Inflammatory Response in Robotic-Arm-Assisted vs. Conventional Jig-Based TKA

A new JBJS study by Fontalis et al. compares the inflammatory response in robotic-arm-assisted total knee arthroplasty (TKA) vs. conventional jig-based TKA. The investigators also assessed the relationship with early functional outcomes.  

As noted in the study, patients may report dissatisfaction with TKA despite its good mid- to long-term clinical outcomes and low revision rates. Surgical trauma is a potential contributing factor to dissatisfaction, say the investigators, as it may lead to inflammatory responses that influence clinical recovery and functional outcomes. 

Inflammatory Response in Robotic-Arm-Assisted Versus Conventional Jig-Based TKA and the Correlation with Early Functional Outcomes: Results of a Prospective Randomized Controlled Trial 

The researchers recently conducted a randomized controlled trial comparing robotic-assisted and conventional TKA, assessing serum inflammatory markers at select postoperative time points¹. They found a significantly lower systemic inflammatory response at 7 days for robotic TKA. They also found less iatrogenic soft-tissue injury and bone trauma among the patients in the robotic TKA group.  

They hypothesized that robotic TKA would be associated with a reduction in local inflammation. 

Study Highlights 

• In the current Level-I analysis, the investigators sought to produce pilot data on local inflammatory response by measuring the levels of inflammatory markers obtained from intra-articular drain fluid (at 6 and 24 hours). They also evaluated functional outcomes and patient-reported outcome measures (PROMs) at 2 years, to explore any potential correlation with local and systemic inflammation. 
• Included were 15 patients with symptomatic knee osteoarthritis who underwent conventional TKA, and 15 who underwent robotic-arm-assisted TKA. 

Findings 

• The patients in the robotic TKA group had lower levels of interleukin (IL)-6 at 6 and 24 hours and a lower level of IL-8 at 6 hours. 
• Patients who underwent robotic TKA had lower pain scores on postoperative days 1, 2, and 7. 
• At 2 years, PROM scores were comparable between the 2 groups. However, the small sample size precluded the ability to identify statistically significant differences in PROMs. 
• The authors found significant correlations between all serum markers except IL-1b and self-reported pain on day 7. They also found a moderate correlation between IL-6, IL-8, and tumor necrosis factor-alpha levels at 6 hours and knee flexion or extension. 

Conclusions 

The authors concluded that robotic-arm-assisted TKA was associated with a reduction in the early postoperative local inflammatory response. In addition, they found “a moderate relationship between the inflammatory responses and self-reported pain, knee flexion, and knee extension.” 

They emphasize the need to validate their findings in a larger study and obtain longer-term data, noting that this “will be key to developing the optimal TKA procedure.”  

Access the full JBJS report along with a video summary.  

A commentary on this study is provided by Sébastien Lustig, MD, PhD: “More Science and Less Passion Around Robotic Surgery” 

References 

1. Kayani B, Tahmassebi J, Ayuob A, Konan S, Oussedik S, Haddad FS. A prospective randomized controlled trial comparing the systemic inflammatory response in conventional jig-based total knee arthroplasty versus robotic-arm assisted total knee arthroplasty. Bone Joint J. 2021 Jan;103-B(1):113-22.