Testing of a predictive risk index for persistent postsurgical pain on patients undergoing total knee arthroplasty: A prospective cohort study

BACKGROUND

We investigated whether a universal predictive risk index for persistent postsurgical pain (PPP) is applicable to patients who undergo total knee arthroplasty (TKA).

METHODS

In this cohort study, 392 participants of a randomized study investigating the effects of anaesthesia methods and tourniquet use on TKA were divided into low-, moderate-, and high-risk groups for PPP, as suggested in the previous risk index study. Patients reported pain using the Oxford Knee Score pain subscale and Brief Pain Inventory-short form preoperatively and 3 and 12 months postoperatively. We compared the pain scores of the low- to moderate- and high-risk groups at respective time points and investigated changes in pain scores and the prevalence of PPP at 3 and 12 months after surgery.

RESULTS

The high-risk group reported more pain 3 and 12 months after TKA than the low- to moderate-risk group. However, of seven variables, only a single difference reached the threshold for minimal clinical importance between the groups at 12 months. Additionally, at 12 months, the low- to moderate-risk group reported slightly worse improvements in three of seven pain variables than the high-risk group. Depending on the definition, the prevalence of PPP ranged from 2% to 29% in the low- to moderate-risk group and 4% to 41% in the high-risk group 12 months postoperatively.

CONCLUSIONS

Although the investigated risk index might predict clinically important differences in PPP between the risk groups at 3 months after TKA, it seems poorly applicable for predicting PPP at 12 months after TKA.

SIGNIFICANCE

Although many risk factors for persistent postsurgical pain after total knee arthroplasty have been identified, predicting the risk of this pain has remained a challenge. Results of the current study suggest that accumulation of previously presented modifiable risk factors might be associated with increased postsurgical pain at 3 months, but not at 12 months after total knee arthroplasty.

Fat tissue is a poor predictor of 1 year outcomes after total knee arthroplasty: A secondary analysis of a randomized clinical trial

BACKGROUND AND OBJECTIVE

Obesity may increase the risk of adverse events after total knee arthroplasty (TKA). Although body mass index (BMI) is commonly used in categorizing obesity, its accuracy is limited. Body fat percentage (BFP) might indicate adiposity status and predict arthroplasty-related outcomes better than BMI. We investigated whether BFP is predictive of TKA-related outcomes.

METHODS

In this secondary analysis, BFP was measured preoperatively from 294 participants of a randomized trial that investigated the effects of tourniquet and anesthesia methods on TKA. Data concerning in-hospital assessments and events were collected. Knee range of motion (ROM) was measured, the Brief Pain Inventory-short form and Oxford Knee Score questionnaires were used to collect data on patient-reported pain and function, and the 15-dimensional health-related questionnaire was used to assess quality of life preoperatively and 3 and 12 months postoperatively. The patients reported satisfaction to TKA 3 and 12 months postoperatively. Data concerning infectious and thromboembolic events within 90 postoperative days and revision surgery, manipulation under anesthesia, and mortality within 1 year were collected. A separate post hoc analysis was performed for 399 participants to assess the effects of BMI on the respective outcomes.

RESULTS

A 1-unit increase in BFP affected the ROM by -0.37° (95% confidence interval (CI) = -0.60 to -0.13) 12 months after surgery. BFP was not significantly associated with the operation time or adverse events. However, the number of most adverse events remained too low for adjusted analysis. A 1-unit increase in BMI increased the operation time by 0.57 min (95% CI = 0.10 to 1.04) and affected the ROM by -0.47° (95% CI = -0.74 to -0.20) 12 months postoperatively. Neither BFP nor BMI was significantly associated with acute pain, pain management, length of stay, or with pain, function, quality of life, or satisfaction to TKA at 12 months after surgery.

CONCLUSIONS

BFP seems to be a poor predictor of in-hospital results and of patient-reported outcomes 1 year after TKA.

TWITTER HANDLE

In this secondary analysis of a randomized trial, body fat percentage was poorly predictive of clinical outcomes during hospital stay and of patient-reported outcomes 1 year after TKA.

Use of a Tourniquet and Spinal Anesthesia Increases Satisfactory Outcomes After Total Knee Arthroplasty: A Randomized Study

BACKGROUND

Total knee arthroplasty (TKA) is usually performed successfully with or without a tourniquet and under spinal anesthesia (SA) or general anesthesia (GA). However, 10% to 34% of patients experience dissatisfaction and pain after TKA. We aimed to compare the effects of tourniquet use and SA or GA on TKA outcomes.

METHODS

We randomly assigned 404 patients to 4 study groups: SA without a tourniquet (NT/SA), SA with a tourniquet (T/SA), GA without a tourniquet (NT/GA), and GA with a tourniquet (T/GA). The primary outcome was the change in the Oxford Knee Score (OKS) at 1 year postoperatively. Secondary outcomes included a satisfactory TKA outcome assessed using the OKS minimal important change (MIC) and OKS patient acceptable symptom state (PASS), adverse events, and quality of life using the 15-dimensional health-related quality of life tool.

RESULTS

At 1 year, the OKS was obtained for 381 patients. In the 2-group comparisons, the tourniquet did not affect the OKS improvement. The SA group had more substantial improvement in the OKS than the GA group (16.21 compared with 14.08 a mean difference of 2.13; 95% confidence interval [CI], 0.55 to 3.71; p = 0.008). In the 4-group comparisons, the T/SA group had more substantial improvements in the OKS than the NT/GA group (16.87 compared with 13.65, a mean difference of 3.2; 95% CI, 0.28 to 6.17; p = 0.026). The SA group reached the OKS MIC more frequently than the GA group (91.7% compared with 81.7%; odds ratio [OR] = 2.49 [95% CI, 1.32 to 4.69]; p = 0.005). The SA group also reached the OKS PASS more frequently than the GA group (86.0% compared with 75.7%; OR = 2.00 [95% CI, 1.18 to 3.39]; p = 0.010). The T/SA group had significantly more patients reaching the OKS MIC than the NT/GA group (95.7% compared with 79.6%; p = 0.005) and more patients reaching the OKS PASS than the NT/GA group (92.6% compared with 74.5%; p = 0.004). No differences were seen with respect to adverse events in any comparisons.

CONCLUSIONS

The tourniquet had no detrimental effects on the outcomes of TKA. SA had a positive effect on the OKS. The use of SA combined with a tourniquet resulted in the best improvement in OKS and the highest proportion of satisfactory outcomes with TKA.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Intravenous patient-controlled analgesia vs nurse administered oral oxycodone after total knee arthroplasty: a retrospective cohort study

OBJECTIVES

Severe post-operative pain is common after total knee arthroplasty. Patient-controlled analgesia is an alternative method of pain management, whereby a patient administers his or her own pain medication. Patients seem to prefer this method over nurse-administered analgesia. However, it remains unclear whether patients using patient-controlled analgesia devices use higher or lower doses of opioids compared to patients treated with oral opioids.

METHODS

This retrospective study examined 164 patients undergoing total knee arthroplasty. Post-operatively, 82 patients received oxycodone via intravenous patient-controlled analgesia devices, while the pain medication for 82 patients in the control group was administered by nurses. The main outcome measure was the consumption of intravenous opioid equivalents within 24 h after surgery. Secondary outcome measures were the use of anti-emetic drugs and the length of stay. Furthermore, we evaluated opioid-related adverse event reports.

RESULTS

The consumption of opioids during the first 24 h after surgery and the use of anti-emetic drugs were similar in both groups. The median opioid dose of intravenous morphine equivalents was 41.1 mg (interquartile range (IQR): 29.5-69.1 mg) in the patient-controlled analgesia group and 40.5 mg (IQR: 32.4-48.6 mg) in the control group, respectively. The median length of stay was 2 days (IQR: 2-3 days) in the patient-controlled analgesia group and 3 days (IQR: 2-3 days) in the control group (p=0.02). The use of anti-emetic drugs was similar in both groups.

CONCLUSIONS

The administration of oxycodone via intravenous patient-controlled analgesia devices does not lead to increased opioid or anti-emetic consumptions compared to nurse-administered pain medication after total knee arthroplasty. Patient-controlled analgesia might lead to shortened length of stay.

Randomised controlled study comparing general and spinal anaesthesia with and without a tourniquet on the outcomes of total knee arthroplasty: study protocol

INTRODUCTION

Total knee arthroplasty is a highly effective treatment for end-stage knee osteoarthritis, and it is usually performed under spinal or general anaesthesia with or without a surgical tourniquet. Some debate about the preferred mode of anaesthesia regarding patient outcomes remains. The aim of this study, which compares general and spinal anaesthesia with and without a tourniquet on the outcomes of total knee arthroplasty, is to determine the optimal type of anaesthesia regimen and assess the effect of a tourniquet on the patient's recovery following total knee arthroplasty.

METHODS AND ANALYSIS

This study is a randomised, controlled, parallel-group, four-arm study comparing spinal and general anaesthesia with and without a tourniquet in 400 patients undergoing fast-track total knee arthroplasty, with a 12-month follow-up. The primary outcome is cumulative intravenous oxycodone consumption by patient-controlled analgesia during the first 24 postoperative hours. Secondary outcomes include postoperative nausea and vomiting, the length of hospital stay, the duration of the surgery, blood loss, demand for surgical unit resources, complications, readmissions, postoperative knee function, range of motion, health-related quality of life, prolonged pain and mortality.

ETHICS AND DISSEMINATION

This study's protocol is in accordance with the declaration of Helsinki. The results of this study will be disseminated in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03364088; Pre-results.