Age-adjusted Charlson comorbidity index as a novel guideline for patient selection between unilateral versus bilateral simultaneous total knee arthroplasty

Purpose The aim of this study was to validate the age-adjusted Charlson comorbidity index as a clinical practice guideline for patient selection between unilateral total knee arthroplasty (UTKA) and bilateral simultaneous total knee arthroplasty (BSTKA). Methods A consecutive series of 1016 patients undergoing UTKA (402 patients) or BSTKA (614 patients) was analysed. The age-adjusted Charlson comorbidity index (ACCI) was measured for all the patients and graded as low (0–2 score), moderate (3–4 score) and high risk (≥ 5 score). The complications occurring within 3 months of surgery were compared between UTKA and BSTKA recipients. Results Following surgery, the complication rate was comparable between both the groups. However, among high-risk patients, there was significant difference in the complication rates between UTKA and BSTKA groups (12% versus 30.76%, minor; 8% versus 23.07%, major complication). The high-risk patients who had bilateral surgery were at more than three times greater risk of developing major and minor complications than those who had unilateral surgery. Conclusion The BSTKA procedure is associated with significantly higher risk of post-operative complications than UTKA procedure in patients with ≥ 5 ACCI scores.