Having your knee replaced with an un-cemeted prosthesis has it advantages and dis-advantages. The advantages however outweigh the disadvantages depending on your age. Younger adults generally but not always get un-cemented components initially for several reasons.
Having components that are un-cemented are used for those patients that have healthy bone stock and quality. The un-cemented components have what is called a porous material that is built within them. This allows for your bone to grow naturally into the prosthesis giving them a more natural fit.
With an un-cemented prosthesis this will allow a younger patient who is active and who typically outlives the original knee replacement to get a revision later down the road with out the damage to the bone stock that the cement causes over time. They are also easier to remove overall then the cemented replacements.
The dis-advantage with un-cemented components is that after surgery generally your weight bearing status will be modified for the first four to six weeks while the bone begins to grow into the implant. This however is only temporary and if allowed to heal properly will work just fine.
Many younger patients and some older ones too however can get somewhat impatient after a couple of weeks and we as rehabilitation professsionals have to at times frequently remind the patient about their weightbearing precautions. Most patients I have found will at times exceed the precautions without further damage to the knee however constant non-compliance or total disregard for weightbearing precautions will have you back in the surgeons office in no time back on the operating table.
After surgery follow closely what your surgeons instructions are carefully and listen to your physical therapist and you will be on the path to a better quality of life in no time.