The results of a retrospective chart review suggest that the use of plasma-mediated bipolar radiofrequency-based arthroscopic microdebridement is associated with notable decreases in self-reported ankle pain in patients who have tried conservative treatments without success.
By Renato Giorgini, DPM, FACFAS; Stephanie Giles, DPM; Omer Aci, DPM; and Christopher Japour, DPM, MS
Transcutaneous procedures to remove loose bodies or section synovial folds to reduce joint pain have traditionally been performed by arthroscopists.1 The first documented intra-articular observation of a cadaveric knee was performed using a cystoscope by Takagi in 1918.2 Arthroscopy came somewhat later in 1922, when Bircher described knee meniscal injury using the Jacobian laparoscope.3 Bircher believed, based only on cadaver experiments, the knee was the only joint suitable for examination because of its size. Using an arthroscope in 1931, Burman described the appearance of almost every major joint in the body.4 He noted the ankle was difficult to evaluate because the joint space was too narrow and the talar dome was too convex for viewing. Takagi in 1939 was able to perform arthroscopy on smaller joints, including one flail ankle.2
There was a renewal of interest in the benefits of joint arthroscopy in the 1960s and early 1970s. Watanabe performed the first resection of meniscal tissue by arthroscopic control in 1962.5 Jackson and Dandy had advocated a partial meniscectomy by arthroscopic means, or, if that was not technically possible, open arthrotomy.6 O’Connor developed instrumentation and an arthroscopic technique for the resection of meniscal tissue.7 Metcalf reported more than 600 arthroscopic partial meniscectomies with uniformly good technical results.8 Chen was also able to perform ankle arthroscopy on 67 patients and reported 94% of arthroscopic diagnoses were confirmed by arthrotomy.9 Currently, with state-of-the-art instrumentation, ankle arthroscopy has been shown to be highly accurate for treating and diagnosing ankle lesions.10,11
Initially, arthroscopic methods involved a transcutaneous procedure performed under direct arthroscopic visualization, with manual tools for biting and cutting tissue in larger joints such as the knee. The multiple passes were sometimes problematic because of “scuffing” of the articular surfaces, even with a smooth instrument. Hence, development of powered instrumentation was the next step to make arthroscopic surgery a viable, useful technique.12-15 The first such model was a hand-operated, battery-powered, unidirectional, rotating-cutting suction device.16 The system was then modified to feature a foot-pedal control with reverse and forward cutting modes. This had a definite advantage over the single mode of rotation in that folded intra-articular tissue could be more effectively addressed from the opposite direction by reversing the rotation. This cutting burr was safe and useful. Patients were experiencing remarkable relief from crepitus, as well as the elimination of pain and effusion,17 but the inability to cut deeply on the articular tissue was discouraging. Improved cutting was achieved in 1978 with a keyhole-shaped burr design and the subsequent development of the cutter.18
Recent arthroscopic advancements using radiofrequency ablation have made the procedure even less traumatic to surrounding tissues. The operating principle of radiofrequency-based microdebridement technology is similar to conventional electrosurgical systems in that voltage difference is maintained between the active and return electrodes. The system uses an electrical conductive fluid, such as isotonic saline, in the physical gap between the active electrodes and the target tissue.19 When the system applies a voltage signal with a frequency of 100 kHz and sufficiently high voltage levels (between 100 V and 300 V), the conductive fluid is converted into ionized water and plasma in the small intervening gap.
The first commercial use of radiofrequency ablation technology in arthroscopic surgery was reported in 1995, and many cases have been reported since, including chondroplasties, partial meniscectomies, meniscal tears, repairs, and ligament reconstructions.20 However, its use remains uncommon in smaller joints such as the ankle. A few radiofrequency ablation studies have evaluated the technique for relief of pain from plantar fasciitis/fasciosis. Results of these early studies suggest radiofrequency-based technology may be an effective treatment for fasciitis/fasciosis because it induces an angiogenic response to promote healing and reduction of pain in chronically inflamed and injured tissue.21,22
We conducted a retrospective patient chart review to evaluate the effectiveness of radiofrequency ablation of dendritic synovitis used in conjunction with ankle arthroscopy for reducing chronic ankle pain.
Institutional Review Board (IRB) approval was obtained before commencement of this retrospective single-center study of patients who underwent ankle arthroscopy using radiofrequency-based microdebridement between 2004 and 2012. The first author performed outpatient surgery. Patients selected for the review had not responded to six months or more of conservative treatment for their ankle pain symptoms. They were selected for the study to determine the procedure’s effectiveness in terms of pain-free or less painful ambulation.
Patients included in the study were aged 16 years or older at the time of surgery and had undergone conservative therapy that included rest, stretching, strengthening exercises, nonsteroidal anti-inflammatory drugs, and steroid injections. Patients had at least six months of documented postoperative follow-up and were asked to rate their overall pain on ambulation using a visual analog scale (VAS) at each visit.23
Exclusion criteria included diabetes, confirmed or suspected pregnancy, coagulopathy, infection, tumor, peripheral vascular disease, autoimmune disease, or other systemic disease. Also excluded were those who had previous ankle arthroscopy using a mechanical debridement device, a history of ankle infection in the six months before surgery, or ankle injections of hyaluronan. Patients who were undergoing litigation, receiving care from worker’s compensation, or participating in a related study were also excluded.
The body mass index (BMI) for patients was calculated using the patient’s height and mass at the time of the preoperative surgical evaluation. The BMI was used to determine obesity, overweight, and healthy weight as calculated by the National Institutes of Health.24,25 Patients with BMIs greater than 30 kg/m2 were considered obese, those with BMIs between 25 and 29.9 kg/m2 were considered overweight, and patients between 18.5 and 24.9 kg/m2 were considered healthy weight.
The patient was positioned supine on the operating room table, per the request of the surgeon of record. The thigh was then placed in a well-padded knee holder, and an ankle tourniquet was applied approximately 2 cm proximal to the affected ankle. Anesthesia consisted of intravenous sedation, and an ankle block was performed at the operative site using approximately 20 cc of lidocaine 1% plain. (General anesthesia alone may be used as an alternative means of sedation but was not for the reported cases.) The ankle was then prepared and draped in the usual sterile manner. Attention was directed to the affected ankle joint, which was anatomically marked and extra-articular structures identified.
Normal saline was injected at the lateral gutter of the ankle joint using a 50-ml syringe and an 18-gauge 1.5-inch needle. The joint was distended and a stab incision made over the portal of entry. The arthroscope cannula, fitted with a sharp trocar, was used to pierce the soft tissue and capsule. It was then replaced with a blunt device (an obturator) to further stretch the joint capsule and prevent injury to healthy intra-articular soft tissue. The obturator was then removed and a 2.7-mm cannula with camera and light source inserted to visualize the joint, using an anterior-central approach. While visualizing the joint, a second cannula was introduced for insertion of other instruments, such as biopsy forceps, probes, power abraders, or radiofrequency ablation wand. This method of joint visualization with accession is known as the triangulation technique.
The arthroscope was swept through the joint and a standard nine-point check was made to visually evaluate the deltoid ligament, medial gutter, medial talus, central talus, lateral talus, talofibular articulation, lateral gutter, anterior gutter, and the central tibiotalar articulation (Figure 1). At this point the joint was ready for treatment with the microtenotomy wand.
The hypertrophic synovitis, or synovial accumulation in the medial and lateral gutters as well as the proximal joint space, was removed using a radiofrequency microtenotomy wand. The ankle joint was then irrigated with copious amounts of normal saline under pressure, and debris was removed with a vacuum. Once the area was clear, all lesions were lysed and abrasion chondroplasty was performed.
The difficulty of assessing the lateral gutter area with the arthroscope requires a small 3-cm incision in an “S” shape, performed at the lateral gutter using a #15 blade, to obtain visualization of the lateral ankle joint. The ankle joint was copiously irrigated with sterile saline. The skin incision was then reapproximated, first closing deep structures with 3-0 Vicryl, subcutaneous tissues with 4-0 Vicryl, and the skin with 4-0 nylon.
A conforming bandage was applied to the operative site, followed by a short-leg nonweightbearing fiberglass cast. The cast and sutures were removed seven to 10 days postoperatively, and a conforming dressing was applied. During postoperative week four, after the edema had reduced, physical therapy was initiated, consisting of whirlpool, ultrasound, and progressive resistance exercises. Therapy was performed twice each week, ideally for one month or more as needed.
Twelve patients (eight women) with an average age of 46.8 years (range 16-63 years) had arthroscopic surgery (Table 1). The average patient BMI was 33.9 kg/m². Seven were obese, three overweight, and two healthy weight.
Patients presented with multiple intraoperative findings. The most common were chronic synovitis, lateral impingement syndrome, and osteochondritis dissecans of the talus. All ankles had hypertrophic synovium, and several had various subchondral osteochondral defects. The arthroscopic intraoperative findings tended to reveal pathology that was not observed clinically or radiographically. For example, many patients with chronic nonspecific ambulatory pain and negative ankle x-rays were observed to have osteochondral defects, including osteochondritis dissecans, during the arthroscopic procedure. All patients completed the physical therapy sessions, which were part of the postoperative office visits.
Six months postprocedure, pain in the overall cohort compared with baseline had improved by an average of 4.5 points on a 10-point VAS (Table 1). Pain improved by an average of four points in the obese patients, 6.6 points in the overweight patients, and three points in the healthy weight patients.
Arthroscopy reduces sources of inflammation by removing loosened and fragmented intra-articular cartilage, bone, and soft tissue that impede ankle joint range of motion. Ultimately the goal is to allow the ankle joint to function pain free. The development of an arthroscopic mechanical debrider historically has given surgeons the option of a less-traumatic technique than the earlier standard of care, open ankle arthrotomy. Further development of arthroscopic equipment has led to development of instrumentation that is less traumatic to surrounding tissues than the mechanical debrider.
Patients in our study were arthroscopically found to have osteochondral talus defects, talus fractures, osteochondritis dissecans of the talar dome, degenerative joint disease of the lateral gutter, and medial groove erosions. These osteochondral findings were undetected by x-ray in this chart review.
Obese and overweight patients six months postoperatively had greater decreases in pain than healthy weight patients.26 Degenerative joint disease is more prevalent in obese patients than those of normal weight, and is thought to be due to greater joint loading forces.26 Hypothetically, obese and overweight patients have more joint pathology and inflammation, hence, when these are arthroscopically removed, pain symptoms decrease.27 However, it’s also possible that the healthy weight patients were more active than the others; if so, even if their pain during low-impact activity was similar to that of heavier patients, they might have had more pain overall because they were participating in more challenging activities.
Weight in obese patients increases stresses on the ankle joint during weightbearing, putting extra pressure on the surrounding bone and soft tissue. Excessive impact loading on ankle bone from obesity, blunt trauma, and microtrauma pressure is thought to cause an indirect inflammatory osteoarthritic response.28 High internal stress also can create microfractures of the bone trabeculae, weakening the superstructure, as well as creates cracks and fissures of the overlying cartilage. The response to these conditions is osteochondral destruction, inflammation, and pain.29 This extra pressure potentially exacerbates the inflammatory process, causing a painful ankle and affecting arthroscopic treatment outcomes.
Cellular trauma is associated with the release of interleukin 1 (IL-1), which stimulates fibroblast synovitis. The fibroblastic synovitis then proliferates and secretes metalloproteases, prostaglandins, and cytokines—all markers of inflammation.30,31 These inflammatory effects are modified by receptor antagonist IL-1RA, of which two structural variants exist.32 The first type is produced by macrophages, and the second type is produced by keratinocytes or other epithelial cells. Both types reproduce simultaneously. In addition, transforming growth factor beta (TGF-β) has been shown to modify IL-1.32
In describing lateral impingement syndrome pain, Fallat et al suggested the hypertrophic synovium is compressed by the talus and fibula, causing increased irritation and inflammatory processes, affecting synovial tissue growth.12 The result is chronic lateral ankle pain. Guhl suggested excessive stress on bone or trauma causes an intra-articular hematoma that is reabsorbed slowly, ultimately by macrophages, and results in a reactive synovitis.29 Meniscoid bodies are composed of capsule, ligament, and synovial tissue and are indicators of advanced stage of ankle joint destruction.33 Both osteoarthritis (OA) and rheumatoid arthritis (RA) are joint destructive processes commonly involving the bone and the soft tissue including ligaments and cartilage, though OA and RA differ in mechanisms.34
Just as important as the procedure is postoperative physical therapy, which can include continuous passive range of motion (CPM), supervised exercise, and therapeutic modalities.
O’Driscoll and colleagues found that CPM effectively accelerates clearance of joint hemarthrosis; in contrast, hemarthrosis slowly cleared from immobilized joints was associated with synovial hypertrophy, intra-articular adhesions, and joint stiffness. It is believed that synovial hyperplasia results in the production of proteolytic enzymes and cartilage destruction.35 Evidence suggests CPM therapy promotes reorientation of blood vessels to a normal state and increases tendon sheath repair.36
Saxena and colleagues reported that the most efficacious method of promoting an expedient and functional recovery after foot surgery is through physical therapy instructional exercises.37 Modalities such as heat, ultrasound, and paraffin wax often have temporary analgesic effects with increased range of motion. This increase in activity and exercise can help to improve extrinsic muscle strength and prevent muscle atrophy.38,39
The results of this retrospective chart review suggest plasma-mediated bipolar radiofrequency-based arthroscopic microdebridement can successfully treat painful ankle joints when conservative treatments fail. Obese and overweight patients had larger reductions in pain level compared with healthy weight patients given the same surgical and postoperative protocol, presumably because more arthritic pathology was removed.
This study was limited because of the small number of cohort patients reviewed. A foot and ankle scoring system also could have been used to measure activities of daily living in addition to a pain VAS.
Renato Giorgini, DPM, FACFAS, is podiatry residency director; Stephanie Giles, DPM, is a podiatry resident; and Omer Aci, DPM, is a podiatry attending at Good Samaritan Hospital Medical Center in West Islip, NY. Christopher Japour, DPM, MS, is section chief and residency director in the Department of Surgery/Podiatry Section at the VA Illiana Health System in Danville, IL.
Authors’ note: Dr. Giorgini died in 2015. He saw that his patients benefited from radiofrequency-based arthroscopic microdebridement and would have been pleased by the publication of this manuscript.
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- Sean NY, Singh I, Wai CK. Radiofrequency microtenotomy for the treatment of plantar fasciitis shows good early results. Foot Ankle Surg 2010;16(4):174-177.
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