Abstract & Commentary
Synopsis: This study examined both fixed and grafted unstable OCD lesions using autologous bone sticks made from the ipsilateral tibia with 90% success.
Source: Navarro R, et al. The arthroscopic treatment of osteochondritis dissecans of the knee with autologous bone sticks. Arthroscopy. 2002;18(8):840-844.
Treatment of symptomatic, unstable OCD fragments in patients at or near completion of growth generally involves drilling across the fragment and some form of (usually) absorbable fixation. Bone grafting with more aggressive curettage facilitates healing if joint fluid is tracking behind the fragment. Navarro and associates used autologous bone sticks to accomplish all 3 tasks: drilling, fixation, and bone grafting. They report their experience with 11 patients who did not improve with nonoperative treatment and had unstable lesions by exam and radiographic evaluation, including MRI.
Three or 4 bone sticks each 2 cm in length were obtained using a micro-saw from the tibial metaphysis. After drilling across the lesion with a Steinmann pin, these were delivered using a cannula and trocar so that the bone sticks were recessed below the articular surface. At a mean follow-up of 4 years, all patients but 1 had good or excellent results according to a scoring system popularized by Hughston. That 1 "poor" patient had some flattening of the condyle due to collapse with effusions. All OCD lesions healed.
Comment by David R. Diduch, MS, MD
OCD can be a challenge to treat, frequently requiring open bone grafting for larger, unstable lesions once the growth plates have closed and the potential for spontaneous healing diminishes. Although absorbable pins are commonly used to fix the fragment, Navarro et al present an interesting and very affordable alternative. These autologous bone sticks appear to both fix and graft the lesion, while the antegrade drilling with the large pin helps to provide vascular access to the fragment.
Unfortunately, the details of how they prepared the bone sticks and mean time to healing are not provided in this somewhat-loose study. Fashioning these sticks with a hand held, micro-sagital saw from a chunk of cortical bone and forcing them inside a delivery cannula could be problematic, I would imagine. However, they do present an interesting new approach to an old clinical problem. It would be appealing to develop instruments that allowed harvest of these sticks percutaneously with arthroscopic delivery. That approach would parallel the technique of osteochondral plug transfer at a smaller diameter with no real limit on graft availability. More studies with both approaches are needed to better evaluate the potential of this treatment for a difficult and not uncommon problem.
Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports.