What are the advantages and evidence for robotic total knee replacement (TKR)?

Robotic Total Knee Replacement: Evidence Does Not Support Routine Use

Based on the strongest available guideline evidence, robotic-assisted TKA should not be used routinely, as it provides no demonstrable advantage in clinical outcomes, complications, or long-term survivorship compared to conventional TKA, while adding significant time and cost. 1

Guideline Recommendations Against Robotic/Navigation Technology

The American Academy of Orthopaedic Surgeons provides strong evidence supporting NOT using intraoperative navigation or patient-specific instrumentation (PSI) in TKA because there is no difference in outcomes or complications compared with conventional instrumentation. 1 This recommendation specifically addresses additive technologies that increase procedural complexity and cost without improving patient outcomes. 1

Long-Term Randomized Controlled Trial Evidence

The highest quality evidence comes from a large randomized controlled trial with 13-year follow-up comparing robotic-assisted TKA (724 knees) versus conventional TKA (724 knees): 2

Clinical Outcomes - No Differences Found:

• Knee Society scores: 93 points (robotic) vs 92 points (conventional), p=0.321 2
• Knee function scores: 83 points (robotic) vs 85 points (conventional), p=0.992 2
• WOMAC scores: 18 points (robotic) vs 19 points (conventional), p=0.981 2
• Range of motion: 125° (robotic) vs 128° (conventional), p=0.321 2
• Activity scores: Identical at 7 points in both groups, p=1.000 2

Radiographic Outcomes - No Differences Found:

• Femorotibial angle: 2° valgus (robotic) vs 3° valgus (conventional), p=0.897 2
• Femoral component position: No significant differences in coronal (p=0.953) or sagittal planes (p=0.612) 2
• Tibial component position: No significant differences in coronal (p=0.721) or sagittal planes (p=0.792) 2

Survivorship - Identical Results:

• Aseptic loosening rate: 2% in both groups 2
• 15-year Kaplan-Meier survivorship: 98% in both groups (95% CI 94-100), p=0.972 2

Meta-Analysis Findings

A 2024 systematic review of 7 RCTs (1,942 knees) found that while robotic TKA achieved statistically better anatomical alignment (p<0.00001) and mechanical axis restoration (p<0.0006), these radiographic improvements did not translate into superior clinical or functional outcomes. 3 Complication rates were statistically similar between groups. 3

Disadvantages of Robotic-Assisted TKA

Documented Drawbacks:

• Increased operating time without outcome benefit 4
• Higher overall costs compared to conventional technique 4
• Need for fiducial marker placement adding procedural steps 4
• No reduction in complications despite theoretical precision 2, 3

Conventional TKA Benchmark Performance

Conventional TKA achieves 89% good or excellent outcomes for pain and function up to 5 years after surgery, establishing a high-quality standard that robotic assistance has failed to improve upon. 1, 5

Critical Interpretation

The disconnect between improved radiographic alignment and unchanged clinical outcomes suggests that the theoretical precision advantage of robotics does not address the actual determinants of patient satisfaction and functional recovery. 2 The AAOS guideline explicitly uses language stating "evidence supports NOT using" these technologies to convey that additive procedures adding no benefit should be avoided. 1

Common Pitfalls to Avoid

• Do not assume radiographic precision equals better outcomes: Perfect alignment on imaging has not translated to improved pain, function, or implant survival 2, 3
• Do not justify robotic use based on early technical studies: Long-term RCT data supersedes short-term radiographic studies 2
• Do not overlook cost-effectiveness: Adding expense without outcome benefit contradicts value-based care principles 4, 2