Dynamic Robotic Assessment may Identify Subtle Joint Instabilities, Suggests Study

Although total knee arthroplasty (TKA) outcomes have improved, soft-tissue imbalance—specifically mid-flexion instability—remains a leading cause of pain and revision surgery. Because traditional gap-balancing tools provide only subjective, static insights, Dr. K T Rajashekhar and colleagues at Apollo Hospitals, Bengaluru, utilized a CT-based robotic system for objective, real-time stability profiling throughout the knee's full range of motion

Therefore, the clinical protocol utilized the Cuvis Joint robotic system for continuous numerical tracking of medial and lateral compartment gaps during total knee arthroplasty (TKA). By assessing joint behavior under controlled stress both before bone resection and after trial placement, surgeons identified range-dependent instabilities often missed by traditional static methods. This data-driven approach replaces subjective tactile feedback with precise, real-time analysis of limb alignment and soft-tissue tension across the full 0–120° flexion arc.

Key clinical findings of the study includes:

• Mid-flexion Instability Detection: The study routinely identified abrupt increases in both medial and lateral gap widths between 30° and 60° of flexion, which are frequently undetectable through standard static evaluations.

• Deep-flexion Monitoring: The research effectively captured rapid reductions in gap width at angles exceeding 90°, enabling surgeons to immediately correct potential tightness by adjusting the posterior condylar offset.

• Objective Gap Targets: The analysis confirmed that surgeons could consistently maintain precise mediolateral gaps of 9–10 mm across the entire range of motion, providing a degree of accuracy unavailable in traditional subjective methods.

• Improved Balancing Precision: Unlike conventional manual assessments that vary significantly between practitioners, the study produced reproducible, numerical stability profiles that allow for highly personalized soft-tissue corrections.

• Real-time Instability Identification: The report demonstrated that continuous tracking identifies range-dependent asymmetries, such as lateral gap widening in flexion, facilitating tailored adjustments to component positioning or ligament tension

The results suggest that continuous dynamic tracking provides a superior method for achieving balanced soft-tissue tension, successfully targeting intended mediolateral gaps of approximately 10 mm throughout the motion arc. This approach provides numerically quantifiable confirmation of stability, significantly reducing the risk of soft-tissue errors in complex cases such as post-traumatic deformities or valgus knee corrections.

Thus, the study concludes clinicians may find that integrating dynamic stability analysis into routine surgical workflows improves intraoperative decision-making and potentially reduces the long-term risk of post-operative instability and subsequent revision surgery.

Although the technique integrates seamlessly into standard surgical routines with minimal added time, additional long-term research is necessary to confirm how these improved intraoperative profiles translate into superior clinical recovery and extended implant longevity.

Reference

Rajashekhar KT, Bhat AKK, Bagrecha A. Robotic-Assisted Dynamic Intraoperative Assessment of Coronal Plane Stability Across the Range of Motion During Total Knee Arthroplasty. Journal of Orthopaedic Case Reports 2026 February; 16(02): 342-345