Determination of factors influencing tissue effect of thermal chondroplasty: an ex vivo investigation

The Arthroscopic Application of Radiofrequency in Treatment of Articular Cartilage Lesions

Articular cartilage lesion is a common disease to be treated by arthroscopic surgery. It will eventually progress to osteoarthritis without proper management, which can affect patients’ work and daily life seriously. Although mechanical debridement and laser have been used clinically for its treatment, due to their respective drawbacks, radiofrequency has drawn increasing attention from clinicians as a new technique with more advantages. However, the safety and efficacy of radiofrequency have also been questioned. In this article, the scope of application of radiofrequency was reviewed following an introduction of its development history and mechanism, and the methods to ensure the safety and effectiveness of radiofrequency through power and temperature control were summarized.

Thermal Chondroplasty Technique for Costal Cartilage Harvesting and Contouring

Although costal cartilage autograft has versatile usage, harvesting the graft is an invasive procedure with potential risks for complications. Therefore, it is important to make every effort to minimize these risks. Moreover, sculpting costal cartilage to the desired shape is challenging and time-consuming because of the natural rigidity. This study aimed to evaluate cases of costal cartilage harvest in terms of the most important donor site complications and to present a novel, practical and inexpensive technique to overcome the challenges in costal cartilage harvesting and contouring. A retrospective review of patient records was made of 103 patients who underwent costal cartilage harvest by the senior author. Costal cartilage harvest was applied using either the thermal chondroplasty technique or the conventional technique on patients undergoing revision rhinoplasty surgery. The number of complications and operation times were compared between the 2 techniques.A cohort of 47 patients (30 males, 17 females; mean age 34.5 years [range, 28-48 years]) underwent costal cartilage harvest using the thermal chondroplasty technique and a cohort of 56 patients (31 males, 25 females; mean age 36 years [range, 28-52 years]) underwent costal cartilage harvest with the conventional technique. The mean operation time for the costal cartilage harvest decreased by 7.5 minutes and the total operation time decreased by 17 minutes with the use of the thermal chondroplasty technique compared to the conventional technique (P < 0.05). Complications of 2 pneumothorax and 1 hematoma developed in the conventional technique group, and no complications were seen in the thermal chondroplasty group. The results of this study suggest that the thermal chondroplasty technique is safer and time-saving compared to the conventional technique.

UPDATING ON DIAGNOSIS AND TREATMENT OF CHONDRAL LESION OF THE KNEE

The treatment of chondral knee injuries remains a challenge for the orthopedic surgeon, mainly owing to the characteristics of the cartilage tissue, which promote low potential for regeneration. Chondral lesions can be caused by metabolic stimulation, or by genetic, vascular and traumatic events, and are classified according to the size and thickness of the affected cartilage. Clinical diagnosis can be difficult, especially due to insidious symptoms. Additional tests, as Magnetic Resonance Imaging (MRI), may be needed. The treatment of these lesions usually starts with non-operative management. Surgery should be reserved for patients with detached chondral fragments, blocked range of motion, or the failure of non-operative treatment. The surgical techniques used for the treatment of partial thickness defects are Debridement and Ablation. These techniques aim to improve symptoms, since they do not restore normal structure and function of the cartilage. For full-thickness defects (osteochondral lesion), available treatments are Abrasion, Drilling, Microfracture, Osteochondral Autologous and Allogeneic Transplantation, and biological techniques such as the use of Autologous Chondrocyte Transplantation, Minced Cartilage and stem cells.

Effects of radiofrequency energy on porcine articular cartilage: higher-power settings in ablation mode show lower thermal radiation injury

PURPOSE

The purpose of this study was to compare the radiofrequency (RF) injury effect on cartilage in the different settings that are mostly used in clinical work under rigidly controlled laboratory conditions.

METHODS

Twelve fresh porcine knees were used in our study. Five treatment areas were created on the femoral condyles of each knee: the control group, coagulation (setting 2) group, coagulation (setting 7) group, ablation (setting 2) group, and ablation (setting 7) group. Hematoxylin/eosin staining, dual fluorescence staining, and the GAG content were observed to evaluate the histological cartilage changes, vacuolar cell rate of chondrocytes, depth of chondrocyte death, and detection of GAG content.

RESULTS

Vacuolar cell rates of chondrocytes in each experimental group were higher than that in the control group (P < 0.05); there was no significant difference in vacuolar cell rate among experimental groups. Dual fluorescent staining showed that the ablation (setting 7) group had a smaller depth of cell death than did the coagulation (setting 2) group (P < 0.05); the other experimental groups showed no statistically significant difference (n.s.). In addition, there was no significant difference in GAG content between the experimental groups and control group (n.s.).

CONCLUSIONS

The coagulation mode results in heavier thermal radiation injury to chondrocytes than does the ablation mode. Higher-power settings in the ablation mode result in lower thermal radiation injury and may be most suitable for cartilage debridement.

The use of radiofrequency energy for arthroscopic chondroplasty in the knee

We present a review of the current literature surrounding the use of radiofrequency energy for arthroscopic chondroplasty in the knee. This review article summarizes basic science, clinical efficacy, and recent advances in the understanding of radiofrequency energy use for the treatment of chondral lesions. Laboratory evidence of increased mechanical stability and decreased release of inflammatory mediators associated with the use of radiofrequency energy chondroplasty is described with clinical evidence of decreased pain and increased functional scores when compared with mechanical chondroplasty. We re-examine concerns about the immediate side effects of radiofrequency energy use, including damage to local structures, in light of new potentially contradictory results, as well as the progression of techniques and probe design. However, although reported complications are few, because the quality of clinical evidence about safety and efficacy remains low, we suggest cautious and judicious use of this technology until future research has clearly defined the long-term clinical outcomes and risks.

Four-year results from a randomized controlled study of knee chondroplasty with concomitant medial meniscectomy: mechanical debridement versus radiofrequency chondroplasty

PURPOSE

This randomized study was undertaken to compare the effectiveness of simple mechanical debridement and 50 degrees C controlled bipolar chondroplasty.

METHODS

A total of 60 patients who had a grade III articular cartilage defect of the medial femoral condyle were included. After randomization, 30 patients underwent simple debridement of articular cartilage defects, which was performed with a mechanical shaver (mechanical shaver debridement [MSD] group). The remaining patients underwent thermal chondroplasty, which was performed with a temperature-controlled bipolar device with a constant thermo-application of a maximum of 50 degrees C (radiofrequency-based chondroplasty [RFC] group). All patients underwent partial (n = 41) or subtotal (n = 19) meniscectomy. Follow-up was undertaken 4 years postoperatively.

RESULTS

No significant differences between the preoperative findings for the 2 groups were observed. One patient from the MSD group had died, and one female patient in the RFC group was lost to follow-up. A total of 18 patients had undergone revision operations for persistent knee problems: in the MSD group, there were 8 endoprostheses, 4 osteotomies, and 2 revision arthroscopies, whereas in the RFC group, there was 1 replacement, 2 osteotomies, and 1 revision arthroscopy with subtotal medial meniscectomy. The proportion of revisions was significantly higher in the MSD group (P = .006). These patients were excluded from the evaluation. The remaining 40 patients from both groups benefited from the operation. The preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) was 11.3 points in the MSD group and 15.5 points in the RFC group (P = .279). Patients from the MSD group had a KOOS of 53.2 points at the time of follow-up. In the RFC group the KOOS (71.8 points) was significantly higher (P < .001).

CONCLUSIONS

Compared with classical mechanical debridement, bipolar radiofrequency currently appears to be the superior method for achieving a good midterm result.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

Arthroscopic knee chondroplasty using a bipolar radiofrequency-based device compared to mechanical shaver: results of a prospective, randomized, controlled study

Both mechanical shavers and radiofrequency-based devices are used to treat symptomatic partial thickness chondral lesions. Controversy exists as to which mode of treatment provides better outcomes. The purpose of this study was to compare clinical results after bipolar radiofrequency-based chondroplasty (RFC) to mechanical shaver debridement (MSD). Patients (n = 60) included in the study presented with knee pain associated with a medial meniscus tear and idiopathic ICRS grade III defect of the medial femoral condyle. Patients who had osteoarthritis, grade II or higher cartilage defects of the tibial joint surface, the lateral compartment, or the femoro-patellar joint, or had previously undergone surgery on the affected knee were excluded. Patients underwent partial meniscectomy; during the procedure, they were randomly assigned to receive bipolar RFC (Paragon, ArthroCare Corporation, Austin, TX) or MSD (Full radius resector LR 4.85 x 12.5 cm), Arthrex, Naples, FL). Postoperatively, the same physiotherapist provided instructions for a daily 2-h home training program consisting of isometric, isotonic, and leg lifting exercises; patients were provided the option of using crutches. Clinical outcomes were assessed using the Tegner score, visual analogue scale (VAS) score, and Knee and Osteoarthritis Outcome Score (KOOS) assessment, which consists of five principal domains including pain, symptoms, function in daily living (ADL), and knee related quality of life (QOL), where a score of 0 indicates extreme symptoms and 100 represents no symptoms. Age and time from injury onset did not differ significantly between the RFC and MSD groups (43 +/- 10 vs. 44 +/- 9 years, P = 0.732; 8 +/- 3 vs. 7 +/- 4 months, P = 0.279). No complications or adverse events were observed. Preoperatively, mean (+/-SD) scores for all KOOS principal domains were <20 and did not differ significantly (P > 0.05) between treatment groups. Postoperatively, the RFC patients returned to activity significantly earlier than MSD patients (17 +/- 7 vs. 22 +/- 6 days, P = 0.002). VAS pain scores at 6 h, 24 h, 6 weeks, and 1 year were significantly (P < 0.001) lower for the RFC group than for the MSD group (4 +/- 2, 2 +/- 0.5, 2 +/- 1, 2 +/- 1 vs. 8 +/- 1, 4 +/- 1, 4 +/- 1, 3 +/- 1, respectively). At 1 year, RFC patients had significantly better Tegner score (4.1 +/- 0.8 vs. 2.8 +/- 0.6, P < 0.001) and KOOS domain scores for pain, symptoms, ADL, QOL, respectively (81.1 +/- 8, vs. 59.4 +/- 12.8; 80.7 +/- 7.5 vs. 59.6 +/- 7.5; 81.5 +/- 6.5 vs. 60.1 +/- 6.9; 80 +/- 10 vs. 61.3 +/- 12.5; P < 0.001) than MSD patients. Significantly fewer RFC patients (2% vs 23%, p = 0.026) reported using NSAIDS for knee pain at 1 year. Patients undergoing radiofrequency-based chondroplasty for ICRS grade III medial femoral condyle chondral lesions in conjunction with partial meniscectomy had significantly better clinical outcomes through 1 year than patients with similar pathology receiving chondral debridement using the mechanical shaver.

Ex vivo comparison of mechanical versus thermal chondroplasty: assessment of tissue effect at the surgical endpoint

PURPOSE

The purpose of this study was to evaluate tissue effect (tissue removal plus underlying cell death) of two chondroplasty techniques: mechanical debridement (MD) using a rotary shaver blade and thermal chondroplasty using radiofrequency energy (RFE).

METHODS

Forty-eight human chondromalacic cartilage samples were treated with either MD or RFE. Pre- and post-treatment arthroscopic images of the cartilage surface were recorded. Samples were incubated with cell viability stain and visualized with confocal laser microscopy to determine tissue effect. Smoothing was quantitated by three surgeons using a visual analog scale (VAS) as well as a subjective rating regarding whether smoothing was "arthroscopically acceptable."

RESULTS

Tissue effect at the surgical endpoint of arthroscopically acceptable smoothing was 385 microm for MD versus 236 microm for RFE, a significant difference (P < .0001). Mean post-treatment VAS for MD was 2.8 points less smooth than for RFE (P < .0001). Overall, arthroscopically acceptable smoothing was achieved in 90% of RFE samples compared to 49% of MD samples.

CONCLUSIONS

Our results shown that chondroplasty using a RFE probe results in greater smoothing of chondromalacic cartilage in fewer treatment passes and with decreased total tissue effect than MD using a rotary shaver blade.

CLINICAL RELEVANCE

If safety and efficacy can be shown in vivo, thermal chondroplasty may represent an alternative for treatment of symptomatic chondromalacia.

Mechanical chondroplasty: early metabolic consequences in vitro

PURPOSE

The purpose of this study was to determine the depth of penetration from mechanical chondroplasty and metabolic consequences of this procedure on the remaining articular cartilage.

METHODS

Mechanical chondroplasty was performed in vitro on a portion of fresh grade I or II articular cartilage from 8 human knee arthroplasty specimens. Treated and control (untreated) explants (approximately 30 mg) were cut from the cartilage. The explants were divided into 2 groups, day 1 and day 4, placed separately in a 48-well plate containing media, and incubated at 37 degrees C for 24 hours. After the 24-hour incubation, the explants were weighed on day 1 and day 4, and explant media were removed and tested for total proteoglycan synthesis and aggrecan synthesis. At time 0, 2 sets (2.6 mm each) of treated and control cartilage slices were cut with a precision saw. One set was stained for confocal laser microscopy via a cytotoxicity stain to determine cell viability. The second set was stained with H&E to determine depth of penetration.

RESULTS

The mean depth of penetration was 252.8 +/- 78 microm. There was no significant difference (P > .25) between total proteoglycan synthesis for control versus treatment groups on day 1 or 4. Aggrecan synthesis was significantly reduced on day 1 when normalized for tissue weight (P = .019) and double-stranded deoxyribonucleic acid (P = .004). On day 4, no significant difference was detected. Confocal laser microscopy did not show cell death below the zone of treatment.

CONCLUSIONS

There was no significant metabolic consequence caused by chondroplasty to the remaining articular cartilage, and the zone of injury was limited to the treatment area.

CLINICAL RELEVANCE

Mechanical chondroplasty causes no significant metabolic consequences to articular cartilage under these conditions.