Thank you for tuning into our course, as well as this talk on the surgical indications and technique for osteochondral grafting for capitellum OCD lesions. These are my disclosures, none of which are relevant to this talk. OCD has been defined by the Rock Study Group as a chronic idiopathic alteration of subchondral bone with risk for instability and cartilage disruption that may result in premature osteoarthritis. It's important to know that because the bone is the primary source of pathology, cartilage involvement is always secondary. We know that hypovascularity is a major contributing cause to OCD, and in the elbow this occurs in the capitellum, which is a watershed area and is only fed by one to two small vessels, and there's a very delicate subarticular venous plexus just deep to the subchondral plate. The subchondral bone layer is very thin, measuring only about one-tenth of one millimeter, and in the setting of this hypovascularity is very sensitive to damage from valgus overload in the setting of overhead athletes or tumbling athletes. Because both bone and cartilage can be affected, it's important to take this into account when we are considering imaging. We initially screen with x-rays, which are very helpful with AP imaging and 45 degrees of flexion, as well as lateral imaging, which you can see there, but MRI is really our workhorse, which helps us understand the presence of loose bodies, the involvement of subchondral bone, the cartilage status, and other pathology going on in the elbow. In discussing who would be a good candidate for an osteochondral graft, I think it's really important to understand when an osteochondral graft is not needed. Here's a case showing a relatively small, shallow, and contained OCD lesion. You can see here there's very little subchondral bone involvement, although there is a loose body anteriorly, as seen on that right image. Axial imaging of the same patient shows a nice intact lateral or radial shoulder with normal osteochondral tissue. In those cases, an elbow arthroscopy is ideal for moving loose bodies and assessing the health of the joint, and in these small, shallow, contained lesions with an intact lateral shoulder, marrow stimulation has been shown to do well, at least in the short term. Another option for these patients who may not need a full osteochondral reconstruction would be an enhanced marrow simulation technique, here using bone marrow aspirate and a cellular cartilage matrix through a small, open approach. On the other hand, patients who would benefit from an osteochondral graft reconstruction include those with lesions that are large, deep, uncontained, or in the setting of revision. Generally, both autograft and allograft tissue sources are available. I prefer autograft when possible, but this is decided based on size with current systems, allowing for harvesting autograft plugs up to 12 millimeters. As far as surgical approach, this has been informed by two studies done at our institution, the first of which, shown here from Journal of Hand Surgery in 2018, showed that the mean location for capitellum OCD lesions on a clock face sagittal view is from about the 3 o'clock to the 515 position, anteroinferiorly. In a cadaveric study published later that year in the Journal of Shoulder and Elbow Surgery, we reported that the Anconeus split approach was the most appropriate for accessing the vast majority of these lesions perpendicularly for osteochondral graft reconstruction. Here's a case example of an Oates autograft performed in an 11-year-old gymnast who had right elbow pain and mechanical symptoms with the inability to fully extend her elbow. On her MRI, you can see the lack of an intact lateral or radial shoulder on the coronal image near the red arrow, and on the sagittal image, you can see substantial bony involvement, although the overall footprint of the lesion was not greater than a centimeter. During diagnostic arthroscopy, she did not have any free-floating loose bodies, but you can see in the top center image, she did have cartilage degeneration at the location of her OCD lesion. Through a 3-centimeter posterolateral Anconeus split approach, you can see the loose body in situ extruding from the joint immediately after capsulotomy. You can also see the unhealthy bony bed in the top center image there, and on the right side, you can see after reaming for a 10-millimeter autograft plug, a small area of devitalized cartilage, but with intact underlying bone. We made a small lateral parapatellar arthrotomy to perform a 10-millimeter autograft harvest, and then implanted the plug into the recipient site with flush edges. You can see a small 1 to 2 millimeter area where I debrided that devitalized cartilage, and then treated this with an augmented merostimulation procedure. Six-month post-operative MRI revealed excellent graft incorporation and healing with creeping substitution, as well as a restored articular surface geometry. Here's a second case with a lesion that was too big for autograft tissue. It's a 15-year-old baseball pitcher who had three years of right elbow pain and mechanical symptoms, who sought medical care after losing range of motion in his elbow and rapidly dropping pitch velocity. You can see here on his preoperative CT and MR imaging a large, uncontained, deep osteochondral defect with a large synovitis in the joint, loose bodies in situ, and destruction of the articular surface geometry. You can see here that the defect is relatively round, which I think is ideal for a single plug, but given that it is about 18 millimeters across, I think this is too large for an autograft reconstruction. Arthroscopy was performed to remove some free-floating loose bodies, and then an ankineus split approach was used in order to remove additional devitalized chondral tissue. You can see there the large osteochondral defect on the right side. As I mentioned, 18 millimeters is too large for a single autograft plug, and so I used allograft in this case. Allograft choices can include either donor capitellum or lateral femoral condyle, and using the posterior aspect of the lateral femoral condyle restores the articular geometry nicely. You can see in the third image here preparation of the recipient site and then implantation of the plug on the right. Six-month postoperative MRI does show a little bit of edema in the plug, but overall excellent early healing with blurring of the junction between the graft and the host, as well as restoration of the articular surface geometry. The joint appeared healthy overall without any synovitis or effusion, and the patient was asymptomatic with a full range of motion. My postoperative rehabilitation protocol is listed here. I have a short period of about one week of immobilization to let things calm down in a splint, but then initiate range of motion with a goal of essentially full range of motion by six weeks postoperatively. We also initiate wrist and periscopular strengthening at that time. Starting at week six, I start with rotator cuff and upper extremity strengthening, but without stressing the elbow. We progress to band work around the elbow at around two to two and a half months. We start throwers ten exercises and are throwing athletes at three months, and at four months we start plyometric activities. At six months, I perform a routine MRI to assess for graft healing, and then initiate hitting and a return to throwing program at that time. As I mentioned, that six-month clearance is determined by a routine postoperative MRI. I rely heavily on the bogey score shown here and described by Don Bay and his colleagues at Boston Children's Hospital, and it's an excellent way of really objectively measuring graft incorporation by independently assessing the graft bone, the host bone, the cartilage contour, and the overall joint health. And then depending on the bogey score as well as the patient's clinical condition, I will either decide on advancing activities or continuing activity restriction at that time. Thank you for your attention, and I hope that this was helpful in understanding the indications and technique for osteochondral graft reconstruction of capitellum OCDs.

osteochondral grafting

capitellum OCD

osteochondritis dissecans

surgical indications

surgical technique