Robotic arm–assisted cementless cruciate retaining total knee arthroplasty without tourniquet: Learning curve of a master surgeon

Abstract

Introduction: Cementless total knee arthroplasty (TKA) can potentially improve implant survivorship for young active patients. Robotic arm improves bone cut precision facilitating cementless fixation, coupled with intra-operative gap balancing this may improve outcomes. Methods: We analysed the learning curves of the first 25 cases of robotic arm–assisted TKA performed between 11 January and 23 May 2019. All surgeries were performed by a single surgeon (KYC) using Mako total knee application with medial parapatellar approach, without tourniquet, using a cementless cruciate retaining implant. 25 Chinese patients, all with primary knee osteoarthritis were included. Mean age was 66 years and 14 were female. Mean preoperative alignment was 11° varus. Results: Significant reduction in total operating time was noticed between the first 10 cases, second 10 cases, and last 5 cases, with mean operating time of 100, 75, and 60 minutes, respectively (p<0.004). Between the first 10 cases and subsequent cases, significant reductions were observed in time for draping and calibration (22 vs 7 minutes, p=0.00002), insertion of trackers and leg holder (9 vs 5 minutes, p=0.00005), registration (13 vs 8 minutes, p=0.00015), soft tissue balance and planning (10 vs 6 minutes, p=0.0003), bone cuts (20 vs 10 minutes, p<0.00001), and trial (17 vs 11 minutes, p=0.0063). Preoperative computed tomography was 100% predictive of actual component sizing. All knees achieved active straight leg raise on day 1. There was one case of distal deep venous thrombosis and one case of superficial wound infection. Conclusion: Once the learning curve has passed, robotic arm–assisted TKA can average 60 minutes, which is faster than navigated TKA (84 minutes) and conventional cemented TKA (64 minutes).