Abstract
Introduction
A large proportion of patients with osteoarthritis of the knee, present with bilateral symptoms at the outpatient department. A simultaneous total knee arthroplasty (TKA) procedure is available for such patients. The first operation in a simultaneous surgery may provide information to the operator to determine component size, soft tissue balancing, and estimate gap size for the second operation, while the second team usually conducts an operation in a confined space on the contralateral side during closure for the first operation, which can disturb cooperation during the second operation and may lead to more intra-operative surgical errors. We hypothesized that the circumstances of the two consecutive operations of a simultaneous bilateral TKA are different, could lead to different outcomes of overlapping bilateral TKAs. We therefore addressed the following research questions to determine whether there would be differences in short-term clinical outcomes, radiographic results, and implanted component size between the two sides
Methods
A retrospective review of 451 consecutive patients, who underwent simultaneous bilateral TKA between January 2011 and April 2012, was conducted. Bilateral TKAs were performed with the senior surgeon conducting the main procedure (from skin incision to implantation of first prosthesis until prior closure of the first knee) on the right side first and subsequently the left side with a second team. At 1 year after surgery, clinical outcome scores (the Knee Society Knee and Function scores, WOMAC score), radiologic findings were evaluated and clinical results as postoperative blood loss, operation time were compared between bilateral sides.
Results
A greater incidence (16.1%) of outliers during postoperative coronal limb alignment (>±3o) were identified in the second TKA than those in the first TKA (9.0%) (p =0.003). Multivariate analysis for the association of outlier rates in the second TKA relative to the first revealed a significance for severity of the preoperative deformity (pre-op. coronal limb alignment, p = 0.002) and decreased ROM (p = 0.042) from the GEE analysis. The second knee also showed more blood loss (735 vs. 656mL), and longer operation time (61, 58 minutes respectively), as compared to the first TKA, while no significant differences in clinical outcomes.
Discussion and Conclusion
There were no significant differences in the clinical outcomes even though few distinct outcomes due to different circumstances of the surgery. Awareness of these findings can help the continued success of bilateral TKA in an increasing patient population.
