Mechanical Versus Restrictive Kinematic Alignment in Robotic-Assisted Total Knee Arthroplasty: A Randomized...

Area of Science:

• Orthopedics
• Biomedical Engineering
• Surgical Innovation

Background:

• Lower limb malalignment is common in knee osteoarthritis.
• Surgical techniques have evolved from mechanical alignment (MA) to kinematic alignment (KA).
• Restrictive kinematic alignment (rKA) is a hybrid approach combining MA and KA principles.

Purpose of the Study:

• To compare short-term functional outcomes of robotic-assisted total knee arthroplasty (RoTKA) using MA versus rKA alignment strategies.
• To evaluate the impact of alignment on pain, range of motion, and patient-reported scores.

Main Methods:

• A prospective, randomized, single-center study involving 96 patients with grade 3-4 knee osteoarthritis.
• Patients were randomized to either MA (n=49) or rKA (n=47) groups.
• Outcomes included Visual Analog Scale (VAS) pain, range of motion (ROM), Knee Society Score (KSS), Oxford Knee Score (OKS), SF-36, and Forgotten Joint Score (FJS-12).

Main Results:

• rKA group showed a statistically significant 5.2% greater increase in knee ROM at 14 days post-surgery (p=0.008).
• VAS pain scores decreased in the rKA group but increased in the MA group (p < 0.001).
• One-year FJS-12 scores were significantly higher in the rKA group (p < 0.001).

Conclusions:

• Restrictive kinematic alignment (rKA) offers superior early postoperative outcomes in RoTKA compared to MA.
• rKA leads to reduced pain and improved ROM in the immediate postoperative period.
• rKA is a viable alignment strategy for robotic-assisted knee arthroplasty, particularly for early recovery benefits.