FRI0402 MAGNETIC RESONANCE IMAGING EVALUATION OF CARTILAGE EROSION AND LIGAMENT INTEGRITY IN EARLY STAGE THUMB CARPOMETACARPAL JOINT OSTEOARTHRITIS
Authors: H. S. Gong, K. J. Bae
Journal: Annals of the Rheumatic Diseases (2020)

Background: Most of the studies on pathogenesis of thumb carpometacaral joint (CMCJ-1) osteoarthritis were from cadavers or patients with advanced osteoarthritis, therefore the findings may not reflect any early changes of cartilage wear and ligament condition. Objectives: We evaluated MRI to address where articular degeneration begins and which ligaments are most often involved in the early clinical stage CMCJ-1 osteoarthritis. Methods: We retrospectively analyzed MRI examinations of 26 patients with early clinical stage CMCJ-1 osteoarthritis without radiologic abnormality and 19 control patients without CMCJ-1 pain or osteoarthritis who underwent MRI for dorsal or ulnar wrist pain. Two independent and blind observers assessed chondral defect of the CMCJ-1 divided into four quadrants: volar-ulnar (VU), volar-radial (VR), dorso-ulnar (DU), and dorso-radial (DR). They assessed the integrity of the four major ligaments of CMCJ-1: the anterior oblique ligament (AOL), the intermetacarpal ligament (IML), the posterior oblique ligament (POL), and the dorsal radial ligament (DRL). The prevalence of cartilage lesion and ligament abnormality between the osteoarthritic and control patients was compared using Fisher’s exact test. Results: Cartilage lesion was significantly more common in the VU quadrant of the trapezium in the osteoarthritic patients than in the control patients (17/26 vs. 2/19; P = 0.002). AOL abnormality was more common in the osteoarthritic patients than in the control patients (14/26 vs. 3/19; P = 0.009). In the osteoarthritic patients, 10 of 17 patients with VU quadrant cartilage erosion had AOL rupture, while four of nine patients without VU cartilage erosion had AOL rupture, thus there was no association between VU quadrant erosion and AOL rupture (10/17 vs 4/9, P = 0.484). Conclusion: MRI evaluation of early clinical CMCJ-1 osteoarthritis commonly demonstrate cartilage lesion in the VU quadrant of the trapezium and ligament abnormality in the AOL. However, no association of cartilage erosion in the VU region and AOL rupture suggests that AOL rupture is not a mechanical factor leading to TMCJ osteoarthritis in specific area, but a common finding secondary to arthritic changes. References: [1]Ladd AL, Lee J, Hagert E. Macroscopic and microscopic analysis of the thumb carpometacarpal ligaments: a cadaveric study of ligament anatomy and histology. J Bone Joint Surg Am. 2012; 94(16):1468-1477. [2]Williams A, Shetty SK, Burstein D, Day CS, McKenzie C. Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) of the first carpometacarpal (1CMC) joint: a feasibility study. Osteoarthritis Cartilage. 2008; 16(4):530-532. [3]Saltzherr MS, Coert JH, Selles RW, van Neck JW, Jaquet JB, van Osch GJ, et al. Accuracy of magnetic resonance imaging to detect cartilage loss in severe osteoarthritis of the first carpometacarpal joint: comparison with histological evaluation. Arthritis Res Ther. 2017; 19(1):55 [4]Dumont C, Lerzer S, Vafa MA, Tezval M, Dechent P, Sturmer KM, et al. Osteoarthritis of the carpometacarpal joint of the thumb: a new MR imaging technique for the standardized detection of relevant ligamental lesions. Skeletal Radiol. 2014; 43(10):1411-1420. Disclosure of Interests: Hyun Sik Gong Speakers bureau: Amgen. Pfizer, Kee Jeong Bae: None declared