Highlighting the Roles of Anemia and Aspirin in Predicting Ninety-Day Readmission Following Aseptic Revision Total Joint Arthroplasty

Prevalence of anemia and association with outcome in joint arthroplasty - is there a difference between primary and revision cases?

PURPOSE

Anemia has been shown to be a modifiable pre-operative, patient factor associated with outcome following arthroplasty. The aims of this retrospective study were to (1) ascertain the prevalence of preoperative anemia in patients undergoing primary and revision hip and knee arthroplasty at a tertiary referral center and (2) to test the association with outcome and whether it differs between primary and revision cases.

METHODS

All hip and knee primary and revision arthroplasties performed at a Canadian academic, tertiary-care, arthroplasty center between 2012 and 2017 were included in this study. The study group consisted of 5944 patients, of which 5251 were primary Total Hip and Knee Arthroplasties or Hip Resurfacings and 693 were revision arthroplasties (65% hip revisions/35% knee revisions). Anemia was classified as per WHO definition (hemoglobin < 130 g/L for men and < 120 g/L for women). All anemic patients were grouped into mild, moderate or severe anemia. Length-of-stay, perioperative transfusion-rate, 90-day readmission, overall complication rate and reoperation rates were recorded. The effect of preoperative anemia and the effect of severity of the anemia was evaluated through multivariable regression analysis controlling for relevant covariates.

RESULTS

Preoperatively, 15% (786/5251) of the primary patients and 47% (322/693) of the revision arthroplasty patients were anemic preoperatively. Anemic revision patients were 3.1 times more likely (95% CI: 1.47-6.33) to obtain blood transfusions during the hospital stay, compared to a 4.9 times higher risk in primary patients. The odds ratio to sustain any postoperative complication if anemic was 1.5 times higher (95% CI: 0.73-3.16) in revision patients and 1.7 in primary cases. In addition, the 90-day readmission rate among both groups was 1.6 times higher in anemic patients. Furthermore, anemic revision patients had a 5.3 days longer length of stay (95% CI: 2.63-7.91), compared to only 1 additional day in anemic primary patients (95% CI: 0.69-1.34).

CONCLUSION

In this study cohort, the prevalence of anemia in patients awaiting revision arthroplasty was 3 times higher (46.6%) than in primary arthroplasty patients (18.7%). Preoperative anemia was associated with similarly, inferior outcomes in both groups. To reduce postoperative complications and the "burden" associated with anemia, these findings strongly recommend optimizing the preoperative hemoglobin in all arthroplasty patients. However, revision patients are affected more frequently, and particular attention must therefore be taken to this growing group in the future.

LEVEL OF EVIDENCE

Level III.

Tranexamic Acid Reduces the Rate of Periprosthetic Joint Infection After Aseptic Revision Arthroplasty

BACKGROUND

Revision total joint arthroplasty (TJA) has a higher rate of periprosthetic joint infection (PJI) compared with primary TJA, possibly as the result of increased allogeneic blood transfusion. Tranexamic acid (TXA) is gaining popularity in revision TJA to minimize blood loss and the need for transfusion; however, its effect on PJI reduction has yet to be investigated. The hypothesis of this study was that the administration of TXA during revision arthroplasty is protective against subsequent PJI.

METHODS

A prospectively maintained institutional database was used to identify patients who underwent revision TJA for aseptic failure from 2009 to 2018 and had a minimum follow-up of 90 days. Patients who developed PJI following revision arthroplasty were identified. All patients with PJI met Musculoskeletal Infection Society (MSIS) criteria. A multivariate analysis was performed to identify variables independently associated with PJI after aseptic revision TJA.

RESULTS

Overall, 1,731 patients who underwent aseptic revision were identified; of these patients, 83 (4.8%) developed PJI. Patients who received TXA had significantly lower rates (p = 0.029) of PJI postoperatively at 3.30% compared with those who did not receive TXA at 5.73%. After controlling for relevant confounding variables, TXA remained a significant independent factor that protected against PJI (odds ratio [OR], 0.47 [95% confidence interval (CI), 0.23 to 0.90]; p = 0.030). Female sex was also identified as a significant independent factor that protected against PJI (OR, 0.52 [95% CI, 0.30 to 0.88]; p = 0.016). However, preoperative anemia was independently associated with an increased risk of subsequent PJI (OR, 2.37 [95% CI, 1.34 to 4.16]; p = 0.003).

CONCLUSIONS

Based on this study conducted at a single institution, the use of TXA during aseptic revision arthroplasty was independently associated with a reduced risk of subsequent acute PJI after adjusting for multiple patient characteristics and surgical factors.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.