, like catching your thumb on the base while sliding into it, as in Mike Trout’s case. Often, the injury occurs when the person extends their hand (and thumb) to try to break their fall, thereby abducting the thumb, and causing too much stress for the MCP joint and UCL to handle, causing it to sprain or tear. The UCL basically is the most important stabilizer in the thumb.
How is it treated? In Mike Trout’s case, his injury was a complete tear requiring surgery. Surgery should be conducted soon after the injury to help prevent the ligament from folding upon itself. In this surgery, an orthopedic surgeon may utilize the aponeuosis of the adductor pollicis muscle between the MCP joint and the torn ligament. After the surgery has been completed, a volar plaster splint is used to immobilize the thumb for typically 4-5 weeks following the operation. After this, the range of motion exercises should begin, wearing the splint on an as needed basis. A strong strengthening program will be vital to the athlete’s recovery, to ensure that they will have both full strength of the thumb as well as full range-of-motion.
I expect Mike Trout to be back in about 6-8 weeks – which would put his RTP timeline sometime in July at the earliest, maybe closer to August with how important he is to the Angels and to the game itself. Many other athletes have suffered this injury, like Dustin Pedroia of the Boston Red Sox. Long-term, as long as the injury is completely healed, there are minimal ramifications. Expect Trout to be posting monster numbers once he returns to the field. If you can get him for cheap, I would buy, buy, buy!
This was written for the @TheFantasyDRS by Dr. Jesse Morse. I am a Family Medicine trained physician, and I will be beginning a Sports Medicine Fellowship in the next couple of months. If you have any questions or comments, you can contact me directly at @DrJesseMorse.