Radiofrequency chondroplasty is a technique where heat is used to remove the unstable edges of the defect producing a smooth, stable articular cartilage surface and slow the progression of discrete chondral defects.
Articular cartilage damage leads to fibrillation, delamination, and swelling of the cartilage due to increased permeability. This reduces its ability to absorb compressive load, and the roughened surface produces crepitus and pain. Untreated chondral lesions are known to progress in size and grade by mechanical wear.
The rough, irregular edges of a defect may cause inflammation, swelling, pain and difficulty walking. Progressive degeneration of a chondral defect can expose the underlying bone and lead to arthritis.
Chondroplasty has been shown to provide effective treatment of the pain associated with chondral damage. The aim of the procedure is to produce a smooth edge without damaging surrounding cartilage, and this has traditionally been performed with hand tools or a mechanical shaver.
However, the longevity of relief after mechanical chondroplasty can be limited. Moreover, it results in fine surface fibrillation of the remaining debrided cartilage after the procedure is completed
In partial thickness cartilage damage in a symptomatic joint, radiofrequency chondroplasty also known as coblation chondroplasty is a good option.
Principle of Radiofrequency Chondroplasty
In radiofrequency chondroplasty, small instruments (wands) that are used in the knee joint via arthroscopy, an electric current is passed through the electrodes in the wand. This current superheats the sodium ions in the saline that is washed through the knee when an arthroscopy is performed, creating a sodium plasma at the tip of the wand at temperatures over 3000 deg C. When passed close to the surface of damaged cartilage, the plasma melts the surface of the cartilage but without causing any thermal damage to the deeper layers of the tissue. This very effectively smoothes off the surface of rough damaged cartilage and stabilizes the damaged tissue.
The use of radiofrequency chondroplasty leads to tissue effect making it less permeable. An annealing effect decreases the permeability of the cartilage, and production of a neo-surface gives greater mechanical stability and resistance to cyclical forces.
Biochemical studies have shown a decrease in the release of inflammatory mediators, and histologic reports suggest that arthritic cartilage responds at a lower temperature, leading to the preferential removal of diseased tissue.
Smoothing off and properly stabilizing damaged articular cartilage surfaces does not make the cartilage grow back> But it leads to pain reduction and improvement of function, helps keeps patients’ knees going for longer and delays the potential need for future bigger operations like arthroplasty.
Technique of Radiofrequency Chondroplasty
The procedure is usually done with the patient under general anesthesia. An arthroscope is inserted into the knee and large chondral defects are trimmed from the weight-bearing surfaces of the femoral condyles, using instruments such as a blunt hook or an electric shaver. Under the arthroscopic guidance, a radiofrequency probe is then used to smooth the edge of the chondral defect using irrigation to stabilize temperature and flush any debris. The aim is to improve mechanical stability and prevent further cartilage damage.
Radiofrequency Chondroplasty is relatively new technique and continued work has increased our understanding of the use of radiofrequency chondroplasty.
Laboratory evidence suggests increased mechanical stability and decreased release of inflammatory mediators associated with the use of radiofrequency chondroplasty, and clinical evidence shows decreased pain scores postoperatively and increased functional scores in the short-term when compared with mechanical chondroplasty.
Still, the quality of evidence about efficacy and safety remains low. Until the long-term clinical outcomes and risks are better understood, the technique needs to be used with caution.