and 4 other(s)
INTRODUCTION: Primary TKA surgeries continue to rise in number exponentially in the USA. This procedure is painful and poorer outcomes have been linked to prolonged narcotic use after surgery. If methods can be proven to decrease the morphine equivalents utilized after surgery then a benefit to the patient should be realized through less fatigue, better improvements and shorter time to achieving goals in physical therapy. Cryoneurolysis is an approved treatment around the knee that has been reported to decrease pain from OA and after TKA.(1,2) The procedure causes axonal degeneration in the nerves which then fully recover typically within a 3 month time frame. This prospective randomized trial compared standard primary TKA with use of an adductor canal block and periarticular injection to a group who underwent cryoneurolysis of the superficial femoral cutaneous (SFA) nerve and the infra patellar branch (IPB) of the saphenous nerve for pain control after primary TKA. METHODS: After IRB approval primary TKA patients were randomized into a control standard of care group or a treatment group with cryoneurolysis. Both groups received the same pre-emptive, intra-operative and post operative pain management treatments except the treatment group underwent cryoneurolysis of their SFA and IPB sensory branches between 3 and 7 days before surgery. Intra-operatively the only difference in treatment was that peri-articular injections were only performed in the posterior capsule in the treatment group and in the control group the perioperative injection was utilized about the circumference of the knee prior to closure. All patients were prescribed 40 narcotic pills at discharge and the pills were then counted at 72 hours and at weeks 2,6 and 12 after surgery. The morphine equivalents in the two groups were then compared at each time interval. In this prospective, randomized trial 120 subjects will be enrolled and to date 102 have been randomized. Exclusion criteria for the study included: chronic and ongoing narcotic use, peripheral neuropathy, and lower extremity deformity greater than 10 degrees. The primary endpoint was daily morphine equivalent (DME) based on opioid pill count and the secondary endpoints were changes in pain scores, Active Range of Motion (ROM), KOOS Jr. and Timed Get-Up and Go (TUG) Test. RESULTS: Preliminary results demonstrate that the DME for the treatment group was significantly lower than the control group at 72 hours (10.9mg vs. 17.6mg, p=0.0193, n=84) and at 6 weeks (3.9mg vs. 5.8mg, p=0.0265, n=68). This difference accounts for a 38% reduction in the amount of opioids taken over each of these periods. The treatment group also demonstrated a greater reduction in pain score from baseline with respect to the control group at 72 hours (0.8 vs. -0.8, p=0.0141, n=84) and at 6 weeks (4.1 vs. 2.9, p=0.0224, n=68). Patients in the treatment group also demonstrated significant improvements in active ROM from baseline relative the control group at 2 weeks (-17.9 vs. -11.9 degrees, p=0.0377, n=83). There have been no differences in the rate or severity of side effects or adverse events between the two groups. DISCUSSION: Preliminary results support that cryoneurolysis prior to a TKA can reduce pain and opioid consumption after primary TKA surgery. Now at the 80% point of enrollment the significant decrease in daily morphine equivalents during the first 72 hours and the following six weeks is significant along with a decrease in pain score which has also resulted in greater flexion at the two week visit. At 80% of enrollment this prospective randomized trial is seeing significant benefit in the treatment group with a nearly 40% reduction in DME’s in the early postoperative window (72 hours post-op) and at the 6 week post-operative period as well. While the 2 week follow up has seen less difference this has been due to several patients not utilizing their tramadol prescriptions as directed in both groups. An almost 7 degree increase in flexion in the treatment group has also been realized at the two week postop physical therapy visit as well but it may not be at a clinically important difference at the 3 month follow up end of study. In a retrospective analysis Dasa et al reported on the same cryoneurolsis reatment comparing 50 treatment to standard of care and found 45% reduction in opioid use and a shorter length of stay. There have also been multicenter trials looking into cryoneurolysis for osteoarthritis pain comparing it to a sham procedure showing superiority for pain relief up to 3 months. (3) The current focus on the opioid crisis in the United States has made all orthopaedic surgeons become more aware of the narcotic use they prescribe for treatments and postoperative pain. Any treatment modalities that can be added to decrease the postoperative pain and improve the progress of physical therapy goals like range of motion after TKA is of very significant importance and surgeons should be made aware of this treatment option especially in those that may be on chronic opioid use for other pain control needs. SIGNIFICANCE/CLINICAL RELEVANCE: The number of TKA surgeries being performed is exponentially increasing year after year. The procedure is known to be painful and multimodal approaches have been developed to decrease narcotic use after surgery but dependence on opioids can occur within the 6 weeks after surgery. With a nationwide focus on the current opioid epidemic any treatment protocol that can significantly decrease narcotic use after TKA will be extremely beneficial to patients. REFERENCES: 1. Dasa V, Lensing G, Parsons M, Harris J, Volaufova J, Bliss R. Percutaneous freezing of sensory nerves prior to total knee arthroplasty. Knee. 2016 Jun;23(3):523-8 2. Lavie LG, Fox MP, Dasa V. Overview of Total Knee Arthroplasty and Modern Pain Control Strategies. Curr Pain Headache Rep. 2016 Nov;20(11):59. 3. Radnovich R, Scott D, Patel AT, Olson R, Dasa V, Segal N, Lane NE, Shrock K, Naranjo J, Darr K, Surowitz R, Choo J, Valadie A, Harrell R, Wei N, Metyas S. Cryoneurolysis to treat the pain and symptoms of knee osteoarthritis: a multicenter, randomized, double-blind, sham-controlled trial. Osteoarthritis Cartilage. 2017 Aug;25(8):1247-1256.
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