Dexmedetomidine, an alpha 2 agonist, has been approved for providing sedation in the intensive care unit. Along with sedative properties, it has analgesic activity through its highly selective action on alpha 2 receptors. Recent studies have examined the use of dexmedetomidine as an adjuvant to prolong the duration of peripheral nerve blocks. Studies showing effectiveness of dexmedetomidine for adductor canal block in knee surgery are small. Also, its effectiveness has not been compared to Epinephrine which is a strong alpha and beta receptor agonist. In a previous study, we showed that motor sparing knee blocks significantly increased the duration of analgesia compared with periarticular knee infiltration using local anesthetic mixture containing Epinephrine following total knee arthroplasty (TKA). In this study, we compared two local anesthetic mixtures: one containing Dexmedetomidine and the other Epinephrine for prolongation of motor sparing knee block in primary TKA patients.

After local ethics board approval and gaining Notice of Compliance (NOC) from Health Canada for use of Dexmedetomidine perineurally, 70 patients between the ages 18 – 95 of ASA class I to III undergoing unilateral primary total knee arthroplasty were enrolled. Motor sparing knee block − 1) Adductor canal continuous catheter 2) Single shot Lateral Femoral Cutaneous Nerve block 3) Single shot posterior knee infiltration was performed in all patients using 60 ml mixture of 0.5% Ropivacaine, 10 mg Morphine, 30 mg Ketorolac. Patients randomized into the Dexmedetomidine group (D) received, in addition to the mixture, 1mcg/kg Dexmedetomidine and the Epinephrine (E) group received 200mcg in the mixture. The primary outcome was time to first rescue analgesia as a surrogate for duration of analgesia and secondary outcomes were NRS pain scores up to 24 hours and opioid consumption.

The time to first rescue analgesia was not significantly different between Epinephrine and dexmedetomidine groups, Mean and SD 18.45 ± 12.98 hours vs 16.63 ± 11.80 hours with a mean difference of 1.82 hours (95% CI −4.54 to 8.18 hours) and p value of 0.57. Pain scores at 4, 6, 12, 18 and 24 hours were comparable between groups. Mean NRS pain scores Epinephrine vs Dexmedetomidine groups were 1.03 vs 0.80 at 4 hours, 1.48 vs 3.03 at 6 hours, 3.97 vs 4.93 at 12 hours, 5.31 vs 6.18 and 6.59 v 6.12 at 24 hours. Opioid consumption was also not statistically significant between both groups at 6, 12 18, 24 hours (p values 0.18, 0.88, 0.09, 0.64 respectively).

Dexmedetomidine does not prolong the duration of knee motor sparing blocks when compared to Epinephrine for total knee arthroplasty. Pain scores and opioid consumption was also comparable in both groups. Further studies using higher dose of dexmedetomidine are warranted.

Pain immediately following total knee arthroplasty (TKA) is often severe and can inhibit patients' rehabilitation. Recently, adductor canal blocks have been shown to provide adequate analgesia and spare quadriceps muscle strength in the early postoperative period. We devised a single injection motor sparing knee block (MSB) by targeting the adductor canal and lateral femoral cutaneous nerve with a posterior knee infiltration under ultrasound. Our primary objective was to evaluate the analgesia duration of the MSB in comparison to a standard periarticular infiltration (PAI) analgesia using patients' first rescue analgesia as the end point. Secondary outcomes measured were quadriceps muscle strength and length of stay.

We randomised 82 patients scheduled for elective TKA to receive either the preoperative MSB (0.5% ropivacaine, 2.5ug/ml epinephrine, 10mg morphine, and 30mg ketorolac) or intraoperative periarticular infiltration (0.3% ropivacaine, 2.5ug/ml epinephrine, 10mg morphine, and 30mg ketorolac). Duration of analgesia, postoperative quadriceps power, and length of stay were evaluated postoperatively.

Analgesic duration was found to be significantly different between groups. The MSB had a mean duration of 18.06 ± 1.68 hours while the PAI group had a mean duration of 9.25 ± 1.68 hours for a mean difference of 8.8 hours (95% CI 3.98 to 13.62), p<0.01. There were no significant differences between groups in quadriceps muscle strength power at 20 minutes (p=0.91) or 6 hours (p=0.66) after block administration. Length of stay was also not significantly different between the groups (p=0.29).

Motor sparing blocks provide longer analgesia than patients receiving periarticular infiltration while not significantly reducing quadriceps muscle strength or increasing length of hospital stay.

The use of spinal anesthesia with adjuvant intra-thecal opioids has been commonly used in total knee arthroplasty without documented clinical benefit. It has been associated with a potential increase in side effects, including nausea, vomiting, pruritus, urinary retention and oxygen usage. This double-blinded RCT investigated whether the addition of epimorph to spinal anesthesia in patients undergoing total knee arthroplasty resulted in superior pain control and decreased narcotic consumption without also causing an increase in postoperative complication rates.

We performed a prospective double-blind trial in patients undergoing primary total knee arthroplasty (TKA). Patients were randomised to receive either spinal anesthesia alone or spinal anesthesia with epimorph (150 ug). All patients received infiltration of a local anesthetic cocktail intraoperatively. Both the study patients and staff measuring outcomes were blinded to the experimental treatment received during data collection. Postoperatively, visual analogue scale (VAS) for pain was recorded at 6, 12, 18, 24, 36 and 48hrs and a final value at 1 week. Narcotic use, Foley insertion, oxygen requirements, nausea, vomiting and pruritus were recorded during the course of hospitalisation.

Forty-one patients were randomised into each of the spinal with epimorph and spinal alone treatment arms. The groups showed no significant differences in BMI, age, and gender distribution. In the first 12 hours postoperatively there was no difference in VAS for pain between the two groups, however there were significantly lower pain scores in the spinal alone patients at 18 hours (p=0.002), 24 hours (p=0.04) and 48 hours (p = 0.03) compared to the spinal with epimorph group. Narcotic usage was greater in the spinal group during the first 6 hours postoperatively, but beyond this time point narcotic usage was similar between the two groups. Additionally, there was a statistically significant increase in rate of complications with spinal epimorph including nausea (p=0.037) and pruritus (p=0.024). The incidence of urinary retention was greater in the spinal epimorph group, however this did not reach statistical significance.

This study demonstrates no clinical benefit with the addition of intra-thecal opioids to spinal anesthetic in primary TKA. In addition to a failing to reduce VAS pain scores and overall narcotic consumption, increased complication rates were seen. For these reasons, this study does not support the use of epimorph in addition to spinal anesthesia for pain control in TKA.

Introduction

Fast track arthroplasty regimens require preservation of motor power to perform early rehabilitation and ensure early discharge (1). Commonly performed nerve blocks like femoral and Sciatic nerve blocks results in motor weakness thereby interfering with early rehabilitation and may also predispose to patient falls (2, 3). Hence, targeting the terminal branches of the femoral and sciatic nerves around the knee joint under ultrasound is an attractive strategy. The nerve supply of interest for knee analgesia are the terminal branches of the femoral nerve, the genicular branches of the lateral cutaneous nerve of thigh, obturator and sciatic nerves (4).

Purpose: Spinal epimorph is commonly used as part of multimodal analgesia for patients undergoing total joint arthroplasty. Patients who receive spinal epimorph are at risk for certain post- operative complications. The purpose of this study was to determine the incidence of complications in patients undergoing total joint arthroplasty with administration of spinal epimorph compared to patients undergoing the same procedure who did not receive spinal epimorph as part of their analgesia.

Method: A retrospective chart review of 72 patients in which two age, sex and procedure matched groups were compared for differences in known spinal epimorph complications. One group received spinal epimorph as part of their analgesia while the comparative group did not receive spinal epimorph but rather continuous infusion of local analgesia. Data extraction involved foley and oxygen usage, documented nausea/vomiting and puritis, associated risk factors and complications such as prostate disease and urinary tract infections, and secondary outcome measures such as Gravol and Benadryl usage.

Results: Comparison of the two well-matched groups demonstrated that patients who received spinal epimorph had increased rates of foley insertion (p=0.0026), foley duration (p=0.015), oxygen usage (p=0.0053), documented puritis (p=0.0006) and Benadryl usage (p=0.0053). Trends towards increased nausea/vomiting (p=0.17), antiemetic use (p=0.16) and urinary tract infections (p=0.15) were seen in the spinal epimorph group, although these differences did not reach statistical significance.

Conclusion: The use of spinal epimorph as part of an analgesia protocol surrounding total joint arthroplasty is associated with increased complications and patient discomfort when compared to patients who received continuous local infiltrative analgesia. Further research is needed to determine if alternate modes of analgesia provide adequate pain relief when compared with spinal epimorph and thus provide suitable alternatives with less complications.

Background: Post-operative analgesia using parenteral opioids or epidural analgesia can be associated with troublesome side effects.

Locally administered pre-emptive analgesia is effective, reduces central hyper sensitisation and avoids systemic drug related side-effects and may be of benefit in total knee replacement.

Materials and Methods: 64 patients undergoing total knee replacement were randomised to receive a periarticular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing.

All patients received patient controlled analgesia (PCA) for 24 hours post surgery, followed by standard analgesia. Visual Analogue Scale (VAS) pain scores during activity and at rest and patient satisfaction scores were recorded pre and post operatively and at 6 week follow up. PCA consumption and overall analgesic requirement were measured.

Results: PCA use at 6,12 and over 24 hours post surgery was significantly less in patients receiving the injection (P< 0.01, P=0.016, P< 0.01). Patient satisfaction in PACU and 4 hrs post operation was greater (P=0.016, P=0.013). VAS for pain during activity in PACU and at 4 hrs were significantly less (P= 0.04, P=0.007) in the injected group. The average ROM at 6 weeks was no different. Overall hospital stay and the incidence of wound complications was not different between the two groups.

Conclusion: Peri-articular intra-operative multimodal analgesia significantly reduces post-operative PCA requirement. Patient satisfaction was greater in the injection group.

This Blinded Randomized Clinical Trial outlines: how peri-articular intra-operative multimodal analgesia significantly reduces post-operative analgesia requirement. Sixty-four patients undergoing total knee replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. Patients who received the injection demonstrated greater satisfaction and pain relief. Finally, patients in the injected group did not show any signs of cardio and central nervous system toxicity.

Post-operative analgesia can be associated with troublesome side effects. Good peri-operative analgesia facilitates rehabilitation, improves patient satisfaction and may reduce hospital stay. The purpose of this study was to assess a novel cocktail for peri-articular analgesia after total knee replacement.

Sixty-four patients undergoing total knee replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. The anaesthetic analgesic regime was standardised. All patients received patient controlled analgesia (PCA) for twenty-four hours post surgery, followed by standard analgesia. VAS pain scores during activity and at rest and patient satisfaction scores were recorded pre and post operatively and at six week follow up. PCA consumption and overall analgesic requirement were measured.

PCA use at six, twelve and over twenty-four hours post surgery was significantly less in patients receiving the injection (p< 0.01, p=0.016, p< 0.01). Patient satisfaction in PACU and four hours post operation was greater (p=0.016, p=0.013). VAS for pain during activity in PACU and at four hours were significantly less (p=0.04, p=0.007) in the injected group. The average ROM at six weeks was no different. Overall hospital stay and the incidence of wound complications were not different between the two groups.

Peri-articular intra-operative multimodal analgesia significantly reduces post-operative analgesia requirement. Patient satisfaction and pain relief is greater in the injection group. No cardio and central nervous system toxicity was observed.

Our novel cocktail of ketorolac, epimorphine, epinephrine and ropivacaine provides superior pain relief with no adverse side effects.

Purpose: Post-operative analgesia using opioids or epidural analgesia can be associated with troublesome side effects. Effective peri-operative analgesia facilitates rehabilitation, improves patient satisfaction and may reduce hospital stay. Locally administered analgesia is effective, avoids systemic drug related side-effects and may be of benefit in minimally invasive joint replacement. This study compares the effects of a peri-articular injection cocktail in patients undergoing total knee and hip replacement surgery

Methods: 128 patients undergoing total knee (TKR) and hip (THR) replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. The anaesthetic analgesic regime was standardised. All patients received patient controlled analgesia (PCA) for 24 hours post surgery, followed by standard analgesia. VAS pain scores during activity and at rest and patient satisfaction scores were recorded pre and post operatively and at 6 week follow up. PCA consumption and overall analgesic requirement were measured.

Results: Both TKR and THR patients used significantly less PCA 6 hours after surgery (p = 0.02 THR, p< 0.01 TKR). TKR patients receiving the injection used significantly less PCA use over 24 hours post surgery (p = 0.013). VAS for pain at 4 hrs post operation was significantly lower in the both groups (p = 0.003 TKR)(p = 0.017 THR). VAS for pain during activity at 24 hours was significantly less (p = 0.001) in the injected TKR group. Overall hospital stay and wound complications were not different between the groups.

Conclusions: Peri-articular analgesia significantly reduces post-operative analgesia requirement in TKR and THR patients. Greater satisfaction and pain relief was seen in TKR patients compared with THR.