Verification and Clinical Translation of a Newly Designed "Skywalker" Robot for Total Knee Arthroplasty: A Prospective Clinical Study

Objective: To evaluate accuracy of an innovative "Skywalker" system, a newly designed, robot-assisted operation system for orthopaedics via a clinical trial at knee joint.

Methods: We conducted a prospective analysis of the clinical data of 31 patients who underwent total knee arthroplasty assisted by the "Skywalker" robot (Microport, Suzhou, China) from June 2020 to January 2021. Five male patients and 26 female patients aged 69.68 ​± ​6.11 years (range: 57-79 years) were diagnosed with knee osteoarthritis and indicated for surgery. The "Skywalker" surgical robotic system was adopted to make a preoperative plan for knee arthroplasty. When the robotic arm reached the specified position during the operation, a single surgeon performed the osteotomy with a cutting saw through the cutting jig, and the difference between the actual and the expected resection thickness, and the preoperative and postoperative lower limb alignments were measured.

Results: The actual error of the resection thickness was the difference between the actual and the expected resection thickness. The absolute error of the resection thickness was the absolute value of the actual error of resection thickness. The absolute errors of the resection thickness of the medial and lateral condyle of the distal femur, the medial and lateral posterior condyle of the femur, and the medial and lateral sides of the tibial plateau were 0.87 ​± ​0.63 ​mm, 1.02 ​± ​0.67 ​mm, 0.74 ​± ​0.46 ​mm, 0.98 ​± ​0.81 ​mm, 0.92 ​± ​0.66 ​mm, and 1.04 ​± ​0.84 ​mm, respectively. The absolute angle errors between the actual postoperative angles and the preoperative planned angles of the lower limb alignment angles, coronal femoral component angles, and coronal tibial component angles were 1.46° ​± ​0.95°, 1.13° ​± ​1.01°, and 1.05° ​± ​0.73°, respectively. Besides, 100% of the absolute error of the HKA angles was within 3°. In addition, compared to the preoperative lower limb alignment angle, 90.32% of the postoperative lower limb alignment angles of 31 patients were closer to 180° after the operation. All 31 patients underwent a successful surgery, and no relevant complications occurred after the operation, such as surgical site infection, deep venous thrombosis, or vascular and nerve injury.

Conclusion: The "Skywalker" system has good osteotomy accuracy, can achieve the planned angles well, and is expected to assist surgeons in performing accurate bone cuts and reconstructing planned lower limb alignments in the relevant clinical applications in future.