Pre-heating of components in cemented total hip arthroplasty.
Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of septic loosening of cemented femoral components. Heating of the component to 44 degrees C is known to reduce the porosity of the cement-prosthesis interface. The temperature of the cement-bone interface was recorded intra-operatively as 32.3 degrees C. A simulated femoral model was devised to study the effect of heating of the component on the implant-cement interface. Heating of the implant and vacuum mixing have a synergistic effect on the porosity of the implant-cement interface, and heating also reverses the gradients of microhardness in the mantle. Heating of the implant also reduces porosity at the interface depending on the temperature. A minimum difference in temperature between the implant and the bone of 3 degrees C was required to produce this effect. The optimal difference was 7 degrees C, representing a balance between maximal reduction of porosity and an increased risk of thermal injury. Using contemporary cementing techniques, heating the implant to 40 degrees C is recommended to produce an optimum effect.
Jafri
A A
AA
Department of Orthopaedic Surgery, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4BN, UK.
Green
S M
SM
Partington
P F
PF
McCaskie
A W
AW
Muller
S D
SD
D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001843:Bone Cements; D002484:Cementation; D005270:Femur Head / Q000502:physiology* / Q000601:surgery; D006622:Hip Prosthesis; D006358:Hot Temperature; D006801:Humans; D010784:Photomicrography; D016062:Porosity; D011475:Prosthesis Failure
D001843:Bone Cements