Should we routinely perform a post-operative hemoglobin check following unicompartmental knee arthroplasty?

OBJECTIVES: To study the significance of checking post-operative hemoglobin and hematocrit following unicompartmental knee arthroplasty (UKA). SETTING: Single center. Multiple surgeons. DESIGN: Retrospective case series. Level of evidence IV. MATERIALS AND METHODS: Following institutional approval, a retrospective analysis of all patients undergoing UKA at our level one academic university hospital was conducted. Operative records of all patients undergoing primary UKA were reviewed between March 2016 and March 2019. Patients' pre-operative hemoglobin and hematocrit, BMI, co-morbidities, application of tourniquet, tourniquet time, administration of tranexamic acid, need for post-operative blood transfusion, hospital length of stay, complications, and re-admission were all recorded. Blood loss was estimated using the post-operative hematocrit. RESULTS: A total number of 155 patients were included. There were 70 females (45%) and 85 males (55%). The mean age was 66 ±â€¯10 years. Median pre-op blood volume was 4700 mLs (interquartile range (IQR); 4200-5100). Median blood loss was 600 mLs (IQR; 400-830). Mean pre-op hemoglobin was 135 ±â€¯14 g/L and mean post-op hemoglobin was 122 ±â€¯13 g/L. No patient had a post-op hemoglobin under 80 g/L (range 93-154). No patients in our study needed transfusion. CONCLUSION: The results of our study indicated that post-operative hemoglobin and hematocrit check proved unnecessary in all of our patients and could have been omitted from post-operative routines. We conclude that routine post UKA check of hemoglobin and hematocrit can be avoided and be saved for special circumstances depending on patient's physiology.

Predictors of extended length of stay after unicompartmental knee arthroplasty.

PURPOSE: To identify factors that independently predict extended length of stay after unicompartmental knee arthroplasty (UKA) surgery (defined as length of stay longer than 3 days), and to identify factors predicting early post-operative complications. METHODS: A retrospective analysis of all patients undergoing UKA from January 2016-January 2019 at our institution was performed. Clinical notes were reviewed to determine the following information: Patient age (years), gender, American Society of Anesthesiologists (ASA) grade, weight (kg), height (meters), body mass index (BMI), co-morbidities, indication for surgery, surgeon, surgical volume, surgical technique (navigated or patient-specific instrumentation), implant manufacturer, estimated blood loss (ml), application of tourniquet during the surgery, application of drain, hospital length of stay (days) and surgical complications. RESULTS: Multivariate regression analysis showed that ASA 3-4 vs. ASA 1-2 [OR 4.4 (CI; 1.8-10.8, p = 0.001)] and a history of cardiovascular disease [OR 2.8 (CI; 1.4-5.5), p = 0.004)] were significant independent predictors of prolonged length of stay. Hosmer-Lemeshow goodness of fit of the model showed a p-value of 0.214. Nagelkerke R-Square was 0.2. For complications, multivariate regression analysis showed that ASA 3-4 vs. ASA 1-2 [OR 5.8 (CI; 1.7-20.7)] and high BMI (BMI >30) [OR 4.3 (CI; 1.1-17.1)] were significant independent predictors of complications. Hosmer-Lemeshow goodness of fit was 0.89 and Nagelkerke R-Square was 0.2. Patients treated with robotics (Navio) techniques had shorter length of stay median 51 h (IQR; 29-96) when compared to other techniques 72 h (IQR; 52-96), p = 0.008. CONCLUSION: Based on the results of our study, high ASA grade (≥3) appears to be the most important factor excluding eligibility for fast-track UKA. Any number of co-morbidities may increase ASA, but in and of themselves, apart from a history of cardiovascular disease, they should not be seen as contraindications. Appropriate patient selection, technical tools and details during the surgery could facilitate fast track surgery.