Denervation Therapy

The Denervation Therapy recommendation has been downgraded two levels because of inconsistent evidence and bias.

For the denervation therapies, there are 2 high quality studies (Radnovic et al 2017 and Mendes et al 2019) and 2 moderate quality studies (McAlindon et al 2017 and El-Hakeim et al 2018) comparing denervation technique with placebo.

One high quality study (Radnovic et al 2017) specifically evaluated the efficacy of cryoneurolysis in comparison to placebo control in patients with knee OA. It was found that the group receiving cryoneurolysis had improved total WOMAC, WOMAC stiffness, WOMAC pain, WOMAC physical function and in VAS pain compared to placebo control group.

Another high-quality study (Mendes et al 2019) evaluated the efficacy of chemical ablation in comparison to placebo control in patients with knee OA. It was found that the group receiving chemical denervation had improved in WOMAC pain compared to placebo control group. Another moderate quality study (McAlindon et al 2017) comparing the efficacy of chemical ablation in comparison to placebo control in patients with knee OA found no major difference between the two groups.

One moderate quality study (El-Hakeim et al 2018) specifically evaluated the efficacy of thermal ablation in comparison to placebo control in patients with knee OA. It was found that the group receiving thermal ablation had improved WOMAC total, WOMAC function and VAS pain compared to placebo control group.

One high quality study (Davis et al) and one moderate evidence study (Davis et al 2018) compared IA HA to thermal ablation in patients with knee OA.  The first study (Davis et al 2018) showed worse Oxford Knee Score, Global Perceived Index and Numeric Rating Scale in the HA group compared to the thermal ablation group, while the second study (Davis et al 2018) showed worse Oxford Knee Score, Change in Medication Use (mg) from Baseline, Knee pain-Numeric Rating scale and Mean Reduction in average NRS score in the HA group compared to the thermal ablation.

One high quality study (Gulec et al 2017) compared unipolar to bipolar radiofrequency ablation of the knee in patients with knee OA. In patients with OA, Bipolar intra-articular pulsed radiofrequency thermocoagulation may be used over Unipolar intra-articular pulsed radiofrequency thermocoagulation to improve patient pain.

One moderate quality study (Sari et al 2018) compared IA steroids to thermal ablation of the knee in patients with knee OA. The study showed worse WOMAC total, WOMAC function, WOMAC stiffness and worse VAS pain in the IA steroids group compared to thermal ablation group

In summary, our analysis demonstrates that denervation therapy may reduce pain and improve function in patients with symptomatic osteoarthritis of the knee.

Benefits/Harms of Implementation

There are no major known or anticipated harms associated with implementing this recommendation anticipated.

Outcome Importance

Pain and function improvement through denervation therapies for the treatment of knee osteoarthritis may have high impact on symptoms and overall health.

Cost Effectiveness/Resource Utilization

The cost-effectiveness of different denervation therapies is still to be determined, in comparison to other treatment strategies and among different denervation alternatives.

Acceptability

Currently denervation treatments are commonly utilized approaches in treating symptomatic knee osteoarthritis, hence there should be no issues implementing this recommendation as it does not influence a major change in clinical practice, and it provides further evidence to support and guide these practices.

Feasibility

These recommendations do not interfere with other interventions or clinical practice therefore it is deemed very feasible in patients with symptomatic knee osteoarthritis.

Future Research

Future research in this area should embrace detailed osteoarthritis characterization including sub-group analyses, osteoarthrosis severity stratification, and end stage disease in patients unable to have total knee arthroplasty (e.g. due to age or comorbities). Furthermore, using clinically relevant outcomes and controls for bias are warranted along with cost-effectiveness analysis.