MRI of Hip Cartilage: Joint Morphology, Structure, and Composition

Abstract

Background Accurate, reproducible, and noninvasive assessment of hip cartilage is clinically relevant and provides a means by which to assess the suitability of candidates for arthroscopic or open surgical procedures and the response to such interventions over time. Given the relatively thin cartilage of the hip and the complex spherical anatomy, however, accurately assessing the cartilage poses a challenge for traditional MRI techniques. Questions/Purposes We assessed the current status of imaging articular cartilage of the hip through a comprehensive review of recent literature. Methods We performed a literature review using PubMed. Topics included quantitative MRI, imaging of the hip cartilage and labrum, femoroacetabular impingement syndrome, and osteoarthritis of the hip. Where Are We Now? With the use of high in-plane and through-plane resolution, reproducible assessment of hip cartilage and labrum is clinically feasible. More recent quantitative MR techniques also allow for noninvasive assessment of collagen orientation and proteoglycan content in articular cartilage, thus providing insight into early matrix degeneration. These techniques can be applied to cohorts at risk for osteoarthritis, helping to predict cartilage degeneration before symptoms progress and osteoarthritic changes are visible on radiographs. Where Do We Need to Go? Prospective longitudinal data registries are necessary for developing predictive models of osteoarthritis and subsequent joint failure to assess the results of surgical intervention and predict the timing of arthroplasty. How Do We Get There? By establishing more hip cartilage registries, a correlation can be made between subjective measures and morphologic MRI to assess the cartilage, labrum, bone, and synovial lining of the hip.

Biochemical MRI Predicts Hip Osteoarthritis in an Experimental Ovine Femoroacetabular Impingement Model

“…Novel biochemical MRI modalities may allow evaluation of cartilage biochemistry long before cartilage loss occurs [5,10]. Among others, noncontrast biochemical MRI techniques include T2 and T2* mapping sequences [6][7][8][9].…”

Regional Articular Cartilage Abnormalities of the Hip

“…Sagittal images are primarily used for the detection of labral abnormalities; they are also particularly suitable for the evaluation of the weightbearing portion of the cartilage of the femoral head and acetabular dome [2]. These regions are prone to cartilage lesions, especially in patients with FAI, avascular necrosis, and insufficiency fractures, and therefore should be assessed with special attention [15,37,38].…”

“…In a study by Kassarjian et al [73], anterosuperior cartilage lesions were found in 95% (40/42) of the patients. Patients with symptomatic FAI typically have rapid cartilage loss over the anterosuperior margin of the dome and active delamination may be seen, which is manifested as hyperintensity in the basilar component of the cartilage over the anterior dome extending down to the tidemark [2,24]. Figures 5-7 show examples of arthroscopically proven carpet lesion or delaminating lesion in patients with FAI.…”

“…Pincer-type impingement-Pincer-type impingement is related to overcoverage of the femoral head and is typically associated with coxa profunda and acetabular retroversion [2]. Retroversion of the upper part of the acetabulum leads to the anterosuperior rim and lateralized medial edge abutting against the head-neck junction during flexion of the hip, whereas acetabular protrusion leads to anterior overcoverage of the head by the acetabulum [79].…”

“…Pfirrmann et al [80] found that cartilage lesions in patients with pincer-type FAI were significantly larger at the posteroinferior position than cartilage lesions in patients with cam-type FAI. Pincer-type impingement typically manifests with primary labral failure followed by slower progressive cartilage loss [2]. Pincer-type FAI is more frequently found in women than in men and in older patients.…”