Retrograde Drilling for Hepple-V Subchondral Lesion of Talus using 3D Image-based Navigation Assisted Endoscopic Technique

Abstract

Category: Ankle; Arthroscopy Introduction/Purpose: Retrograde drilling remains technically challenging, due to the difficulty of identifying the accurate location of cysts on fluoroscopic images or matching the tip of the drill guide under arthroscopic visualization. This studies aim was to evaluate the 3-dimentional(3D) image-based surgical navigation system assisted endoscopic retrograde drilling technique for subchondral lesions of the talus. Methods: From Mar 2018 to Jun 2020, 21 cases with Hepple-V type subchondral lesions of the talus were treated with 3D image- based surgical navigation system assisted endoscopic retrograde drilling technique. Arthroscopic views were categorized per Pritsch’s classifications. The American Orthopaedic Foot and Ankle Society (AOFAS) scores and Visual Analog Scale (VAS) scores were evaluated at the preoperative and final follow-up appointments. All complications were also recorded. Results: The average follow-up time was 29.2 ± 9.4 months (range, 24 – 48). Only 9 cases (42.9%) showed intact and normal cartilage surfaces (grade 0, group A), 12 cases (57.1%) had intact, soft cartilage surfaces (grade I, group B). At the final follow-up, the average of the AOFAS scores and VAS scores were 89.0 ± 2.1 vs 88.3 ± 2.0 and 0.8 ± 0.2 vs 0.8 ± 0.3, respectively. There were no significant differences between both groups. In group B, however, two patients were documented with signs of recurrence after 2 years postoperative. Also, an additional overlying cartilage lesion was noticed in another patient. Finally, two patients were given revised surgery. Conclusion: The 3D image-based surgical navigation system assisted endoscopic retrograde drilling technique is accurate, effective and safe for the subchondral lesions of the talus. The ideal indication is subchondral cysts with intact and normal cartilage surfaces. However, these patients are uncommon.