Mortality following primary total knee replacement in public hospitals in Hong Kong

More than 2000 total knee replacements are performed each year in Hong Kong and more than 10 000 patients are on the waiting list. How safe is total knee replacement, however? The aims of the study were to review the mortality of primary total knee replacement in public hospitals in Hong Kong and to identify risk factors for mortality in a high-volume hospital.

All primary total knee replacements performed in Hospital Authority hospitals and Yan Chai Hospital from October 2011 to September 2014 were reviewed. Case-control analysis was performed for risk factors of total all-cause mortality in total knee replacement at Yan Chai Hospital.

There were 6588 patients in Hospital Authority hospitals and 1184 in Yan Chai Hospital (1095 unilateral and 89 bilateral total knee replacement). The mean follow-up time of patients in Yan Chai Hospital was 12.8 months. The mortality at 30 days, 90 days and 1 year was 0%, 0.08%, 0.34% for Yan Chai Hospital; and 0.1%, 0.2%, 0.7% for Hospital Authority hospitals, respectively. For Yan Chai Hospital, the mean operation-to-death interval was 21 months (range, 1-35 months). The mean age at death was 78 years and main causes were malignancy (50%) and pneumonia (21%). Predictors of mortality included age at surgery, American Society of Anesthesiologists class 3, and preoperative range of motion. Hospital surgery volume, preoperative co-morbidities, and postoperative deep vein thrombosis were not significant factors.

Mortality after primary total knee replacement was low in public hospitals in Hong Kong. Patients of older age or poorer general well-being in terms of poor range of motion or American Society of Anesthesiologists class 3 should be in optimal health before surgery and counselled about the higher mortality rate. A citywide joint replacement registry may help monitor and analyse postoperative total knee replacement mortality specific to our locality.