Modern Cartilage Imaging of the Ankle

Abstract

ABSTR AC TBackground Talar osteochondral lesions are an important risk factor for the development of talar osteoarthritis. Furthermore, osteochondral lesions might explain persistent ankle pain. Early diagnosis of accompanying chondral defects is important to establish the optimal therapy strategy and thereby delaying or preventing the onset of osteoarthritis. The purpose of this review is to explain modern cartilage imaging with emphasis of MR imaging as well as the discussion of more sophisticated imaging studies like CT-arthrography or functional MR imaging.Methods Pubmed literature search concerning: osteochondral lesions, cartilage damage, ankle joint, talus, 2 D MR imaging, 3 D MR imaging, cartilage MR imaging, CT-arthrography, cartilage repair, microfracture, OATS, MACT.Results and Conclusion Dedicated MR imaging protocols to delineate talar cartilage and the appearance of acute and chronic osteochondral lesions were discussed. Recent developments of MR imaging, such as isotropic 3 D imaging that has a higher signal-to noise ratio when compared to 2 D imaging, and specialized imaging methods such as CT-arthrography as well as functional MR imaging were introduced. Several classifications schemes and imaging findings of osteochondral lesions that influence the conservative or surgical therapy strategy were discussed. MRI enables after surgery the noninvasive assessment of the repair tissue and the success of implantation. Key points▪ Modern MRI allows for highly resolved visualization of the articular cartilage of the ankle joint and of subchondral pathologies. ▪ Recent advances in MRI include 3 D isotropic ankle joint imaging, which deliver higher signal-to-noise ratios of the cartilage and less partial volume artifacts when compared with standard 2 D sequences. ▪ In case of osteochondral lesions MRI is beneficial for assessing the stability of the osteochondral fragment and for this discontinuity of the cartilage layer is an important factor. ▪ CT-arthrography can be used in case of contraindications of MRI and in unclear MRI findings as further diagnostic approach. Citation Format

Update: Posttreatment Imaging of the Knee after Cartilage Repair

“…17 However, it can be used to identify associated joint damage, such as subchondral fractures, osseous defects, or detached osseous fragments. 18 Loss of cartilage can only be assessed by radiography indirectly in the form of nonspecific joint space narrowing.…”

“…Whenever MRI is not possible due to patient-specific concerns or a lack of availability, computed tomography (CT) arthrography may be an alternative for the detection and evaluation of focal cartilage defects. 18 55 Furthermore, it was shown that CT arthrography is also able to evaluate differences in the local sulfated GAG content of the cartilage in cadaveric knee joints, thereby providing an assessment of the quality of the cartilage. 56 However, studies assessing the potential of CT arthrography after surgical repair of focal cartilage defects are lacking.…”

Imaging of the Knee Following Repair of Focal Articular Cartilage Lesions

“…underlying cause of articular defects such as subchondral fractures, osseous defects, or detached osseous fragments in osteochondral lesions that can be visualized. 12 However, radiography is not sufficient in the work-up of articular cartilage lesions due to its lack of soft tissue differentiation.…”

“…The current gold standard to evaluate articular cartilage lesions as well as to monitor postoperative follow-up is magnetic resonance imaging (MRI). [11][12][13] Current advances in MRI technology provide high spatial resolution and superior soft tissue contrast allowing detection of articular cartilage lesions with a sensitivity of 74.6% and a specificity of 97.8%. 14 During the MRI examination the patient is placed supine with the knee in a neutral position.…”

“…In patients with contraindications for MRI examinations and in those with unclear MRI findings, computed tomography arthrography (CTA) may be a useful alternative to detect small cartilage defects. 11,12 Furthermore, it was shown that CTA is also able to evaluate differences in the local sulphated glycosaminoglycan (GAG) content of the cartilage, thereby assessing the quality of the cartilage. 15 However, this technique needs further evaluation in the setting of cartilage repair surgery.…”