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The effect of peri-operative blood loss on postoperative pain following total knee arthroplasty
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/jor
Original Article
The effect of peri-operative blood loss on postoperative pain following total knee arthroplasty Paul Hegarty a,*, Seamus O'Brien a, Mike Stevenson b, David Beverland a a b
Outcomes Department, Musgrave Park Hospital, Belfast BT9 7JB, UK Statistical Advisory Committee, Queen's University Belfast, Belfast BT7 1NN, UK
article info
abstract
Article history:
Aim: This study aimed to investigate a possible link between peri-operative blood loss and
Received 23 September 2014
post-operative pain following primary total knee arthroplasty (TKA).
Accepted 4 January 2015
Method: A retrospective study was carried out using data from two RCTs (403 patients).
Available online 23 February 2015
Blood loss was estimated using Gross et al's formula. Blood transfusions were factored into calculations. Pain scores were obtained using a visual analogue score.
Keywords:
Results: Multiple regression analysis showed no relationship (0.09) and analysis of variance
Arthroplasty
showed no significant difference (p ¼ 0.597). Null hypothesis accepted.
TKA
Conclusion: Minimising blood-loss remains an important goal during surgery. On-going ef-
Pain
forts should be made to improve patient satisfaction following TKA.
Blood loss
Copyright © 2015, Professor P K Surendran Memorial Education Foundation. Publishing Services by Reed Elsevier India Pvt. Ltd. All rights reserved.
Patient satisfaction
1.
Introduction
There are many factors that are recognised as contributing to patient dissatisfaction following Total Knee Arthroplasty (TKA): Age, co-morbidities, function, expectations, mental health and pain.1e8 The aim of this study was to investigate the relationship between peri-operative blood loss and pain in the first two months following TKA. It was hypothesised that a direct positive correlation between blood loss and pain in the first two months following TKA would exist, i.e. patients with increased blood loss would demonstrate increased postoperative pain. To date, a number of small studies have
looked at this in the opposite way proposing that postoperative pain could increase post-operative blood loss.9e11
2.
Method
This was a retrospective study of 403 patients that had been enrolled in one of two prospective Randomised Controlled Trials (RCTs) performed between 2006 and 2009. Both RCTs contained cementless TKAs only. The first RCT, consisting of 203 patients, compared the LCS RP Porocoat Femur and Tibia to the LCS RP Porocoat Femur and Duofix Tibia (DePuy, UK).
* Corresponding author. Tel.: þ44 28 9090 2000. E-mail address: [email protected] (P. Hegarty). http://dx.doi.org/10.1016/j.jor.2015.01.011 0972-978X/Copyright © 2015, Professor P K Surendran Memorial Education Foundation. Publishing Services by Reed Elsevier India Pvt. Ltd. All rights reserved.
148
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
Table 1 e Patient demographics. Total # of patients DuoFix study ROCC study Females Males Age (Range) BMI (Range)
403 203 200 242 161 69 (45e89) 31 (20e43)
The second RCT, consisting of 200 patients, compared the LCS Duofix Femur and Duofix Tibia to the ROCC Knee (DePuy, UK). All procedures were performed by or under direct supervision of the senior author (DEB). The conclusion of the aforementioned RCT trials was that no significant difference was found between the two groups. Blood loss was calculated using the formula by Gross et al which estimates blood loss using haematocrit values [Equation (1)].12 Estimated blood volume was calculated as 65 ml/kg in females and 75 ml/kg in males. This value was then multiplied by the log of the pre-operative haematocrit minus the post-operative haematocrit divided by the pre-operative haematocrit. The majority of patients had bloods on Days 1 and 2 post operatively therefore these values were used in this study. EBL ¼ EBVx ln
Ho Hf Ho
(1)
TKA is associated with considerable blood loss and historically patients frequently required a blood transfusion post-operatively. Recently, this rate has fallen significantly, largely as a result of changes to transfusion guidelines. This means that the trigger for transfusion with respect to haemoglobin level has dropped significantly.13,14 Local transfusion guidelines suggests that transfusion should be considered when the post-operative haemoglobin falls below 8 g/dL for over patients over 65 years and less than 7 g/dL for under 65 years. This threshold is adjusted for patients with a cardiac history to <9 g/dL.14 For these patients, each unit of
Table 2 e Pearson correlation for Estimated Blood Loss (EBL) vs. Pain scores.
Initial VAS pain score 4 Week VAS pain score 8 Week VAS pain score 3 Month VAS pain score 1 Year VAS pain score
Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N
EBL day 1
EBL day 2
.032 .548 360 .064 .224 360 .031 .563 360 .091 .223 182 .059 .450 166
.033 .545 343 .018 .734 343 .025 .651 343 .001 .986 170 .058 .473 154
packed red cells transfused, an extra 285 ml of additional blood loss was added to the calculation. As part of the original prospective RCTs, all patients had been asked to complete a Visual Analogue Score (VAS) to record their pain level. This was performed within one week from surgery and then subsequently at 4 and 8 weeks. Further Oxford pain scores (extracted from the Oxford Hip Score) were recorded during one of the prospective RCTs at 3 months and 1 year post-operatively. Statistical analysis was performed using SPSS v20. Data was compared using multiple regression analysis, one way ANOVA, t-tests and Pearson's correlation. A p value of <0.05 was deemed statistically significant.
3.
Results
From the initial 403 patients, 43 had to be excluded from the analysis; 31 due to inadequate pain diaries and a further 12 because of insufficient recording of post-operative haemoglobin values. Patient demographics are summarised in Table 1. Blood loss data was normally distributed. A total of 15 patients (4%) were transfused with a mean of 1.17 units within the first two days post surgery, this data was included in blood loss calculations. Multiple regression analysis, on Day 2 post surgery of blood loss values with initial pain score data highlighted no relationship with a multiple correlation coefficient of 0.09. One way ANOVA, used to show significance, which cannot be gathered from regression analysis, showed the difference was not significant (p ¼ 0.597). Pearson's correlation, which measures the strength and direction of the linear relationship between two variables, was used to analyse all blood and pain score data [Table 2] and again found no significant difference. Correlation graphs of Estimated Blood Loss (EBL) vs. Pain on Days 1 and 2 post-operatively can be visualised in Figs. 1 and 2 respectively. One of the RCTs obtained additional VAS pain scores for patients post operatively at 3 months (n ¼ 182) and 1 year (n ¼ 166). As highlighted in Table 2, no significant difference was found between blood loss and pain at this follow-up time either. Patients at either end of the bell curve (least and greatest calculated values of blood loss) were then analysed further. To do this, independent samples t-tests were performed on patients whose blood loss results were one standard deviation from the mean on Days 1 and 2 postoperatively [Table 3]. No statistically significant difference was found between these groups.
4.
Discussion
TKA continues to have greater patient dissatisfaction when compared to Total Hip Arthroplasty and efforts continue to try and improve this.15 The present study did not demonstrate any link between the blood lost and pain or Oxford Hip Score in either the early post-operative period or at the intervals up to and including three months and one year. Therefore, the null hypothesis was accepted: Increasing levels of peri-operative blood loss have no direct relationship with levels of post-operative pain following TKA. Despite this,
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
149
Fig. 1 e EBL day 1 compared with initial visual analogue scale pain score: Scatter plot with linear regression line.
Fig. 2 e EBL day 2 compared with initial visual analogue scale pain score: Scatter plot with linear regression line.
Conflicts of interest Table 3 e Independent samples t-test for blood loss where visual analogue scale pain score at least 1 Standard Deviation (SD) above and below the mean. Blood loss Day 1 Day 2
N +1 SD 1 SD +1SD 1 SD
53 50 48 52
Mean (SD) 74.6 72.7 76.2 73.1
(20.6) (20.1) (20.6) (21.0)
All authors have none to declare.
P value 0.605
references
0.472
minimising blood loss remains an important goal at the time of surgery which may aid in; reduced need for transfusion and its associated risks, reduced recovery time, shorter durations of hospital stay and a reduction in haematoma formation post-operatively.
1. Scott CEH, Howie CR, MacDonald D, Biant LC. Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br. 2010;92B:1253e1258. 2. Baker PN, van der Meulen JH, Lewsey J, Gregg PJ. The role of pain and function in determining patient satisfaction after total knee replacement. Data from the National Joint Registry for England and Wales. J Bone Joint Surg Br. 2007;89-B:893e900.
150
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
3. Bullens PH, van Loon CJM, de Waal Malefijt MC, Laan RFJM, Veth RPH. Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments. J Arthroplasty. 2001;16:740e747. 4. Anderson JG, Wixson RL, Tsai D, Stulberg SD. Functional outcome and patient satisfaction in total knee patients over the age of 75. J Arthroplasty. 1996;11:831e840. 5. Noble PC, Conditt MC, Cook KF, Mathis KB. The John Insall Award: patient expectations affect satisfaction with total knee arthroplasty. Clin Orthop Relat Res. 2006;452:35e43. 6. Mahomed NN, Liang MH, Cook EF, et al. The importance of patient expectations in predicting functional outcomes after total joint arthroplasty. J Rheumatol. 2002;29:1273e1279. 7. Kim TK, Chang CB, Kang YG, Kim SJ, Seong SC. Causes and predictors of patient's dissatisfaction after uncomplicated total knee arthroplasty. J Arthroplasty. 2009;24:263e271. 8. Gandhi R, Davey JR, Mahomed NN. Predicting patient dissatisfaction following joint replacement surgery. J Rheumatol. 2008;35:2415e2418. 9. Yeon Kim So, Jun An Yong, Hwan Kim Soo, Kim Ha-Kyoung, Soo Park Jeong, Shin Yang-Sik. The effect of postoperative
10. 11.
12. 13.
14.
15.
pain on postoperative blood loss after sequential bilateral total knee arthroplasty. Korean J Anesthesiol. 2011 Feb;60:98e102. Friedman RJ. Limit the bleeding, limit the pain in total hip and knee arthroplasty. Orthopedics. 2010 Sep;33(9 suppl):11e13. Guay J. Postoperative pain significantly influences postoperative blood loss in patients undergoing total knee replacement. Pain Med. 2006 NoveDec;7:476e482. Gross JB. Estimating allowable blood loss: corrected for dilution. Anesthesiology. 1983 Mar;58:277e280. Rosencher N, Kerkkamp HE, Macheras G, et al. Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) study: blood management in elective knee and hip arthroplasty in Europe. Transfusion. 2003;43:459e469. No authors listed. Guidelines for Red Cell Transfusion. GAIN. http://www.gain-ni.org/images/Uploads/Guidelines/blood% 20poster.pdf; (date last accessed 28.04.14). Ethgen O, Bruyere O, Richy F, et al. Health-related quality of life in total hip and total knee arthroplasty. A qualitative and systematic review of the literature. J Bone Joint Surg Am. 2004;86-A:963e974.
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/jor
Original Article
The effect of peri-operative blood loss on postoperative pain following total knee arthroplasty Paul Hegarty a,*, Seamus O'Brien a, Mike Stevenson b, David Beverland a a b
Outcomes Department, Musgrave Park Hospital, Belfast BT9 7JB, UK Statistical Advisory Committee, Queen's University Belfast, Belfast BT7 1NN, UK
article info
abstract
Article history:
Aim: This study aimed to investigate a possible link between peri-operative blood loss and
Received 23 September 2014
post-operative pain following primary total knee arthroplasty (TKA).
Accepted 4 January 2015
Method: A retrospective study was carried out using data from two RCTs (403 patients).
Available online 23 February 2015
Blood loss was estimated using Gross et al's formula. Blood transfusions were factored into calculations. Pain scores were obtained using a visual analogue score.
Keywords:
Results: Multiple regression analysis showed no relationship (0.09) and analysis of variance
Arthroplasty
showed no significant difference (p ¼ 0.597). Null hypothesis accepted.
TKA
Conclusion: Minimising blood-loss remains an important goal during surgery. On-going ef-
Pain
forts should be made to improve patient satisfaction following TKA.
Blood loss
Copyright © 2015, Professor P K Surendran Memorial Education Foundation. Publishing Services by Reed Elsevier India Pvt. Ltd. All rights reserved.
Patient satisfaction
1.
Introduction
There are many factors that are recognised as contributing to patient dissatisfaction following Total Knee Arthroplasty (TKA): Age, co-morbidities, function, expectations, mental health and pain.1e8 The aim of this study was to investigate the relationship between peri-operative blood loss and pain in the first two months following TKA. It was hypothesised that a direct positive correlation between blood loss and pain in the first two months following TKA would exist, i.e. patients with increased blood loss would demonstrate increased postoperative pain. To date, a number of small studies have
looked at this in the opposite way proposing that postoperative pain could increase post-operative blood loss.9e11
2.
Method
This was a retrospective study of 403 patients that had been enrolled in one of two prospective Randomised Controlled Trials (RCTs) performed between 2006 and 2009. Both RCTs contained cementless TKAs only. The first RCT, consisting of 203 patients, compared the LCS RP Porocoat Femur and Tibia to the LCS RP Porocoat Femur and Duofix Tibia (DePuy, UK).
* Corresponding author. Tel.: þ44 28 9090 2000. E-mail address: [email protected] (P. Hegarty). http://dx.doi.org/10.1016/j.jor.2015.01.011 0972-978X/Copyright © 2015, Professor P K Surendran Memorial Education Foundation. Publishing Services by Reed Elsevier India Pvt. Ltd. All rights reserved.
148
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
Table 1 e Patient demographics. Total # of patients DuoFix study ROCC study Females Males Age (Range) BMI (Range)
403 203 200 242 161 69 (45e89) 31 (20e43)
The second RCT, consisting of 200 patients, compared the LCS Duofix Femur and Duofix Tibia to the ROCC Knee (DePuy, UK). All procedures were performed by or under direct supervision of the senior author (DEB). The conclusion of the aforementioned RCT trials was that no significant difference was found between the two groups. Blood loss was calculated using the formula by Gross et al which estimates blood loss using haematocrit values [Equation (1)].12 Estimated blood volume was calculated as 65 ml/kg in females and 75 ml/kg in males. This value was then multiplied by the log of the pre-operative haematocrit minus the post-operative haematocrit divided by the pre-operative haematocrit. The majority of patients had bloods on Days 1 and 2 post operatively therefore these values were used in this study. EBL ¼ EBVx ln
Ho Hf Ho
(1)
TKA is associated with considerable blood loss and historically patients frequently required a blood transfusion post-operatively. Recently, this rate has fallen significantly, largely as a result of changes to transfusion guidelines. This means that the trigger for transfusion with respect to haemoglobin level has dropped significantly.13,14 Local transfusion guidelines suggests that transfusion should be considered when the post-operative haemoglobin falls below 8 g/dL for over patients over 65 years and less than 7 g/dL for under 65 years. This threshold is adjusted for patients with a cardiac history to <9 g/dL.14 For these patients, each unit of
Table 2 e Pearson correlation for Estimated Blood Loss (EBL) vs. Pain scores.
Initial VAS pain score 4 Week VAS pain score 8 Week VAS pain score 3 Month VAS pain score 1 Year VAS pain score
Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N Pearson correlation Sig. (2-tailed) N
EBL day 1
EBL day 2
.032 .548 360 .064 .224 360 .031 .563 360 .091 .223 182 .059 .450 166
.033 .545 343 .018 .734 343 .025 .651 343 .001 .986 170 .058 .473 154
packed red cells transfused, an extra 285 ml of additional blood loss was added to the calculation. As part of the original prospective RCTs, all patients had been asked to complete a Visual Analogue Score (VAS) to record their pain level. This was performed within one week from surgery and then subsequently at 4 and 8 weeks. Further Oxford pain scores (extracted from the Oxford Hip Score) were recorded during one of the prospective RCTs at 3 months and 1 year post-operatively. Statistical analysis was performed using SPSS v20. Data was compared using multiple regression analysis, one way ANOVA, t-tests and Pearson's correlation. A p value of <0.05 was deemed statistically significant.
3.
Results
From the initial 403 patients, 43 had to be excluded from the analysis; 31 due to inadequate pain diaries and a further 12 because of insufficient recording of post-operative haemoglobin values. Patient demographics are summarised in Table 1. Blood loss data was normally distributed. A total of 15 patients (4%) were transfused with a mean of 1.17 units within the first two days post surgery, this data was included in blood loss calculations. Multiple regression analysis, on Day 2 post surgery of blood loss values with initial pain score data highlighted no relationship with a multiple correlation coefficient of 0.09. One way ANOVA, used to show significance, which cannot be gathered from regression analysis, showed the difference was not significant (p ¼ 0.597). Pearson's correlation, which measures the strength and direction of the linear relationship between two variables, was used to analyse all blood and pain score data [Table 2] and again found no significant difference. Correlation graphs of Estimated Blood Loss (EBL) vs. Pain on Days 1 and 2 post-operatively can be visualised in Figs. 1 and 2 respectively. One of the RCTs obtained additional VAS pain scores for patients post operatively at 3 months (n ¼ 182) and 1 year (n ¼ 166). As highlighted in Table 2, no significant difference was found between blood loss and pain at this follow-up time either. Patients at either end of the bell curve (least and greatest calculated values of blood loss) were then analysed further. To do this, independent samples t-tests were performed on patients whose blood loss results were one standard deviation from the mean on Days 1 and 2 postoperatively [Table 3]. No statistically significant difference was found between these groups.
4.
Discussion
TKA continues to have greater patient dissatisfaction when compared to Total Hip Arthroplasty and efforts continue to try and improve this.15 The present study did not demonstrate any link between the blood lost and pain or Oxford Hip Score in either the early post-operative period or at the intervals up to and including three months and one year. Therefore, the null hypothesis was accepted: Increasing levels of peri-operative blood loss have no direct relationship with levels of post-operative pain following TKA. Despite this,
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
149
Fig. 1 e EBL day 1 compared with initial visual analogue scale pain score: Scatter plot with linear regression line.
Fig. 2 e EBL day 2 compared with initial visual analogue scale pain score: Scatter plot with linear regression line.
Conflicts of interest Table 3 e Independent samples t-test for blood loss where visual analogue scale pain score at least 1 Standard Deviation (SD) above and below the mean. Blood loss Day 1 Day 2
N +1 SD 1 SD +1SD 1 SD
53 50 48 52
Mean (SD) 74.6 72.7 76.2 73.1
(20.6) (20.1) (20.6) (21.0)
All authors have none to declare.
P value 0.605
references
0.472
minimising blood loss remains an important goal at the time of surgery which may aid in; reduced need for transfusion and its associated risks, reduced recovery time, shorter durations of hospital stay and a reduction in haematoma formation post-operatively.
1. Scott CEH, Howie CR, MacDonald D, Biant LC. Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br. 2010;92B:1253e1258. 2. Baker PN, van der Meulen JH, Lewsey J, Gregg PJ. The role of pain and function in determining patient satisfaction after total knee replacement. Data from the National Joint Registry for England and Wales. J Bone Joint Surg Br. 2007;89-B:893e900.
150
j o u r n a l o f o r t h o p a e d i c s 1 2 ( 2 0 1 5 ) 1 4 7 e1 5 0
3. Bullens PH, van Loon CJM, de Waal Malefijt MC, Laan RFJM, Veth RPH. Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments. J Arthroplasty. 2001;16:740e747. 4. Anderson JG, Wixson RL, Tsai D, Stulberg SD. Functional outcome and patient satisfaction in total knee patients over the age of 75. J Arthroplasty. 1996;11:831e840. 5. Noble PC, Conditt MC, Cook KF, Mathis KB. The John Insall Award: patient expectations affect satisfaction with total knee arthroplasty. Clin Orthop Relat Res. 2006;452:35e43. 6. Mahomed NN, Liang MH, Cook EF, et al. The importance of patient expectations in predicting functional outcomes after total joint arthroplasty. J Rheumatol. 2002;29:1273e1279. 7. Kim TK, Chang CB, Kang YG, Kim SJ, Seong SC. Causes and predictors of patient's dissatisfaction after uncomplicated total knee arthroplasty. J Arthroplasty. 2009;24:263e271. 8. Gandhi R, Davey JR, Mahomed NN. Predicting patient dissatisfaction following joint replacement surgery. J Rheumatol. 2008;35:2415e2418. 9. Yeon Kim So, Jun An Yong, Hwan Kim Soo, Kim Ha-Kyoung, Soo Park Jeong, Shin Yang-Sik. The effect of postoperative
10. 11.
12. 13.
14.
15.
pain on postoperative blood loss after sequential bilateral total knee arthroplasty. Korean J Anesthesiol. 2011 Feb;60:98e102. Friedman RJ. Limit the bleeding, limit the pain in total hip and knee arthroplasty. Orthopedics. 2010 Sep;33(9 suppl):11e13. Guay J. Postoperative pain significantly influences postoperative blood loss in patients undergoing total knee replacement. Pain Med. 2006 NoveDec;7:476e482. Gross JB. Estimating allowable blood loss: corrected for dilution. Anesthesiology. 1983 Mar;58:277e280. Rosencher N, Kerkkamp HE, Macheras G, et al. Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) study: blood management in elective knee and hip arthroplasty in Europe. Transfusion. 2003;43:459e469. No authors listed. Guidelines for Red Cell Transfusion. GAIN. http://www.gain-ni.org/images/Uploads/Guidelines/blood% 20poster.pdf; (date last accessed 28.04.14). Ethgen O, Bruyere O, Richy F, et al. Health-related quality of life in total hip and total knee arthroplasty. A qualitative and systematic review of the literature. J Bone Joint Surg Am. 2004;86-A:963e974.