Diagnostic study, Level III.

The present study demonstrates that TKA leads, at 1 week and 1 year follow-up, to patellar height alteration more than 10% in a significant number of knee joints. However, with the use of ISI and MIS the changes of patellar height did not exceed the defined thresholds to be classified as patella alta or baja.

Purpose. To evaluate the safety of simultaneous bilateral total knee replacement (TKR). Methods. 124 women and 26 men (mean age, 66 years) underwent simultaneous bilateral TKR for tricompartmental osteoarthritis using a posterior-stabilised, high-flexion implant. All patients underwent dobutamine stress echocardiography for detection of any silent cardiac comorbidity by a cardiologist. None had any adverse effect after testing. Five patients had positive outcome and underwent coronary angiography to detect any significant coronary blockage. Functional outcome was evaluated using the Knee Society Score (KSS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Tranexamic acid was given intravenously to reduce peri-operative blood loss. Femoral blocks and patient-controlled analgesia were used to facilitate early recovery. Aggressive physiotherapy was allowed. Patients were followed up at months 3, 6, and 12, and yearly thereafter. Results. At the 2-year follow-up, the mean range of motion improved from 95° to 129° (p=0.032), the mean KSS from 120 to 158 (p<0.001), and the WOMAC from 51 to 88 (p=0.002). One patient developed patellar crepitus at week 6, which resolved with conservative treatment. Another patient developed infection in both knees at month 6. Despite salvage procedures, infection recurred after 3 months and the patient underwent bilateral arthrodesis. No patient developed deep vein thrombosis or pulmonary embolism, myocardial infarction, atrial fibrillation, or other cardiac event. Conclusion. Simultaneous bilateral TKR is safe for properly selected patients.