Radiofrequency Energy vs. Mechanical Debridement of Patellar Chondral Lesions
Radiofrequency Energy vs. Mechanical Debridement of Patellar Chondral Lesions
Abstract & Commentary
Synopsis: At 2 years, bipolar radiofrequency energy had superior clinical outcome compared to mechanical debridement of patellar grade 2 or 3 chondral lesions.
Source: Owens BD, et al. Arthroscopy. 2002;18:151-155.
Mechanical debridement is an established treatment for patellar chondral lesions. Radiofrequency energy is a relatively new device that is able to smooth cartilage surface, and Owens and colleagues cite that bipolar radiofrequency energy is both safe and effective.1,2 The present study compared the clinical treatment outcomes of radiofrequency energy and mechanical debridement of patellar chondral lesions.
In a prospective, clinical study, 39 consecutive patients undergoing arthroscopy for symptomatic, isolated, patellar cartilage lesions were randomized into radiofrequency energy and mechanical debridement groups. All patients had failed conservative therapy, which included lifestyle modifications, a course of non-steroidal anti-inflammatory drugs, and physical therapy. Patients with evidence of instability, malalignment, or patellar tracking dysfunction were excluded. All patients were evaluated with preoperative plain radiographs, magnetic resonance imaging, and Fulkerson-Shea Patellofemoral Joint Evaluation Score.
The chondral lesions were characterized by grade and location, and patients with Outerbridge grade-4 lesions were excluded from the study. Standard mechanical debridement was performed with a mechanical shaver (Dyonics EP-1 Shaver, Smith & Nephew, Andover, Mass). The bipolar radiofrequency energy device (VAPR, Mitek, Westwood, Mass) was set at 20W in nonablative mode, and the side effect probe was passed over the lesion in a side-to-side motion until a smooth contour was visualized.
Nineteen patients (mean, 37.5 years) underwent chondral debridement using a mechanical shaver and 20 patients (mean, 36.9 years) underwent chondral debridement using bipolar radiofrequency energy. The preoperative scores were 59.2 for the mechanical debridement group and 59.6 for the radiofrequency energy group. At 12 months postoperation, the mechanical debridement group had a mean score of 80.0 and the radiofrequency energy group had a mean score of 87.9 (P = 0.0031). Postoperative scores at 24 months follow-up were 77.5 for the mechanical debridement group and 86.6 for the radiofrequency group (P = 0.0006).
Both groups demonstrated clinical improvement, but patients treated with radiofrequency energy had statistically significant improvement at 1-year follow-up and 2- year follow-up. Owens et al felt that radiofrequency energy was able to produce better long-term clinical results due to less destruction to surrounding healthy chondrocytes and to the production of a smoother rim of tissue. The present study presents superior clinical outcomes of patellar grade 2 or 3 chondral lesions with the use of bipolar radiofrequency energy vs. mechanical debridement.
Comment by Brian J. Cole, MD, MBA
Over the past several years, radiofrequency energy has received considerable attention for its use in thermal chondroplasty. At this point, the application of radiofrequency energy is investigational, and further studies are required before this treatment modality is acceptable in patients. Several studies have been published that demonstrate both monopolar and bipolar radiofrequency energy cause significant chondrocyte death when evaluated with cell viability staining and confocal laser microscopy. Bipolar devices can cause 2-3 times the depth of chondrocyte death, often to the level of subchondral bone, compared to monopolar devices.3,4 In an ovine model, the effects of monopolar radiofrequency energy were evaluated immediately and up to 6 months after treatment by scanning electron microscopy and confocal laser microscopy. These studies determined that the smooth surface and chondrocyte death at the time of treatment persisted throughout the evaluation period.5
It is thought that radiofrequency energy may improve the stability of damaged cartilage by reducing the release of proteoglycans and collagen fragments to ultimately slow the progression of joint degeneration. Interestingly, Owens et al observed that the improvement in clinical outcome was more or less preserved between the first and second years in the radiofrequency energy group but showed signs of deterioration in the mechanical debridement group. However, it is important to bear in mind that Owens et al used the bipolar radiofrequency energy on patellar lesions, and their results cannot necessarily be applied to other areas of the knee. The patella may prove to be a relatively safe area for this technology given its inherently thick cartilage surface. No postoperative MRIs were performed on these patients, which we believe would be a critical component to rule out any effect on the subchondral bone. Further basic science and long-term clinical studies are required to demonstrate the efficacy and safety of this treatment modality.
Author Acknowledgments: The reviewer would like to acknowledge Shane J. Nho, MS, for his assistance in preparation of this report.
References
1. Kaplan L, et al. Arthroscopy. 2000;16:2-5.
2. Turner AS, et al. Arthroscopy. 1998;14:585-591.
3. Edwards RB 3rd, et al. Am J Sports Med. 2002;30: 90-97.
4. Lu Y, et al. Arthroscopy. 2001;17:117-123.
5. Lu Y, et al. Arthroscopy. 2000;16:527-536.
Dr. Cole, Assistant Professor, Orthopaedic Surgery, Rush Presbyterian Medical Center, Midwest Orthopaedics, Chicago, IL, is Associate Editor of Sports Medicine Reports.
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