Article Type: Original Article

Title:  Blood transfusion incidence in primary Total Knee Arthroplasty of Unilateral vs Bilateral group with a high prevalence of low hemoglobin concentration: A Retrospective Observational Study

Year: 2021; Volume: 1; Issue: 1; Page No: 8 – 11

Authors:  Jai Thilak Kailathuvalapil1, Madhusudhan Tammanaiah2, Nabeel Mohamed Therakka Parambil3, Sujith Paliath Shaju4, Senthilvel Vasudevan5

Affiliations: 1, 2, 3, 4Department of Orthopaedics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India. 5Assistant Professor of Statistics, Department of Pharmacy Practice, College of Pharmacy, King Saud Bin Abdulaziz University for Health Science, Riyadh, Saudi Arabia.

Paper Summary: 
Submitted: 10-March-2021
Revised: 28-April-2021
Accepted: 22-May-2021
 Published: 10-June-2021


Background: Blood transfusion is one of the major concerns following Total Knee Arthroplasty. We assessed the incidence rate of blood transfusion (packed red cells) in our geographical group based on age, gender, preoperative Haemoglobin and following both unilateral and bilateral primary TKA done either in single-stage or sequentially after a week.

Materials and Methods:  This was a retrospective observational study which included 200 patients who underwent primary TKA unilateral, bilateral done in single stage and sequential from June 2015 to May 2016.  Two doses of parenteral Tranexamic acid and periarticular cocktail injection given. Transfusion was indicated with postoperative Hgb below 8 g/dl associated with or without clinical signs of tissue hypoperfusion.

Results:  The study group was 200 patients with age group of 50-81 years, of which 154 (77%) were female and 46 (23%) were male and had a mean preoperative Hgb level of 12.6 g/dl. 88 (44%) unilateral, 40 (20%) bilateral and 72 (36%) sequential TKA were performed and 7 (7.95%), 12 (30%) and 26 (36%) patients received blood transfusion respectively.  Among the transfused 45 patients, 38 patients were bilateral group, of which 30 (66.6%) patients had a preoperative Hgb levels of 10–12 g/dl, indicating high incidence of transfusion in bilateral cases compared to unilateral and with preoperative Hgb levels of 10–12g/dl which was statistically significant with p-value <0.05.

Conclusion: In our study, age and gender were not the major factors for blood transfusion, but low preoperative Hgb levels and bilateral single stage and sequential TKA showed significantly higher incidence of blood transfusion.

Keywords: total knee arthroplasty, blood transfusion, preoperative Hgb

Corresponding Author:
Dr. Madhusudhan Tammanaiah,
Consultant Orthopaedic Surgeon,
Kamakshi Multispecialty Hospital,
Mysore, Karnataka, India.
 Email ID:
Cell No: +918333873990


Total knee arthroplasty (TKA) is an elective procedure widely used for treating osteoarthritis of knee which is a disease of inflammatory and degenerative nature that causes knee joint cartilage destruction leading to pain and variable deformities. It is one of the most common procedures performed in the orthopedic department in recent years. The frequency of TKA has shown a growth projection of 601% between 2005 and 2030. [1]  Like other major surgeries, there are several complications also noticed during and after TKA such as persistent knee pain, stiffness, blood loss and thromboembolism. [2–4] The bleeding is mainly noticed after release of the tourniquet. [5] The amount of blood loss is variable and sometimes it leads to scenarios where blood transfusion becomes inevitable. [6]  Surgical blood loss and transfusion is a concern for both patients and surgeons despite advances in blood conservation techniques. While the popularity of preoperative autologous donation has declined for logistical reasons, erythropoietin (EPO) and perioperative autologous blood salvage strategies have increased in popularity. [7]  Still, homologous blood transfusion remains the gold- standard approach for increasing blood cell count in anaemic patients in the perioperative period.

An incidence rates of 9-84% blood transfusion have been reported following TKA [8] and several factors were found associated with increased risk of blood transfusion which includes patient related factors like gender, body mass index (BMI), preoperative hemoglobin (Hgb) level,     American Society of Anesthesiologists (ASA) score,  and  associated  medical  comorbidities and surgery  related  factors  like operation time, technique, usage of tourniquet and amount of blood loss during perioperative period. [9-12] Though blood transfusion is lifesaving, it is associated with several complications such as hemolytic reactions, transfusion-related lung injury (TRALI), transmission of infectious pathogens and overall high risk of morbidity and mortality. [13, 14]  The aim of this study is to fill the knowledge gap on blood transfusion (packed red cells) following TKA in a variant geographical and ethnic group by estimating its incidence rate based on demographic parameters such as age, gender, preoperative Hgb and following both unilateral     and bilateral TKA done either in single stage or sequentially.

Materials and Methods:

This is a retrospective observational study which includes 200 patients who underwent primary TKA – unilateral, bilateral single stage, bilateral sequential (one week apart) from June 2015 to May 2016.  Patients with coagulation disorders, thrombocytopenia, disturbances of platelet function, or other hematological diseases were excluded from the study. Gender, age, preoperative Hgb, unilateral, bilateral, sequential were evaluated for their relationship to blood transfusion in the perioperative period.  All TKA were performed by a single senior arthroplasty surgeon. All patients received intravenous tranexamic acid 1gm before incision and 4 hours after the surgery unless contraindicated. Tourniquet was used at the time of exposure and cementation only.  Periarticular cocktail injection of 30 ml consisting of Bupivacaine, Morphine, epinephrine, antibiotics diluted in normal saline given for all patients. Drain was not used, and compression bandage was applied for adequate tamponade.  Hgb levels assessed in the post-anesthesia care unit on postoperative day-1.  The trigger for blood transfusion was Hgb ≤8 g/dl with or without presence of symptoms of tissue hypoperfusion. [15] In patients undergoing sequential TKA, subcutaneous Enoxaparin sodium was given in the interim period between the two surgeries and stopped the day prior.  Aspirin orally was given in all patients as DVT prophylaxis for a period of 4 weeks.

Statistical analysis: All data were procured retrospectively from a prospectively maintained electronic database (AHMS version 6.0.7) by an independent investigator not involved in the surgery. Institutional review board (IRB) approval was taken. Results were analyzed using SPSS 20.0 version.  Quantitative data were expressed as the mean ± SD.  Categorical data were analyzed with Chi-Square test / Fisher’s Exact test wherever applicable. p-value less than 0.05 was considered as statistically significant.


221 patients underwent TKA from June 2015 to May 2016, of which 21 (9.5%) patients were excluded from the study (Revision TKA, coagulation disorders).  Of the 200 patients, 46 (23%) were males and 154 (77%) were females. 88 (44%), 40 (20%) and        72 (36%) patients underwent unilateral, bilateral (single stage) and sequential TKA respectively.  Mean preoperative Hgb was 12.6 g/dl with overall incidence of blood transfusion in 45 (22.5%) patients and mean postoperative Hgb level with or without transfusion was 11.28 g/dl.

Age: To analyze the relationship between age and incidence of blood transfusion, patients were divided into  two age groups, 94 (47%) patients with age less than 65 and 106 (53%) patients with age more than 65, of which 20 (21%) patients and 25 (23.5%) patients were transfused respectively. No statistically significant relationship between age and blood transfusion noted with p-value 0.696.  Gender: Out of 154 females and 46 males, 37 (24%) patients & 8 (17%) patients received blood transfusion respectively. And the relationship between gender and blood transfusion in TKA was not statistically significant with p-value 0.231.

Unilateral / Bilateral / Sequential:   Out of 200 TKA performed, 88 (44%) unilateral, 40 (20%) bilateral and 72 (36%) sequential TKA. Among them, 7 (7.95%), 12 (30%) and 26 (36%) patients received blood transfusion respectively.  Patients who underwent bilateral (single stage) and sequential TKA received high blood transfusion in comparison to unilateral TKA, which was statistically highly significant with p-value <0.0001.

Relation to preoperative Hgb:  On further evaluation, the need of blood transfusion based on preoperative Hgb was classified under  10–12g/dl and >12g/dl. 101 patients (50.5%) had preoperative Hgb level of 10–12 g/dl and 99 patients (49.5%) >12 g/dl. 45 (22.5%) patients were transfused and of which 30 (66.6%) patients had preoperative Hgb levels of 10–12 g/dl.  In unilateral and bilateral TKA the incidence of blood transfusion in patients with 10–12g/dl didn’t show statistical significance with p-value 0.676 and 0.494 respectively whereas in sequential  TKA statistical significance noted with p-value 0.027. Overall transfusion rate in patients with preoperative Hgb levels of 10–12g/dl was high and results were statistically significant with p-value 0.019 (<0.05) as shown in Figure-1.

Figure 1. Chart showing the incidence of blood transfusion with variable preoperative Hgb levels in unilateral/ bilateral/ sequential TKA patients.


Blood loss during total knee arthroplasty is variable.  Several studies didn’t consider “hidden” blood loss, including loss due to extravasation into the tissues; residual blood in the joint; and loss due to hemolysis, hematoma formation, or bleeding around the prosthesis for assessment of actual blood loss during the surgery.  The inability to predict the need for transfusion in these patients has clinically and economically important consequences. During unpredicted clinical scenarios, patients often receive allogeneic blood which increases the risk of allergic reactions, transmission of infectious agents, and immunomodulatory effects. Beirbaum et al [16] reported rates of 39% of  TKA patients received transfusion and, in our study, the mean incidence of blood transfusion was      22.5%. There was no statistically significant relationship in specific age groups or gender who were transfused in unilateral or bilateral TKA. In one of the recent studies by Abdullah A.  Al-Turki et al [17] conducted in a tertiary care centre, Riyadh, Saudi showed high incidence of blood transfusion in older females with high BMI. In our study BMI was not included.

Beirbaum et al [16] prospectively evaluated the need for autologous or homologous blood transfusion in patients undergoing both Total hip arthroplasty and Total Knee arthroplasty based on preoperative Hgb level and found that patients with Hgb level less than 13gm/dl, particularly 10-13 g/dl needed transfusion. Gerardo Alvarez-Uria et al [18] analyzed the prevalence of anemia  in our geographical area and noted a mean haemoglobin concentration of 11.3g/dl. In our study group also >50% of patients had preoperative Hgb levels of 10–12g/dl and in turn the need for blood transfusion was high. David W. Fabi et al [19] retrospectively analyzed the complications rate of unilateral TKA and bilateral simultaneous TKA and found 4 times higher rate of single stage or sequential compared to unilateral TKA, blood transfusion in bilateral simultaneous TKA.  In our study cohort also, blood transfusion rate was high in bilateral    TKA done either single stage or sequential compared to unilateral TKA.

Joshua B. Holt et al [20] conducted a prospective study in which 488 patients underwent Primary    TKA with a multimodal, multidisciplinary approach to perioperative blood loss management and in turn reducing the blood transfusion which included preoperative hemoglobin optimization, minimization of perioperative blood loss and evidence-based transfusion guidelines.  This approach was also substantiated by Sara Moráis et al [21] which also included femoral canal obturation; peri and intra-articular cocktail injection; and two doses of parenteral tranexamic acid  (TXA).  In our study group we also followed many of these protocols for reducing blood loss.

Complications like blood borne disease, allergic reaction, immunomodulatory reactions, post-operative infection, DVT post transfusion were also observed in the study group. Nicholas B.  Frisch et al [22] reported DVT rate of 1.99% and deep surgical site infection (DSSI) rates of statistically higher in the transfused patients.  Bierbaum et al [16] reported infection rates of 7% in transfused patients. But no such complications noted in our transfused patients. Though DVT prophylaxis was given in all patients, assessment of DVT in the form of ultrasound doppler was done only in symptomatic patients.  Hence actual incidence of DVT or pulmonary embolism in asymptomatic patients not assessed.


In conclusion age and gender variability were not the major confounding factors for blood transfusion but low preoperative Hgb levels in between 10–12g/dl found in above half of our geographic population had increased incidence of blood transfusion.  In comparison with unilateral vs bilateral, bilateral TKA done either single stage or sequential showed a higher incidence of blood transfusion and more significantly in the group with Hgb 10–12g/dl.

Acknowledgement: The authors thank the parents of the participants, members of the Department of Anesthesia, Operation Theatre Services and the Staff Nurses for co-operating throughout the study period.

Authors’ Contributions: JTK, MT: Conception and design, Acquisition of Data.  SV, MT: Analysis and Interpretation of data, all authors.  JTK, MT, NMTP, SPS, and SV: Drafting the article, revising it for Intellectual content. All authors were checked and approved of the final version of the manuscript.

Here, JTK-Jai Thilak Kailathuvalapil, MT-Mohana Rangam Thirupathi, NMTP-Nabeel Mohamed Therakka Parambil, SPS- Sujith Paliath Shaju and SV-Senthilvel Vasudevan.

Source of funding: We didn’t get any types of financial support from any financial organization.

Conflict of Interest:  The authors declared no conflict of interest


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