What’s the optimum treatment for a talar osteochondral lesion (OLT) that develops after an ankle sprain or other ankle trauma?
The answer depends on the size of the lesion: Smaller lesions have been successfully treated with microfracture or arthroscopic marrow stimulation, while larger lesions (more than 150 mm2) generally respond well to osteochondral autograft transplantation (OAT), with good short-term functional and radiographic outcomes.
What about medium-sized lesions? Is microfracture a good option, or is OAT the superior treatment?
A new retrospective study from Hospital for Special Surgery (HSS) sought to answer that question, comparing clinical outcomes after treatment of medium-sized OLTs – defined as 80 mm2 to 165 mm2 – using a microfracture technique augmented with extracellular matrix and bone marrow aspirate concentrate (MFX) versus treatment with OAT (single-plug transplantation).
The researchers evaluated 50 patients with at least 12 months of follow-up who were treated at HSS between 2015 and 2018 for a medium-sized OLT, with 27 treated with MFX (age range, 14 to 58 years) and 23 treated with OAT (age range, 22 to 64 years). Postoperative MRIs were assessed using a modified magnetic resonance observation of cartilage repair tissue (MOCART) score. The researchers obtained information on treatment, lesion size, lesion location, concurrent injuries, and demographics through retrospective chart review.
Responses to patient-reported functional outcome questionnaires were available through the HSS prospective registry database. Patients treated before March 2016 completed the Foot and Ankle Outcome Score (FAOS) questionnaire preoperatively, while patients treated from March 2016 onward completed the Patient-Reported Outcome Information System (PROMIS) domains of physical function, pain interference, global physical health, global mental health, depression, and pain intensity preoperatively. FAOS and PROMIS were administered postoperatively before and after March 2016.
Patients in the OAT group had a higher MOCART score than patients in the MFX group, with the difference being statistically significant: 71 (± 15.60) for OAT and 55.67 (± 24.11) for MFX (P=0.04). The researchers says this finding indicates that a single osteochondral autograft plug may result in better structural repair than use of microfracture augmented by extracellular matrix and bone marrow aspirate concentrate.
Higher average FAOS scores, better-than-average PROMIS scores and greater preoperative to postoperative change in the OAT group suggest functional results may be better in this group as well. Patients treated with OAT reported significantly less pain and depression and better psychological benefits than those who were treated with MFX.
The authors concluded that, “[t]hese results suggest filling the lesion with transplanted autograft bone and native, hyaline cartilage may perform better than the biomechanically inferior fibrocartilage produced following microfracture, even when augmented with adjuvant therapy. OAT may result in better overall clinical outcomes, specifically in a population of patients with medium-sized lesions.”
Senior study author Mark C. Drakos, MD, a foot and ankle orthopaedic surgeon at HSS, noted that, “[t]he key takeaway from this research [is that] the open procedure more closely replicates the normal anatomy than the arthroscopic procedure – they are not equal.
“The findings validate the need to perform additional research to ensure [that] the less invasive arthroscopic procedure has better outcomes similar to those of the open procedure.”
Cabe T, Sofka CM, Deland JT, Drakos MC. A Comparison of Functional and Radiographic Outcomes following Microfracture with Extracellular Matrix Augmentation versus Osteochondral Autograft Transplantation for the Treatment of Medium-Sized Osteochondral Lesions of the Talus. Paper 764. AAOS Virtual Education Experience.