I had a TKR about 4 mo. ago. I recovered remarkably well with the ability to bend my knee to 122 degrees within 1 month post surgery. About a month ago I suddenly began hearing a sound like velco ripping open when straightening the knee from a sitting to standing position. I is a little painful when it happens and sometimes, depending on the position of the knee, it hurts badly. I had an appt with my OS today but they called and postponed it. Can you give me an idea what may be causing this?
You can surely visit the Orthopedic for this. meantime you start doing static qua Chat Doctor.  Try to hold onto something and try doing reverse walking as well. It will help to avoid any extension lag available and help you get ease of any pain.