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

Youichi Yasui; Charles P Hannon; Ethan J Fraser; Jakob Ackermann; Lorraine Boakye; Keir A Ross; Gavin L Duke; Yoshiharu Shimozono; John G Kennedy

doi:10.1177/2325967118825261

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

Orthop J Sports Med. 2019 Feb 12;7(2):2325967118825261. doi: 10.1177/2325967118825261. eCollection 2019 Feb.

Authors

Youichi Yasui^{1

2}, Charles P Hannon^{1

3}, Ethan J Fraser¹, Jakob Ackermann¹, Lorraine Boakye¹, Keir A Ross¹, Gavin L Duke⁴, Yoshiharu Shimozono⁵, John G Kennedy⁵

Affiliations

¹ Hospital for Special Surgery, New York, New York, USA.
² Teikyo University School of Medicine, Department of Orthopaedic Surgery, Tokyo, Japan.
³ Department of Orthopaedic Surgery, Rush University Medical Center (C.P.H.), Chicago, Illinois, USA.
⁴ East River Medical Imaging, New York, New York, USA.
⁵ NYU Langone Health, New York, New York, USA.

Abstract

Background: Lesion size is a major determinant of treatment strategy for osteochondral lesions of the talus (OLTs). Although magnetic resonance imaging (MRI) is commonly used in the preoperative evaluation of OLTs, the reliability of the MRI measurement compared with the arthroscopic measurement is unknown.

Purpose: To compare preoperative lesion size measured on MRI versus intraoperative lesion size measured during arthroscopy.

Study design: Cohort study (diagnosis); Level of evidence, 2.

Methods: We retrospectively reviewed a consecutive series of patients treated with bone marrow stimulation for OLTs. The diameter of the lesion was measured at its widest point in 2 planes, and MRI measurements were compared with those made during arthroscopy using a custom-made graduated probe.

Results: A total of 39 patients with 45 OLTs were analyzed. Mean ± SD area measurements on MRI were significantly greater than the equivalent arthroscopic measurements (42.2 ± 30.5 vs 28.6 ± 23.1 mm², respectively; P = .03). Compared with the arthroscopic measurement, MRI overestimated OLT size in 53.3% (24/45) of ankles and underestimated OLT size in 24.4% (11/45). The mean MRI diameter measurement was significantly greater than the arthroscopic measurement in the coronal plane (MRI diameter vs arthroscopic measurement coronal plane, 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). Further, MRI overestimated coronal diameter in 48.9% (22/45) of ankles and underestimated in 26.7% (12/45) compared with the arthroscopic measurement. Similarly, sagittal plane MRI diameter measurements overestimated lesion size in 46.7% (21/45) of ankles and underestimated lesion size in 28.9% (13/45) compared with the arthroscopic findings.

Conclusion: In a majority of lesions, MRI overestimated OLT area and diameter compared with arthroscopy. Surgeons should be aware of the discrepancies that can exist between MRI and arthroscopic measurements, as these data are important in making treatment decisions and educating patients.

Keywords: ankle; arthroscopy; articular cartilage; defect size; magnetic resonance imaging; osteochondral lesions of the talus.