I am wondering if you can fully extend the knee.

Many times the poplitus and planterius muscle are overlooked. They cause a normal rotation of the tibialis on the femur.

If you can straighten the knee fully, then it may just be a structural problem.

If you cannot straighten the leg completely, but are walking with a flexed leg, it may be tight popliteus and planterius that are keeping the knee from rotationg at the end of the movement.

Hope that this is helpful

Best regards,

Neuromuscular.