Makoplasty medial unicondylar knee replacement: Correction or postoperative angle matters?

Int J Med Robot. 2022 Apr;18(2):e2356. doi: 10.1002/rcs.2356. Epub 2022 Jan 3.


Introduction: Various considerations prevail around optimal postoperative varus deformity, correction angle and physiological constitutional varus deformity. The goal of our present study was to understand correlation between these parameters and their influence over Western Ontario McMaster University Osteoarthritis Index scale (WOMAC).

Materials and methods: Consecutive robotic-arm-assisted medial onlay fixed bearing unicompartmental knee arthroplasty (UKA) in 143 knees studied. WOMAC score was recorded preoperatively and at specific intervals after surgery for consecutive 2 years.

Results: Mean preoperative and postoperative varus deformities were 10.2° and 4.8°, respectively, and mean correction angle was 5.4°. The preoperative varus and correction angles were found well correlated (r = 0.815). The amount of improvement in the WOMAC total score was not influenced by the postoperative varus angle.

Conclusion: The correction angle has a stronger correlation with preoperative varus deformity, and postoperative varus deformity does not imply favourable clinical outcomes.

Keywords: UKA; WOMAC; correction angle; knee; makoplasty; osteoarthritis; postoperative varus; preoperative varus; robotic-arm-assisted.

MeSH terms

  • Arthroplasty, Replacement, Knee*
  • Humans
  • Knee Joint / surgery
  • Osteoarthritis, Knee* / surgery
  • Postoperative Period