Abstract
Pain control is critical in the management of TKA patients and is crucial to allow for early ambulation and accelerated physical therapy. Currently data suggests that 19% of patients are not satisfied with their results following TKA, and failure to control pain may result in prolonged hospitalization, worse outcomes, and increased patient dissatisfaction. Studies suggest that local analgesics coupled with both pre- and post-operative multimodal pain management may result in improved pain control and increased patient satisfaction. Minimization of opioid use is helpful in decreasing complications, accelerating physical therapy milestones, minimizing length of stay and increasing discharge to home.
Femoral nerve blocks (FNB) can reduce pain scores for up to 48 hours post-operatively, but may delay ambulation and result in an increased rate of falls. Periarticular injection (PAI) with local analgesics can provide significant short term relief comparable to FNB and can also facilitate decreased opioid consumption. One commonly used local anesthetic is bupivacaine, but the average half-life of this drug is only 2.7 hours. An alternative to this for PAI during TKA is liposomal bupivacaine (LB). LB is a multivesicular drug designed for rapid absorption, prolonged release of bupivacaine, and analgesia that is maintained for up to 72 hours with a single injection. LB exhibits a bimodal peak of distribution, one immediate associated with extra-liposomal bupivacaine, and a second 10–36 hours later associated with the release of liposomal encapsulated bupivacaine. The safety profile of LB has been investigated and adverse events are similar to standard bupivacaine and demonstrate acceptable tolerability. Multiple studies have demonstrated efficacy of this drug compared to other pain control modalities. LB is highly technique dependent and only one piece of a multimodal pain management protocol.
Our study consisted of 1808 consecutive primary TKA patients from Sept 2013 to Sept 2015. Three patient cohorts were compiled by date, from Sept 2013 to May 2014 was cohort 1, consisting of FNB and PCA. Department wide adoption of LB began in May 2014 and became routinely used in all patients undergoing total joint arthroplasty at our institution. Cohort 2 entailed a PCA along with LB injection from May 2014 through Feb 2015. Cohort 3 consisted of LB injection only and was from Feb 2015 through Sept 2015. All patients undergoing TKA were eligible and there were no exclusion criteria as long as the protocols were followed.
The standard multi-modal analgesia protocol was provided to all patients in all three cohorts. Prior to entering the operating room, patients received preemptive oral analgesics, consisting of: 200 mg celecoxib, 1000 mg acetaminophen, and 50 mg pregabalin. Intra-operative analgesia was chosen at the discretion of the anesthesiologist and preferentially consisted of spinal anesthesia with general anesthesia as an alternate. For all three cohorts, a peri-incisional analgesic cocktail was injected prior to closure consisting of: 40 cc 0.25% Marcaine, 5 cc of (1 mg/cc) morphine, and 1 cc of (30 mg/cc) ketorolac. Cohorts 1 and 2 received PCA post-operatively for pain control post-operatively with prn oral narcotic administration as well. Cohort 3 did not receive a PCA.
The cohort treated without FNB and without a PCA using a multimodal pain management protocol including a short acting periarticular injection and a longer acting periarticular injection with LB, had equivalent pain control, less narcotic use, faster achievement of physical therapy milestones, earlier and more frequent discharge home, less complications and a lower cost of the episode of care.
