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.