Aims: Thrombembolic complications, which include the fat embolism syndrome, are well known consequences of cementless and cemented total hip replacement. Embolic phenomena could be demonstrated clinically and experimentally with both fixation techniques. Methods: We investigated in a standardized animal model in 15 Merino sheep the fat intravasation into the blood stream during bilateral simultaneous prosthetic implantation (cemented versus cementless). After identical preparation of the intramedullary canal a cement restrictor was additionally inserted on the cemented side and the canal was cleaned with 250ml jet-lavage. By catheters in the external iliacal veins the drained blood was collected in two phases, one after preparation of the intramedullary canal and another during insertion of the prosthesis, and the fatty contents of these blood samples were measured. Results: Cemented implantation (2,2749g; S=±1,0079) produced a two-fold amount of fat intravasation into the venous draining system of the femur compared to the cementless implantation (1,1586g; S=±0,4555)(p= 0,0002). An obvious effect of the canal preparation was recognizable with the cemented implantation. Eight of thirteen evaluated animals showed a peak in the fat intravasation caused by the application of the cement restrictor. Conclusions: Our results emphasize the importance of a thorough preparation of the intramedullary canal, particularly when cemented fixation is performed. The jet lavage, which should be standard in cemented total hip arthroplasty, should be implemented prior to the insertion of the plug in order to further reduce the risk of fat embolism.

Aims: The aim of the study was to determine the efþcacy of jet lavage in comparison to syringe lavage with respect to cement penetration and stability of the poly-ethylene patellar component after patellar resurfacing in total knee arthroplasty. Methods: In a cadaver study, we prepared 37 fresh frozen human patella pairs. The retropatellar bed was randomly cleaned with either jet lavage or a bladder syringe. The polyethylene component was cemented using Palacos R. For 12 patella pairs, sagittal sections were obtained at predeþned levels using a diamond saw. Mikroradiograms were digitised and analysed with respect to cement penetration. For the remaining 25 patella pairs, pullout tests were performed on patellar components using a traction-compression device. Results: Cement penetration was signiþcantly greater (P< 0.0001) in the jet lavage specimens compared to the syringe lavage specimens. The maximum force required to cause mechanical failure was signiþcantly greater (P< 0,0001) in jet lavage specimens compared to syringe lavage specimens. Conclusions: Our results support the routine use of jet lavage for cleansing the patellar bed prior to cement application in cemented patellar resurfacing.