Comparison of Liposomal Bupivacaine with Bupivicaine Pain Pump in TKA Patients: Commentary on an article by Eric B. Smith, MD, et al.
In this randomized, double-blinded, clinical controlled superiority trial, patients scheduled to undergo TKA were randomly assigned to treatment with either Exparel plus a dummy catheter (n = 104) or ON-Q* (n = 96). The primary study outcome measure was cumulative narcotic consumption on postoperative days 0 through 3. Secondary outcome measures included assessment of pain, side effects, patient satisfaction, length of stay, and catheter-related complications. The authors found no significant difference in mean cumulative narcotic consumption between patients who received Exparel and those who received ON-Q* (10.9 compared with 10.4 morphine equivalents; p = 0.641). Additionally, no significant differences were observed in any secondary outcome measures, with the exception of clinically unimportant differences in pain with walking (4.6 compared with 3.5 points; p = 0.019) and pain with physical therapy (4.5 compared with 3.2 points; p = 0.010) as measured by a visual analog scale.
This study serves as an important step in continued efforts toward optimizing the value of care. Prior to the Affordable Care Act of 2010, the emphasis of health care was placed on volume. Since then, the overarching goal for both medical and legislative communities has been to achieve highly valued care for patients. Value, defined as health outcomes achieved per dollar spent6, is now the focal point of newer implemented reimbursement models such as the Value-Based Purchasing (VBP) program4, Bundled Payments for Care Improvement (BPCI) initiative7, and Comprehensive Care for Joint Replacement (CJR) model8. These models reward entities that provide optimal care value to patients through either low cost of care or better outcomes. The authors discuss potential cost savings associated with the use of ON-Q* when compared with the more expensive Exparel. However, they rightfully suggest that these cost savings be weighed against potential risks associated with indwelling catheter use.
While no infections were reported in the ON-Q* cohort, the authors mention anecdotal accounts of an increased risk of infection associated with the presence of an intra-articular catheter. Interestingly, the current literature reflects a different stance. In a retrospective study of 1,915 consecutive primary TKA-treated patients, Ham et al.9 reported no significant difference in rates of deep-space surgical site infection between patients who did (n = 1,138) and those who did not (n = 777) receive an intra-articular catheter (0.53% compared with 0.77%; p = 0.56). Notwithstanding, orthopaedic surgeons must still consider catheter-specific complications such as leakage and breakage, which may lead to reduced satisfaction or a return to the operating room.
The study by Smith et al. had confounding factors that warrant mentioning.