Retrograde Drilling and Bone Graft for Hepple Stage V Subchondral Bone Lesion of Talus Using 3D Image–Based Navigation-Assisted Endoscopic Technique

Retrograde drilling remains technically challenging, because of the difficulty of identifying the accurate location of cysts during surgery. This study's aim was to evaluate the 3-dimensional (3D) image-based surgical navigation-assisted endoscopic retrograde drilling technique for subchondral bone lesions of the talus.From March 2017 to June 2020, a total of 21 cases with Hepple stage V subchondral bone lesions of the talus were treated with 3D image-based surgical navigation-assisted endoscopic retrograde drilling and bone graft technique. Arthroscopic views were categorized per Pritsch classifications. The correlation between the drilled tunnel with preoperative cystic lesions were assessed under postoperative computer tomographic (CT) scans. The American Orthopaedic Foot & Ankle Society (AOFAS) scores, visual analog scale (VAS) scores, and Foot and Ankle Ability Measure (FAAM) sports scales were evaluated at the preoperative and final consultation. All complications were recorded.On postoperative CT scans, in 20 cases (95.2%), the drilled tunnel was judged to have been in the center of previous cysts. Only 9 cases (42.9%) showed intact normal cartilage (grade 0, group A); 12 cases (57.1%) had intact, but soft, cartilage (grade I, group B). The median follow-up time was 24 (24, 30) months, and at final follow-up, there were no significant differences between the mean AOFAS and VAS scores in both groups (89.0 ± 6.4 vs 88.3 ± 7.0 and 1 vs 0.5) or postoperative FAAM sports scales (28.2 ± 2.2 vs 26.6 ± 4.9, P = .363). Two patients had revision surgery in group B.The 3D image-based surgical navigation-assisted endoscopic retrograde drilling and bone graft technique for the subchondral bone lesions of the talus in this small case series showed encouraging results.Level IV, retrospective case series.