Improved joint-line restitution in unicompartmental knee arthroplasty using a robotic-assisted surgical technique

Purpose Joint-line restitution is one objective of unicompartmental knee arthroplasty (UKA). However, the joint line is often lowered when resurfacing femoral implants are used. The aim of this study was to compare the joint-line height in UKA performed by robotic-assisted and conventional techniques. Methods This retrospective case-control study compared two matched groups of patients receiving a resurfacing UKA between 2013 and 2016 by either a robotic-assisted (n = 40) or conventional (n = 40) technique. Each group comprised 27 women and 13 menm wuth a mean age of 69 and 68 years, respectively. Indications for surgery were osteoarthritis (n = 35) and condylar osteonecrosis (n = 5). Two validated radiologic measurement methods were used to assess joint-line height. Results Forty UKA (23 medial and 17 lateral) were analysed in each group. Restitution of joint-line height was significantly improved in the robotic-assisted group compared than the control group: +1.4 mm +/- 2.6 vs +4.7 mm +/- 2.4 (p < 0.05) as assessed using method 1, and +1.5 mm +/- 2.3 vs +4.6 mm +/- 2.5 (p < 0.05) as assessed using method 2. Conclusions Restitution of joint-line height in resurfacing UKA can be improved with robotic-assisted surgery. Improvement in clinical outcome measures must be demonstrated with long-term studies.