Los Angeles Angels trainer Mike Frostad made waves on Wednesday when he told reporters that Mike Trout had been diagnosed with a “rare condition” in his back, a condition that he would likely have to deal with throughout the rest of his career.
The condition in question is called T5 costovertebral dysfunction. The costovertebral joint is the location where a rib connects with a vertebra; the term “T5” identifies which vertebra and associated rib(s) are causing the pain. In short, the joints that pair the fifth thoracic (or upper back) vertebra and the fifth and/or sixth rib are causing pain.
Dysfunction is a medical term used to explain that pain is present and something isn’t functioning properly. As it pertains to the thoracic spine, dysfunction often presents as pain with certain activities (like bending or rotating), limited range of motion, and perhaps some change in sensation, such as numbness or tingling. In comparison to other back injuries, costovertebral dysfunction is rarer—though not necessarily rare in the grand scheme—but an exact epidemiology is difficult to pin down.
Although connected to the thoracic vertebra, rotational motions do not occur at the costovertebral joints. Yet, forceful rotations—such as those experienced when swinging a bat or throwing a ball—trigger pain. This is primarily caused by local muscle spasms induced by the pain as well as forced inhalation or exhalation, both of which increase the strain placed on the costovertebral joints.
Costovertebral dysfunction can be successfully treated conservatively, often through stretching and strengthening the core and back muscles to reduce pressure on the joints, undergoing spinal maniuplations (i.e. cracking the back) to improve mobility, with corticosteriod injections to reduce inflammation, or any combination of the above. However, they can be frustratingly difficult to treat as they are prone to flare up and recovery times vary, which may result in an athlete enduring periods of feeling good and bad.
As such, it may be a condition that Trout truly does have to contend with for the remainder of his career. But in the big picture, it isn’t overly serious in that it is unlikely to progress to a more significant injury.
