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Case Reports in Orthopedics
Volume 2019, Article ID 7604897, 4 pages
Case Report

Spontaneous Flexor Tendon Rupture due to Primary Distal Radioulnar Joint Osteoarthritis

1Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Nabeshima 5-1-1, Saga 849-8501, Japan
2Department of Orthopaedic Surgery, Karatsu Red Cross Hospital, Watada 2430, Karatsu, Saga 847-8588, Japan

Correspondence should be addressed to Motoki Sonohata; pj.oc.oohay@9179cpe

Received 25 December 2018; Accepted 21 March 2019; Published 9 April 2019

Academic Editor: Paul E. Di Cesare

Copyright © 2019 Akira Hashimoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Spontaneous flexor tendon rupture is rare, occurring most commonly in the little finger or flexor pollicis longus. To the best of our knowledge, there have been no reports of spontaneous flexor tendon rupture due to primary distal radioulnar joint (DRUJ) osteoarthritis (OA). We present a case of spontaneous flexor tendon rupture in the index finger due to primary DRUJ OA in a 71-year-old female farmer. Surgical exploration confirmed that, at the wrist joint level, the flexor digitorum profundus of the index finger had undergone degeneration and complete rupture. The flexor digitorum superficialis of the index finger was elongated and thinned. A bony spur toward the volar side was covered with synovial fluid from a pinhole-sized perforation of the capsule. The combination of direct friction from the DRUJ spur and the matrix metalloproteinases in the synovial fluid from the perforation of the DRUJ capsule may have caused the spontaneous flexor tendon rupture. Palmar-side symptoms associated with DRUJ OA should be carefully examined because of the risk of spontaneous flexor tendon rupture.