Time, she’s (ever noticed inanimate objects/concepts that cause grief are personified as females???) a tricky bugger. Whisky and wine improve over time. Your body on the other hand, is more like milk; old injuries-more like milk left out on the counter. If I only had a dime for every time I heard someone in their 30’s, 40’s, 50’s and on tell me that they’ve been fighting with a high school/rec league/drunken foolishness injury from decades previous, thinking it would just go away. Given that a clean fracture completely heals in 6 weeks- if the pain of an injury hasn’t gone away by then, it’s not going to.

First we need to separate pain from injury and disease. If you’ve heard this from me once, you’ve heard it a 1000times. Pain is not a disease, but a sign of disease. Just like the check engine light in your car-it’s not a broken light bulb, but a broken engine. Pain is your body’s way of telling your brain something is wrong and needs to be fixed. If something hurts-fix it! (no dear Liza needed).
Just like diabetes, infections or high blood pressure, leaving a joint or tissue injury un-checked just worsens the condition. When you are injured, many things go wrong. First, the part that’s injured stops working correctly, which means it starts to break down faster, which leads to degenerative joint disease, muscle contractures/trigger points and arthritis.

Second, injuries become epicenters that spread degenerative changes. Take a foot for example. You hurt your foot, you walk funny so your knee starts to wear out, which taxes your hip, which alters your low back, which affects your upper spine and before you know it, a twisted ankle in high school gymnastics becomes chronic headaches by 35 (true story-saw it with my own 2 eyes on a patient a few years back. Also-Google upper and lower cross syndromes).

Third, they change your internal biochemistry. When you’re injured, you start the inflammatory process. Only a small percentage of inflammation is pain, the rest is manifested by other chemical changes in your system. These mediators are the same as the ones in the fight or flight reaction. Higher blood pressure, altered metabolism, shunting blood away from and shrinking genitalia is a great idea when trying to escape the clutches of a saber-tooth tiger, but not so much when sitting on the couch watching the O’s blow the division.
In conclusion, that tricky knee from a football injury isn’t a badge to be worn proudly, it’s a sign you’re asking for trouble down the road.