Example of product registration technical review report

published by Chinese authority CMDE

Product name: Knee replacement surgery navigation and positioning system

Product Management Category: Category III

Applicant Name: Suzhou MicroPort Changxing Robot Co., Ltd.

1.Product Overview

(1) Product structure and composition

The product consists of a navigation console (navigation trolley, optical navigation equipment, display), Surgical platform (manipulator, surgical trolley), surgical aids, optical positioning markers, Foot switch and cable composition.

(2) Scope of product application

This product is used in combination with a proven knee prosthesis in the adult total knee joint in replacement surgery, it is used for the navigation and positioning of knee prostheses and surgical tools.

(3) Model/Specification

OSR-1000

(4) Working principle

The working principle of this product is preoperative planning and intraoperative positioning. That is, the surgeon is based on the preoperative

Complete preoperative planning based on patient condition and preoperative CT images. intraoperative optical navigation system

Real-time clinical parameters fed back by the system can be used to complete intraoperative assessment and adjust preoperative planning.

The robotic arm completes the positioning of the osteotomy surface with the assistance of the optical navigation system, and the surgeon completes the osteotomy with the assistance of the robotic arm.

2. Overview of preclinical research

(1) Product performance research

The product performance indicators include physical performance, software functions (navigation software, control

software, usage restrictions), operational performance (system positioning accuracy (position repeatability,

attitude repeatability and distance accuracy), system accuracy (position accuracy and attitude accuracy)

degrees), the motion range of each axis of the manipulator, the starting force of the end of the manipulator, the working space range, the target tracking response time, the fault response time, the moving force of the trolley, the locking force of the trolley, the holding force of the manipulator, the offset of the fully loaded manipulator displacement, mechanical arm brake locking force, noise, refresh rate, maximum tracking number), network security, optical positioning markers, surgical aids, alarm requirements, pedal performance, electrical safety, electromagnetic compatibility, etc.

The applicant submitted product performance research materials for the above performance indicators, and also submitted product technical requirements and test reports, and the test results were consistent with the product technical requirements.

(2) Biocompatibility

The surgical aids included in this product include the osteotomy plate, part of the head end of the target bracket,

Fixing needle fixing assembly, target fixing screw, target fixing swivel, tightening handle, fixed needle installation guide, fixed needle, bone positioning needle, trochlear plane positioning piece, screwing and compression column are in short-term contact with human bone/tissue; the optical positioning mark has the risk of falling off, Evaluation is based on short-term contact with bone/tissue.

The applicant is based on GB/T 16886.1-2011 "Biological Evaluation of Medical Devices No. 1. Section: Evaluation and Testing in the Risk Management Process" conducted a biocompatibility evaluation to demonstrate that the  Biocompatibility risk of the product is acceptable

(3) Sterilization

Optical positioning markers are supplied sterile and sterilized by irradiation. The applicant submits a sterilization process validation report confirming that the product sterility assurance level (SAL) meets the requirements.

Surgical aids are sterilized by the end user before use. The applicant submitted sterilization research data, meet the requirements.

(4) Product validity period and packaging

The applicant has provided information on the expiry date study of the optical positioning marker, which was determined by accelerated The shelf life of the product is 0.5 years, as determined by the accelerated ageing test.

The product stability study was submitted in accordance with the Guideline on the Useful Life of Active Medical Devices. The product stability study was submitted in accordance with the Guideline on the Useful Life of Active Medical Devices. The product's shelf life was confirmed through ageing tests and analysis of the life of key components. The product's useful life has been confirmed by means of ageing tests and life-time analyses of key components, and the product's useful life is 7 years.

The applicant provided information on the confirmation of the sterile primary packaging with optical positioning markings and submitted a report on the verification of the product's transport packaging. The applicant provided confirmation of the optical positioning mark sterile primary packaging and submitted a transport packaging verification report, confirming that the packaging integrity meets the design requirements.

(5) Software research

The product software includes motion control software, power board embedded software, and surgical navigation software. The software security level is C, the release version is 1, the full version of the motion control software is 1.3.0.1, and the full version of the power board embedded software is 1.1.1.1, the complete version of the surgical navigation software is 1.3.0.10; the applicant submits the corresponding level of software description documents and software version naming rules authenticity statement in accordance with the "Guidelines for Technical Review of Medical Device Software Registration", confirming the design and development of the product software The process specification is controllable, and the comprehensive residual risk is acceptable.

The applicant submitted a network security description document in accordance with the requirements of the "Guiding Principles for Technical Review of Medical Device Network Security Registration", proving that the existing network security risks of the product are controllable, and a network security emergency response plan has been established.

(6) Active equipment safety indicators

This product meets the following safety standards:

GB 9706.1-2007 "Medical Electrical Equipment Part 1: General Requirements for Safety"

GB 9706.15-2008 "Medical Electrical Equipment Part 1-1: General Requirements for Safety

Seeking Parallel Standard: Safety Requirements for Medical Electrical Systems

YY 0505-2012 "Medical Electrical Equipment Part 1-2: General Requirements for Safety

Seeking Parallel Standards: Electromagnetic Compatibility Requirements and Tests

YY 0709-2009 "Medical Electrical Equipment Part 1-8: General Requirements for Safety

Seeking Collateral Standard: General Requirements, Medical Electrical Equipment and Alarms in Medical Electrical Systems Testing and Guidelines

YY 1057-2016 "General technical conditions for medical foot switches"

The applicant submitted the corresponding test report, which confirmed that the product complies with the above-mentioned standard requirements.

3. Overview of clinical evaluation

The applicant conducts clinical evaluation through the clinical trial pathway. The study adopted a prospective, multicenter, single-group target design, and conducted clinical trials in five medical institutions.

The study included 106 patients, and the clinical success rate (lower extremity before discharge after operation)

The angle of deviation between the force line and the expected plan is ≤ 3°. The number of clinically successful cases accounted for the number of completed surgeries percentage of numbers) was the main evaluation index; the distal lateral angle of the femur, the Lateral angle, KSS score (difference from baseline after treatment), WOMAC score (after treatment difference from baseline) as a secondary outcome measure; all adverse events that occurred during the study period. The position of the implanted joint prosthesis after surgery was used as the safety evaluation index.

The clinical trial results of the study are:

The main evaluation indicators, FAS set 106 cases, 105 (99.06%) cases were clinically successful;

There were 105 cases in the PPS set, and 104 (99.05%) cases were clinically successful. FAS set and PPS set,

The 95% confidence intervals for the clinical success rate were [94.86%, 99.98%] [94.81%,

99.98%]. The lower limit was greater than the target value of 89%, and the clinical trial conclusion was established.

The results of the secondary evaluation indicators are shown in the table

Evaluation index                       FAS                 PPS

Lateral angle of distal femur     90.58±2.08°    90.57±2.09°

Medial angle of proximal tibia   89.93±1.49°    89.92±1.50°

WOMAC score                         -16.09±18.61   -16.06±18.69

KSS Score-

Total Functional Score              22.59±23.48    22.29±23.38

KSS score

-Total clinical score                   74.52±9.58      74.42±9.57

Safety evaluation indicators: SS set 106 subjects, the incidence of adverse events was 50.94%, and the incidence of serious adverse events was 3.77%, all of which were determined to be irrelevant to the declared product.

No device defects occurred in clinical trials.

4. Product benefit risk determination

(1) Benefit assessment

The main benefits of this product are: in combination with proven knee prostheses, in adult total knee replacement surgery, for the navigation and positioning of knee prostheses and surgical tools, and reducing the risk of X-ray radiation for patients and physicians .

(2) Risk assessment

The main risks of this product are:

1. The optical positioning system is at risk of being blocked and unable to be positioned. Risk control is carried out through software prompts and user training.

2. Risk of unintended movement of the robotic arm, risk control through optimized design

3. Disposable instruments are not used as required, the sterilization of reusable instruments is incomplete, and the cleaning and disinfection are not carried out in accordance with the instructions, resulting in cross-infection, and risk control is carried out through user training.

4. Risks caused by irregular user operations shall be controlled through user training. The above risks are indicated in the instruction manual.

Product Contraindications:

Any patient with relative or absolute contraindications to traditional knee replacement surgery is also not suitable for knee replacement surgery with navigation and positioning system assisted knee replacement surgery.

The patient selection of the navigation and positioning system for minimally invasive knee replacement surgery should be based on the surgeon’s judgment on the specific situation of the patient. Before preparing for navigation-assisted TKA, the surgeon should consider the following situations:

1. The integrity of the hip joint connection is a necessary condition to complete the bone registration;

2. Metal objects near the surgical area will affect the quality of CT scans, which in turn affects the accuracy of surgical planning;

3. Patients with infection or recent infection are not suitable for surgery;

4. Patients with severe osteoporosis will affect the stability of the prosthesis;

5. The size of the patient will affect the complexity of the operation, and the patient's BMI should be evaluated before surgery;

6. Loss or instability of ligament structure may affect postoperative joint stability;

7. The impact of significant deformities (such as flexion contractures, fixed knee valgus, etc.) on surgery should be carefully evaluated;

8. Patients who cannot use the designated total knee replacement system for surgery cannot use this system for surgery;

9. Factors considered by other doctors that may affect the normal operation of the operation.

(3) Determination of benefit-risk

To sum up, according to the application materials provided by the applicant, after a comprehensive evaluation, at the current level of cognition, the clinical benefits of the product outweigh the risks.

2022-04-18