Summary

When bilateral total knee arthroplasty is performed using specific techniques it is a safe option when compared to unilateral total knee arthroplasty, and should be offered to all patients who meet the criteria for this procedure and have a preference for bilateral surgery.

Abstract

Introduction

With a significant number of patients presenting with bilateral knee osteoarthritis (OA) there has been increased interest in bilateral total knee arthroplasty under a single anaesthetic (BTKA), but ongoing concerns about safety of the procedure. This study examined whether mortality and risks of BTKA were comparable to propensity matched patients undergoing unilateral total knee arthroplasty (UTKA) during the same period.

Methods

Between January 2014 and May 2017, 423 sequential BTKAs were performed by two surgeons across two sites. The UTKA group was propensity matched for gender, age, BMI, ASA grade, and VR-12 scores. This resulted in two matched groups of 398 patients. Patients underwent identical peri-operative courses, utilising neuroaxial anaesthesia and high volume local infiltration of analgesia and anaesthetic, and navigated alignment. Outcome data including readmission data was collected by reviewing medical notes and hospital records. The national joint registry was used to collect revision surgery and mortality data. At 1-year post-operatively the change in Patient Recorded Outcome Measures (PROMs) was calculated (Oxford Knee Score, Lysholm, Tegner).

Results

The mortality rate in the study was low with 1 death in the BTKA group and none in the UTKA group. Cardiac complications were comparable between BTKA and UTKA (2 cases of new onset Atrial Fibrillation (AF) and 2 cases of Myocardial Infarction (MI) versus 3 patients with AF and 1 MI respectively). The mean Haemoglobin drop was significantly higher in the BTKA group than the UTKA group (29.2g/dL versus 24.3g/dL p<0.05) but this did not reach a threshold for a significantly increased transfusion rate. Thromboembolism, and both superficial and deep infection rates showed no significant difference between groups. A further total of 50 minor complications and 4 major (small bowel obstruction, femoral artery occlusion requiring angioplasty, and two upper gastrointestinal bleeds requiring endoscopy) were seen in the BTKA group, and 42 minor and 2 major complications in the UTKA, with no significant difference between groups. The mean length of stay and rehabilitation requirements were significantly higher in the BTKA group. Other than deep infections reported above there were no further cases of readmission within 90 days. At 1-year, all PROMs and patient satisfaction reports were significantly improved, with no significant difference between groups.

Discussion And Conclusion

The results conclude that BTKA is as safe as UTKA. Patients in both groups have a similar low rate of all complications and demonstrate the same improvement in all PROMs at 1-year. Whilst recovery after a BTKA is slower it is not twice that of a UTKA. Use of spinal anaesthetic, tranexamic acid, and navigation to avoid medullary canal breach, has negated the need for a tourniquet and demonstrated very low rates of blood transfusion. With close to a third of patients with knee OA undergoing BTKA in this centre, we have demonstrated that when BTKA is performed using specific techniques it is a safe option when compared to UTKA , and should be offered to all patients who meet the criteria for this procedure and have a preference for bilateral surgery.