SLR - April 2018 - Sara A. Naguib

Added Value of Preoperative Computed Tomography for Determining Cartilage Degeneration in Patients with Osteochondral Lesions of the Talar Dome

Reference: Nakasa T, Ikuta Y, Yoshikawa M, Sawa M, Tsuyuguchi Y, Adachi N. Added Value of Preoperative Computed Tomography for Determining Cartilage Degeneration in Patients with Osteochondral Lesions of the Talar Dome. Am J Sports Med. 2018;46(1):208–216.

Scientific Literature Review


Reviewed By:
Sara A. Naguib, DPM
Residency Program: Temple University Hospital, Philadelphia, PA

Podiatric Relevance:
Several imaging studies exist to diagnosis osteochondral lesions of the talar dome. However, computed tomography can provide more accurate information about the state of subchondral bone compared to magnetic resonance imaging. A damaged subchondral bone plate disrupts cartilage homeostasis, and therefore, examining the status of subchondral bone can reflect the degeneration of the articular cartilage. The aim of this study was to compare CT findings, arthroscopy findings and histological findings in osteochondral lesions of the talar dome.

Methods:
Thirty ankles with osteochondral lesions with a fragment present were reviewed retrospectively. CT scans were obtained preoperatively for each ankle, and all patients underwent arthroscopic surgery. Nineteen ankles had preservation of the osteochondral fragment by fixation or drilling, while 11 required excision of the fragment. Histological specimens of the osteochondral fragments were analyzed. In addition, the clinical outcome was assessed via the AOFAS ankle-hindfoot scale preoperatively and postoperatively.  

Results:
By examining the CT images, it was noted that the rate of absorption of the subchondral bone plate in the preservation group was lower than that in the excision group. Conversely, the lesion bed absorption was higher in the preservation group than in the excision group. About 42 percent of lesions in the preservation group exhibited bed sclerosis, compared to 100 percent in the excision group. Histologically, specimens with subchondral plate disruption had cartilage degeneration and abundant chondrocyte cloning. The AOFAS scores significantly improved from preoperatively to postoperatively in both groups.

Conclusions:
This study analyzed the features of osteochondral lesions of the talus both histologically and on computed tomography. The authors have concluded that computed tomography provides crucial information on the condition of the subchondral bone, which in turn, determines the state of the cartilage. This data can assist in determining the type of surgical treatment, with either preservation or excision of the osteochondral fragment in osteochondral lesions of the talus. Computed tomography is a helpful diagnostic tool, which can be utilized for surgical planning. 

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