Stair climbing is a difficult skill for many people who have had total knee replacement. This is true even one year after surgery. After surgery, the support from leg muscles is only one-third of the strength and force needed to climb stairs.
Bring your concern to your doctor's attention. A physical therapist can help you begin an exercise program specifically designed to assist you with stairs. If you saw a physical therapist during your recovery from surgery, do not hesitate to contact the therapist and request additional services.