Multicenter, Prospective, Nonrandomized Study of Bipolar RF for the Treatment of Articular Cartilage Defects of the Knee (SS-20)

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Introduction: Bipolar radiofrequency-energy (bRFe) technology, including ablative devices, are gaining acceptance as a new method for treating articular cartilage lesions. These instruments operate via a novel mechanism that enables precise, controlled ablation of damaged cartilage. To date however, controlled clinical data about the safety and effectiveness of this approach have been lacking. The current study was undertaken to assess outcomes after bRFe articular cartilage surgery using Coblative devices. Methods: Nine U.S. sites participated in a prospective, nonrandomized study. Patients aged 18-60 with arthroscopically-documented partial-thickness chondromalacia of the knee were eligible for inclusion. Patients with full-thickness chondral lesions, osteochondral defects or preexisting osteonecrosis were excluded. Outcomes data using a modified Larson pain questionnaire and subjective evaluation of function and activity were collected at baseline, 3-6 weeks, 12 weeks, 6 months and 1 year. MRI evaluation was also conducted within a subset of the population at least 12 months postoperatively to provide more direct evidence about tissue effects, in particular, the presence or absence of osteonecrosis. Results: One hundred and ten patients were enrolled. Accompanying meniscal injury was present in 50% of the study population, while 39% presented with chondral disease alone. A total of 263 lesions were treated, of which 67% were located on the medial condyle or patella. Improvement in all measures of pain, function and activity were noted at every period of followup. Knee pain was significantly reduced compared to baseline at all intervals, with increasing improvement noted from the first follow-up assessment to the 1-year point. Similar improvements in function and activity level were also demonstrated. A comparable degree of improvement was demonstrated in patients with chondral disease only and those with other forms of concomitant knee pathology. The MRI substudy evaluated 25 patients. Subgroup outcomes analysis demonstrated that this sample was representative of the study population overall. No evidence of osteonecrosis was found in any of the MRI patients. Conclusion: BRFe articular cartilage surgery with ablative devices resulted in significant improvements in all measures of postoperative pain, function and activity. There were few adverse events and no cases of osteonecrosis. This method appears to be safe and effective for treating chondromalacia of the knee.