Published 11/20/2025
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Rebecca Araujo
Italian researchers from the University of Bologna reported a novel technique for the treatment of ankle osteochondral lesions (OCLs). The findings were presented by Cesare Faldini, MD, at the AAOS 2025 Annual Meeting. Dr. Faldini is a professor and chair of the Department of Orthopaedic and Trauma Surgery at the University of Bologna Istituto Ortopedico Rizzoli.
Patients with ankle OCLs, which are defects of the subchondral bone and overlying cartilage, are often young and active and present with chronic ankle pain, swelling, stiffness, and instability.
“We decided to conduct this study because there is no ideal surgical technique [for ankle OCL] described in the literature. Various techniques have been proposed, each with its own advantages and disadvantages, but it has not yet been determined which one is superior to the others,” Dr. Faldini told AAOS Now. “We therefore aimed to evaluate the clinical and radiological outcomes of an innovative technique called SECRET [sub-endo-chondral regenerative treatment], which combines the minimally invasive approach of retrograde drilling with the regenerative properties of a biological scaffold soaked with bone marrow aspirate concentrate (BMAC).”
The study included 21 patients aged 18 years or older with ankle OCLs who presented with either cysts with intact cartilage or wide osteochondral defects.
The mean age was 40.6 years. In this group, 20 lesions were located on the talus, with 81% on the medial side, 14% on the lateral side, and 5% on the tibia. American Orthopaedic Foot and Ankle Society Score (AOFAS) and visual analog scale (VAS) scores were collected pre- and postoperatively, along with radiographs and MRI imaging.
For the proposed technique, bone marrow aspiration was performed from the posterior iliac crest, and 60 mL of bone marrow aspirate was collected and inserted into a concentrator device. The aspirate was reduced to 6 mL of BMAC. From there, ankle arthroplasty was performed with standard anteromedial and anterolateral portals. Different entry points were used to reach the OCLs.
A Kirschner wire (K-wire) was driven through the lesion via fluoroscopy, and placement was confirmed via anteroposterior and lateral views. The authors noted that an arthroscopic intra-articular view may be utilized in this phase to verify that the K-wire is not penetrating intact cartilage. Using the K-wire as a guide, the surgeon then placed a 6 mm cannulated reamer, reaching the lesion using fluoroscopic view. A 6 mm tarsal tunnel was created retrogradely toward the lesion, preserving healthy cartilage while allowing complete sub-endo-chondral debridement. Then, a hyaluronan scaffold soaked with BMAC was retrogradely positioned under the cartilage surface, and homologous bone graft was used to fill the tunnel.
“The technique proved effective in improving patients’ symptoms,” Dr. Faldini reported. “At a follow-up of 15.3 months, there was a statistically significant improvement in all the clinical parameters assessed. The technique was demonstrated to be safe, with no intraoperative complications. Radiographic evaluations also showed good bone remodeling.”
At follow-up, the mean AOFAS score increased significantly from baseline (60 to 75.3; P < .001). At rest, the mean VAS score improved from 2.6 to 0.7 (P < .003); during activity, VAS scores improved from 7.96 to 3.1 (P < .001). One patient experienced delayed wound healing, which resolved over time.
Additionally, postoperative MRI showed that bone edema was effectively resolved, along with satisfactory bone and cartilage remodeling. At one-year follow-up, regenerated tissue was seen on T2 mapping, with T2 values ranging from 35 to 45 milliseconds, “closely resembling hyaline cartilage,” Dr. Faldini noted. He added that the regenerated tissue covered a mean of 81% of the repaired lesion area, ranging from 69 to 90%.
The clinical takeaway of this study, Dr. Faldini reported, is that “the SECRET technique, which combines the minimally invasive approach of retrograde drilling with the regenerative properties of a biological scaffold soaked with BMAC, seems a viable solution to treat both subchondral cysts and large OCL of the ankle.”
Regarding limitations, Dr. Faldini acknowledged the small sample size and the medium-term follow-up. He called for future studies with larger sample sizes and longer follow-up to verify the results. Looking ahead based on these findings, he added, “This technique can also be applied to other joints, both in the upper and lower limbs.”
Dr. Faldini’s coauthors of “A novel retrograde technique for ankle osteochondral lesions: The Sub-Endo-Chondral Regenerative Treatment (SECRET)” are Elena Artioli; Alberto Arceri; Simone Ottavio Zielli; Laura Langone; Pejman Abdi; and Antonio Mazzotti, MD.
Rebecca Araujo is the managing editor of AAOS Now. She can be reached at raraujo@aaos.org.