Non-invasive Procedure Found to Be Superior to Steroid Injection for Knee OA
Cooled radiofrequency ablation (CRFA) provides better pain reduction and functional improvement than steroid injections in patients with knee osteoarthritis (OA), according to a study published online by Regional Anesthesia & Pain Medicine.
Intra-articular steroid injections are commonly offered to patients with knee OA that has not advanced enough to justify total knee replacement, but they provide only short-term pain relief. In addition, steroids may have adverse effects on cartilage over time.
The study authors evaluated CRFA as an alternative to steroid injection in 151 patients with chronic pain from knee OA. These patients had experienced knee pain for an average of 10 years. They were randomly assigned to undergo CRFA or steroid injection.
The non-invasive CRFA procedure uses radiofrequency energy to interrupt pain transmission by the genicular nerve of the knee. Before the procedure, a local anesthetic nerve block is performed to confirm that numbing the genicular nerve reduces the patient’s knee pain. Cooled radiofrequency ablation is performed on an outpatient basis, with local anesthesia and minimal sedation.
In this study, patients undergoing CRFA had significant and lasting reduction in pain scores – from 7 (on a 10-point scale) before treatment to about 3 in the CRFA group and 4 in the steroid group 1 month after treatment.
With further follow-up, pain scores remained lower in the CRFA group but increased toward the pre-treatment level in the steroid group. At 6months, 74% of patients assigned to CRFA had at least a one-half reduction in pain scores, compared with 16% of those undergoing steroid injection.
Forty percent of patients in the CRFA group rated their knee function as “satisfactory” at 6 months after treatment, compared with just 3% of patients in the steroid group. Ninety-one percent of patients in the CRFA group felt their overall health had improved, compared with 24% of patients in the steroid group.
Patients undergoing CRFA had greater reduction in the use of conventional, non-opioid pain medications. There was no significant difference in opioids, which were used by a minority of patients in both groups. There were no serious treatment-related adverse events in either group.
The results suggest that CRFA provides “clinically meaningful” pain reduction and functional improvement in patients with knee OA, with better and longer-lasting improvement than steroid injection. The authors are planning longer follow-up to assess outcomes at 1 year and beyond. They said that pain may return as the treated nerve regenerates; if so, repeating the CRFA procedure is a “reasonable and sensible” option.
Davis T, Loudermilk E, DePalma M, et al. Prospective, multicenter, randomized, crossover clinical trial comparing the safety and effectiveness of cooled radiofrequency ablation with corticosteroid injection in the management of knee pain from osteoarthritis. Reg Anesth Pain Med. Author corrected manuscript published online ahead of print on November 1, 2017. doi: 10.1097/AAP.0000000000000690