The purpose of this study is to conduct a prospective randomized clinical trial to compare the accuracy of prosthesis, radiographic alignment, total blood loss, the risk of venous thromboembolism between pinless-navigated total knee arthroplasty (TKA) and traditional TKA.
Minimal invasive surgery total knee arthroplasty (MIS-TKA) is an excellent surgical procedure for patients with end-stage knee diseases and can reduce the postoperative complications compared with traditional TKA procedures. However, MIS-TKA procedures require a long learning curve to avoid malposition of prosthesis. In previous studies have demonstrated that the position of prosthesis and the postoperative mechanical axis are critical factors of outcome. Malposition of prosthesis and deviation more than 3 degrees of mechanical axis will lead to asymmetrical tibia-femoral tracking between prosthesis with the wear of linear, and increase the incidence of prosthesis loosening. Computer navigation assisted system has been used in TKA procedures for more than one decade and has been proven to improve the accuracy of prosthesis placement and postoperative mechanical alignment. Moreover, navigated TKA avoids the use of intramedullary guide and preserve the medullary cavity of femur, so the risks of bleeding and venous thromboembolism are reduced. However, traditional navigation system requires additional procedure to set reference arrays with pin fixation of femur and tibia. Pin wound complications including bleeding, infection, and iatrogenic fracture were reported. Moreover, traditional navigation system requires conventional TKA approach in which the wound length of the knee will be as long as 15 to 20 cm. Therefore a combination of new navigation system with a MIS technique to perform TKA procedure is required The new pinless navigated system for TKA procedures has been developed, as the navigation tools were fixed in the surgical field without additional pin wounds. This advantage meets the rationale of MIS-TKA to take care of both minimal invasive procedures and accuracy of prosthesis placement. Therefore, the investigators want to investigate the application of this pinless navigation system in MIS-TKA procedures. Our purpose is to conduct a prospective randomized clinical trial to compare the accuracy of prosthesis, radiographic alignment, total blood loss, the risk of venous thromboembolism between pinless-navigated MIS-TKA and traditional MIS-TKA. Material and Methods: The investigators plan to enroll 100 patients who plan to undergo unilateral primary MIS-TKA and will be randomly assigned into two groups. The first group (50 patients) will be treated by pinless-navigation (Stryker, OrthoMap Express Knee Navigation) MIS-TKA, and the second group (50 patients) will undergo traditional MIS-TKA. The investigators will record the surgical wound length, surgical time cost and calculate daily hemoglobin drainage and total blood loss after TKA procedures for all patients. At 3 months after operation, the whole leg scanography, AP and lat view of knee radiography will be take and the mechanical alignment (MA), anatomic alignment (AA), femoral bowing angle (FBA), and coronal femoral-component angle (CFA), coronal tibia-component angle (CTA) in coronary view and sagittal femoral component angle (SFA), sagittal tibial component angle (STA) in lateral view will be measured. The operating time and surgical wound length in knee full extension will be recorded. All complications including bleedings, wound complications, venous thromboembolism will be recorded. Study year: one year Expecting Result The investigators anticipate that the position of prosthesis in pinless-navigated MIS-TKA is more accurate or equal to traditional MIS-TKA group. And the total blood loss in pinless-navigated MIS-TKA is less than traditional MIS-TKA group. The complication rate is similar between the two groups
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
100
The varus/valgus, extension/flexion, thickness of distal cut of femur was determined and done by pinless navigation system. After cutting, the instant information of resection level can show on the display screen. If the alignment is satisfying, the anterior/posterior femoral cut, chamfer cut and box resection were done by conventional jig
The femoral alignment was determined by intramedullary guide. The femoral alignment jig was set to 5-7 degree valgus dependent on the preoperative radiograph. A bone plug is impacted into the entry hole of femoral medullary canal before prosthesis placement.
Kaohsiung Chang Gung Memorial Hospital
Kaohsiung City, Taiwan
RECRUITINGRadiographic outcome: the mechanical alignment (MA)
The mechanical alignment (MA): an angle between the mechanical axis of the femur and the tibial shaft axis
Time frame: Three months after operation
Radiographic outcome: anatomic alignment (AA)
The anatomic alignment (AA): an angle between the axis of the femoral shaft and the tibial shaft axis
Time frame: Three months after operation
Radiographic outcome: femoral bowing angle (FBA)
The femoral bowing angle (FBA): the angle between the distal and proximal femoral anatomical axes
Time frame: Three months after operation
Radiographic outcome: coronal femoral-component angle (CFA)
Tthe angle between the femoral mechanical axis and the femoral component
Time frame: Three months after operation
Radiographic outcome: coronal tibia-component angle (CTA)
The angle between the tibial shaft axis and the tibial component
Time frame: Three months after operation
Total Blood Loss
The total blood loss was calculated according to Nadler et al., which uses maximum postoperative decrease of the Hb level adjusted for weight and height of the patient. Total blood loss consists of amount of blood loss calculated from the maximum Hb loss and amount of blood transfused
Time frame: Postoperative Day 3
Blood transfusion rate
Record the event of blood transfusion, and calculate the incidence of transfusion
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Time frame: Three months after operation
Operating Time
Time needed for the surgical procedure (skin to skin) is recorded
Time frame: After the procedure is done
Surgical wound length
The surgical wound length at full extension of knee is also recorded
Time frame: After the procedure is done
Wound complications
Any wound complications including superficial infection, wound dehiscence, poor healing, etc. are all recorded
Time frame: Three months after operation
Venous thromboembolism
perform duplex ultrasound study of both lower limbs in all patients on postoperative day 4
Time frame: Postoperative Day 4