Dorsal Root Ganglion Stimulation for the Treatment of Arthritic Knee Pain

Dorsal root ganglion stimulation (DRG-S) is a novel form of neuromodulation used to treat chronic neuropathic pain of the groin and lower extremities related to complex regional pain syndrome type I or II (causalgia). DRG-S has shown promise in treating traditionally mixed neuropathic and mechanical pain syndromes such as axial low back pain, suggesting DRG-S may be able to treat mechanical pain in addition to neuropathic pain. Additionally, in a rodent model of osteoarthritis of the knee, DRG-S alleviated pain related behavior in rats.

This open label feasibility study seeks to evaluate if dorsal root ganglion stimulation with Abbott's Proclaim Dorsal Root Ganglion Neurostimulator System can effectively treat osteoarthritis of the knee. Patients with either osteoarthritis of the non-operated knee or osteoarthritis of the surgically repaired knee will be trialed for one week with dorsal root ganglion stimulation to determine if they positively respond with 50% or greater pain relief. For those patients that have a successful trial, they will be implanted with a permanent stimulation device system and followed for one year post implant to measure knee pain, function and disability, and other related outcomes with sustained DRG-S therapy.

Patients will be seen and evaluated prior to DRG-S trial, and for those that receive permanent implants, re-evaluated at 1, 3, 6, 9 and 12 months after implant.

Inclusion criteria

• Age >= 21 years old
• Able to provide informed consent
• Primary complaint of chronic knee pain for at least 1 year that interferes with functional activities
• Current pain score on visual analog scale (VAS) intensity ≥60 mm
• One of two groups: 1) Non-operated knee pain patients who want to pursue alternative therapies and delay surgery or are not candidates for knee arthroplasty based on age, frailty, non-operable condition, or poor outcome with other side arthroplasty, or 2) Post traumatic knee pain patients with history of surgical repair (such as meniscal or ligament repair).
• Radiologic confirmation (x-ray/MRI/CT) of Kellgren-Lawrence OA grade of 2 (mild) or 3 (moderate) or 4 (severe) noted within 6 months for the index knee
• Continued pain in the target knee despite at least 3 months of conservative treatments with documented failure of physical therapy and standard conservative therapy, including trials of at least two different classes of analgesic medication
• Failure of one or more prior interventional pain procedures such intraarticular corticosteroid or hyaluronidase knee injections, cooled radiofrequency ablation therapy, or regenerative medicine or prior surgery of the knee

Exclusion criteria

• Non-English speaking
• Douleur neuropathique 4 (DN4) score ≥4
• Receiving opioid analgesic medication at a dose of ≥90 mg oral morphine equivalents
• Workers' compensation or no-fault insurance
• Signs or symptoms of active infection in the index knee joint
• Pregnancy
• BMI >45
• Presence of any contraindication for DRG stimulation, including neurological, medical, psychiatric, or social conditions.
• Widespread pain conditions like fibromyalgia
• Autoimmune/Inflammatory arthritic conditions such as Rheumatoid and psoriatic arthritis and other allied disorders (sjogren, felty, inflammatory bowl disease etc)
• Collagen diseases (systemic lupus erythematosus, Scleroderma, etc)
• Infectious arthritis
• Evidence of prespecified joint safety conditions (eg, rapidly progressive OA, subchondral insufficiency fracture, osteonecrosis, pathologic fracture) in the index knee on screening radiographs
• Scheduled for or anticipating any surgery during the trial period