Clinical outcomes after arthroscopic microfracture for osteochondral lesions of the talus are better in patients with decreased postoperative subchondral bone marrow edema.

PURPOSE

Magnetic resonance imaging (MRI) findings of subchondral bone marrow edema (SBME) in osteochondral lesions of the talus (OLT) after arthroscopic microfracture are associated with poor clinical outcomes. However, the relationship between SBME volume change and clinical outcomes has not been analyzed. It was hypothesized that clinical outcomes correlated with SBME volume change and extent of cartilage regeneration in patients with OLT.

METHODS

64 patients who underwent arthroscopic microfracture for OLT were followed up for more than 2 years. SBME volume change was measured by comparing preoperative and 2-year follow-up MRI. Clinical outcomes were assessed using the visual analogue scale (VAS) and the American orthopedic foot and ankle society ankle-hindfoot scale (AOFAS) at the 2-year and final follow-up. To compare clinical outcomes, patients were categorized into two groups: decreased SBME (DSBME) group (cases without SBME on either MRI or with a decreased SBME volume between the MRIs) and increased SBME (ISBME) group (cases with new SBME on postoperative MRI or with an increased SBME volume between the MRIs). Additionally, the effects of age, sex, body mass index, symptom duration, OLT size, OLT location, containment/uncontainment, preoperative subchondral cysts, pre- and postoperative SBME volumes, and MRI observation of cartilage repair tissue score on clinical outcomes were analyzed.

RESULTS

The DSBME group included 45 patients, whereas the ISBME group included 19. The mean age was 40.1 ± 17.2 years, and mean follow-up period was 35.7 ± 18.3 months. Preoperative SBME volume was significantly higher in the DSBME group, while the ISBME group had higher volumes at the final follow-up. In both groups, the VAS and AOFAS scores significantly improved at the final follow-up (p < 0.001, < 0.001). The VAS scores were significantly lower in the DSBME group at the 2-year and final follow-up (p = 0.004, 0.011), while the AOFAS scores were significantly higher (p = 0.019, 0.028). Other factors including cartilage regeneration did not affect clinical outcomes.

CONCLUSION

SBME volume change correlated with clinical outcomes after arthroscopic microfracture for OLT. Clinical outcomes were worse in patients with new postoperative SBME and increased postoperative SBME volume. In patients with an unsatisfactory clinical course that show decreased SBME via postoperative MRI, an extended follow-up in a conservative manner could be considered.

LEVEL OF EVIDENCE

Level III.