Radiofrequency Chondroplasty

Introduction

Articular cartilage damage in the knee is an extremely common problem. When the articular cartilage is completely worn off the surface of the bones in the knee and there is widespread bare bone exposed, then this is ‘arthritis’ – and if the symptoms are severe then in older patients this is best treated by artificial joint replacement surgery.

The issue comes when there is just partial thickness cartilage damage in a symptomatic joint, where the damage is not actually severe enough to contemplate major surgery such as a joint replacement. There is an answer, which is a highly useful and effective option for many patients, and this is radiofrequency chondroplasty (otherwise know as coblation chondroplasty).

What is RF?

 

Coblation chondroplasty was developed by a company called Arthrocare. They have developed small instruments (wands) that can be used in the knee via keyhole surgery (arthroscopy). These wands have electrodes in their tip; an electric current is passed through the electrodes in the wand and this superheats the sodium ions in the salt water (saline) that is washed through the knee when an arthroscopy is performed. This creates a sodium plasma at the tip of the wand. This plasma field is very small and contained, but extremely hot – 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 – much like using a blow torch to tidy up flaky paint peeling off a rusty gate. In particular, the Arthrocare wands are, in my opinion, by far the best wands of their type on the market, because many of the wands made by other companies can potentially heat the adjacent tissues significantly, which can actually cause tissue damage. The Arthrocare wands, however, have a far more focal effect and the temperatures that the surrounding cartilage tissue is subjected to are far lower, with alarms that go off if the temperatures reach even quite low raised levels (e.g. 42 deg C). The term ‘coblation’ comes from the fact that the wands can ablate tissue and also coagulate tissue too.

 

 

Arthroscopic intra-operative video showing rough unstable partial thickness articular cartilage damage on the back a patella.

 

Video showing the unstable chondral tissue being treated with a minimal amount of careful delicate ‘abrasion chondroplasty’, with an arthroscopic shaver.

 

The use of an Arthrocare radiofrequency probe for coblation chondroplasty, to smooth off and stabilise the damaged articular cartilage surface.

Does it cause 'damage'?

Some less well-informed people seem somehow ‘scared’ of the potential for the cartilage cells to be ‘fried’, burnt and killed by the use of coblation wands. However, studies have shown that the depth of cell necrosis from coblation chondroplasty is no greater than about 200microns (just 1/5th of a millimeter!), which is only half the depth of the cell damage that is actually caused by an arthroscopic shaver – a tool that is used regularly in knee arthroscopic surgery by many surgeons. Also, arthroscopic shavers leave cartilage surfaces rough and can only stabilize unstable surfaces by aggressively removing large amounts of tissue. Studies have demonstrated quite clearly and definitely that coblation chondroplasty causes less damage than an arthroscopic shaver and gives better clinical results.

Smoothing off and properly stabilizing damaged articular cartilage surfaces does not make the cartilage grow back (articular cartilage has no blood supply and thus has extremely poor healing/regenerative capacity); however, it does reduce knee pain, thereby improving function, and it helps keeps patients’ knees going for longer, delaying the potential need for future bigger operations.

What are the uses of RF in a knee?

Radiofrequency wands have several other very handy potential uses inside a knee, and they are invaluable during knee arthroscopy for the following:-

• The wands are the ideal size and shape for reaching tight and narrow areas in the knee that are otherwise difficult to reach with larger instruments such as arthroscopic shavers or meniscal punches (tiny scissors). This means that the wands are perfect for tidying up ragged tears of the posterior horn of a meniscus in tight knees.

• I also regularly use the wands to weld over horizontal tears/splits in a meniscus, which means that the meniscal tear can be repaired and the tissue salvaged rather than having to chop out meniscal tissue with a trim (meniscectomy).

• If a partial meniscectomy has been required, then I use the Arthrocare wand to smooth off the surface of the trimmed meniscus. This leaves the surface much smoother and more stable.

• The wands are ideal for getting rid of torn ligament tissue in a knee, for example from an ACL tear, leaving the knee as tidy as possible, and I always use the wands during ACL reconstruction surgery.

• The wands are perfect for clearing away excess articular cartilage edges when making the gap in the middle of the joint bigger to allow more room for an ACL graft (a notchplasty) – in conjunction with tiny arthroscopic burrs.

• The probes can also be used for techniques such as an arthroscopic lateral release.

• Finally, the wands actually have two modes: the first mode is ablation, which melts/evaporates the surface of tissues. The second is coagulation. This is where the wand can be used like a diathermy probe, to cauterize any small bleeding vessels within the joint during the arthroscopy. This allows us to trim tissue such as inflamed plicae that have a very good blood supply, coagulating vessels as we go. Doing this properly and taking due time significantly reduces the likelihood of post-operative bleeding into the knee, reducing the likelihood of post-operative pain and swelling. In fact, the Arthrocare wand is so effective for coagulating vessels that I no longer need to use a tourniquet on the thigh (to stop bleeding) when performing knee arthroscopies.

What I really think

Frankly, it amazes me that there are still a significant number of alleged ‘specialist knee surgeons’ out there who, despite the evidence available in the scientific literature, still don’t actually perform radiofrequency coblation chondroplasty. When I asked one surgeon why he doesn’t use coblation wands, his answer was “it’s too slow”!?!? …. So, he clearly considers speed to be more important than quality – which, quite frankly, is nothing less than despicable as well as being shoddy! Personally, if an Arthrocare wand was not available in theatre when I was due to perform a knee arthroscopy then I would actually cancel the case rather than proceed knowing that if the wand was needed but not available then I’d be ending up doing a second-rate sub-standard job! … And would I never allow a knee surgeon to operate on my knee if they didn’t routinely use coblation wands!

Case history

CLICK HERE to read Leo Camish’s story about the treatment of his cartilage damage on his patella by radiofrequency chondroplasty.