The locking was in relation to the statment: "The main issue i am still having is the stiffness of my leg especially behind my knee as i struggle to straighten my leg fully" this is a sign of joint irritation. Runners knee tends to be from reparative flexion of knee under load and causes pain in the upper outside of knee during bending not straightening.
Please clarify what movements cause you pain?
Also can you explain what oblique twist are ?? Standing trunk twists or sit ups with a trunk twist or something else??