Variability of cement mantle thickness in total knee arthroplasty

Abstract

Introduction: The optimal thickness of the cement mantle in total knee arthroplasty (TKA) has been proposed to be 3-5mm for implant stability. However, there is a paucity of studies on the capacity to obtain a constant cement mantle thickness in practice. The aim of this study was to assess whether there is a difference in the cement mantle thickness in TKA performed between different surgeons. Methodology: The 20 most recent primary TKA performed by each surgeon were selected to make up a total of 100 patients. There is varying cementing techniques between the surgeons. For all surgeons, pulsatile lavage and cement vacuum mixing was used. Some surgeons used a technique of finger packing to pressurise the intramedullary cavity before insertion of the implant. One surgeon did not use a tourniquet. Initial postoperative anteroposterior (AP) and lateral radiographs were assessed to measure the cement penetration according to zones proposed by the Knee Society. Results and Analysis: Between the surgeons, there were no difference in the cement thickness at the tibial tray (p>0.05), but there was a difference around the tibial stem (p<0.05). Particularly, a surgeon using a finger pressurisation technique produced a significantly thicker mantle around the stem (mean lateral 6.1mm; AP 5.1mm) compared to 2 other surgeons who didn’t use this technique (mean lateral 3.5mm, 3.6mm; AP: 3.6mm, 3.2mm). Discussion and Conclusion: Between the joint surgeons in our centre, there was no difference in cement thickness at the tibial tray, but there was a difference around the tibial stem, which may be affected by the cementing technique.