Summary

Bilateral total knee arthroplasty- simultaneous Vs staged- concepts revisited

Abstract

Objective

1. To determine complications at 3 months following bilateral simultaneous total knee arthroplasty. 2. To find out correlation between various demographic parameters (age, sex, BMI and Pre-op haemoglobin), Functional comorbidity index (FCI) and ASA scores with these complications.

Methods

All the patients undergoing bilateral simultaneous total knee arthroplasty over a period of five years at a tertiary care hospital were evaluated in the present prospective interventional study. All demographic data of the patients were collected along with pre-op haemoglobin, Functional comorbidity index (FCI) and ASA score. Patients were followed up till three months post op and assessed for complications if any. All complications were divided into four broad categories- Cardio-respiratory, functional , wound related and miscellaneous (delirium, seizures, Pyrexia, gastri-intestinal, dyselecrolytemia etc). Data analysis was done using Python software using various libraries- pandas, numpy, matplotlib and seaborn. Pearson correlation was calculated. T- test was run. Since, the data was unbalanced, gradient boosting rather than logistic regression was done to calculate precision, sensitivity and F1 score. For imbalanced data sets, Gradient boosting is crucial in reducing false negative population which means increased ability to identify patient with complications which require care. Logistic regression fails to do that due to its linear nature and inability to handle complex class boundaries effectively.

Results

Out of 1121 patients, 271 (24.1%) developed complications at 3 months follow up, out of which 34 (12.5%) were cardio-respiratory, 140 (51.6%) were functional, 49 (18.1%) were wound related and 48 (17.8%) miscellaneous. Age of the patients showed slightly positive correlation of 0.059 (p-value 0.047). Study showed positive correlation (-0.28) of BMI and complications at three months. FCI showed negative correlation (-0.0339) whereas ASA showed a positive correlation (0.052) with complications at 3 months. Pre-op haemoglobin and post op blood transfusion shows slightly negative correlation (-0.027). DVT prophylaxis given in the form of Aspirin and Rivaroxaban showed negative correlation (-0.02554) whereas Low molecular weight Heparin showed slightly positive correlation (0.0288) with complications at three months.

Conclusions

Incidence of developing complication within 90 days post bilateral simultaneous total knee arthroplasty is 24.1%. Age, BMI, FCI and ASA score show weak correlation in occurence of complications post total knee arthroplasty, however, these parameters does not show cause-effect relationship.
Keywords: Bilateral simultaneous total knee arthroplasty, complications, age, pre-operative hemoglobin, Functional comorbidity index (FCI), ASA score
Level II evidence