Osteoarticular tuberculosis (TB)
According to a 2015 article, osteoarticular TB addresses 5% of all instances of TB. A swollen knee joint is a common sign of joint TB and it usually causes pain in the inner knee.
Reflex thoughtful dystrophy (RSD)
RSD is an less common sensory system issue that can cause nagging pain in inner knee.
Harmful tumors:
Malignant tumors in the in the knee joint can cause damage to the inner knee structures and may lead to pain and inflammation.