One of the things I assess is whether or not your pelvis is functioning correctly. If it's not then this can lead to one leg being longer than the other.
This then can cause the spine to compensate for the longer leg as will the knee and foot too. The longer leg will flex more and adopt a valgus (knock kneed) position in an attempt to shorten the long leg. This then increases the load on the menisci. It also means that the ACL and MCL (ligaments in your knee) are more vulnerable to injury.
So Biomechanics isn't just about getting rid of pain. It's about injury prevention too. And the crazy thing is that so many of my client's don't even realise that their pelvis isn't 'normalised' simply because there is not always pain. In fact quite often there isn't (or at least not in the areas you would think are restricted)
But it's only when we start to get the body moving more freely can you appreciate just how 'stiff' or 'tight' you actually felt in the first place (And how much better you can feel!)