This surgical positioning system helps knee joint replacement to achieve millimeter-level accuracy
Using sensor technology, IKPAS can measure the osteotomy angle of the distal femur and tibial plateau in real time during the operation without relying on the image data of the patient before the operation, through the use of gyroscopes and accelerometers in conjunction with specific algorithms, and calculate and obtain personalized angle data. To assist the doctor to more accurately complete the lower limb force line measurement and osteotomy positioning during knee replacement surgery.
——Wang Yuji, Director of Joint Surgery, Changzhou Second People's Hospital
◎Our reporter Guo Guozhong, correspondent Sun Zhenjiang
On December 13, a reporter from the Science and Technology Daily learned from the Second People’s Hospital of Changzhou City, Jiangsu Province that the hospital recently applied the Total Knee Surgery Positioning System (IKPAS) to successfully treat 2 elderly patients with knee osteoarthritis (hereinafter referred to as knee joints). Inflammation), the knee joint resurfacing surgery was performed, allowing the knee joint replacement surgery to achieve millimeter-level accuracy.
This means that my country's orthopedic diagnosis and treatment is transforming to precision, intelligence, and technology, which will bring the gospel to more patients in the future.
Traditional treatment methods often treat the symptoms but not the root cause
According to statistics, there are more than 100 million arthritis patients in my country, of which more than 30% of knee arthritis, and knee replacement patients increase at a rate of 25%-30% every year.
As my country gradually enters an aging society, knee arthritis has become a common and frequently-occurring disease. More than half of women over 60 and men over 65 have knee arthritis of varying degrees.
There are many types of traditional treatments for knee arthritis.
Clinically, anti-inflammatory and analgesic drugs are commonly used to reduce the local inflammation of the patient's joints and reduce pain.
In addition, it can also increase local blood circulation through external application of drugs to achieve anti-inflammatory and analgesic effects.
In terms of physical therapy, hot compresses, acupuncture and moxibustion also have an auxiliary therapeutic effect on pain relief, but these methods are not very helpful for the development or delay of the disease.
Some experts believe that the injection of sodium hyaluronate, corticosteroids and other drugs into the joint cavity has a certain lubricating and anti-inflammatory effect, and has a certain effect on the treatment of early to mid-stage arthritis. However, if the arthritis is already very serious, repeated injections can cause damage to the joints. Cartilage will also be destroyed, which is not conducive to subsequent treatment.
In fact, because these methods cannot achieve the purpose of cartilage repair, they cannot fundamentally treat knee arthritis.
Moreover, if conservative treatment is excessive, it will delay the deterioration of the condition. In the end, only knee replacement surgery can be considered.
Traditional knee replacement requires sawing off the patient's own knee joint before replacing it with a false joint. The operation is risky and expensive.
In March 2016, the Ministry of Science and Technology proposed China's precision medicine plan, and knee replacement has gradually developed in the direction of precision medicine.
Intelligent positioning solves traditional knee surgery problems
Professor Wang Kunzheng, head of the Joint Surgery Group of the Orthopedic Branch of the Chinese Medical Association and director of the Joint Surgery Center of the Medical Department of Xi’an Jiaotong University, believes that patients undergoing traditional knee arthroplasty have not improved their postoperative well-being. A large part of the reason is that the treatment is not available. Precise.
"There are several key points in knee replacement surgery. It is necessary to determine the position of the virtual force line of the lower limbs, the vertical force line of the lower limbs should be cut, and the soft tissue balance of the knee joint extension and flexion gap should be balanced, as well as the positioning of the knee joint osteotomy. "National artificial joint expert and director of joint surgery of Changzhou Second People's Hospital, Wang Yuji, said that the lower limb force line is the axis that passes through the hip joint center, the knee joint center and the ankle joint center, and is regarded as the lifeline of knee replacement surgery. The accuracy of the placement of the force line greatly determines the patient's postoperative functional recovery and the life of the prosthesis.
Wang Yuji told reporters that the current conventional knee replacement surgery is mainly performed by intramedullary positioning technology, inserting an intramedullary rod into the femoral medullary cavity, and then adjusting the valgus 5°-7° through the preoperative X-ray film and the surgeon’s experience. Osteotomy of the distal femur.
Relevant literature shows that in nearly 35% of patients with conventional surgery, the error of the lower limb line of force is greater than 3°.
IKPAS is a portable navigation system based on sensor technology, which can accurately measure the lower limb force line and position the osteotomy of the patient during the operation. It is easy to operate and does not extend the operation time.
The lower limb force line measuring instrument used by IKPAS contains a MEMS accelerometer, which is a microelectronic sensor designed based on the inertial force measurement principle of sensing mass.
The integrated inertial unit selected by IKPAS includes a 3-axis accelerometer and a 3-axis gyroscope, which can collect the attitude angle and spatial position of the lower limb force line measuring instrument in a static state; in the motion state, the direction and speed of the human body's movement can be obtained through the change of acceleration .
In Wang Yuji's view, the hip joint of the human body is a ball-and-socket joint. With the pelvis fixed, the movement of the lower limbs can be regarded as a spherical movement with the center of the hip joint as the center of the sphere.
IKPAS regards the center of rotation of the human hip joint as the center of the sphere, and the center of the knee joint is a point on the sphere. During the movement of the knee joint, acceleration with the center of rotation of the hip joint as the center of the sphere and the mechanical axis of the femur as the radius of the sphere can be collected. Set, establish a spherical motion model.
When you find the center of the sphere, you can find the cut surface of the sphere, that is, the osteotomy surface perpendicular to the mechanical axis of the femur.
"IKPAS utilizes sensor technology to not rely on preoperative patient image data. Through gyroscopes and accelerometers in conjunction with specific algorithms, it can measure the osteotomy angle of the distal femur and tibial plateau in real time during the operation, and calculate and obtain personalized angle data. , To assist the doctor to more accurately complete the lower limb force line measurement and osteotomy positioning during knee replacement surgery." Wang Yuji said.
Compared with traditional knee replacement surgery, sensor-assisted knee replacement surgery can easily achieve individualized and precise osteotomy, with an accuracy error of less than 1.5°; without opening the marrow, it effectively reduces the occurrence of complications and reduces the use of tourniquets Time; less bleeding, shorter tourniquet use time, good postoperative experience for patients; single-module design, easy to use, no statistical difference in operation time with traditional surgery; tibial platform posterior osteotomy angle can be controlled, rotating platform prosthesis surgery High controllability; obvious advantages in cases of total knee replacement such as extra-articular deformity and internal fixation not removed.