Limited analgesic effect of continuous intraarticular ropivacaine for 48h TKA
Doubtful effect of continuous intraarticular analgesia after total knee arthroplastyActa Orthop. 2015 Jun;86(3):373-7
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200 patients undergoing total knee arthroplasty (TKA) were randomized to receive either 7.5mg/mL of ropivacaine or 9mg/mL of saline via a continuous intraarticular infusion pump for 48 hours postoperative. The purpose of this study was to determine the effectiveness of a continuous intraarticular infusion of ropivacaine in prolonging the effect of local infiltration analgesia (LIA). With the exception of lower pain in the first postoperative day, results demonstrated no significant differences in postoperative pain, requirement of additional analgesia, or functional recovery between groups.
Was the allocation sequence adequately generated?
Was allocation adequately concealed?
Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?
Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?
Blinding Patients: Was knowledge of the allocated interventions adequately prevented?
Was loss to follow-up (missing outcome data) infrequent?
Are reports of the study free of suggestion of selective outcome reporting?
Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?
Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?
Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?
Yes = 1
Uncertain = 0.5
Not Relevant = 0
No = 0
The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.
Inclusion / Exclusion
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.
Why was this study needed now?
Severe pain is often experienced after total knee arthroplasty. Periarticular local infiltration analgesia (LIA) has been introduced in an attempt to improve pain relief, promote early postoperative mobilization and potentially reduce patient length of stay. However, previous studies on its use have provided inconsistent results. Continuous intraarticular analgesia (CIAA) has been suggested as an alternative to prolong the effects of LIA beyond the first 24 postoperative hours. Previous studies have been conducted to measure the efficacy of postoperative CIAA, however the results have been controversial and thus this study was conducted.
What was the principal research question?
In patients undergoing total knee arthroplasty, how does continuous intraarticular infusion of ropivacaine compare to saline with regards to analgesia outcomes, assessed over the first 3 months postoperatively?
What were the important findings?
- VAS pain was significantly lower in the ropivacaine group compared to the control group at 12pm (33 +/- 24 vs. 40 +/- 22; p=0.02) and 8pm (36 +/- 24 vs. 43 +/- 21; p=0.03) on the first postoperative day. There were no significant differences between groups in any subsequent follow-up time point (all p>0.05).
- Significantly more postoperative wound infections were seen in the ropivacaine group compared to the control group (11 vs. 2, respectively; p=0.02)
- There was no significant difference between groups in additional analgesic consumption (p=0.06).
- The groups demonstrated similar knee range of motion at both 3 days (p=0.6) and 3 months (p=0.1) postoperatively.
- There was no significant difference between groups in the percentage of patients who were able to perform the straight leg test on the third postoperative day (ropivacaine group: 93/97; control group: 92/95; p=1.0).
What should I remember most?
In patients who underwent total knee arthroplasty, those treated with continuous intraarticular analgesia (CIAA) for 48 hours postoperatively demonstrated significantly lower pain than those treated with saline only on the first postoperative day, with differences between groups non-significant thereafter to 3 months. Additionally, no significant difference was noted in requirement of additional analgesia, or parameters of functional recovery. The group treated with CIAA demonstrated a significantly higher incidence of infection compared to the control group.
How will this affect the care of my patients?
The results of this study suggest that continuous intraarticular infusion of ropivacaine for 48 hours following total knee arthroplasty may have a limited effect on pain outcomes which may not be clinically relevant. Further study is necessary to determine the role of continuous intraarticular analgesia in pain management following total knee arthroplasty.
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