Preoperative Malnutrition Is Associated With Increased Risk of Periprosthetic Joint Infection and Reduced Revision-Free Survival Following Unicompartmental Knee Arthroplasty.

BACKGROUND

Malnutrition is a recognized risk factor for adverse outcomes following total joint arthroplasty, yet its influence on unicompartmental knee arthroplasty (UKA) remains poorly defined. This study aimed to evaluate the potential association between preoperative laboratory markers of malnutrition and the risk of 90-day postoperative medical complications, as well as implant-related complications in patients undergoing UKA.

METHODS

A retrospective cohort study was conducted using a collaborative network database. Malnutrition was defined by at least one preoperative laboratory value of serum albumin ≤ 3.5 g/dL, transferrin ≤ 204 mg/dL, or total leukocyte count ≤ 1.5 × 103/μL. Propensity score matching (one-to-one) was performed using demographic and clinical variables, yielding two matched cohorts of 1,719 patients. Both 90-day and 2-year complications, including periprosthetic joint infection (PJI), mechanical complications, and revision rates, were compared. Risk estimates with 95% confidence intervals were generated using the database's analytical platform.

RESULTS

At 90 days, malnourished patients demonstrated increased risks of emergency department visitation (10.7 versus 6.0%; risk ratio [RR] 1.77, P < 0.001), wound complications (3.6 versus 1.1%; RR 3.36, P < 0.001), venous thromboembolism (3.2 versus 1.4%; RR 2.36, P = 0.005), and acute kidney injury (4.6 versus 1.4%; RR 3.36, P < 0.001). At two years, malnutrition remained independently associated with higher rates of PJI (2.4 versus 0.8%; RR 3.00, P < 0.001), revision surgery (6.3 versus 4.6%; RR 1.38, P = 0.025), and mechanical complications (2.8 versus 1.6%; RR 1.82, P = 0.010). Kaplan-Meier analysis similarly showed reduced revision-free survival in malnourished patients, with a 2-year survival of 93.34% compared with 95.14% in controls.

CONCLUSIONS

In this study, preoperative malnutrition was associated with significantly increased 90-day medical complications, higher 2-year rates of PJI, mechanical complications, and revision surgery, as well as reduced revision-free survival in UKA patients. These findings highlight nutritional status as a clinically relevant and potentially modifiable risk factor and support routine preoperative nutritional screening in patients undergoing UKA.