what is int derangement knee causes
Anatomy and Physiology. Internal derangement of the knee is a mechanical disorder of the knee which interferes with normal joint motion and/or mobility. A fragment of soft tissue or bone that suddenly becomes interposed between the articular surfaces is the classic cause of internal derangement.natomy and Physiology. Internal derangement of the knee is a mechanical disorder of the knee which interferes with normal joint motion and/or mobility. A fragment of soft tissue or bone that suddenly becomes interposed between the articular surfaces is the classic cause of internal derangement.