ISAKOS: 2019 Congress in Cancun, Mexico

2019 ISAKOS Biennial Congress ePoster #958


Pre-Anesthetic Knee Flexion Angle is the Most Accurate Predictor of Flexion Angle After Total Knee Arthroplasty (TKA)

Pakpoom Ruangsomboon, MD, Bangkok THAILAND
Keerati Chareancholvanich, MD, Bangkok THAILAND
Rapeepat Narkbunnam, MD, Bangkok THAILAND
Chaturong Pornrattanamaneewong, MD, Bangkok THAILAND

Siriraj Hospital, Mahidol University, Bangkok, THAILAND

FDA Status Not Applicable


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.