Ruptured quadricep Tendon

I ruptured my right quadricep tendon at work in May 2015, l had surgery to repair the damage l was told it was repaired with 3 screws and spent a week in hospital with my leg in a cast for six weeks then a course of physiotherapy it helped but not enough to get me back to work, 18 months later l am still not back to work because of the pain and discomfort in my knee.Could anyone give me a timescale as to how long this will take to heal enough to get myself back to work (I drive an HGV it’s my brake and throttle leg)