Pre-anesthetic knee flexion angle had the highest correlation with the final knee flexion angle at 6 months after unilateral primary TKA.
Title: Pre-anesthetic knee flexion angle is the most accurate predicting parameter of 6-month follow-up(F/U) flexion angle after Total Knee Arthroplasty(TKA)
Three-time point of knee flexion angle included pre-anesthetic flexion, post-anesthetic flexion and intraoperative post prosthesis implantation flexion compared to 6-month F/U knee flexion angle after TKA in this prospective cohort study.
We followed 200 TKA of 3 cohort groups. Group I, 12 patients, had Pre-operative flexion < 90?, Group II,124 patients, had pre-operative flexion 90-120?, Group III, 64 patients, had pre-operative flexion > 120?. We calculated the Pearson’s correlation of each time point to flexion angle at 6-month F/U. We also calculate the multiple Logistic regression to find predictable formula for 6-month F/U flexion angle.
The demographics and comorbid conditions were similar between the groups. The Pearson’s correlation of pre-anesthetic flexion angle had high positive correlation (Correlation Coefficient = 0.806, p<0.05) to 6-month F/U angle, post-anesthetic flexion had moderate positive correlation (0.620, p <0.05) while intraoperative post prosthesis implantation had low positive correlation (0.397, p<0.05). The predictable formula for 6-month F/U equal to 45.378 + [0.596 x pre-anesthetic flexion(degrees)] with coefficient of determination (R2 = 0.65)
Pre-anesthetic knee flexion angle had highest correlation to 6-month F/U in this prospective cohort study.