Abstract
Introduction
For restoration of neutral limb alignment in Total Knee Arthroplasty (TKA), we usually start by removing osteophytes in varus osteoarthritic knees. However, we have found no reports in the literature regarding research on the exact influence of osteophyte removal on angle correction. The purpose of this study was to define the influence of osteophyte removal on limb alignment correction in the coronal plane in TKA.
Materials and Methods
Nine patients with varus malalignment that were scheduled for TKA were included in this study. Only patients with degenerative osteoarthritis were considered. After registration of a navigation system, each knee was tested at maximum extension, and 30 and 60 degrees of flexion before and after osteophyte removal. The same examiner applied all external loads of 10 N-m valgus torque at each angle and in both states. Subsequently, the widths of the osteophytes were measured. All data were analyzed statistically using paired t-test and correlation coefficient. A significant difference was determined to be present for P < .05.
Results
The average pre-operative femoral tibial angle (FTA) was 185.1 degrees. The average width of femoral osteophytes was 6.4±2.36 mm, and the average width of tibial osteophytes was 3.4±1.16 mm. There were no significant differences in maximum extension angles between before and after osteophyte removal. The corrected angles after osteophyte removal were 1.4±1.31 degrees at maximum extension, 1.8±1.33 degrees at 30 degrees flexion and 1.7±1.15 degrees at 60 degrees flexion; and at all angles, the difference was significant. There was positive correlation between the widths of femoral osteophytes and the degree of angle correction at 30 degrees (r=0.829).
Conclusion
At 30 degrees of knee flexion, there was a correlation between the widths of osteophytes and the degree of angle correction. In this study, the degree of angle correction for 1mm width of osteophyte removal was 0.3 degrees.
