Unstable Knee Condition: Causes, Signs, Diagnosis, Risks, Treatment And Recovery Instability of the knee joint is a frequently seen joint issue where the knee feels loose. Many patients describe it as the knee slipping suddenly during movement or while climbing stairs. At our orthopedic center, we regularly treat such cases https://www.diigo.com/item/note/b2kvl/bqc5?k=f8a2c593ecbde9a2c6b1a38edcc8a912