Short-term benefits of image-based robotic assistance in TKA after prior HTO: A comparative study

High tibial osteotomy (HTO) is used to treat medial knee osteoarthritis with varus alignment in young, active patients. While robotic-assisted total knee arthroplasty (TKA) may improve implant positioning and soft-tissue balance, its benefits in post-HTO patients remain unclear. This study compares surgical, clinical and radiological outcomes between robotic-assisted and conventional TKA following HTO.

A retrospective study included 87 patients with prior HTO who underwent TKA between August 2017 and October 2023 (46 robotic-assisted and 41 conventional), with a minimum 1-year follow-up. Demographic data, surgical characteristics, clinical outcomes (Knee Society Score [KSS], range of motion), radiological alignment (hip-knee-ankle angle) and complications were analysed. Mean follow-up was 23 months.

Operative time was similar between groups (82 vs. 95 min; p = 0.07). Robotic-assisted TKA was associated with fewer lateral releases (30% vs. 54%; p = 0.03) and no tibial tubercle osteotomies (0% vs. 10%; p = 0.03). Cruciate-substituting implants were used more frequently in the robotic group (13% vs. 0%; p = 0.001), whereas stemmed implants were more common in the conventional group (49% vs. 17%; p = 0.001). Postoperative KSS Knee scores were comparable between groups (p = 0.28), while KSS Function scores were slightly higher in the conventional group (p = 0.048). Complication rates did not differ significantly.

Robotic-assisted TKA after HTO was associated with a similar operative times and comparable short-term clinical outcomes to conventional TKA. It was also associated with lower rates of additional procedures and a less frequent use of stemmed or constrained implants. These findings should be interpreted with caution, given the baseline differences between the groups. Longer follow-up is warranted.

Level III, therapeutic studies, retrospective comparative study.