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Carpometacarpal (CMC) osteoarthritis (OA), also known as trapeziometacarpal osteoarthritis or osteoarthritis at the base of the thumb, is a reparitive joint disease affecting the first carpometacarpal joint (CMC1).〔Pellegrini VD Jr. Osteoarthritis of the thumb trapeziometacarpal joint: a study of the pathophysiology of articular cartilage degeneration. II. Articular wear patterns in the osteoarthritis joint. J Hand Surg () 1991;16:975–982〕 This joint is formed by the trapezium bone of the wrist and the first metacarpal bone of the thumb. Because of its relative instability, this joint is a frequent site for osteoarthritis.〔A.L. Armstrong, J.B. Hunter, T.R.C. Davis. The prevalence of reparative arthritis of the base of the thumb in post-menopausal women. J Hand Surg 1994;19B:340-341.〕 Carpometacarpal osteoarthritis (CMC OA) of the thumb occurs when the cushioning cartilage of the joint surfaces wears away, resulting in damage of the joint.〔 〔Kihara H. Anatomical study of the normal and degenerative articular surfaces on the first carpometacarpal joint. J Jpn Orthop Assoc 1992;66:228. 〕 The main complaint of patients is pain.〔Burton, R. I. Basal joint arthrosis of the thumb. Orthop. Clin. North Am. 4: 347, 1973. 〕〔Glickel, S. Z. Clinical assessment of the thumb trapeziometacarpal joint. J. Hand Surg. (Am.) 17: 185, 2001.〕 Pain at the base of the thumb occurs when moving the thumb and might eventually persist at rest.〔〔 Other symptoms include stiffness, swelling and loss of strength of the thumb.〔〔 Treatment options include conservative and surgical therapies.〔Carr, M. M., and Freiberg, A. Osteoarthritis of the thumb: Clinical aspects and management. Am. Fam. Physician 50: 995, 1994. 〕 ==Anatomy== The CMC1 joint is a synovial joint between the trapezium bone of the wrist and the metacarpal bone at the base of the thumb. This joint is a so-called saddle joint (articulatio sellaris), unlike the CMC joints of the other four fingers which are ellipsoid joints.〔Sobotta Anatomy, 14th ed., Elsevier, ISBN 9780702034831〕 This means that the surfaces of the CMC1 joint are both concave and convex. Because of its specific shape, the CMC1 joint allows a wide range of motion of the thumb. Movements possible in this CMC1 joint are:〔Gray’s Anatomy for Students, second edition, Elsevier, ISBN 9780443069529〕 * Flexion * Extension * Abduction * Adduction * Opposition * Reposition * Circumduction This high mobility is due to the little intrinsic osseous stability of the joint. This causes the CMC1 joint to be more unstable compared to the CMC joints of the other fingers.〔Pomerance, J. F. Painful basal joint arthritis of the thumb: Part I. Anatomy, pathophysiology, and diagnosis. Am. J. Orthop. 24: 401, 1995. 〕 Because of this instability, the joint is more susceptible to be damaged.〔Cooney W, Chao E. Biomechanical analysis of static forces in the thumb during hand function. J Bone Joint Surg 1977;59:27–36.〕 To remain stable the CMC1 joint has to rely on the surrounding ligaments for support. These ligaments provide the ability to subject high pressure loads, particularly during pinch and grasp manoeuvres.〔Bettinger PC, Linscheid RL, Berger RA, et al. An anatomic study of the stabilizing ligaments of the trapezium and trapeziometacarpal joint. J Hand Surg () 1999;24:786–798.〕 16 ligaments surrounding the CMC1 joint are identified, which give strength and stability to the joint. Of these ligaments, the deep anterior oblique ligament, also known as the palmar beak ligament, is considered to be the most important stabilizing ligament.〔Pellegrini VD Jr, Olcott CW, Hollenberg G. Contact patterns in the trapeziometacarpal joint: the role of the palmar beak ligament. J Hand Surg () 1993;18:238–244.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carpometacarpal osteoarthritis」の詳細全文を読む スポンサード リンク
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