Total knee arthroplasties, or replacements, can be done with or without special cement to hold them in place. One of the drawbacks of using cemented implants is the cement needs to be applied into the marrow cavity without causing any problems around the area and the cement can crack as it ages, causing debris in the joint. Therefore, doctors do like the idea of cementless implants.
However, cementless implants have their own problems, the main one being that the bone that will hold the implant has to be in good enough condition to do so. Therefore, the doctor has to decide what type of implant is best for each patient, individually, taking into account the reason for the replacement, the general health of the patient, the bone health, the patient's age, and the patient's lifestyle.