I think I just haven't explained myself clearly!
I'm talking about someone who sustains a specific injury, ie 'twisting the knee' giving medial Wikipedia reference-linkmeniscus damage.
Then, because of poor rehab, they go on to devolp early OA due to postural compensations, ie reduced weight bearing on the injured leg because of pain.
This you would assume would give weakness of that lower limb, and perhaps imbalance of postural muscles and then secondary Lx problems.
Wikipedia reference-linkFacet joints may then be hypomobile, but they are not causing the knee pain, the injury and poor rehab are!
This is obviously a hypothetical situation, I can see how you would get results if there was an element of facet joint hypomobility, but I don't think in all cases as you suggest, that this is the main issue to address.

Rehab the knee injury properly, and you won't get postural adjustments and in turn you won't get secondary problems in the Lx.