Early Radiographic and Clinical Outcomes of Robotic-Arm-Assisted Versus Conventional TKA
Condition: Total Knee Arthroplasty; Robotic
Study type: Interventional

Summary: 
      Purpose: A robotic system was recently introduced to improve prosthetic alignment during
      total knee arthroplasty (TKA). The purpose of this multicenter prospective randomized
      controlled trial (RCT) study was to determine whether robotic-arm-assisted TKA improves the
      clinical and radiological outcomes in patients compared to conventional TKA.

      Methods: One hundred and thirty patients who underwent primary TKA were enrolled in this
      prospective, multicenter RCT conducted in 3 hospitals. Five patients were lost to follow-up
      at 6 weeks after surgery. Therefore, 125 patients (63 in the intervention group and 62 in the
      control group) remained in the final analysis. The primary outcome was the rate of patients
      whose mechanical axis of the femur was less than 3° deviated from the mechanical axis of the
      tibia evaluated by full-length weight-bearing X-rays of the lower limb at 6 weeks
      postoperatively. Secondary outcomes will include operation times, 6-week postoperative
      functional outcomes evaluated by the American Knee Society Score (KSS) and the Western
      Ontario and McMaster Universities Osteoarthritis Index (WOMAC), SF-36, adverse events (AEs)
      and serious adverse events (SAEs).

      Hypothesis: Robotic-arm-assisted TKA is safe and effective as demonstrated in this trial.
    

Detailed description: 
      2. Materials and methods 2.1 Study design Our study was a prospective, multicenter and
      randomized controlled trial that was approved by the Institutional Review Board of Peking
      University Third Hospital (IRB # 2022-134-02), the First Affiliated Hospital of Shandong
      First Medical University (IRB # 2022-QX-S003-01) and Chifeng Municipal Hospital (IRB #
      2022-LLSCGVK4-101-06). All patients had provided written informed consent.

      2.2 Patient recruitment From November 2022 to May 2023, a total of 130 patients were
      randomized into two groups - 65 patients underwent robotic-assisted TKA and 65 underwent
      conventional TKA. The inclusion criteria were as follows: older than 18 years old and younger
      than 80 years old with knee osteoarthritis undergoing primary and unilateral TKA; after
      receiving both an oral and a written explanation of the study protocol, they provided written
      informed consent that they were willing to complete all of the assessments and potential
      interventions. The exclusion criteria were as follows: patients with infection, severe
      systemic disease (severe diabetes, severe osteoporosis, severe muscle loss, etc.),
      neuromuscular dysfunction of lower limbs, who are allergic to metal implants, participated in
      other clinical studies, whose knee joint has been fused for a long time without pain or
      deformity, unable to tolerate surgery on a systemic assessment, women who are pregnant or
      breastfeeding, or who expect to give birth during the clinical period, and there are other
      factors that affect the efficacy of observation in this study. All operations were performed
      by experienced surgeons for the conventional and robotic-assisted groups at three hospitals.
      All patients who underwent TKA with the robotic-assisted or conventional operations underwent
      the radiologic and clinical assessment.

      Main effectiveness evaluation index The main evaluation index of the knee navigation and
      positioning system clinical trial was the proportion of subjects whose mechanical axis of the
      femoris deviated from the mechanical axis of the tibia by ≤3° on the full-length lower
      extremity weight-bearing X-ray at 6 weeks (±2 weeks) after surgery.

      X-ray shooting requirements: Full-length weight-bearing X-ray of both lower limbs, that is,
      X-ray of both lower limbs including hip joint, full length of femur, knee joint, full length
      of tibia and fibula and ankle joint taken by the patient in the standing state. Key points:
      The patient stands upright on the camera frame, the back is close to the camera frame, the
      hands naturally droop, the knee joint is as straight as possible, the feet are the same width
      as the shoulders, and the internal rotation is about 15°, so that the small head of the
      fibula overlaps with the tibia nearly one-third, and the patella is pointed vertically in
      front.

      The lower limb force line was evaluated by non-surgeon.

        1. Measurement method of mechanical shaft of femur:

           The mechanical axis of the femur is the line from the center of the proximal joint
           (center of the hip joint) to the center of the distal joint (center of the knee joint).

           The central point of the hip joint is located in the central point of the femoral head
           circle, and the Mose circle is used to determine the central point of the femoral head.
           When determining the central point of the knee joint, the apex of the femoral
           intercondylar fossa was used as the central point of the knee joint, without measuring
           the width of bone tissue or soft tissue.

        2. Measurement method of tibial mechanical axis:

           The mechanical axis of the tibia is the line from the center of the proximal joint
           (center of the knee joint) to the center of the distal joint (center of the ankle
           joint).

           The central point of the knee joint is located in the center of the tibial plateau.
           Measure the midpoint of the talus width to determine the ankle joint center point.

        3. Measurement method of the medial Angle between the mechanical axis of femur and the
           mechanical axis of tibia:

      The medial Angle between the mechanical axis of femur and the mechanical axis of tibia is the
      hip knee ankle Angle (HKA).

      Criteria: After measurement, the Angle of HKA does not exceed 180°±3°, and it is regarded as
      an example of compliance with the mechanical shaft deviation Angle ≤3°. The proportion of
      subjects in the experimental group and the control group whose mechanical axis deviation
      Angle was ≤3° on the full-length lower extremity weight-bearing X-ray film 6 weeks (±2 weeks)
      after surgery was calculated.

      Secondary effectiveness evaluation index

        1. Operation time The operation time of control group was from the establishment of
           surgical incision to the end of skin suture. The operation start time of the
           experimental group was the first time when the equipment started to work and the
           surgical incision was established, and the operation end time was the end time of skin
           suture.

        2. KSS score The knee society score (KSS) is one of the most commonly used scores to
           evaluate knee function. This method is to evaluate the patient's knee joint and its
           function in two aspects according to the particularity of joint replacement surgery
           through the evaluator interview and physical examination, that is, to obtain the
           information of joint anatomy, biomechanics and other aspects, and to understand the
           patient's functional recovery. Knee joint evaluation is to evaluate the impact of
           surgery on the joint and the recovery of the joint after surgery, such as: joint pain,
           joint range of motion, ligament stability, muscle strength, bone alignment, contracture
           deformity; Functional assessments include activities of daily living, walking ability,
           going up and down stairs, and the need for AIDS. Subjects and subjects were evaluated by
           KSS scale.

        3. WOMAC score This score is used to assess the severity of arthritis and its therapeutic
           effectiveness based on the patient's relevant signs and symptoms. The structure and
           function of the knee joint were evaluated by pain, stiffness and joint function. The
           functional description of the knee joint was mainly for the lower limbs. You can use the
           entire system or pick a part of it when you use it. In terms of content, this rating
           scale assesses the structure and function of the knee joint from the three aspects of
           pain, stiffness, and joint function, with a total of 24 items, including the basic
           symptoms and signs of the entire joint. The pain part had five items, the stiffness part
           had two items, and the joint function part had 17 items. The reliability, validity and
           sensitivity of the assessment of the knee joint were objectively evaluated by the WOMAC
           scoring scale.

        4. SF-36 Health questionnaire The SF-36 Health Survey is a universal measurement scale
           developed by the Medical Outcomes Study (MOS). It consists of 36 entries covering eight
           areas: physical function, physical role, physical pain, general health, vitality, social
           function, emotional role, and mental health. It is widely used in the measurement of the
           quality of life of the general population, the evaluation of clinical trial effect and
           the evaluation of health policy.

      Safety evaluation

        1. Incidence of adverse events Adverse events were collected and recorded throughout the
           clinical trial, and the incidence rate was calculated.

        2. Incidence of serious adverse events Serious adverse events were collected and recorded
           throughout the clinical trial, and the incidence rate was calculated.

      Statistical analysis and sample size calculation The description of quantitative indicators
      will calculate the mean, standard deviation, median, minimum, maximum, lower quartile, upper
      quartile, and qualitative indicators describe the frequency and frequency of each type. The
      comparison of two groups of general conditions will be analyzed by appropriate methods
      according to the type of indicators. Group t test or Wilcoxon rank sum test will be used for
      comparison between groups of quantitative data, U-test, chi-square test or Fisher exact
      probability method will be used for qualitative data, and Wilcoxon rank sum test will be used
      for rank data.

      Test level α=0.025 (unilateral), according to β=0.2 to calculate the test grasp, the ratio of
      test group and control group is 1:1. According to the results of efficacy analysis, the
      required sample size was calculated to be 55 cases, and the sample size was expanded to 65
      cases considering the 15% shedding rate. The experimental group and the control group
      completed 65 subjects each.
    

Intervention name(s): robotic system
Intervention type(s): Procedure
Intervention description(s): Total knee arthroplasty assisted by knee navigation and positioning system
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Intervention group: Total knee arthroplasty assisted by knee navigation and positioning system. Specification Model: OP-RKL22 Control group: Total knee arthroplasty without knee navigation and positioning system The same joint prosthesis was used in both the experimental group and the control group, and was approved by the manufacturer.
Masking: Double (Investigator, Outcomes Assessor)
Primary purpose: Treatment