Conditions: Total Hip Arthroplasty Postoperative Pain
Keywords: Peripheral nerve blocks Ropivacaine concentrations in lumbar plexus catheters Postoperative pain Total hip replacement
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 41
Healthy volunteers: no

Brief summary:
Peripheral nerve blocks are the standard of care for pain management after hip replacement surgery at UPMC Shadyside. This prospective, randomized study is intended to assess the effect of 0.1 versus 0.2% ropivacaine in lumbar plexus nerve catheter infusions after total hip arthroplasty. Ropivacaine peripheral nerve block infusions have been utilized as the standard of care at UPMC Shadyside for many years. Ropivacaine, a less potent left-isomer of bupivacaine, is often used in place of bupivacaine due to less motor blockade and less severe cardiovascular and central nervous system potential toxicity.

The primary goal of this study to examine the effect of a low concentration infusion of ropivacaine (0.1%) on postoperative analgesia (evaluated by opioid consumption after 36 hours) compared with the standard accepted concentration of 0.2% ropivacaine in lumbar plexus catheters after primary total hip arthroplasty. Secondary goals are to examine motor function, VAS scores and patient satisfaction with pain control in low concentration 0.1% ropivacaine compared with 0.2% ropivacaine lumbar plexus infusions upto 36 hours after primary total hip arthroplasty.

Detailed description:
Lumbar plexus catheters are the standard of care for postoperative pain management following total hip arthroplasty (THA) at UPMC Shadyside. The safety and efficacy of this technique has been demonstrated by multiple studies. Ropivacaine 0.2% was used for many years at UPMC Shadyside and throughout the UPMC system and this concentration of ropivacaine is the standard local anesthetic utilized by multiple other studies. However, this concentration of ropivacaine was later decreased to 0.1% in our institution in order to decrease patient's motor weakness and promote postoperative physical therapy. Patients were clinically observed to continue to have adequate postoperative analgesia while demonstrating improved motor function. A randomized, double blinded clinical trial has never compared 0.1 and 0.2% ropivacaine.

Arms:
arm 1: 0.2% ropivacaine in lumbar plexus nerve catheter infusions for postoperative analgesia arm 2: 0.1% ropivacaine in lumbar plexus nerve catheter infusions

Interventions: intervention 1: 0.1% or 0.2% ropivacaine nerve blocks
Intervention descriptions: intervention 1: Either 0.1% or 0.2% ropivacaine will be infused at 7 mL/hr through lumbar plexus nerve block catheter based upon randomization, and can then receive a 6 ml bolus of either 0.1% or 0.2% ropivacaine. Additional pain relief will be available by nurse administered boluses of additional local anesthetic (from their randomized infusion) with a maximum dose of an extra 3 ml per bolus and limited to one bolus per hour. This bolus of their randomized local anesthetic will remain available until the nerve catheters are removed. Nerve block infusion rates may be increased to 9 ml/h for patients with increased pain without increased motor blockade as determined by the acute interventional perioperative pain service (AIPPS) or decreased to 5 ml/h for patients with increased motor blockade or weakness from the peripheral nerve block as determined by the AIPPS .All continuous lumbar plexus catheters will be removed on post operative day (POD) 2.

Protocol document: