Which Way Should We Treat an Osteochondral Lesion: Up or Down?

Abstract

The treatment of an osteochondral lesion of the talus (OLT) can be challenging and the results are not always predictable long-term. The literature can be confusing regarding the best treatment method, especially in an osteochondral lesion with an adjoining cyst.10 In this issue, Huber et al6 have described their results utilizing retrograde drilling, ossoscopy, and autologous bone grafting of osteochondral lesions of the talus. This technique was used in 24 patients, with the largest lesion 1.4-cm2 with a mean follow-up of 89 months. The American Orthopaedic Foot & Ankle Society (AOFAS) and pain value scores were significantly improved. The use of retrograde (also called transtalar) drilling and bone grafting is not a new procedure. It was described in detail in 1996.4 In addition, Guhl et al5 mentioned the procedure in their third edition of Foot and Ankle Arthroscopy. Technically, this is not an easy operation. There are a number of potential problems and pitfalls: (1) the guidepin can broach the articular cartilage or wander out of the correct zone of the OLT; (2) the drill can cause thermal damage to the surrounding bone and cartilage and be too aggressive; (3) insertion of the bone graft and excision of the cyst can be challenging and excess bone can end up in the subtalar joint; and (4) the procedure requires careful arthroscopic and fluoroscopic evaluation to do correctly. Kennedy et al7 injected a viscous calcium sulfate paste retrograde up into the talus, to improve cyst fill and hasten weight bearing. They reported a significant improvement in AOFAS scores and a 68% partial or complete resolution on magnetic resonance imaging. Anders et al1 described fluoroscopy-guided retrograde core drilling and insertion of bone graft in 41 patients with an osteochondral lesion of the talus. The results were better with intact cartilage. Huber et al6 have provided us with further evidence of the validity of retrograde drilling of cystic OLT and insertion of autologous bone graft. However, further questions remain in our struggle to treat these difficult lesions. In our experience of treating thousands of cases of osteochondral lesions of the talus, there is only a small percentage that are amenable to this specific treatment. Most osteochondral lesions that are encountered are unstable or have diseased cartilage covering the bone that needs to be removed and cannot be left intact. However, the pediatric patient with an osteochondral lesion is especially amenable to retrograde drilling treatment, even if no cyst exists, because frequently their osteochondral lesion has an intact cartilage that should not be violated.2,3 Also, CT/MRI stage 4 lesions can be treated with retrograde drilling to avoid injuring the cartilage with transmalleolar drilling. In addition, it is important to remember this technique should only be used in lesions sized approximately 1.0 to 1.4 cm2 or smaller.8 Huber et al6 have shown the technique and utility of retrograde drilling in removal of cystic lesions. Long-term prospective studies are necessary to determine this technique’s future role. Significant concern exists regarding restoration of the subchondral bone and the interaction of the subchondral bone with the overlying articular cartilage.9 Although much progress has been made in treating osteochondral lesions of the talus, additional basic research and clinical work still remains to provide a long-term, lasting solution to this very difficult problem.