Ilio-tibial band syndrome (ITBS)
This interesting condition causes pain on the outer side of the knee due to a tight Ilio-tibial band rubbing over the lateral femoral epicondyle (a sharp edge to the thighbone above the knee where the lateral ligament of the knee attaches to the femur). The condition usually occurs in runners or cyclists and comes on after a certain distance (which gets less as then condition worsens) and settles quickly if the running is stopped. There will be tenderness over the epicondyle.
The road camber can be a factor and running in the opposite direction and camber (IF SAFE) can help. Treatment is by diligent physiotherapy stretches of the tight ITB and recovery may take several months. The stretches may need to be continued long term. Very occasionally this does not work and other treatment options include anti-inflammatory injection. Very occasionally surgery to slightly lengthen the ITB is required.