Negative pressure intrusion cementing technique for total knee arthroplasty.

Negative pressure intrusion (NPI) is an alternative cementing technique for the tibial baseplate of total knee arthroplasty that uses a suction cannula in the proximal tibia to remove excess fluids and fat before cementing. This technique was compared with standard third-generation positive pressure intrusion (PPI) techniques in an in vitro implantation and analysis of 6 pairs of cadaveric tibiae. Six matched pairs of fresh frozen tibiae were prepared by cutting the tibial surfaces, standard cleaning and surface drying, then performing PPI and NPI on 1 of each pair. No objective differences were noted on radiographs or direct cement depth measurement analysis. Scanning electron micrograph evaluation revealed that the PPI specimens had consistently more voids in the cement-bone composite, and the NPI specimens had consistently narrower empty spaces between bone and cement, resulting in tighter fill in NPI specimens. NPI was shown to enhance characteristics known to improve tensile and shear strength in cement-bone composites.