Functional and radiological outcomes of computer-assisted and handheld robotic total knee arthroplasty: A prospective randomised study

Abstract

Background: Computer navigation (CAS) and robotic assisted surgery (RAS) have been shown to improve component alignment and decrease mechanical alignment outliers. However, the difference between soft tissue releases in both imageless technologies is not well known. The objective of this prospective randomised study was to compare the soft tissue releases, functional and radiological outcomes in TKA operated with CAS or RAS and find out the mean error between planned and achieved cuts with both technologies.

Methods: One-hundred patients were enrolled in each group after randomisation by computer-generated sequence: Group R, robotic assisted TKA; and Group C, CAS TKA. Functional and radiological outcomes were recorded preoperatively at 6 weeks, 3, 6, 12 and 24 months.

Results: Group R had significantly less soft tissue releases compared with Group C (P = 0.04). The robotic-assisted procedures achieved statistically higher accuracy for femoral distal femur cut thickness, femoral rotation, femoral flexion and femoral coronal angle (51%, 46%, 44%, 56%, respectively) in comparison with CAS TKA (44%, 25%, 29%, 46%, respectively). RAS achieved higher accuracy for tibial cut thickness, tibial slope, tibial cut coronal plane in comparison with CAS. Group R had significantly higher KOOS, HFKS and FJS-12 than Group C (P < 0.05) at the end of 2 years of follow up which, however, did not reach the minimal important clinical difference levels for each score.

Conclusion: The use of the handheld robotic system led to decreased soft tissue releases and mean cutting errors as compared with CAS, potentially leading to better pain scores and patient-reported outcomes.

Keywords: Computer navigation; Robotic assisted; Total knee arthroplasty.