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