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ORIGINAL ARTICLE

Comparison Of The Different Modalities Of  Post Operative Analgesia In Unilateral Total Knee Arthroplasty Patients

Mohammad Ashik, Chia Shi-Lu, Yeo Seng Jin, Tan Mann Hong, Lo Ngai Nung.

Department of Orthopaedic Surgery,Adult Reconstruction Service,Singapore General Hospital.
Address for Correspondence:

Mohammad Ashik Zainuddin
Singapore General Hospital
Department of Orthopaedic Surgery
Outram Road
Singapore 169608

Phone :+65 81232821
E-mail:
med50091@yahoo.com

Abstract:

Introduction: We report the results of a prospective  randomised trial comparing different modalities of post operative analgesia in unilateral total knee replacement(TKR) patients.

Methods:  90 patients aged between 50 to 80 years undergoing unilateral TKR were randomised into 3 groups.

Group 1:. Patients only received  patient controlled morphine analgesia (PCA). (control)

Group 2:  Patients received  PCA and  intra-articular  marcaine via continuous infusion pump.

Group 3: Patients received PCA and intra-operative periarticular injection of steroid and marcaine.

Visual analogue pain scores (VAS) , morphine consumption via PCA, number of days to ambulation, active range of movement(AROM) of operated knee, and length of stay(LOS) were the primary outcomes measured.

Results:Adequate pain control achieved in all 3 arms.

Group 3 demonstrates :

1.     significant reduction in  pain scores  (p= 0.002) in the first 6 hours post surgery.

2.     Significant reduction in the total morphine usage (p=0.042).

3.     Decreased LOS  compared to Group 1 (p=0.006) and Group 2 (p=0.01)

The number of days to ambulation, and AROM of  the operated knee during the inpatient stay were similar in all 3 groups.The mean duration of surgery for Group 2 (100min +/- 23) was significantly longer compared to the other groups (p=0.03). After 24 months of follow up, no post surgical complications (eg, infection) were demonstrated in this study.

Conclusion: The periarticular injection of analgesia with steroid appears to be a safe and effective modality for pain control post TKR and demonstrates superiority over both  control and infusion arms.

J.Orthopaedics 2010;7(1)e11

Keywords:

knee; arthroplasty; analgesia

Introduction:
 

Total knee replacement (TKR) is a major surgical procedure, with patients often requiring large amounts of post-operative analgesia. It has been reported that more than 50% of patients receive suboptimal pain control (1) and half of all patients undergoing total knee replacement will experience severe pain (2,3) in the early post op period.

Effective pain management is essential for the early recovery and rehabilitation after total knee replacement. No amount of patient education and encouragement can motivate patients to undergo an accelerated rehabilitation program, if pain control is not achieved. Hence it cannot be overemphasized that the focus of any total knee post operative rehabilitation program should be in controlling post operative pain.

Post operative analgesia with intravenous patient controlled  analgesia with a narcotic has been the gold standard. However , it is not without its detrimental and unwanted side effects.

Current methods of post operative pain control include a multimodal regimen of oral analgesia combined with epidural analgesia or continuous peripheral nerve blockade, both of which have risk of side effects and demand expertise(4,5,6).The concept of multimodal pain control including the use of peri articular injections has received increasing interest in the recent literature.(7,8,9)

The use of non-opiod analgesia may possibly decrease or eliminate opiod use. Better pain management would also encourage early mobilisation of patients, shorten length of stay and reduce complications associated with prolonged bed rest(10).

We report the results of a prospective randomised trial comparing intra-articular anaesthetic infusion  to patient-controlled morphine analgesia (PCA) alone or intraoperative periarticular injection of anaesthetic and steroids, as a modality for pain management after TKR.

Materials and Methods:

We obtained approval for our study protocol from our hospital’s ethics committee (IRB) and obtained written informed consent from each patient.

Statistical analysis was performed with SPSS statistical software. A power analysis was performed to determine the number of subjects required. To demonstrate a P value less than 0.05, it was determined that 30 patients were needed in each group for a total number of 90.

A total of 90 patients aged between 50 to 80 years undergoing unilateral TKR were randomised into 3 groups below using randomization tables.

Group 1:. Patients only received  PCA. (This is the control group).

Group 2:  Patients received  PCA and  intra-articular  marcaine via continuous infusion pump for 2 days post surgery.

Group 3: Patients received PCA and intra-operative periarticular injection of steroid and marcaine.

Exclusion criteria included patients undergoing bilateral total knee arthroplasties, patients with previous surgeries to the knees, immunodefiency, hypothyroidism, renal failure and allergies or intolerance to any component of the injection or to oral non-steriodal anti-inflammatory medication..

Group 1 received PCA which consists of morphine given as a bolus of 1mg, followed by patient controlled dose of up to 8mg/hour and a lock out time of 5 minutes.

The same PCA was used in groups 2 and 3, in order to compare the amount of morphine consumption used across the three groups and also to provide “rescue” for breakthrough pain if it occurs.

Group 2 received an initial  loading dose of  20ml 0.5% marcaine given intra-articular after wound closure, followed by a continuous infusion of  0.25% marcaine given at 4ml/hr ( 2ml/site using dual cathether). This is achieved by preparation of the intra articular marcaine perioperatively into a small infusion container (Figure A). The patient carries the container  until it is completely emptied of its contents after 48 hours.

Figure A: The apparatus used to set up the intra articular marcaine continuous infusion.

Group 3 received periarticular injection of 20mls 0.5% marcaine mixed with 50mg of triamcinolone, diluted to a total of 40mls. The anaesthetic was then injected into the deep tissues of the knee pre and post liner insertion and reduction. (Figure B)

Before insertion of liner and reduction

 

After liner insertion and reduction

 

Posterior capsule

Posteromedial and posterolateral structures

 

Extensor mechanism

Synovium

Capsule

Pes anserinus, anteromedial capsule, and periosteum

 

Figure  B: Table showing the periarticular injection sites before and after liner insertion.

Meticulous hemostasis was achieved prior to wound closure after the leg tourniquet was deflated. No drains were used in our study, ensuring no leakage of the injected components.

All patients in this study received intravenous antibiotics, cephazolin 1 gram 8 hourly for 24 hours postoperatively.

Standard post operative  analgesia given included paracetamol 1 gram every 6 hours and etoricoxib 120mg once daily.

Visual analogue pain scores (VAS) , morphine consumption via PCA, number of days to ambulation, active range of movement(AROM) of operated knee, and length of stay(LOS) were the primary outcomes measured.

Results :

Total visual analogue pain scores were reduced in all 3 arms (p >0.05) , implying  adequate pain control post operatively.  However in the first 6 hours post surgery, Group 3 has statistically significant reduction in  pain scores  compared to Group 1 and 2 respectively (p= 0.002, 0.028).(Figure D)

Figure D: VAS scores significant reduction in group 3 in the first 6 hours.

The number of days to ambulation, and AROM of  the operated knee during the inpatient stay were similar in all 3 groups.

The age and BMI profiles of the patients were similar across the 3 groups. There were no significant difference in length of stay , and the number of days taken for the patient to ambulate.

The mean duration of surgery for Group 2 (103.25 min +/- 23) was significantly longer compared to the other groups (p=0.03) and is attributed to the  additional time taken to prepare and insert the intra articular infusion pump intraoperatively. (Figure C).

 

Group 1

Group 2

Group 3

 

Age (years)

69.3

70.4

65.8

p>0.05

BMI

27.4

28.03

29.1

p>0.05 

LOS (days)

5.2

5.5

5.4

p>0.05

Ambulation (days)

2.4

2.3

2.3

p>0.05 

Op duration (minutes)

84

103.25

83.1

P<0.05

Figure C: Significantly longer duration of surgery in group 2.

Total  morphine usage was reduced in both Groups 2 (p=0.51) and Group 3 with statistically significant reduction demonstrated in Group 3 (p=0.042). (Figure E)

Figure E: Significant reduction in morphine usage seen in group 3.

No immediate post surgical complications (eg, infection, wound breakdown, bleeding, deep vein thrombosis) and complications  associated with the use of continuous intra-articular infusion pump, and periarticular steroid injection were demonstrated in this study.

Discussion :

Our knowledge and understanding of the pain-generating process is improving, and so does our ability to control pain especially in the postoperative period. However, the concept of pain is still not fully understood, which is a complex phenomenon controlled by humeral, neural and cellular mechanisms, with a strong emotional and psychologic component.

A multimodal protocol is therefore relevant in this context and this includes preoperative patient education and clarification of expectations, preemptive analgesia, good anaesthesia technique, meticulous surgical technique to minimise tissue trauma, intraoperative agents and postoperative analgesia and accelerated rehabilitation protocol.

Ranawat et al(11) have demonstrated that the right cocktail of periarticular injection offers the most effective pain control with the least amount of side effects. The safety and efficacy of this injection has been duplicated by other authors as well.

A local study done in patients undergoing unicondylar knee arthroplasty(12) also showed the effectiveness of the local periarticular injections of marcaine and steroids.

The reported complications of intra articular steroids are rare and this include septic arthritis, tissue atrophy, tendon ruptures and avascular necrosis(13). By observing strict asepsis and stringent exclusion criteria, we did not encounter any of the above complications in our study at 24 months of follow up.

The use of continuous intra-articular infusion of  local anaesthetic post surgery has been an effective modality for post operative pain control in arthroscopic shoulder and knee surgeries(14). In open joint surgeries such as TKR, mixed results were reported by various authors(15,16) However, we were unable to demonstrate any advantages of the use of continuous intra articular marcaine infusion over the PCA morphine.

In this study, we conclude that periarticular injection of marcaine and steroid is superior and effective  because it decreases pain significantly in the immediate post operative period, decreases morphine consumption and there is no increased risk of infection.

Reference :

  1. Filos KS, Lehmann KA. Current concepts and practice in postoperative pain management: need for a change? Eur Surg Res 1999;31:91.

  2. Follin SL, Charland SL. Acute management: operative for medical procedures and trauma. Ann Pharmacother 1997;31:1068.

  3. Bonica JJ. Postoperative pain. In: Bonica JJ, editor.The management of pain. Malvern (Pa): Lea & Febiger; 1990. p. 461.

  4. Boezaart AP. Perineural infusion of local anesthetics. Anesthesiology 2006;104:872-80.

  5. Choi PT, Bhandari M, Scott J, Douketis J. Epidural analgesia for pain relief following hip and knee replacement. Cochrane Database Syst Rev 2003:CD003071.

  6. Davies AF, Segar EP, Murdoch J, Wright DE, Wilson IH. Epidural infusion or combined femoral and sciatic nerve blocks as perioperative analgesia for knee arthroplasty. Br J Anaesth  2004;93:368—74.

  7. Venditolli PA, Makinen P, Drolet P. A multimodal analgesia protocol for total knee arthroplasty. A randomized, controlled study. J Bone Joint Surg Am 2006;88- :282.

  8. Busch CA, Shore BJ, Bhandari R. Efficacy of periarticular multimodal drug injection in total knee  arthroplasty. A randomized trial. J Bone Joint Surg Am 2006;88-A:959.

  9. Hebl JR, Kopp SL, Ali MH. A comprehensive anesthesia protocol that emphasizes peripheral nerve blockade for total knee and total hip arthroplasty. Bone Joint Surg Am 2006;88-A:63.

  10. Rasmussen S, Kramhøft MU, Sperling KP, Pedersen JH. Increased flexion and reduced hospital stay with continuous intraarticular morphine and ropivacaine after primary total knee replacement: Acta Orthop Scand. 2004 Oct;75(5):606-9.

  11. Ranawat AS,Ranawat CS; Pain management and Accelerated Rehabilitation for Total Hip and total knee replacement: Journal of Arthroplasty Vol 22 No 7 Suppl. 3 2007.

  12. HN Pang, NN Lo, SJ  Yeo , KY Yang ;Periarticular steroid injection improves outcome after unicondylar knee arthroplasty- a 2 year prospective randomised controlled trial; 2007 ,JBJS-A.

  13. Hunter JA, Blyth TH. A risk-benefit assessment of intr-articular corticosteroids in rheumatic disorders. Drug Safety. 1999; 21:353-365.

  14. Hoenecke HR Jr, Pulido PA, Morris BA, Fronek J. The efficacy of continuous bupivacaine infiltration following anterior cruciate ligament reconstruction. Arthroscopy. 2002 Oct;18(8):854-8.

  15. DeWeese FT, Akbari Z, Carline E. Pain control after knee arthroplasty: intraarticular versus epidural anesthesia. Clin Orthop Relat Res. 2001 Nov;(392):226-31.

  16. Busch CA, Shore BJ, Bhandari R, Ganapathy S, MacDonald SJ, Bourne RB et al. Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial J Bone Joint Surg Am. 2006 May;88(5):959-63.

 

This is a peer reviewed paper 

Please cite as: Mohammad Ashik Zainuddin: Comparison Of The Different Modalities Of  Post Operative Analgesia In Unilateral Total Knee Arthroplasty Patients

J.Orthopaedics 2010;7(1)e11

URL: http://www.jortho.org/2010/7/1/e11

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