Background

Bilateral simultaneous total knee arthroplasty (BSTKA) is associated with higher complication rate especially in high risk patients. There is a common consensus among clinicians to avoid BSTKA in patients with advanced age and higher comorbidity load. However, there isn’t a valid objective clinical practice guideline available to facilitate patient selection between BSTKA and unilateral total knee arthroplasty (UTKA).

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 three months of surgery were compared between UTKA and BSTKA recipients, among the whole population and subsequently in different risk-groups.

Results

The mean age was 67.8 (8.8) and 65.8 (7.7) in UTKA and BSTKA respectively (p<0.001). 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%, p=0.028 minor; 8% versus 23.07%, p=0.045 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.