Pre-Operative Selection Criteria for Simultaneous Bilateral Total Knee Arthroplasty (TKA)

Background: A large percentage of the patients who present for unilateral TKA have bilateral disease. Performing simultaneous, bilateral TKA has been debated and currently there is no consensus on the risks and benefit of this approach. In addition, specific selection criteria have not been defined to more accurately identify which patients are potentially appropriate candidates for this approach. Objectives: The purpose of this study was to evaluate the clinical outcomes and peri-operative complications in simultaneous, bilateral TKA9s using pre-operative patient selection criteria. Methods: A retrospective analysis of 117 consecutive patients, (234 knees), was performed between February 2008 and March 2012 who underwent simultaneous, bilateral TKA performed by one surgeon under a single anesthetic. Pre-operative selection criteria were used for all patients to qualify for a simultaneous bilateral approach. This included the following: 1).BMI less than 34, 2).Minimum arc of motion to 100 degrees flexion, 3).Flexion contracture less than 10 degrees, 4).Varus or valgus alignment less than 10 degrees, 5).No prior history of cardiovascular disease. 6).Age Less than 70 years old. Clinical outcomes were assessed including anesthesia type, tourniquet time, length of stay, transfusion rate, pre- op hemoglobin, post-op hemoglobin, pre-op range of motion, post-op range of motion, DVT and PE. Knee Society Score (KSS) and Functional KSS were assessed pre-operatively and 1 year post-operatively. Anatomic and mechanical axis evaluation was also performed on all patients with long standing radiographs pre and post operatively. A control group of 573 consecutive patients undergoing unilateral total knee arthroplasty during this same time period were identified and matched for the year of surgery, and prosthesis type. The same selection criteria were used for the control group and the same data points were evaluated. Results: One hundred and seventeen consecutive patients, (234 knees), undergoing simultaneous, bilateral TKA were reviewed. There were no DVT9s, or PE9s. Nineteen percent required a transfusion for post-operative anemia. There were no cases of deep infection. Average pre-op KSS score was 49, with a post KSS score of 89 at an average follow-up of 1 year. Average pre-op Functional KSS score was 52, with an average post-op Functional KSS score of 91. Average ROM at one year post-op was 0 degrees of extension and 123 degrees of flexion. Average anatomic axis was 6 degrees valgus with a neutral mechanical axis restored in all patients. The clinical outcomes of the control group were comparable, with no statistically significant increase in the incidence of perioperative complications between the study group and the control group. Conclusion: When the degenerative process involves both knees with comparable severity, the decision to perform total knee arthroplasty on one knee at a time with a staged approach, verses a simultaneous bilateral approach, has been challenging for many surgeons. There have been previous reports of increased perioperative complications associated with bilateral total knee arthroplasty, including increased risks of cardiovascular, neurological complications, as well as the increased demands on rehabilitation. Similarly, benefits of simultaneous bilateral total knee arthroplasty have also been identified such as, shortened rehabilitation, improved patient satisfaction, and decreased costs both to the patient and the hospital system. Using pre-operative patient selection criteria, the decision process in determining which patients are appropriate candidates for a bilateral approach can be facilitated, with clinical outcomes comparable to unilateral total knee arthroplasty.