Orthopedic surgeons are always looking for ways to make joint replacement surgery more successful. One method is to apply joint cement to the implant. Unfortunately, the cement sometimes loosens its grip on the stem that fits into the top of the thighbone (femur). The implant no longer fits snugly and may eventually require a second operation to revise the hip joint.
Doctors think that the cement loosens because tiny air pockets form pores in the cement around the stem. Heating the stem before insertion has shown some promise in the past. These authors did tests in a laboratory to see how well heating the implant worked. They heated implants to at least body temperature before applying the cement. After the procedure was done, the cement was checked for pores. The implant was also tested for strength.
Preheating the stem proved effective in decreasing pores in the cement. This approach strengthened the bond between the cement and the implant by more than 50 percent when compared to stems that were implanted at room temperature. After simulating the effects of aging, the preheated implants showed 155 percent greater strength. The cement also set more quickly when the stem was preheated.
The authors conclude that preheating the stem can help prevent cement loosening in artificial hip joints. They recommend that preheating be considered for other types of implants as well.