Radiographic Assessment in Bilateral Primary Total Knee Arthroplasty: Computer-Assisted Surgery vs. Conventional Surgery
Nathee Ruangthong MD*, Pornpavit Sriphirom MD**
Affiliation : * Department of Orthopaedic Surgery, Banmi Hospital, Lopburi, Thailand ** Department of Orthopaedic Surgery, Rajavithi Hospital, Bangkok, Thailand
Objective : The purpose of this retrospective study is to compare the efficiency of computer-assisted surgery (CAS) and
conventional method (CONV) in TKA using mechanical axis (MA) and component alignment measured on the post-operative
radiograph in the same patient by different technique for TKA on both sides of the knee.
Material and Method: Fifty-two TKA in twenty-six patients with primary osteoarthritis of both knees that underwent stage
bilateral TKA by computer-assisted surgery one side and conventional method on the other side were inclusion criteria.
Digital long-leg weight-bearing radiographs were taken. The mechanical axis (MA), femoral component in coronal plane
(FFC), tibial component in coronal plane (FTC), femoral component in sagittal plane (SFC) and tibial component in sagittal
plane (STC) were measured and compared.
Results : The MA indicated that computer-assisted surgery (CAS) is significantly improved accuracy compared with conventional
method (178.12° + 1.56° and 176.15° + 1.85° respectively, p = 0.00). For FFC alignment, the results showed that CAS
group is significantly more accurate than CONV group (88.58° + 1.30° and 87.38° + 2.02° respectively, p = 0.07). CAS
group showed less distribution and fewer outliers of data than CONV group. For FTC, SFC and STC alignment, the means
of both groups were no difference (p > 0.05). Otherwise, the numbers of outlier CONV group trend toward greater than CAS
group (FTC 3.8% and 0%, SFC 30.8% and 0%, respectively). There was no report of change in the navigator group
procedure to conventional method during surgery and no perioperative or postoperative complications were noted.
Conclusion : Computer-assisted surgery (CAS) is a safe and useful intraoperative tool for total knee arthroplasty to improve
accuracy of mechanical axis, good implant position and reduce number of postoperative implant outlier. Clinical studies will
be required for clinical outcome assessment.
Keywords : Computer-assisted surgery, Arthroplasty, Total knee replacement
