Freezing Nerves Before Knee Replacement Surgery Improves Outcomes

A new study concludes that freezing sensory nerves prior to total knee arthroplasty (TKA) together with traditional pain management approaches significantly improves patient outcomes.

Researchers at Louisiana State University (LSU; Baton Rouge, LA, USA) conducted a retrospective chart review of 100 patients who underwent TKA to assess if adding cryoneurolysis to a multimodal pain management program improved outcomes. The study group consisted of the first 50 patients treated with cryoneurolysis five days before surgery as part of a standard pain management protocol; the control group included 50 patients treated before the practice was introduced. Outcomes included hospital length of stay (LOS), post-operative opioid requirements, and patient-reported outcomes of pain and function.

The results showed that almost half of patients treated with cryoneurolysis were discharged on the day of surgery, compared with only 14% in the control group; 45% required less opioids during the first 12 weeks after surgery. The treatment group also reported a statistically significant reduction in symptoms at six- and 12-week follow-up, compared with the control group, as well as a within-group significant reduction in pain intensity and pain interference at two- and six-week follow-up, respectively. The study was published online on February 10, 2016, in the Knee.

“The shorter length of stay of the patients in the treatment group may be due to better local control of pain and a reduced need for nerve blocks that can impair motor function, as well as reduced use of opioids for pain control, which allows patients to walk and function well enough to go home sooner,” concluded lead author Vinod Dasa, MD, an associate professor of clinical orthopedics at LSU, and colleagues. “Promising results from this preliminary retrospective study warrant further investigation of this novel treatment in prospective, randomized trials.”

The use of cold as an analgesic dates back to the days of Hippocrates and the ancient Egyptians. More recent work has shown that cryoneurolysis, when applied to peripheral branches of the trigeminal nerve in rats causes degeneration distal to the site of freezing, without causing disruption of the anatomical architecture. This is followed by structural regeneration of the nerve at about six weeks of post-injury, and recovery of normal sensation in two to four months.

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