Accelerometer-based portable navigation, a faster guide compared to computer-assisted navigation in bilateral total knee arthroplasty-a randomized controlled study

Purpose There are limited studies in the literature comparing the alignment accuracy of the large console, imageless, computer-assisted navigation (CAN) and portable, hand-held, accelerometer-based navigation (ABN) in total knee arthroplasty (TKA). This study was aimed to compare the operative time, blood loss, radiological, clinical and functional outcomes between CAN- and ABN-guided bilateral TKA. Methods From Jan 2016 to Dec 2017, 50 patients who underwent bilateral TKA were randomized to undergo either CAN-guided or ABN-guided TKA. Tourniquet time and blood loss were recorded, and intra-op complications were noted. Post-op radiological outcomes at 2 weeks were compared between the groups. The clinical and functional outcomes using the American Knee Society Scores (KSS) and Oxford Knee Score (OKS) were recorded pre-operatively and post-operatively at 3, 6, 12 months and at the end of the study with a minimum follow-up of 48 months. Results Both groups were well-matched in terms of patient demographic parameters. The mean surgical time per knee was significantly lower in the ABN group (54.5 +/- 5.6 min) compared to the CAN group (61.7 +/- 13.7 min; p < 0.01). Mean blood loss per knee in the ABN group was 592.1 +/- 245.3 mL compared to 682.8 +/- 322.0 in the CAN group (p = 0.11). In the ABN group, the mean post-op mechanical axis was 1.2 +/- 3.2 degrees (vs 1.5 +/- 2.2 degrees in the CAN group, p 0.6), the frontal femoral angle was 88.8 +/- 2.3 degrees (vs 88.8 +/- 1.8 degrees in the CAN group, p 1.0) and frontal tibial angle was 90.1 +/- 1.6 degrees (vs 89.7 +/- 1.1 degrees in the CAN group, p 0.14). At 48 month follow-up, the mean functional KSS in the ABN group was 89.0 +/- 5.7 (vs 88.1 +/- 4.5 in the CAN group, p 0.37) and the mean OKS was 40.5 +/- 2.8 (vs 39.6 +/- 3.2 in the CAN group, p 0.12). Conclusion Portable, hand-held ABN offers alignment accuracy and functional outcomes in TKA similar to that with CAN, with a reduced duration of surgery. There was no advantage of either of the techniques in terms of clinical or functional outcomes at 48 month follow-up.