ROCK Complex Case of the Month Jason Rhodes, MD Stephanie W. Mayer, MD Jay Albright, MD Children’s Hospital Colorado

HPI 12 yr old African-American male, BMI: 32.5 kg/m2 Bilateral knee pain, worsened with activity, for past several months Bilateral clinical genu varum on exam No prior surgical intervention

Initial Presentation

Metaphyseal-diaphyseal angles: Varus deformity in the proximal tibia with medial tibial physeal changes consistent with Blount’s disease Metaphyseal-diaphyseal angles: Left 6◦ Right 5 ◦ Anatomic axis Left 6◦ varus Right 2◦ varus Lucency in bilateral media femoral condyle concerning for OCD

Left knee MRI evaluation consistent with Hefti Stage 4

Right knee MRI evaluation consistent with Hefti Stage 4

Plan Proximal tibial growth modulation Arthroscopic transchondral drilling 1.1 mm chondral dart drill with guide used 20 drill holes in 12 X 14 mm OCD = 12 drill holes/cm2

Right knee Left knee

Postoperative

3 mo post op: no knee pain; radiographs show significant OCD healing with subchondral bone formation 9 mo post op: knee pain completely resolved and back to full activities 2 yr post op: complete healing of OCD’s and correction of genu varum and back to full activities with no pain