SLR - August 2019 - Greg Lifferth

Lesion Size Measured on MRI Does Not Accurately Reflect Arthroscopic Measurement in Talar Osteochondral Lesions

Reference: Yasui Y, Hannon CP, Fraser EJ, Ackermann J, Boakye L, Ross KA, Duke GL, Shimozono Y, Kennedy JG. Lesion Size Measured on MRI Does Not Accurately Reflect Arthroscopic Measurement in Talar Osteochondral Lesions. Orthop J Sports Med. 2019;7(2):2325967118825261. Published 2019 Feb 12.

Scientific Literature Review

Reviewed By: Greg Lifferth, DPM
Residency Program: Maricopa Medical Center/Creighton University – Phoenix, AZ

Podiatric Relevance: Talar dome lesions are commonly treated by podiatrists with a variety of surgical modalities available, which are often based on measurements found on MRI. Standard practice for bone marrow stimulating procedures such as micro fracturing using the arthroscopic approach is indicated when the lesion is typically less than 10 mm. However, when the lesion is larger, treatment options often require a medial malleolar or fibular takedown for exposure that is associated with increased morbidity and prolonged recovery. This study suggests that MRI overestimates lesion size and that the more aggressive procedures might not always be necessary.

Methods: This is a retrospective cohort study that compared Pre-operative MRI measurements of osteochondral lesions of the talus (OLT) with intra-operative arthroscopic measurements prior to a bone marrow stimulating procedure. A total of 39 patients were included in the study who had an MRI within 6 months of surgery and had not undergone previous surgical intervention. An independent radiologist and orthopedic surgeon measured lesions on MRI and two orthopedic surgeons measured lesions intraoperatively.  

Results: Of the 39 patients included and 45 OLT’s, MRI findings overestimated lesion size in 53.3 percent and underestimated lesion size in 24.4 percent of the cases when compared intra-operatively. Lesion diameters were reported as 6.1 ± 2.6 vs 4.9 ± 2.3 mm, P = .03; sagittal plane, 8.0 ± 3.6 vs 6.3 ± 3.6 mm, P= .05) for MRI and arthroscopic measurements.

Conclusions:
These authors concluded that MRI overestimated the size of osteochondral lesions of the talus about 50 percent of the time. Though MRI is useful in diagnostic purposes, surgeons should understand discrepancies when planning surgical treatment. Due to discrepancies on the size of the lesion, arthroscopy may be beneficial for the performing surgeon to confirm the size before committing to more aggressive approaches.

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