Negative pressure intrusion cementing technique for total knee arthroplasty

Negative pressure intrusion (NPT) is an alternative cementing technique for the tibial baseplate of total knee arthroplasty that uses a suction cannul a in the proximal tibia to remove excess fluids and fat before cementing. T ills technique was compared with standard third-generation positive pressur e intrusion (PPT) techniques in an in vitro implantation and analysis of 6 pairs of cadaveric tibiae. Six matched pairs of fresh frozen tibiae were pr epared by cutting: the tibial surfaces, standard cleaning and surface dryin g, then performing PPT and NPI on 1 of each pair. No objective differences were noted on radiographs or direct cement depth measurements analysis. Sca nning electron micrograph evaluation revealed that the PPI specimens had co nsistently more voids in the cement-bone composite, and the NPI specimens h ad consistently narrower empty spaces between bone and cement, resulting in righter fill in NPI specimens. NPI was shown to enhance characteristics kn own to improve tensile and shear strength in cement-bone composite.