Effectiveness of Denervation Therapy on Pain and Joint Function for Patients with Refractory Knee Osteoarthritis: A Systematic Review and Meta-Analysis

Background: Recently, denervation therapy has been applied clinically for the treatment of intractable osteoarthritis (OA). This therapy provides an alternative for patients who are insensitive to conservative therapies or unwilling to receive surgery and general anesthesia. However, therapeutic effect of this method, especially the long-term efficacy, is still controversial. Objectives: The aim of this systematic review was to examine the efficacy of denervation therapy for the treatment of OA, especially on pain alleviation and functional recovery in the short and long term. Study Design: This systematic review and meta-analysis was designed to investigate whether denervation therapy is more useful than conservative methods for achieving clinical outcomes in patients with refractory OA. Methods: A literature search was performed in MEDLINE, EMBASE, and the Cochrane library for studies published from inception to August 2018. From those found meeting the search criteria, manuscripts comparing the clinical efficacy of denervation therapy and control agents, such as conservative therapies or sham operation, were included in this study. After reviewing the titles, abstracts, and the full text, 6 studies were included in the quantitative synthesis. Data, including postoperative pain scores, rate of 50% pain relief, and joint functional scores were extracted and combined to obtain effect size and statistical significance. Results: In terms of postoperative pain intensity, denervation therapy showed significantly better short-term (4, 12, and 24 weeks) pain relief. The rates of 50% pain relief at 12 and 24 weeks after operation were also higher compared with the control group. In terms of joint functional improvement, denervation therapy showed favorable outcomes at 4 and 12 weeks after treatment, but no significant difference was found at 24 weeks after procedure between the groups. Overall, better results were reported in denervation therapy with a relative high-grade of evidence. Limitation: Analyses of long-term (one year and longer) effects could not be conducted owing to a lack of existing studies. Conclusions: Denervation of the knee joint may become a promising therapy for patients with knee OA who are refractory to conservative treatment. This therapy can provide short-term therapeutic effect in pain alleviation for 6 months and joint function recovery for 3 months. The therapeutic effect in joint function may decrease 6 months after operation. The long-term efficacy in pain remission and function improvement is still elusive and controversial; therefore, further research with larger sample sizes are needed in the future.