Comparison of Mobile-Bearing and Fixed-Bearing Designs in High Flexion Total Knee Arthroplasty: Using a Navigation System

Abstract

PurposeWe compared and analyzed the short term results of high flexion total knee arthroplasty (TKA) with mobile-bearing and fixed bearing designs.Materials and MethodsWe studied 32 patients that had undergone TKA with LPS-Flex Mobile and 34 patients with LPS-Flex Fixed using an electromagnetic navigation system between January 2010 and June 2010, and were followed up for at least 1 year.ResultsKnee Society Functional Score (KSFS) and Knee Society Knee Score (KSKS) of the mobile-bearing group were 94.5 and 93.8 points, respectively, and were 48.2 and 45.3 points preoperatively, whereas those of the fixed-bearing group were 95.1 and 94.2 points, respectively, and were 49.5 and 46.9 points preoperatively. Postoperative mechanical axis deviation and implant position of the femoral and tibial component both on the coronal and sigittal planes showed no significant differences between the two groups. Range of motion (ROM) and maximal flexion angle (MFA) of the knee joint also showed no significant differences between the two groups. The possibility of crossed-legged sitting and kneeling position also showed no significant differences between the two groups.ConclusionsClinical and radiologic parameters, ROM and MFA of knee joints showed no significant differences in both the groups, but long term follow-up results may be necessary, including survival rate.

Electromagnetic Navigation in Total Knee Arthroplasty—A Single Center, Randomized, Single-Blind Study Comparing the Results With Conventional Techniques

“…Our experience was that in the presence of ferrous materials the system would go 'blind' and prior to loss of signal, no unexplained change in the system readout values was noted. Other in vitro and in vivo studies looking at the results of electromagnetic navigation have confirmed that system accuracy is not problematic, with good results comparable to infra-red systems [35,40,41]. Two clinical studies have compared the electromagnetic technique directly with traditional infra-red navigation systems and found similar, high degrees of accuracy [42,43], although the numbers in these studies were small.…”

Different femorotibial contact points between fixed- and mobile-bearing TKAs do not show clinical impact

“…In high-flexion prostheses, Kim et al [16] reported no differences in clinical and radiological parameters, range of motion and maximum flexion angle at a follow-up of a year.…”

Is there reduced polyethylene wear and longer survival when using a mobile-bearing design in total knee replacement?

“…Of these, we included 34 clinical trials with 4754 patients (6861 TKRs) in the meta-analysis. [4][5][6][7][11][12][13][14][15][16][17][18][19] There were 32 RCTs, two were CCTs, 6,29 and two were from the same trial. 23,41 The characteristics of the studies that were included are shown in Tables I and II.…”

“…[3][4][5][6][7][8][9][10] However, these studies focused on the clinical outcome and did not evaluate the polyethylene wear and prosthetic survivorship, including radiolucent lines, osteolysis, aseptic loosening and the rate of revision. 3,[8][9][10] In all, nine RCTs comparing outcomes of these two designs were published in 2012, [11][12][13][14][15][16][17][18][19] without conclusive results.…”