Proposal of a new CT arthrographic classification system of osteochondral lesions of the talus

Abstract

Background: Surgical treatment of osteochondral lesions of the talus (OLT) is warranted if medical treatments fail, achieving good results in around 85% of cases. Numerous classification systems, based on all possible imaging modalities (radiography, MRI, CT scan, scintigraphy, and CT arthrography), have been proposed to guide surgical treatments, but none has proven to be superior. A recent study demonstrated the prognostic value of CT arthrography by accurately describing the subchondral bone plate. A systematic review of the literature has brought new criteria to predict good outcome following bone marrow stimulation surgical techniques: lesions should measure less than 1 centimeter in size and 5 millimeters in depth. Based on these data, we are proposing a new simple, 3-stage CT arthrographic classification system of OLT.

Materials and methods: After a brief overview of the classification, 60 CT-arthrographies of ankles with OLT were organized according to this new CT arthrographic classification system by four surgeons (two juniors and two seniors). Two imaging assessments were performed one month apart. Statistical analysis was performed using the Fleiss' kappa coefficient to determine the inter- and intraobserver agreement.

Results: An excellent inter- and intraobserver agreement was found with overall Fleiss' kappa coefficients of 0.897 and 0.847, respectively.

Conclusion: The results of our study showed an excellent inter- and intraobserver agreement for this new CT arthrographic classification system of OLT. The principal advantage of this new classification system, based on the latest data in the literature, is its ability to easily distinguish lesions that are more amenable to bone marrow stimulation techniques.

Level of evidence: II.

Keywords: CT arthrography; Classification; Osteochondral lesions of the talus.