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The recent research finds that preoperative MRI may miss a substantial number of associated lesions intraoperatively in patients with chronic ankle instability, and surgeons may be better than radiologists at identifying these lesions on preoperative images.

“The results of our study support routine arthroscopy and peroneal tendon exploration,” Patrick J. O’Neill, MD, said during his presentation at the 25th Annual Summer Meeting of the American Orthopaedic Foot and Ankle Society. “When it comes to MRI, it is important to discuss with patients that even though they had an MRI that was negative, there are could be lesions that need to be addressed in the OR.” It is also important that surgeons read their own MRIs, he said.

Intraoperative findings

In a retrospective chart review, O’Neill and his colleagues compared the preoperative MRI reports of community radiologists and the attending foot and ankle surgeon to the intraoperative findings of 133 consecutive patients who underwent 135 lateral ankle ligament reconstruction procedures for chronic ankle instability. The patients had a mean age of 29 years and all underwent
arthroscopy and peroneal exploration.

Intraoperatively, the researchers found 72 associated lesions, including 38 chondral injuries, 18 brevis tears, seven loose bodies, and nine other pathologies. Compared to the preoperative MRI reports, the investigators discovered that the radiologist missed 50% of the associated lesions found intraoperatively and the attending surgeon missed 33%.

The radiologist missed 61% of the chondral injuries, 44% of the brevis tears, 43% of loose bodies and 29% of the other pathologies. The surgeon missed 53% of the chondral injuries, 11% of the brevis tears, 29% of the loose bodies and none of the other pathologies.

Causes for discrepancies

O’Neill said many of the lesions might have been missed on MRI due to a potentially high number of superficial lesions that lack bony edema, as well as the inherent challenges in visualizing peroneal tears. He also said the surgeon may have had the advantage of performing patient exams, while the medical community at large may not be as attuned to examining foot and ankle pathology.

O’Neill cited the retrospective study design as a limitation and noted that complete data was not available for 10 patients. He also noted that the quality of MRIs can vary as can the ability among radiologists.

During the paper discussion, an audience member asked O’Neill if he treats superficial lesions.

“As far as the natural history of the superficial lesion, I do not think we really know what will happen to that lesion later down the line,” O’Neill said. “I think that most folks do the routine arthroscopy and I probably would do the same as with a full-thickness lesion. I would probably microfracture and debride it., I do not know if that is the right answer.”

Source: AOFAS

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