Improved accuracy of implant placement with an imageless handheld robotic system compared to conventional instrumentation in patients undergoing total knee arthroplasty: a prospective randomized controlled trial using CT-based assessment of radiological outcomes

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA sports traumatology, arthroscopy : official journal of the ESSKA, 2023-12, Vol.31 (12), p.5446-5452
• Main Authors: Bollars, Peter, Janssen, Daniel, De Weerdt, Wim, Albelooshi, Ali, Meshram, Prashant, Nguyen, Thang D., Lacour, Michael T., Schotanus, Martijn G. M.
• Format: Article
• Language: English
• Subjects: 3D‐CT; Alignment; Ankle; Arthroplasty (knee); Arthroplasty, Replacement, Knee; Biomedical materials; Classification; Clinical trials; Computed tomography; Control equipment; CPAK classification; CT‐shape match; Femoral components; Femur; Humans; Imageless; Image‐free; Implant placement accuracy; Instrumentation; Joint replacement surgery; Knee; Knee Joint - diagnostic imaging; Knee Joint - surgery; Knee phenotypes; Knee Prosthesis; Medicine; Medicine & Public Health; Orthopaedic implants; Orthopedics; Osteoarthritis; Osteoarthritis, Knee - diagnostic imaging; Osteoarthritis, Knee - surgery; Outliers (statistics); Phenotypes; RATKA; Robotic assisted; Robotic surgery; Robotic Surgical Procedures; Robotics; Sports Medicine; Statistical analysis; TKA; Tomography, X-Ray Computed; Total knee arthroplasty; Transplants & implants
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-023-07590-x

Purpose Image-free handheld robotic-assisted total knee arthroplasty (RATKA) has shown to achieve desired limb alignment compared to conventional jig-based instrumented total knee arthroplasty (CTKA). The aim of this prospective randomized controlled trial (RCT) was to evaluate the accuracy of a semi-autonomous imageless handheld RATKA compared to CTKA in order to achieve the perioperative planned target alignment of the knee postoperatively. Methods Fifty-two patients with knee osteoarthritis were randomized in 1:1 ratio to undergo unilateral CTKA or an imageless handheld RATKA. A full-length lower limb CT-scan was obtained pre- and 6-week postoperative. The primary outcomes were radiologic measurements of achieved target hip–knee–ankle axis (HKA-axis) and implant component position including varus and external rotation and flexion of the femur component, and posterior tibial slope. The proportion of outliers in above radiographic outcomes, defined as > 3° deviation in postoperative CT measurements as compared to perioperative planned target, were also noted. Knee phenotypes were compared with use of the Coronal Plane Alignment of the Knee (CPAK) classification. Results Baseline conditions were comparable between both groups. The overall proportion and percentage of outliers ( n  = 38, 24.4% vs n  = 9, 5.8%) was statistically significant ( p