Hi, I'm Crystal Perkins with Children's Health Care of Atlanta, and this is a presentation on retroarticular drilling of osteochondritis desiccants made easy. So as a background, OCD in the knee has a prevalence of 15 to 30 per 100,000. It occurs more commonly in males than females at a ratio of four to one, and most commonly affects children ages 10 to 15 years of age. It most commonly occurs along the posterior lateral aspect of the medial femoral condyle, although we can certainly see lateral femoral condyle, trochlear, and patellar OCDs as well, and it can be bilateral and up to a third of patients. The ROCK study group has provided us with excellent information in regards to the treatment and history of osteochondritis desiccants. This is an arthroscopy classification describing the morphology of these OCDs, and they're largely grouped into two categories, stable or immobile lesions, and unstable or mobile lesions. And for the purposes of drilling, we're really looking at those lesions on the left hand of the screen, all stable. In regards to options for operative treatment, drilling, the topic we'll discuss today, can be done retroarticular, transarticular, as well as through the notch. This can be augmented with bone grafting, bone marrow aspirate concentrate, autograft bone, and allograft products are all viable options. And then for those with perhaps impending instability, fragment fixation can be utilized. My indications for retroarticular drilling or drilling in general are those stable lesions that are when one of two groups, those who have failed to heal with nonoperative treatment, which includes activity restrictions with or without an unloader brace and vitamin D supplementation, or those with radiographic risk factors or patient risk factors concerning for failure to heal with nonoperative treatment. And the two biggest of those categories are larger lesions, as well as older patients approaching skeletal maturity. In terms of drilling technique, a diagnostic knee arthroscopy is first performed to assess the OCD stability. Here you see a lesion with slight softening of the overlying cartilage. This would be considered a shadow lesion. If the OCD is stable, I then proceed with drilling. For those lesions where I can see a slight outline of the lesion, I do like to proceed with a few passes through the notch in drilling. As you can see demonstrated on the image on the right before proceeding with retroarticular drilling. These are the sequence of steps for drilling. So first positioning, I use a supine position with the leg and a leg holder. It's important that you maximally abduct the well leg, especially when you're working on a medial femoral condyle OCD to allow room to stand to be able to drill the medial femoral condyle. The mini C-arm then enters from the lateral side, and you can use that to identify the best well visualized area of the OCD, which is most commonly a notch view. And then I use this three by three guide, which allows the passage of parallel drill paths. So first I use a 062K wire within the epiphysis to obtain a center center position within the OCD, both on the AP and the lateral. It's important to determine both the coronal and sagittal plane orientation of the OCD. And you can see shown in the images here, I've used a K wire to mark the alignment of the OCD so that I ensure that my pin is placed perpendicular to the OCD lesion. So as I march anterior and posterior along this line, it ensures full coverage of the OCD. Make a small two millimeter, two centimeter incision over the medial or lateral distal femur, depending on the condyle that's being drilled. It's important with this guide to main two K wires in place at all times that helps secure the guide. And then you can drill with the third wire. The wire should be made parallel to one another, and you can use a wet sponge to clean each pin between drill passes as there tends to be some metallic residue that will accumulate. And be sure radiographically you've ensured complete medial lateral as well as anterior posterior coverage. And you see examples of that in the images here. You can criticize your postoperative radiographs for your completeness of your drilling and orientation of your drill pass. Here are an example of the AP and a lateral x-ray in two different patients showing at two weeks post-op. You can see the drill pass, which are completely covering the lesion on the lateral interperpendicular to it. Postoperatively, I treat these patients touchdown weight bearing for six weeks and then lean crutches over one to two weeks. I use a neomobilizer over the first four weeks that allow them to have range of motion as tolerated in physical therapy and home exercises. I supplement their vitamin D, typically 2000 to 4000 international units daily, depending on their blood levels. I stress to them the importance that we don't return to impact sports any sooner than four to six months, depending on radiographic healing. You can see some examples here of medial femoral condyle, OCDs, which have been drilled, and you can see their sequence of radiographic healing with serial follow-up. Thank you.

retroarticular drilling

osteochondritis desiccans

OCD

knee

drilling techniques