CONDITIONS AFFECTING THE KNEE JOINT CONDITIONS AFFECTING THE KNEE JOINT The commonest conditions a ff ecting the knee include injury to the soft-tissue structures and osteoarthritis (OA). CONDITIONS AFFECTING THE KNEE JOINT The commonest conditions a ff ecting the knee include injury to the soft-tissue structures and osteoarthritis (OA). CONDITIONS AFFECTING THE KNEE JOINT The commonest conditions a ff ecting the knee include injury to the soft-tissue structures and osteoarthritis (OA).