Okay, let's spend some time and talk about transarticular drilling for OCD lesions. Here's the plan. We'll go through the indications and supporting literature, how you should set up your OR, talk about the technique in general, and the rehab protocol afterwards. What is transarticular drilling? Well, it's an arthroscopic surgical technique to stimulate healing of a stable OCD lesion. You first identify the OCD, use a wire to drill multiple passes perpendicular through the lesion and into the healthy cancellous bone below to stimulate healing and restoration of blood flow. I love transarticular drilling and there's a couple of reasons why. First of all, it's easy. You can directly visualize the OCD. You don't need to bring fluoro into the case. You don't have to wear lead and you can directly visualize a blood flow after you're done drilling and ensure that you've actually done something. And one of the most important benefits is that it works. There's a study that Ben Hayworth did where he pulled multiple studies together and he looked at the healing rate for transarticular drilling cases and at four and a half months, 91% of the lesions had healing with no reported complications. Some people worry about the articular surface. You're disrupting the cartilage to transarticular drill. Maybe you should consider a retro drill, but the literature doesn't show that there is a difference in that. Here's a systematic review that looked at comparing transarticular drilling to retro drilling. They found no differences in patient reported outcomes, no complications and comparable healing between both approaches. So what are the indications? Well, in general, you want to have a stable lesion and a skeletally immature patient that has failed conservative treatment or a stable lesion in a skeletally mature patient. So you have to be careful though. Transarticular drilling can be a component of the management for your unstable lesions, but not a treatment in isolation. So you have to think about, are you going to possibly need fixation? Do you need bone grafting, curettage? Be prepared and make sure that you have all the other things in case you encounter in the OR which you weren't expecting based on the MRI. So you should do some prep work as you should before any surgery. And you want to look at that preoperative MRI and your radiographs. And a couple of things that you want to consider is how big should you expect this lesion to be? What's its diameter? I also like to measure out specifically the lesion depth, what the maximum depth is of the lesion. So I know how far I have to penetrate in order to fully get through the lesion and into the healthy bone below. And then I also like to measure out the minimal distance from the lesion to the physis to ensure that I have some ability to protect the physis while I'm drilling without flora. So here's your pick list. You obviously need your arthroscopy equipment, your bone power tool and wire driver. I like to use a 6-2K wire. Others prefer a 4-5 because they think that it disrupts the articular chondral surface less. But I think that that risk is worth the benefit of having more disruption of the subchondral bone to stimulate more healing and having a less likelihood of breaking that wire into the bone. So in order to help keep it simple and work safely without flora, I'll take the K wire that I'm planning to use and use a wire cutter to gently score two basically like laser lines onto the K wire. And the first one measures that maximal depth of the lesion and the second one measures that minimum depth of the physis. The area between those two lines then is the sweet spot for drilling. Your mission when you're scoping is to first identify the OCD and its margins. You want to probe it and ensure that it's stable and then drill multiple passes through the OCD into the healthy bone that are three or four millimeters apart perpendicular to the chondral surface. Double check your stability and then ensure restoration of vascularity. So here's an OCD lesion and you can see that it's pretty large taking up most of the chondyle. So we can percutaneously put our K wire through, drill down into the healthy cancellous bone below, drill multiple passes three or four millimeters apart. And then when we have completed drilling the lesion, we can turn down the outflow, make sure the tourniquet is deflated, make sure that we have satisfactory blood return from each of those tunnels. There's no great standardized evidence-based rehab protocols yet, but here's what I do. I'll have the kids be non-weight-bearing and assume they're going to be toe touch for about six weeks, partial weight-bearing then for another two, and then weight-bearing again for another two weeks. And then weight-bearing is tolerated for another month. And all of this is with their knee and a knee immobilizer locked in full extension, but any incidental knee motion is okay. Then we'll start formal physical therapy and discontinue their restrictions based on their radiographic and MRI healing. Sometimes we think about a second lobe scope and based on their function as well. Thanks.

transarticular drilling

surgical technique

OCD lesions

healing

blood flow