2015 ISAKOS Biennial Congress ePoster #112
The Relationship Between Computed Tomography and Histopathologic Findings in the Osteochondral Lesion of Talar Dome
Tomoyuki Nakasa, MD, PhD, Matsuyama JAPAN
Nobuo Adachi, MD, PhD, Hiroshima JAPAN
Tomohiro Kato, MD, Hiroshima JAPAN
Mitsuo Ochi, MD, PhD, Higashi, Hiroshima JAPAN
Hiroshima University , Hiroshima, JAPAN
FDA Status Not Applicable
Summary: CT findings on osteochondral lesion of talar dome based on the state of the subchondral bone relate to the damage of cartilage and stability of the lesion and this relationship was validated by the histopathology
In the pathogenesis of osteochondral lesion of talar dome (OLT), it is recognized the subchondral bone plate (SBP) is important because the SBP plays an important role in cartilage metabolism. Focusing on the condition of the SBP may be important in diagnosing OLT by CT, and we hypothesized that there may be a distinct relationship between the CT and arthroscopic findings, especially the state of cartilage damage. The purpose of this study is to evaluate the relationship between the arthroscopic findings including articular cartilage surface and the CT findings, focusing on the subchondral bone, and analyze the relationship between CT findings and histology.
Thirty-three patients (25 males and 7 females) diagnosed as OLT were included in this study. Mean age was 28.9 years (ranging from 14 to 59 years). All patients underwent CT, MRI and arthroscopic surgery. CT and MRI findings were compared with International Cartilage Repair Society (ICRS) grade and arthroscopic findings. The CT findings of cystic and fragment lesions were classified into 3 types. The 3 types for the cystic lesion were irregular shape, round shape with sclerotic wall, and irregular shape with opening to an articular cavity. The 3 types for the fragment lesion were no bone absorption, bed absorption without fragment absorption, and bed sclerosis and fragment absorption. In this series, total 11 biopsies of OLT lesion from 6 patients of OLT were performed using biopsy needle (F2mm) during operation or excised osteochondral fragment. Histological findings of each specimens by HE and safranin O staining was compared with CT and arthroscopic findings.
Round and sclerotic cystic lesions revealed cartilaginous flap with nearly normal cartilage surface. An irregular shape with opening showed an unstable lesion with severely damaged cartilage. In the lesion with an osteochondral fragment, the condition of the cartilage in the bone fragment group without bone absorption was almost intact, and the lesion was stable. A lesion with bone absorption of the fragment and sclerosis of its bed revealed an unstable lesion and severe cartilage damage. In diagnosis of ICRS grade or arthroscopic findings by CT, ?2 test revealed that diagnosis for ICRS grading and arthroscopic findings using CT was superior to that by MRI.
In the area with no bone absorption and sclerosis of fragment and its bed on CT, SBP was well remained and cartilage degeneration was little observed in the histology. There was a continuity between fragment and its bed by fibrous tissue with catilageous tissue and empty lacuna was not observed. In the area with bone absorption of SBP on CT, sequestration of cartilage in deep layer and trabecular bone fracture with severe cartilage degeneration were observed. There was empty lacuna and necrotic debris in bone sclerotic area on CT.
In conclusion, CT findings on OLT based on the state of the subchondral bone relate to the damage of cartilage and stability of the lesion and this relationship was validated by the histopathology. It is important to evaluate the condition of subchondral bone in diagnosing OLT.