Degenerative knee osteoarthritis pain is one of the main reasons for consultation in
general and specialized medicine. Its assessment and treatment impose a high cost on
healthcare systems, accounting for 0.5% of Spain's gross domestic product. Given the
magnitude of the disease and the disability it causes in affected individuals, multiple
therapies have been proposed, ranging from pharmacological therapy with nonsteroidal
anti-inflammatory drugs, opioids, antidepressants, capsaicin cream treatment, and
physiotherapy, to intra-articular treatments with corticosteroids and viscosupplements
like hyaluronic acid, platelet-rich plasma, etc. Knee arthroplasty is one of the most
successful orthopedic surgeries in current medicine, significantly improving pain,
disability, and the overall quality of life for patients who undergo it. However,
postoperative pain following knee arthroplasty remains a challenging problem, with
incidence rates of pain and disability after the procedure ranging from 48% to 34%,
respectively, at 3 and 6 months post-surgery, with iatrogenic nerve injury being the most
common cause. There are limited therapeutic alternatives available from this point
onwards.
Since the first description of using radiofrequency for the treatment of intractable
chronic pain, it has become not only a tool for pain management but also a cornerstone in
pain units' treatment. The use of radiofrequency ablation for pain is based on the
premise that the transmission of radiofrequency current near nociceptive pathways would
interrupt the pain stimulus through the destruction of the nervous tissue. Thermal
radiofrequency has been successfully used in the treatment of facetogenic low back pain,
sacroiliac joint pain, and discogenic low back pain.
In the year 2011, the first study was conducted on radiofrequency of the sensory nerves
of the knee, known as the genicular nerves, using femoral and tibial condyles as
anatomical references and fluoroscopy as an imaging guide. Unfortunately, discrepancies
in terminology and anatomical descriptions have led to confusion among interventional
physicians. Other researchers have demonstrated discrepancies with the studies published
in 2011, making it more difficult to standardize the technique of neuroablation of these
nerves. More recently, other researchers demonstrated a specific anatomical-ultrasound
correlation of sensory terminal branches of the femoral and sciatic nerves that innervate
the knee. The involved nerves include the infrapatellar branch of the saphenous nerve,
the nerve to the medial vastus muscle, the nerve to the intermediate vastus muscle, the
nerve to the lateral vastus muscle, the anterior branch of the obturator nerve, the
recurrent peroneal nerve, and the lateral retinacular nerve.
Study justification:
Post-knee arthroplasty pain remains an unresolved problem, with various techniques
applied to different anatomical targets yielding inconsistent results. To date, no
studies have addressed post-knee arthroplasty pain through the application of thermal
radiofrequency on sensory branches of the femoral nerve, namely the infrapatellar branch
of the saphenous nerve, nerve to the medial vastus muscle, nerve to the intermediate
vastus muscle, and nerve to the lateral vastus muscle guided by ultrasound.
Therefore, The investigators propose to conduct a randomized double-blind clinical trial
where The investigators will apply thermal radiofrequency on the sensory terminal
branches of the knee from the femoral nerve, including the medial vastus nerve, lateral
vastus nerve, intermediate vastus nerve, and infrapatellar branch of the saphenous nerve.
Hypothesis:
Patients who receive radiofrequency ablation would experience a percentage reduction of
at least 50% in baseline pain and disability at 3 months, which The investigators
consider a clinically significant effect.