KS38: A RADIOLOGICAL COMPARISON OF CEMENT MANTLE THICKNESS AROUND TOTAL KNEE ARTHROPLASTY WITH OR WITHOUT THE USE OF PRESSURIZED CARBON DIOXIDE LAVAGE

Cemented total knee arthroplasty has excellent long term survivorship however deficiencies of the cement mantle can compromise results. Minimising mantle deficiencies and increasing mantle size, may improve implant fixation and survivorship. The aim of this study was to evaluate the effectiveness of pressurized carbon dioxide lavage in an attempt to increase cement penetration into bone. Two consecutive series of TKAs where performed by the senior surgeon. During the first series standard cementing techniques where utilised prior to prosthesis implantation. The bone surfaces were cleaned with pulsatile lavage and then dried prior to cementation (n=69). During the second series a jet of high pressure carbon dioxide was also delivered to the bone surfaces via a hand held device (CarboJet, Kinamed Inc, Global Orthopaedic Technology)(n=50). A single investigator reviewed standardised post operative radiographs with respect to, depth of cement mantle around the prosthesis, and the presence of mantle defects. The cement mantle around the tibial and femoral prosthesis was divided into multiple zones, similar to that applied by the Knee Society. The depth of cement penetration was then measured for each zone in 0.5 mm increments using a 115% rule. Depths were averaged and then analysed using students’ T test. Cement penetration was greater with the use of pressurized carbon dioxide lavage. The greatest difference was seen in zones 1 and 4 beneath the Tibial prosthesis. A Significant difference was noted between groups. The size of the cement mantle can be increased with the use of pressurized carbon dioxide lavage. It is postulated that the bone interstices are cleared of fat and fluid more effectively than with fluid lavage alone. This may lead to an improved outcome for cemented total knee arthroplasty.