Time course and reasons for 90‐day mortality in fast‐track hip and knee arthroplasty

Background Post‐operative mortality is an important adverse outcome, including in total hip (THA) and knee arthroplasty (TKA). However, whether mortality is due to anaesthetic/surgical complications, surgically induced organ dysfunction or unrelated to surgery is rarely considered. Methods Prospective observational study in 13,775 consecutive THA/TKAs with similar fast‐track protocols and a median length of stay of 2 days. Complete 90‐days follow‐up through national registries, followed by review of medical records and death certificates. Relation between mortality and surgically induced organ dysfunction were classified as certain, probable, possible or unlikely. Results Of a total of 44 deaths (0.3%), 28 (0.2%) were found to have certain or probably relation with surgery and were considered as surgery‐related. Surgery‐related deaths were more common after THA than TKA (0.3% vs. 0.1% P = 0.044), occurred after median 14 days and 19 of 28 were between day 0–30. Of the remaining 16 deaths (0.1%), nine were found to be possible and seven to be unlikely related to surgery, and occurred a median of 42 and 61 days after surgery. The most common initial organ dysfunction for surgery‐related deaths was pulmonary (6/28) and gastrointestinal (6/28), while the most common reported cause of death were pulmonary (9/28) and cardiac events (6/28). In five of the seven unlikely related deaths mortality was attributed to underlying cancer. Conclusion Ninety‐days mortality was 0.3% in THA and TKA, but only 28 of 44 deaths (64%) were found to be surgery‐related. Reporting total mortality rate or cause of death without considerations on surgery induced organ dysfunction, may be insufficient for future aims to reduce post‐operative mortality.