Summary

Inaccurate Implantation has been identified as cause for early failure in UKA. Therefore, improve accuracy could improve results. Aim: to assess the immediate effect of image-free handheld robot on implant accuracy compared to conventional surgery in a cadaveric study based on X-Rays Conclusion: Robotic assisted UKA improves accuracy of bone cuts reducing the outliers and component size prediction

Abstract

Unicompartimental knee arthroplasty (UKA) represent 10% of knee arthroplasty. Potential advantages of this technique over total knee arthroplasty include improved functional outcome, proprioception, bone and ligaments preservation, faster recovery and less blood loss. However, higher revision rates have been described.
Inaccurate implantation has been identified as a cause for early failure. Therefore, improve the accuracy could play a role to achieve better results.

Objective

of the present study was to evaluate the immediate effect of image-free handheld robot on implant accuracy compared to conventional procedure, assessed by radiologic parameters. Method: Cadaveric Pilot study. 26 cadaveric pelvis to foot pieces, Random assignment to UKA robotic assisted (R) or conventional (C) UKA.
Preoperative and postoperative radiologic study: Frontal-lateral knee X-Rays and long leg X-Rays. Measurement: Medial distal femoral angle (MDFA), Medial Proximal Tibial angle (MPTA), Tibial slope(TS), Tibiofemoral mechanical angle(TFMA), Sagital Femoral Angle(SFA), and femoral component size (FCS). Primary outcome: difference between planned and achieved parameters on sagittal and coronal planes.

Results

MDFA with median for C and R, 1.85º and 1.07º (p=0.5114) not significant, but with significant difference in variances (3.45º vs 1.18º, F=5.787, p=0.0057), as well as in MPTA and TS variances (p=0.0057 and p=0.0279) . No differences founded in SFA and TFMA. Differences were also founds in FCS, with better accuracy in R group (p=0.0188)

Conclusion

Robotic assisted UKA improves the accuracy of bone cuts reducing the outliers and femoral component size determination.