How Accurate Are We With Conventional Surgical Methods?

• As many as 40% to 60% of components may be malaligned by more than 2° from the preoperative plan with conventional methods.

–Cobb J, Henckel J, Gomes P, Harris S, Jakopec M, Rodriguez F, et al. Handson robotic unicompartmental knee replacement. J Bone Joint Surg Br. 2006 Feb;88(2):188–97.

– Keene G, Simpson D, Kalairajah Y. Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br. 2006 Jan;88(1):44–8.

Use of Computer Navigation

• Navigation has been shown to improve postoperative leg alignment over that obtained in conventional UKA.

–Keene G, Simpson D, Kalairajah Y. Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br. 2006 Jan;88(1):44–8.

– Jenny JY, Boeri C. Unicompartmental knee prosthesis implantation with a nonimage- based navigation system: rationale, technique, case-control comparative study with a conventional instrumented implantation. Knee Surg Sports Traumatol Arthrosc. 2003 Jan;11(1):40–5.

• Although navigation is a powerful visual aid, surgical outcomes still depend on the mechanical tools used in procedures.
• Even with computer navigation, the number of outliers (beyond 2° of the preoperatively planned implant position) may approach 15%.

–Keene G, Simpson D, Kalairajah Y. Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br. 2006 Jan;88(1):44–8.